MXPA05000654A - Block copolymers containing functional groups. - Google Patents

Abstract

The invention relates to a styrene block copolymer and an unsaturated cyclic anhydride, such as maleic anhydride, a process for producing the copolymer by means of controlled polymerisation with free radicals, in which certain parameters are adjusted in order to control the microstructure and the molecular weight of the copolymer, and a method of using the block copolymer, including the use thereof as a compatibility agent. The microstructure and the molecular weight of the block copolymer can be controlled by adjusting the initiator to monomer ratio and/or by adjusting the stable free radical to initiator ratio. Said copolymer, which can be produced in a single-step process, comprises a controlled microstructure which enables one block to be reactive towards various chemical groups available in the engineering polymers and the other block to be completely miscible with polystyrene or miscible with polymers that are miscible with polystyrene, such as polyphenylene ether.

Description

BLOCK COPOLYMERS THAT CONTAIN FUNCTIONAL GROUPS Priority is claimed to the U.S. Provisional Patent Application. with Serial No. 60 / 397,420, filed by the inventors on July 19, 2002, and the Non-Provisional Patent Application Serial No. 10 / 621,929, filed by the inventors on July 16, 2003, both incorporated herein by reference .

BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION The present invention relates to the synthesis and the process for making block copolymers of styrene and an unsaturated cyclic anhydride, such as maleic anhydride or itaconic anhydride, via free radical polymerization, in the presence of a stable free radical. Furthermore, this invention relates to a composition comprising block copolymers of styrene and unsaturated cyclic anhydride, and the use of the composition as a compatibilizer in polymer blends. 2. DESCRIPTION OF PREVIOUS ART Random copolymers of styrene and unsaturated cyclic anhydride (ACI), in particular of maleic anhydride (AM), with different compositions have been synthesized by means of free radical polymerization processes. One of the applications of these materials is the compatibility of mixtures of styrenic polymers with other thermoplastics. It has been determined that the maleic anhydride content in the copolymer and its molecular weight play an important role in the ability of these materials to act as compatibilizing agents. In general, compatibilizing agents having a block copolymer structure, in which one of the blocks is thermodynamically compatible with one of the two polymeric materials to be mixed, have a more efficient performance as a compatibilizer in comparison with random copolymers. The foregoing allows the use of a smaller amount of compatibilizing material to achieve the desired final properties of the polymer blend. In some cases, the use of block copolymers is the only way to achieve compatibilization of two incompatible polymers. The traditional processes of polymerization by free radicals do not allow to obtain block copolymers because each individual polymer chain that is formed has a half-life time (time in which it remains as polymeric free radical) extremely short. During this short active life it is practically impossible to modify the conditions surrounding the active chain, so it is not feasible to change to a second monomer to obtain a block copolymer. The processes of living polymerization, in which the termination reactions have been suppressed or significantly reduced, allow the formation of block copolymers, since the life of each individual chain extends at intervals comparable to the duration of the process (minutes or hours). ). It is possible to produce block copolymers by anionic polymerization, but this technique presents severe limitations for a broad application. On the one hand it requires conditions of extreme purity in the monomers because traces of moisture destroy the catalyst. Some monomers require extremely low temperatures to carry out the polymerization. In addition, the polymerization of monomers having functional groups is not practical since again the catalyst can be destroyed in the presence of a variety of functional groups. As a result of the above, the industrial application of this technique is reduced to a few monomers, leaving out functional monomers of technological importance.

Due to the limitations in the anionic polymerization process, a more promising technique for producing block copolymers with a wide range of monomers is that based on living or quasi-living free radical polymerization. This can be achieved by adding to a formulation for standard free radical polymerization, a chemical agent that significantly reduces the extent of irreversible termination and chain transfer reactions., thus conferring a living or quasi-living behavior to the polymerization, which is also called "controlled polymerization" or "controlled free radical polymerization". There are different ways to obtain this behavior, but most of them are restricted to industrial practice because they require chemical agents that are not commercially available in the market today.

Among these techniques, one that is particularly useful and that employs a chemical agent available on the market is a free radical polymerization quasi-live controlled by 2,2,6,6 tetramethyl-piperidin-N-oxyl, which is known as TEMPO, and derivative compounds, which act as stable free radicals that block and unblock the polymeric radicals in a fast and reversible manner, allowing propagation through monomer addition steps for short periods. The American patent US. No. 5,401,804 issued to Georges et al., The disclosure of which is incorporated herein by reference, describes a polymerization process for producing low polydispersity polymers and block copolymers via a free radical polymerization process employing a free radical initiator and derivative compounds of TEMPO. However, in order to produce block copolymers, Georges et al. they require the sequential addition of monomers, in some cases depleting the first monomer before the addition of the second monomer, which results in a process with many steps and long reaction times.

The American patent U.S. No. 6,531,547 Bl, issued to Visger and Lange discloses a polymerization process in the presence of a stable free radical for the preparation of a block copolymer formed by a vinyl aromatic monomer (which may be styrene) in the first block and, in the second block a copolymer from a vinyl aromatic monomer and an acrylic monomer (which may be maleic anhydride), which is used as an additive of lubricating oil compositions. However, it is believed that the process requires the sequential addition of the monomers.

International Patent Publication No. WO 99/47575 issued to Vertommen et al., Describes a process for the copolymerization of a vinyl monomer and a maleic monomer in the presence of an initer (for example an alkoxyamine) for the production of copolymers in low molecular weight block. It is believed that in this application only the production of low molecular weight polymers is disclosed. Additionally, this process requires an alkoxyamine that believes it is accessible in the market at an industrial level.

As an improvement to previous techniques, a process described in "One-Step Formation of Functionalized Block Copolymers," Macromolecules, Vol. 33, 1505-1507 (2000), to produce in a single step, block copolymers containing functional groups via Quasi-free-radical polymerization mediated by nitroxide compounds has been proposed by Benoit et al. However, in an application of styrene-maleic anhydride copolymers, Benoit et al. they could not obtain living behavior using a standard formulation for free radical polymerization and a single stable free radical. On the contrary, they required the coed use of an a-hydrido-alkoxyamine and a stable free radical nitroxide type to achieve living character. This approach is difficult to scale to an industrial process from the economic point of view, due to the complexity of the synthesis of the alkoxyamine as described by Benoit et al. in Journal of the American Chemical Society, 121, 3904 (1999), since it includes several reaction steps.

In another attempt to produce block copolymers with functional groups Park et al. report in "Living Radical Copolymerization of Styrene / Maleic Anhydride," J. Polym. Sci., Parí A: Polym. Chem., Vol. 38, 2239 (2000), the synthesis of diblock copolymers containing one block of styrene-co-maleic anhydride and another block rich in styrene, starting from a mixture of TEMPO, benzoyl peroxide as initiator and from the two monomers They observed some degree of living character in their polymerizations, but they obtain polymers that have molecular weight (Mn) not higher than 23,000 after 20 hrs of reaction, which is too small a chain length to serve as a compatibilizer or for another use in applications potential In other efforts, terminal functionalisations were tested on polystyrene chains, that is, the synthesis of styrene polymers having a single monomer unit with functional group at one end of the chain. The general idea in this approach is the use of a living or quasi-living styrene polymerization process, which is terminated by the addition of a second functional monomer that is not capable of homopolymerizing. Harth et al. In "Chain End Functionalization in Nitroxide-Mediated Living Free Radical Polymerization," Macromolecules, 34, 3856 (2001), describe the synthesis of such materials by quasi-living polymerization procedures by alkoxyamine-mediated radicals; however, these latter compounds are not currently available in the market and their preparation requires several reaction steps. Also Koulouri et al. in "Terminal Anhydride Functionalized Polystyrene by Atom Transfer Radical Polymerization Used for the Compatibilization of Nylon 6 / PS Blends ,," Macromol. 32, 6242 (1999), employ a similar approach, but using radical polymerization with atom transfer (ATRP) to give the polymerization living nature. This technique, however, presents several drawbacks due to the fact that ATRP requires a catalyst-ligand system based on a metal, which results in a series of technical problems that include metal removal, catalyst removal and regeneration, coloration in the polymer . A related manner of synthesizing terminally functionalized polystyrenes with maleic anhydride is by adding trimellitic anhydride chloride for the purpose of terminating living ammonium chains of polystyrene, as disclosed by I. Park et al. in J. Polym. Sci., Polym. Chem. Ed., 29, 1329 (1991). With this method, a single functional group is obtained at one end of a polymer chain. However, this method suffers from the aforementioned deficiencies that are common to anionic polymerization processes, and allows only one maleic anhydride monomer unit to be added, limiting the versatility in compatibilization of the materials produced.

The American patent U.S. No. 6,143,848 issued to Lee et al., Describes one more attempt to obtain polystyrene with terminal functionalization. The authors carry out a radical polymerization controlled by degenerative transfer, using a reagent functionalized with iodine. However, one drawback of the degenerative transfer is that a low molecular weight radical is always present which carries out termination reactions, which results in little control during the polymerization.

It is well known in the art that the reactivity ratios of styrene and maleic anhydride are close to zero at temperatures below 80 ° C, which produces almost perfectly alternating copolymers. In the literature, kinetic data at temperatures above 80 ° C are scarce, but there seems to be a tendency towards alternating copolymers at these high temperatures, see Zhen Yao et al., In Continuous Thermal Bulk Copolymenzation of Styrene and Maleic Anhydride, Journal of Applied Polymer Science, 73, 615-622 (1999). The tendency towards alternating copolymers in the free radical copolymerization of styrene and itaconic anhydride is less pronounced than in the case of styrene and maleic anhydride, but is present.

With regard to the commercial production of copolymers of styrene and maleic anhydride, special processes have been developed in mass and heterogeneous processes for the production of random and alternating copolymers. Molar compositions with less than 10% maleic anhydride require the controlled addition of small amounts of maleic anhydride. On the other hand, continuous mass processes aimed at achieving this goal are described in European Patent EP No. 27, 274, granted in Aug. 5, 1984, to Daicel Chemical Industries KK; in Japanese Patent JP No. 74, 313, issued May 10, 1982, to Mitsubishi Monsanto Co., but all these approaches result in basically random copolymers.

The styrene-maleic anhydride random copolymers (rSAM) have previously been used as compatibilizers in polymer blends. In a random copolymer the maleic anhydride groups are distributed randomly along the copolymer chain. Therefore the structure of the resulting compatibilizer can not be controlled. The key to achieving the desired performance is the reaction of the maleic anhydride units of the copolymer with some functional group present in any of the polymers included in the mixture, as well as the miscibility or compatibility of the rSAM with the other components of the mixture. However, this has proven to be a defect for the application of these copolymers, because the window of miscibility of the rSAM with other polymers is generally narrow, and is restricted to compositional and molecular weight ranges of the copolymer. It is well documented in the literature that random copolymers with maleic anhydride content greater than 8% are not miscible with styrene (see Merfeld et al in Polymer, 39, 1999 (1998)), and that their window of miscibility with others Styrenic copolymers (SMMA, rSAM, SAN) are also restricted (see Gan et al in J. Appl. Polym, Sci., 54, 317 (1994)). The miscibility of styrene-itaconic anhydride random copolymers shows a similar behavior (see Bell et al., In Polymer, 35, 786 (1994).) This limits the applications of rSAM as a compatibilizer for many systems, although it has been sought to compatibilize mixtures with engineering polymers containing reactive groups capable of reacting with the carboxyl functionality present in maleic anhydride.

Engineering thermoplastics, for example polyamides, polycarbonates, and polyesters exhibit excellent physical properties such as strength and stiffness, but often it is required to mix or make alloys of these with other thermoplastics in order to improve impact resistance or reduce costs. However, the components of such mixtures are generally extremely incompatible. It is therefore a common practice to include a compatibilizer whose function is to improve the adhesion between the incompatible components and / or to modify the surface tension at the interface.

Of particular interest are mixtures of polyphenylene ether (PPE) and polyamides which are inherently incompatible. Molded articles made from these blends and without compatibilizing agent exhibit inferior mechanical properties, such as low impact resistance. A series of efforts have been reported to make this system compatible, the U.S. No. 4, 315, 086 describes the grafting of direct PPE onto the polyamide; U.S. Patents Nos. 4, 600, 741 and 4, 732, 937 describe the formation of PPE and polyamide copolymers using epoxide-functionalized PPE. The U.S. Patents Nos. 5, 231, 146 and 5, 141, 984, as well as Chiang et al, in J. of Appl. Polym. Se, 61, 1996, 2411-2421, report the use of polyepoxides and compounds that have the glycidyl group to achieve compatibilization of the mixture. The U.S. Patent No. 6, 444, 754 discloses the use of an epoxide-functionalized oligomer which has been prepared by free-radical polymerization from an unsaturated ethylenic monomer or oligomer in the presence of a glycidyl-functionalized nitroxide initiator.

Other commercially important systems are blends of polycarbonate and polyester with styrene copolymers, in particular with high impact polystyrene. Among the works of compatibilization of these systems are the U.S. No. 4,748,203, which discloses a mixture of aromatic polycarbonate and rubber modified polystyrene. The binding promoting agent is a polymer or copolymer of a vinyl aromatic monomer with free carboxyl groups obtained by polymerization in the presence of an unsaturated carboxylic monomer (e.g. maleic anhydride), acrylic or methacrylic acid or acrylic esters). The U.S. Patent No. 5, 274, 034 describes a polymeric composition consisting of an aromatic polycarbonate, an aromatic polycarbonate with ester or acid functionality, a styrene-based polymer and a styrene polymer having oxazoline groups. U.S. Patent No. 5, 204, 394 exemplifies blends comprising an aromatic polycarbonate, a styrene-containing copolymer and a styrene-grafted polymer useful in the molding of objects with matt surfaces. The U.S. Patent No. 6, 066, 686 describes the use of epoxidized SBS copolymers as compatibilizer and optionally polyester such as PET, PBT, polyphenylene ether. The U.S. Patent No. 6, 069, 206 describes the use of a styrene-acrylonitrile copolymer with a low content of acrylonitrile and with a solubility parameter within a certain range, as a compatibilizer.

Compatibilizers for the mixtures of interest described in the prior art are based on copolymers where it is not possible to control the microstructure (the functionalized polymers are generally random copolymers or melt-functionalized polymers). The miscibility of such copolymers is compromised by their composition, limiting their application as compatibilizer as in the case of the random copolymers of styrene and maleic anhydride (Gan et al, J. Appl. Polym, ScL, 54, 317 (1994)). ).

SUMMARY OF THE INVENTION In the present invention, a compatibilizer for the mixtures mentioned above and for other mixtures is a block copolymer based on styrene and an unsaturated cyclic anhydride (ACI). This copolymer is produced in a single step chemical polymerization process and has a controlled microstructure that allows one block to be reactive towards several chemical groups present in the engineered polymers, and the other block that is completely miscible with polystyrene or polymers miscible with polystyrene, such as phenylene polyoxide. The copolymers of the present invention provide a direct and novel route for obtaining compatibilizers for polymer blends, where both reactivity and miscibility can be controlled separately. In a first object, the control of the microstructure and the molecular weight in the block copolymer are maintained by adjusting the ratio of initiator to monomer and / or adjusting the ratio of stable free radical to initiator.

The present invention provides an efficient process by means of which it is possible to create styrene-rich polymers possessing a few monomeric units of maleic anhydride or itaconic anhydride located near one end of the chain, resulting in better compatibilizing compounds that can be obtained in existing polymerization facilities adding minimal changes and using PMID materials that are available in the market.

The present invention provides a process and a block copolymer synthesized with said process, based on styrene and an unsaturated cyclic anhydride (ACI), such as maleic anhydride or itaconic anhydride, in which the composition, microstructure and molecular weight are carefully controlled. of the copolymer. The first object of the present invention is a block copolymer comprising: a first block consisting of a random copolymer of styrene and an ACI, having a total length between 1 and 720 monomer units, a second block consisting of polystyrene with between 100 and 2000 monomer units, where polydispersity can be relatively narrow.

The first block of random copolymer of styrene and ACI preferably has some degree of alternating character given by the reactivity ratios of the monomers. The polydispersity is preferably between 1.2 and 3.0. These copolymers are better compatibilizers of blends of styrenic polymers and some polar polymers compared to random copolymers of the same overall composition.

The present invention further provides a single step chemical process employing a stable free radical, a traditional free radical initiator, optionally a solvent, styrene and maleic anhydride or itaconic anhydride; these last components in the proportions established in the first object of this invention, preferably all added simultaneously in a reactor and heating for several hours to produce the block copolymer mentioned in the first object of this invention.

The present invention also provides a batch process of a single chemical step, similar to that described in the previous paragraph, but carried out in two stages in the following manner: a) in a first stage all the reactants are added to a first reactor with stirring and heating until conversions are reached between 10% and 50%, and b) in the second stage the reaction continues heating the reaction mixture in the same reactor or other , without agitation, until reaching conversions of between 90 and 100%. a) The present invention further provides a continuous process in bulk or in solution which is chemically similar to that described above, and which includes a process of three sequential steps: An optional step for heating and passing the reaction mixture through a reactor tubular type in which the fractional conversion of monomer at the exit of the reactor is numerically twice or greater than the action of the monomer mass ACI in the feed (with respect to total monomer) to form a first intermediate polymer; and one of reaction of the first intermadiary in a continuous stirred tank reactor with output conversion of between about 10 and about 50% by weight to form a second intermediate polymer; and one through which the second intermediate polymer passes through a tubular type reactor in which the final conversion is between about 60 and about 100% by weight.

The present invention provides a method for the application of a block copolymer of styrene and unsaturated cyclic anhydride (ACI), which has been produced according to the present invention, as a compatibilizer for blends of thermoplastics including polystyrene or a miscible polymer or compatible with polystyrene and an engineering thermoplastic with functional groups capable of reacting with the dicarboxylic groups of the ACI units.

The fact that the location of the unsaturated cyclic anhydride (ACI) units is controlled as part of an initial block of the copolymer provides an advantage over a styrene-maleic anhydride random copolymer. In the melt processing of a polymer mixture containing a block copolymer according to the present invention, the unsaturated cyclic anhydride (ACI) groups react with the functional groups of a variety of engineering thermoplastic polymers, resulting in a graft copolymer that functions as a compatibilizer of an incompatible mixture. In the present block styrene-unsaturated cyclic anhydride (ACI) block copolymer, the location and average number of ACI units can be precisely controlled, and thus the structure of the grafted copolymer formed in situ during mixing with functionalized thermoplastics can also be controlled. . This control allows the new graft copolymer to act better as a compatibilizer, because there is a large portion of the chain that remains as an essentially pure polystyrene block which is miscible and compatible with other polymers. Among the polymers that are miscible and compatible with block polystyrene are polyphenylene ether, tetra methyl polycarbonate, high impact polystyrene (polystyrene reinforced with rubber), and block and random copolymers of styrene. Examples of thermoplastics with functional groups capable of reacting with the unsaturated cyclic anhydride include, but are not limited to: polyamide, polycarbonate, poly (ethylene terephthalate), and poly (butylene terephthalate).

In addition, the present invention provides a method of using the styrene-ACI block copolymer as a coupling agent for polystyrene and styrene copolymers and various fillers, including polystyrene or a polymer miscible or compatible with polystyrene and a filler with chemical affinity and / or groups functional groups capable of reacting with the dicarboxylic group of the ACI monomer units.

BRIEF DESCRIPTION OF THE FIGURES FIG. 1A. It is a schematic representation of a block copolymer of styrene and maleic anhydride forming a poly ((styrene-alt-maleic anhydride) -b-styrene) according to the present invention.

FIG IB It is a schematic representation of a block copolymer of styrene and maleic anhydride forming a poly ((styrene-random-maleic anhydride) -b-styrene) according to the present invention.

FIG. 2. is a schematic representation of a batch process for preparing a block copolymer according to the present invention.

FIG 3. is a schematic representation of a continuous process for preparing a block copolymer according to the present invention.

FIG. 4A. is a photomicrograph by transmission electron microscopy of a mixture of phenylene polyoxide, a triblock copolymer SEBS and polyamide 6. The polyamide was dyed dark using phosphotungstenic acid.

FIG. 4B is a photomicrograph by transmission electron microscopy of a mixture of phenylene polyoxide, a triblock copolymer SEBS and polyamide 6 compatibilized with the block copolymer of styrene and maleic anhydride synthesized in Example III (sample 18). The polyamide was dyed dark using phosphotungstenic acid DETAILED DESCRIPTION OF THE INVENTION The present invention provides a process and a block copolymer from said process, based on styrene and an unsaturated cyclic anhydride (ACI), such as maleic anhydride or itaconic anhydride, in which the composition, microstructure and weight are carefully controlled molecular weight of the copolymer. The term "microstructure" refers to a detailed sequence or to an array of units of each of the monomers in an average or typical copolymer chain. The term composition refers to the average overall relative amount of monomer 1 and monomer 2 in the copolymer chains, which can be expressed on a molar or weight basis. In particular, an object of the present invention comprises block copolymers having a first block of a styrene random copolymer and an unsaturated cyclic anhydride (ACI), such as maleic anhydride or itaconic anhydride, with some degree of alternate character given by the reactivity ratios of the monomers, and a total length between 1 and 720 monomer units and a second block of basically pure polystyrene with a length between 100 and 2000 monomer units, where the polydispersity is relatively narrow, preferably between 1.2 and 3.0 Figure 1A is a schematic representation of a block copolymer of styrene and maleic anhydride forming a poly ((styrene-alt-maleic anhydride) -b-styrene) according to the present invention. Figure IB is a schematic representation of a block copolymer of styrene and maleic anhydride forming a poly ((styrene-random-maleic anhydride) -b-styrene) according to the present invention The term "random copolymer" is well known in the art and refers to a copolymer in which the monomer units of different chemical nature are located in a random sequence along the polymer chain. On the other hand, the term "block copolymer" is also well known in the art and refers to a copolymer in which there are at least two segments of the chain each having a different and given composition. In general, a segment or block consists of units of identical chemical nature and another segment or block is also composed of units of identical chemical nature, but different from those of the first block. Other variants of block copolymers include segments formed by units having more than one chemical identity, and their sequence within the segment may be arranged in practically any manner known in the prior art, such as random or alternate for example. The element that characterizes a block copolymer is that it has at least two distinct and well-defined composition and / or microstructure segments.

The term "polydispersity" is also well known in the art as the ratio of the weight average molecular weight to the number average molecular weight of the copolymer. Polymers are not materials formed by molecules of a single and well-established molecular weight, but rather by molecules with different lengths, which gives way to molecular weight distribution. This distribution is characterized by averages in number and weight, and its amplitude is characterized by polydispersity. The larger the polydispersity, the wider the molecular weight distribution. Traditional free radical polymerization processes result in polymers with relatively broad molecular weight distributions, ranging from 1.5 to 3.5 or greater, depending on the specific polymer and the polymerization process used in the synthesis.

It is believed that it is not possible to obtain polymers with polydispersities of less than 1.5 by means of traditional free radical polymerization. On the other hand, the polymers provided by this invention, which are produced via an almost-living or controlled free-radical polymerization process, have polydispersities that start at values well below 1.5 and thus have relatively low molecular weight distributions. narrow. Consequently, the different individual chains in a polymer sample tend to have a similar overall length, composition and microstructure, resulting in a more homogeneous polymer that performs in a more uniform manner when used as a compatibilizer or as a coupling agent.

CHEMICAL SYNTHESIS OF COPOLYMERS IN BLOCK It is possible to obtain a block copolymer according to the present invention employing a chemical step (or one step) polymerization process to polymerize the copolymer using a stable free radical and a traditional free radical initiator. The preferred stable free radical contains the group 0-? < and is selected from the family of nitroxide radical compounds. Typical examples of nitroxide radical compounds include, but are not limited to The last family of compounds (3,3-dimethyl-1, 1-diphenyl azabutane-N-oxides) are not commercially available, but a procedure for their synthesis can be found in an article entitled "New controllers for nitroxide mediated polymerization. A study of electronic effects and of the [nitroxide] / [initiator] ratio on the polymerization control "by R. Cuatepotzo, M. Albores-Velasco and E. Saldivar, submitted for publication in the Journal of Polymer Science (2003), which is incorporated here as a reference. Other compounds of this family can be taken from nitroxy radicals derived from those mentioned in U.S. Pat. No. 4,581,429, issued to Solomon et al., Which is incorporated herein by reference.

TEMPO-derived compounds such as 4-oxo-TEMPO and 4-hydroxy-TEMPO have been used for a long time to inhibit the polymerization of monomers in distillation columns. Because these compounds are commercially available through various suppliers at reasonable prices, they are the prime candidates for use as stable free radicals in the process of the present invention.

Preferred free radical initiators include peroxy and azo compounds. Typical examples of these compounds include, but are not restricted to 2,2'-Azobis (2-methylpropanonitrile), 2,2-azobis (2-methylbutanonitrile), dibenzoyl peroxide (BPO), tert-amyl peroxy-2-ethylhexanoate , Ter-Butyl peroxy-2-ethylhexanoate, 2,5-Bis (2-ethylhexanoylperoxy) -2,5-dimethylhexane and tert-Butyl peroxydiethyl acetate.

The synthesis conditions in the polymerization reaction to obtain the copolymers of the present invention are described below. It is possible to use mass or solution processes. For the solution process, any solvent can be used that forms a solution with styrene, ACI, initiator and stable free radical. Typical solvents include substituted aromatic or aromatic hydrocarbons, as well as substituted aliphatic and aliphatic hydrocarbons. If their use is required, the preferred solvents are the substituted aromatics, more preferably toluene, xylene, or ethylbenzene, or polar solvents such as acetone, chloroform or ethyl acetate. The solvent should be present in amounts of between about 5 to about 95% by weight preferably, based on the total mixture of monomers and solvent.

Through extensive experimentation, it was discovered that bulk polymerization allows a maximum amount of maleic anhydride to be incorporated in the process, around 6% based on total monomer, maintaining the homogeneous reaction conditions and the homogeneous product. Amounts of maleic anhydride greater than about 6% by weight based on total monomer lead to precipitation of the polymer in the early stages of the reaction resulting in an unusable product. To overcome this difficulty and be able to incorporate higher percentages of maleic anhydride in the product, it has been dev to use a process in solution with polar solvents. It has been found that the best solvents for this process are ethyl acetate, chloroform, acetone or toluene or their mixtures. When looking for compositions of maleic anhydride with a content of less than about 6% by weight, based on total monomer, a much higher number of solvents can be used.

Many useful solvents are volatile and at the recommended reaction temperatures will tend to be in the gas phase, which will render them useless as solvents. In order to overcome this difficulty, the pressure of the reactor can be adjusted by adding an inert gas such as nitrogen, carbon dioxide or argon, so that the reaction is carried out at a pressure higher than the vapor pressure of the mixture. reaction, therefore most of the solvent will remain in the liquid phase. As the calculation of the vapor pressure of the reaction mixture can be complicated with polar solvents and the experimental evaluation requires time, a simple rule to estimate the pressure required for the process, which also guarantees that most of the solvent remains in the liquid phase, is given by the formula: 2. 5 * P0 * Xs, if Xs is less than about 0.2 and 1.4 * P0 * Xs, if Xs is equal to or greater than about 0.2 where P0 is the vapor pressure of the solvent at the reaction temperature and Xs is the mole fraction of the solvent in the mixture of solvent and monomer. The coefficients used in this correlation were found by comparing the vapor pressure of the reaction mixture for several of the recommended solvents, estimated with rigorous thermodynamic calculations, with the value of the partial pressure exerted by the solvent and estimated as P0 * Xs- The value of the coefficients can be modified somewhat to reach the objective.

With a percentage of solvent under the process in solution is similar to a mass process, and the solvent is used mainly to control the reaction speed, to improve the heat removal, to decrease the viscosity and to allow compositions with higher content of maleic anhydride without phase separation. A low percentage of solvent is preferably 10-30% by weight and more preferably 15-25% by weight with respect to the mixture of monomers and solvent. A solvent content of less than about 5% by weight has no practical use because the advantages of using solvent are not apparent, and it is better to change to a mass process.

With a high percentage of solvent the process is a typical process in solution that presents low viscosity, low reaction speed, as well as a better control of temperature and better removal of heat of reaction. In addition, this interval allows more easily to incorporate high levels of maleic anhydride a homogeneous product. A high percentage of solvent is preferably between about 60 and about 95% by weight, more preferably between about 70 and about 90% by weight, and the most preferred range is between about 75 and about 88% by weight with respect to the mixture of monomers and solvent. A solvent content greater than about 95% results in the production of a very small amount of polymer which makes the process inefficient. Solvent contents can be used between 30 and 60% by weight but the system will be so diluted that it will not have the advantage of high productivity of a mass process, and so concentrated that it will not have the low viscosity benefits of a typical solution process .

Preferred process temperatures are within the range of about 110 to about 200 ° C, but more preferably in the range of about 120 to about 170 ° C and the most preferred range is between about 120 to about 150 ° C. Temperatures below about 110 ° C do not allow the nitroxide radical to act as a blocking-unblocking group for a living polymer, as explained in detail below, because at these temperatures the nitroxide radical prevents the living character of the polymerization. Temperatures greater than about 200 ° C promote many undesirable parallel reactions and the living character of the polymerization is also impeded under these conditions. The initiator is typically used in a ratio of about 1 part of initiator to about 100 to about 12., 000 parts by mole of monomer, more preferably from about 1 to about 200 moles of initiator per about 3000 moles of monomer, and most preferably from about 1 to about 400 moles of initiator per about 1500 moles of monomer monomer The molar ratios of about 1 part of initiator to less than about 100 parts of monomer produce very low molecular weight polymer, which is not very suitable for compatibilization applications of polymer blends. On the other hand, molar proportions of about 1 part of initiator to more than about 12,000 parts of monomer lead to polymerizations essentially thermally autoinitiated by styrene, with the consequent loss of control of the final molecular weight of the polymer and loss of the living character of the polymerization. .

The mentioned initiators have half-life times of the order of a few minutes (less than 10) or less, at the preferred process temperatures. The amount of stable free radical (RLE) with respect to initiator is preferably in the range of about 1.3 to about 3.0 moles per mole of initiator, more preferably between about 1.6 and about 2.5 moles per mole of initiator, and the most preferred range is between about 1.9 and about 2.5 moles per mol of initiator. The RLE to initiator ratios of less than about 1.3 moles of RLE per mole of initiator lead to the loss of the living character of the polymerization. On the other hand, ratios greater than about 3.0 moles of RLE per mole of initiator can make the reaction and the process too costly. Also during the experimentation it was found that the molar ratio of RLE to initiator to ensure the living character of the polymerization depends on the concentration of ACI. The higher the concentration of ACI, the higher the ratio of RLE to initiator recommended to obtain living character in the polymerization. It is believed that this is due to the fact that at higher concentrations of ACI the greater the polymerization rate and the greater the difficulty to achieve living character. Experimentally it was found that for optimal results the molar ratio of stable free radical to initiator must be at least the result of the calculation: 1.3 + 0.10 * (percentage by weight of ACI with respect to total monomers), preferably around 1. 3 + 0.25 * (percentage by weight of ACI with respect to total monomers).

The lower molar ratios of RLE to initiator will result in the loss of the living character of the polymerization.

With respect to the composition, the percentage of ACI, for example maleic anhydride or itaconic anhydride, in the styrene-maleic anhydride mixture the amount is in the range of about 0.09 to about 18% by weight, more preferably from about 0.3. at about 5% and the most preferred range is from about 0.9 and about 2% by weight. ACI compositions less than about 0.09% by weight can lead to poor functionalization of the copolymer, possibly with some polymer chains that do not even have an ACI unit, and with overall compatibilization properties of poor polymer blends. On the other hand, compositions of ACI, in particular maleic anhydride, greater than about 18% can lead to very fast reaction rates and to reactions which are difficult to control, as well as to a serious loss of the living character of the polymerization.

After loading the ingredients, styrene, ACI, initiator and stable free radical into the reactor, and heating it to the appropriate temperature, most of the polymer chains will start at the early stage of the reaction, due to the rapid decomposition of the initiator to the specified temperature. During the investigation that led to the present invention, the authors found that the reaction proceeds extremely rapidly in the initial stage, achieving a moderate conversion of 20 to 30% by weight in a few minutes. After this period the reaction becomes slower and continues at a moderate reaction rate. Apparently the initial acceleration in the rate of reaction is due to the interaction between styrene and ACI, in particular maleic anhydride. The almost simultaneous initiation of most chains helps to narrow the polydispersity. Additionally, shortly after the initiation has begun and having added only one or a few monomer units, each living polymer chain (growing or active) will become dormant (deactivated) after being blocked by the stable free radical, and will be present in a slight excess with respect to the number of growing chains or living chains. The dormant chain will remain in this state for some time until the stable free radical is released again (activation) and the chain becomes active or living again., and capable of adding one or more monomer units until it becomes dormant again. The cycle of living-dormant-living-sleeping states repeats itself a number of times until no more monomer is available for the reaction, or until the temperature drops below the minimum temperature of activation of the stable free radical. (below 100 ° C for most available nitroxide radicals). Irreversible termination reactions, such as those that occur by the coupling reactions between two living chains, are impeded due to the low effective concentration of living polymer. The resulting process is similar to a true living process (for example, ammonic polymerization) and is therefore considered to be quasi-live (also called "controlled"). Since all polymer chains grow at about the same rate and initiate their growth at about the same time, the molecular weight distribution tends to be narrow, with relatively low polydispersity. It is well known in the art that the degree of living character of such polymerizations can be measured with the linear tendency of the growth of the number average molecular weight of the polymer with respect to the conversion, as well as by the change of the molecular weight distribution curves. towards larger values as the polymerization proceeds.

Another important feature of the polymerization of the present invention is the sequence of monomeric units of unsaturated cyclic anhydride (ACI) and styrene (S) along the polymer chain. Because the proportion of ACI is relatively low, and since the ACI tends to react alternately with styrene, almost all of the ACI will be consumed in the early stages of reaction, in molar quantities similar to the styrene consumed. The consumption of most ICA will occur at a percentage of the conversion that can be estimated as approximately two times the weight percent composition of ACI in the reactor feed. Up to this point, a random block of styrene and ACI has been formed, but with a certain alternate character. Then, because the chains are able to grow as stages or steps through the repetition of the dormant-living cycles, and since most of the styrene is still unreacted, the chains will continue their growth by adding styrene units. to form a second block of styrene along the polymer chains until the monomer is exhausted, or the reaction is terminated in some other way. The resulting polymeric material has the structure described in the first object of the present invention. The process described above can be considered as a single step chemical process, since all the ingredients are loaded at the beginning of the reaction as opposed to other processes to make block copolymers, in which a mixture containing a second monomer until the monomer mixture forming the first block has been consumed. In the process described above, the temperature can be constant and set within the values mentioned in the preferred objects of this invention, or it can be changed incrementally, even within the preferred ranges of the present invention, so that can accelerate the depletion of monomer after the initial stages of conversion.

Another important additional feature of the polymerization of the present invention is the control of the total molecular weight and the overall composition of the polymer. In truly living polymerization processes it is possible to estimate the average molecular weight in number of a given reaction by dividing the monomer mass by the number of moles of effective primary radicals generated by the initiator. The number of moles of effective primary radicals of an initiator can be calculated as the number of free radicals generated by the decomposition of the initiator multiplied by the efficiency of the initiator. Since each effective primary radical generates a polymer chain that grows along the polymerization, the number of moles of polymer is equal to the number of moles of effective primary radicals. Although the process disclosed herein is not a fully living process, the aforementioned calculation provides an approximate estimate of the number average molecular weight of the polymer formed, so that a polymer of a certain molecular weight can be roughly designed. A more accurate estimate of the molar concentration of initiator required for a specific number average molecular weight, obtained by linear regression of many experimental data generated during the investigation that led to this invention, is given by 0. 00775 - (5x10"8 * Mn), if the desired molecular weight is greater than about 61500, and 0. 02519 - (3.33xl0"7 * Mn), if the molecular weight is less than about 61500. in which Mn is the average molecular weight in objective number and is determined by the technique of gel permeation chromatography relative to polystyrene standards according to ASTM # D3536. Among the reasons for having two straight lines instead of one that would correspond to an ideal living process with instantaneous initiation, is that the process is not completely living and the presence of thermal autoinitiation of styrene, which is more pronounced in the range of larger molecular weights (lower concentrations of initiator). On the other hand, the previous correlations provide the best average value for the experimental data used, but the actual data show some dispersion because the data include series of experiments carried out in a variety of conditions with wide ranges of free radical ratio stable to initiator and different concentrations of maleic anhydride. Real data falls in a band rather than along a line. The band is best represented by the following correlations: A - (5x10"8 * Mn), if the desired molecular weight is greater than about 61500, and B - (3.33xl0'7 * Mn), if the desired molecular weight is less than about 61500, in which Mn is the average molecular weight in objective number; A is between about 0.005 and about 0.01 and B is between about 0.016 and about 0.042.

For the calculation of the average number of ACI groups in each polymer chain, it can be predicted with good approximation considering that all the ACI reacts. The number of ACI groups per polymer molecule will be equal to the number of moles of ACI charged to the reactor divided by the number of moles of polymer, which is estimated in the manner cited in the previous paragraph. Using this calculation and the number average molecular weight it is possible to design the block copolymer in advance with the desired parameters.

Although two of the works cited as prior art (Benoit et al., 2000, and Park et al., 2000) describe different processes for obtaining copolymers of styrene and ACI with block structure similar to that described in this invention, they do not provide Simultaneously, a process that uses raw materials that are readily available in the market and that allows obtaining sufficiently high molecular weights for compatibilization of polymers. Furthermore, these works present facts that are apparently contradictory. Benoit et al. they argue that it was not possible to obtain such a block copolymer structure using only TEMPO, and therefore, they used a combination of a more complex nitroxide radical and an alkoxyamine to be able to control the copolymerization of styrene and maleic anhydride. On the other hand, Park et al. report the synthesis of such structures (although relatively low molecular weight) with TEMPO as stable free radical. After exhaustive experimentation carried out in the present invention, in which the relative composition of the components of the copolymerization was varied, it was found that the nitroxide to initiator radical ratio is an important parameter to obtain the desired control in the polymerization that leads to block copolymers with well-defined structure, and that this ratio depends on the amount of maleic anhydride to be copolymerized. The nitroxide to initiator radical ratio (on a molar basis) must range between 1.3 and 2.5 or more to obtain control. One possible explanation for this, without relying on this theory, is that at the beginning of the polymerization in the presence of unreacted maleic anhydride, the effective propagation speed of the polymer chains is very high and higher concentrations of stable free radical are required. to be able to exercise control over this rapid growth of chains. The relatively low concentrations of nitroxide radical, although useful for the homopolymerization of styrene, are insufficient in this case to compete effectively with the propagation of chains which leads to out-of-control reactions.

STRUCTURE OF THE COPOLYMERS IN BLOCK The evaluation of the structure of the block copolymers formed is not a trivial matter. It is possible to investigate the overall composition in a general manner using nuclear magnetic resonance of gates (H1 NMR), but this technique is restricted to compositions greater than a few percentage points of the less abundant component in a copolymer. Due to this limitation, this technique would be of little use in the characterization of the composition of the final copolymers formed, since many of the compositions of interest comprising this invention are between 1% or less of ACI. Therefore, in order that the specific structure of the copolymers provided by this invention, it was necessary to perform kinetic investigations in which the evolution of the composition of the growing chains of copolymer at different incremental conversions was studied with the aid of H1 NMR, especially in the low conversion interval (below 20-30%). At low conversions and given that the ACI reacts mainly in the initial stages of the reaction, the H1 NMR technique will be able to detect the composition of the rich chains of ACI. These determinations, together with the determinations of the molecular weight distribution that show the degree of living character of the chains, provide the evidence supporting the presence of the structures described in the object of the present invention. The living character is required to ensure that the same chains that showed an ICA-rich composition at low conversions and low molecular weight, continue their growth to longer chains, which are on average richer in styrene and that contain a rich end. ACI.

In another process for the production of block copolymers using living polymerization, the sequence of two chemical steps is necessary: in the first step the monomer forming the first block homopolymerizes until exhaustion so that pure blocks are obtained. If the first monomer is not consumed completely it must be removed before adding the second monomer, which polymerizes by extending the living chains formed during the first step and thus generating the second block. The need to remove the residual monomer and the charge of a second monomer that must be perfectly mixed before the second reaction step proceeds, represents additional and difficult steps, which can be avoided with the process of the present invention.

The rapidity of incorporation of ACI monomer units, in particular maleic anhydride and itaconic anhydride, and of styrene is given by the inherent reactivities of these copolymerization systems, and the laws governing the incorporation of the monomers into the copolymer are well understood and documented in standard texts on free radical polymerization chemistry such as Graeme Moad's The Chemistry of Free Radical Polymerization and David H. Solomon, Pergamon, 1995. As mentioned on pages 280-283 of the aforementioned reference, one of the simplest but most effective models that correlate the relative rate of monomer incorporation in a copolymer is the terminal model, which considers that the reactivity of the polymer radical to a particular monomer depends solely on the chemical nature of the terminal or active unit in the radical. According to this model, there are four possible propagation speed constants that are relevant; that is, the kinetic constants of propagation of a polymer radical terminating in monomer i and reacting with monomer j. These are represented by means of ky, where i and j take values of 1 or 2 corresponding to monomer 1 or monomer 2. The kinetic scheme for the possible propagation reactions is represented as follows: ? * +? - ^ ??? * M¡ + M2 - ^? M¡ M2 * + M1 - ^ 1? M? 2 * +? 2 - ?? 2 * where Mn * represents the polymeric radical ending in the monomer unit n (where n, i or j) and Mn represents the monomer n (where n, i or j).

Reactivity ratios rn are defined as the ratio between the propagation constant of monomer n with a radical of the same type divided by the propagation constant of monomer n with a second type of radical. For a system of two monomers, two reactivity ratios are defined as: The relative magnitudes of r; and determine the type of copolymer that will be formed (e.g., random or alternate). In the case of the polymerization of styrene and maleic anhydride, the reported reactivity ratios obtained experimentally are close to zero at temperatures below 80 ° C and the inventors do not know of any data reported in the open literature at higher temperatures. For the styrene-itaconic anhydride pair the reactivity ratios are also close to zero although the one corresponding to itaconic anhydride is slightly higher than that of styrene. It is pertinent to mention that there is some evidence that the terminal model can inadequately describe the mechanism of copolymerization of the two pairs of monomers mentioned, however, the ratios of reactivity are used in any way to describe the behavior observed even for these systems.

BATCH PROCESS The present invention also provides a batch process of a single chemical step to carry out the polymerization reaction, but carried out in a two-step process as follows: a) in the first stage all the reactants are charged in a first reactor with stirring, which is heated to reach conversions of between about 10 to about 50%, and b) in the second stage the reaction continues heating the system in the same or in different reactor or reactors, without agitation until reaching conversions between around 90 and around 100%.

The reactor used in the first stage is a well spent reactor with a propeller or anchor type stirrer. This reactor must have some means of heat exchange with the outside such as a jacket or a coil for heating and cooling. After reaching the conversions within the range of 10-50%, the viscosity of the reaction mixture will increase and make agitation difficult, so that the reaction should continue without agitation, preferably in a different reactor without stirring attachments to facilitate cleaning , such as a cell or cylindrical reactor or reactors. This second reactor must also have some means of heat exchange such as an outer jacket, immersion in a thermal bath or any other similar means. After reaching high conversion, which can be promoted by increasing the temperature as the reaction proceeds, the polymer is removed from the reactor or second stage reactors and cut into small pieces in a mechanical mill. Final conversions of less than about 90% are inconvenient since the presence of residual monomer affects the properties and handling of the final product.

With reference to Figure 2, a one-step batch 10 process according to the present invention is shown schematically. A solution of nitroxide radical and an unsaturated cyclic anhydride (ACI) in styrene are added to a tank 12, which is connected through a line 14 to a pump 16. The mixture in tank 12 is pumped through the line 18 to a reactor 20. In tank 22 a catalyst or initiator is placed, which is connected by a line 24 to a pump 26. Pump 26 pumps the catalyst or initiator through a line 28 to reactor 20. The reactor 20 is a stirred tank continuous reactor and is connected by a line 30 to a pump 32. In the reactor 20 a block copolymer is formed, and the copolymer and the unreacted monomer, which is mainly styrene, are pumped by the pump 32 through a line 34 to the cells for plate 36. The conversion in the reactor 20 is typically within the range of about 10 to about 50%. The plate cells provide a second reactor without agitation, and heat removal through the line 38 to the thermal bath 40 is schematically shown. The block copolymer of the reactor 36 flows through a line 42 to an oven 44. The residual monomer is removed from the block copolymer in the furnace 44 and recycled. The block copolymer is removed from the furnace and milled in a mechanical mill, which is not shown. The unsaturated cyclic anhydride, the styrene, the stable free radical and the initiator can be charged directly to the reactor 20. By adjusting or manipulating the ratio of nitroxide radical to initiator, the molecular weight of the block copolymer can be controlled. Examples are given below that give a better perception of the impact of these ratios on molecular weight. In this way, the microstructure of the block copolymer can be controlled and thus made in the desired manner. The reactor 20 is shown as a continuous stirred tank reactor, but another type of reactor may be used, preferably providing some type of agitation. Reactor 36 is shown as a plate cell reactor, but other types of reactors, such as a tubular reactor, may be used, which preferably provides a reaction zone without agitation.

CONTINUOUS PROCESS The present invention further provides a continuous process in mass or in solution, which includes three stages of serial processing as follows: An optional step of heating the reaction mixture in a tubular type reactor, in which the fractional conversion of monomer to the outlet is numerically two times or more than the mass fraction of ACI in the feed (with respect to total monomer) . A second step comprising heating the reaction mixture in a continuous stirred tank reactor with outlet conversion of between about 10 and about 50% by weight, and A third heating step in a tubular type reactor, in which the output conversion is between about 60 and about 100%.

The first reactor is a tubular type reactor in order to have a better heat removal during the polymerization stage in which the ACI is reacting and the reaction speed is higher. A conversion numerically less than twice the mass fraction of ACI in the monomer mixture in this step will lead to molecular architectures of the polymer in which the ACI will not be located preferably in a block with almost alternating styrene-ACI structure. The reactor used in this second stage is similar to that described above for the batch process; that is, a reactor with good agitation that has a propeller-type or anchor-type stirrer and also with some means for exchanging heat with the outside. Preferred conversions are between about 10 and about 50% at the preferred temperatures in this invention. Conversions of less than about 10% will make the use of the first reactor inefficient, and conversions greater than about 50% will make the process difficult to control due to the high viscosity of the reaction mixture and can greatly expand the molecular weight distribution of the polymer, returning to the heterogeneous material. The third reactor, which is tubular, provides greater conversion without expanding the molecular weight distribution too much, and allows for easier polymer transport and heat removal. Tubular type reactors have more closed residence time distributions compared to stirred tank reactors, and it is well known in the art that for living or near-living polymerization reactions, the molecular weight distribution of the polymer is determined by the distribution of residence time of the reactor.

Additionally, because the conversion in the third reactor is higher than in the second reactor, the viscosity will also be higher and under these conditions the tubular reactor will provide a better means of transport of the polymer as well as heat removal, since these Reactors generally do not require agitation and have a better area-volume ratio for heat exchange. Minor conversions of around 60% at exit result in inefficient use of the third reactor and leave a lot of unreacted monomer. After the third reactor, the process must have some means to remove the unreacted monomer, such as a devolatilization equipment or a vented extruder. The unreacted monomer can be recovered and recycled to the process.

With reference to Figure 3, a process 50 according to the present invention is schematically shown. A solution of a nitroxide radical and an unsaturated cyclic anhydride in styrene are added to tank 52. The contents of tank 52 flow through a line 54 to a pump 56, which pumps the contents through a line 58 to a tubular reactor. 60. A catalyst or initiator is placed in the tank 62, and the contents of the tank 62 flow through a line 64 to a pump 66, which pumps the catalyst or initiator through a line 68 to the tubular reactor 60. The block copolymer and the unreacted monomer, which is mainly styrene, flows from the tubular reactor 60 through a line 70 to the reactor 72, which may be a continuous stirred tank reactor. A stirred reactor is preferred. The conversion in the tubular reactor is preferably twice the mass fraction of unsaturated cyclic anhydride such as maleic anhydride.

The conversion in the reactor 72 is preferably within the range between about 10 and about 50%, and the block copolymer and unreacted monomer, which is mainly styrene, flows from the reactor 72 through a line 74 to a pump 76, which pumps the fluid through a line 78 to the tubular reactor 80. A conversion ranging from about 60 to about 90% is achieved in the tubular reactor 80, a block copolymer and unreacted monomer, which is primarily styrene, flows from the tubular reactor 80 through a line 82 to the devolatilizer 84. Monomer, which is primarily styrene, is recovered from the devolatilizer 84 through a line 86, which flows to the condenser 88. A condensate is formed which flows through a line 90 to a condensate tank 92, and the monomer can be recirculated through a line 94 to a pump 96 and to the tank 52. block copolymer is removed from the devolatilizer 84 through a line 98 to a pump 100. The molecular weight of the block copolymer can be controlled through manipulation and adjustment of the ratio of initiator to monomer and / or through the ratio of the free radical stable to initiator. These variables can be adjusted to achieve the desired microstructure of the block copolymer.

The process of the present invention can be thought of in general terms as one that includes the steps of heating styrene and an unsaturated cyclic anhydride at temperatures between about 110 and about 200 ° C and adding a free radical initiator to the reactor in a ratio molar from monomer to initiator of around 100 and around 12,000. A stable free radical is added to the reactor, and the molecular weight and microstructure of the produced block copolymer can be controlled in part by adjusting the molar ratio of the stable free radical to initiator according to formula 1.3 + 0.25 times the weight percent of the anhydride cyclic unsaturated with respect to the total content of monomer. The percentage by weight of ACI with respect to total monomer is preferably between about 0.1 and about 6% by weight. The reaction mixture is cooled, and a block copolymer according to the present invention is recovered by isolating the block copolymer from the unreacted monomer. This process typically produces a molecular weight greater than about 25,000, and molecular weights within the range of from about 50,000 to about 100,000 can be achieved in a controlled manner. Additionally it is believed that molecular weights of up to about 200,000 can be achieved with the present invention.

Even when the process described is a mass process, a solvent can be used. The same ratio of monomer to initiator works with a solvent based process, and the same ratio of stable free radical to initiator can be used according to the formula described above, but the percentage of ACI with respect to total monomers is preferably between about 0.1 and around 16%. Similar molecular weights are obtained for the block copolymer using the solvent base process.

COMPATIBILIZATION OF MIXTURES Another object of this invention is the use of the block copolymer of unsaturated cyclic anhydride (ACI) as a compatibilizer in compositions comprising a polymer miscible or compatible with the polystyrene block and an engineering thermoplastic containing functional groups that can react with the dicarboxylic functionality of the ACI units in the styrene / ACI block copolymer. Still another object of the present invention are the polymeric compositions resulting from this method of use.

The styrene-based polymers miscible or compatible with the polystyrene block of the aforementioned block copolymer include those which can be described as hydrogenated or partially hydrogenated homopolymers, and random, graded or block polymers (copolymers including terpolymers, tetrapolymers, etc.) of dienes conjugates and / or monovinyl aromatic compounds. Conjugated dienes include isoprene, butadiene, 2,3-dimethylbutadiene and / or mixtures thereof, such as isoprene and butadiene. The monovinyl aromatic compounds include any of the following (and mixtures thereof): monovinyl aromatic compounds, such as styrene or styrene with alkyl substituents on the alpha carbon of styrene, such as alphamethyl styrene, or on the ring carbons, such as or -, m- and p-methylstyrene, ethylstyrene, propylstyrene, isopropylstyrene, butylstyrene, isobutylstyrene, tert-butylstyrene (for example p-tert-butylstyrene). Also included are vinylxilenes, methylethylstyrenes and ethylvinylstyrenes. Specific examples include random polymers of butadiene and / or isoprene and polymers of isoprene and / or butadiene and styrene, and also stereospecific polymers such as syndiotactic polystyrene. Typical block copolymers include polystyrene-polyisoprene, polystyrene-polybutadiene, polystyrene-polybutadiene-polystyrene, polystyrene-ethylene, butylene-polystyrene, hydrogenated polyvinylcyclohexane-polyisoprene, and hydrogenated polyvinylcyclohexane-polybutadiene. The graded polymers include those of the aforementioned monomers prepared by methods known in the art. Other non-styrenic polymers miscible or compatible with the polystyrene block present in the styrene-ACI copolymer include, but are not restricted to, polyphenylene ether (PPE), polyvinylmethyl ether and tetramethyl polycarbonate.

The engineered thermoplastic to be modified in accordance with this invention will include: aliphatic and aromatic polycarbonates (such as polycarbonate bisphenol A), polyesters (such as poly (butylene terephthalate) and poly (ethylene terephthalate)), polyamides, polyacetal, polyphenylene ether or mixtures of the above. All these engineering thermoplastics are prepared according to well-known commercial processes. A reference to such processes can be found in technical publications such as Encyclopedia of Polymer Science and Engineering, John Wiley and Sons., 1988, within the topic of engineering thermoplastic. Below are specific details on polycondensation of engineering thermoplastics The polyphenylene ethers and the polyamides of the present invention are described in U.S. Pat. No. 5,290,863, which is incorporated herein by reference.

The polyphenylene ethers comprise a variety of unit structures having the formula: In each of said units, each Qi is independently halogen, primary or secondary lower alkyl (i.e., an alkyl group containing up to 7 carbon atoms), phenyl, haloalkyl, aminoalkyl, hydrocarbonoxy, or halohydrocarbonoxy where at least two carbon atoms separate the halogen and oxygen atoms; and each Q2 is independently hydrogen, halogen, primary or secondary lower alkyl, phenyl, haloalkyl, aminoalkyl, hydrocarbonoxy, or halohydrocarbonoxy as defined for Qi.

Examples of primary or lower alkyl groups are methyl, ethyl, n-propyl, n-butyl, isobutyl, n-amyl, isoamyl, 2-methylbutyl, n-hexyl, 2,3-dimethylbutyl, 2-, 3- or 4- methylpentyl and the corresponding heptyl groups. Examples of alkyl under secondary are isopropyl and secbutyl.

Preferably, any alkyl radical is straight chain rather than branched. More frequently, each Qi is alkyl or phenyl, especially C 1-4 alkyl, and each Q 2 is hydrogen. Suitable polyphenylene ethers have been described in a large number of patents.

The polyphenylene ethers are typically prepared by oxidative coupling of at least one corresponding monohydroxy aromatic compound. Particularly useful and easily obtainable monohydroxy-aromatic compounds are 2,6-xylenol, where each Q! is methyl and each Q2 is hydrogen and where the resulting polymer is characterized as a poly (2,6-dimethyl-l, 4-phenylene ether), and 2,3,6-trimethylphenol, where each and a Q2 are methyl, and the other Q2 is hydrogen.

Both homopolymers and polyphenylene ether copolymers are included. Suitable homopolymers are those containing, for example, 2,6-dimethyl-1,4-phenylene ether units. Suitable copolymers include random copolymers containing such units in combination with, for example, 2,3,6-trimethyl-1,4-phenylene ether units. Many random copolymers, as well as homopolymers suitable for the present invention are found in the patent literature.

Also included are polyphenylene ethers that contain groups that modify properties such as molecular weight, melt viscosity and / or impact resistance. Such polymers are described in the patent literature and can be prepared by ingestion in the polyphenylene ether in a known manner vinyl aromatic monomers such as acrylonitrile and vinyl aromatic compounds (for example styrene), or such polymers as polystyrene or elastomers. The product typically contains grafted and ungrafted groups. Other suitable polymers are the coupled polyphenylene ethers in which the coupling agent is reacted in a known manner with the hydroxyl groups of two phenylene ether chains to produce a high molecular weight polymer containing the hydroxyl group and the hydroxyl group. coupling agent. Examples of coupling agents are low molecular weight polycarbonates, quinones, heterocycles and formols.

The polyphenylene ether generally has a number average molecular weight within the range 3,000-40,000 and a weight average molecular weight within the range 20,000-80,000, determined by gel permeation chromatography. Its intrinsic viscosity is often in the range of 0.15 to 0.6 dl / g, determined in chloroform at 25 ° C.

The polyphenylene ethers that can be used for the purposes of this invention include those which contain molecules having at least one of the terminal groups of the formulas (II) where Qi and Q2 are as previously defined; each ¾ is independently hydrogen or alkyl, provided that the total number of carbon atoms in both radicals ¾ is 6 or less; and each R2 is independently hydrogen or a primary alkyl radical with C1-6. Preferably, each is hydrogen and each R2 is alkyl, especially methyl or n-butyl. The polymers containing substituted aminoalkyl terminus groups of the formula (II) can be obtained by the incorporation of a primary or secondary monoamine as one of the constituents of the oxidative coupling reaction mixture, especially when a copper or manganese catalyst is used. Such amines, especially dialkylamines and preferably di-n-butylamine and dimethylamine, often chemically bind to the polyphenyl ether, most frequently replacing one of the hydrogen atoms found in one or more of the radicals. The main reaction site is the radical Q adjoining the hydroxy group in the terminal unit of the polymer chain. During further processing and / or mixing, the aminoalkyl-substituted terminal group may undergo several reactions, which propably involve an intermediate quinone of formula with several beneficial effects that often include an increase in impact resistance and compatibility with other components of the mixture, as mentioned in U.S. Pat. Pat. No. 5,290,863.

It will be clear to those skilled in the art from the foregoing that the polyphenylene ethers contemplated for use in the present invention include all those currently known, regardless of variations in structural units or auxiliary chemical characteristics.

The polyamides included in the present invention are those which are prepared by the polymerization of a monoamino-monocarboxylic acid or a lactam having at least two carbon atoms between the amino and carboxylic acid groups, of substantially equimolar proportions of a diamine containing the minus two carbon atoms between the amino groups and a dicarboxylic acid, or of a monoaminocarboxylic acid or a lactam as defined above together with substantially equimolar proportions of a diamine and a dicarboxylic acid. The term "basically equimolar" proportions includes both strictly equimolar proportions and small deviations which are involved in conventional techniques to stabilize the viscosity of the resulting polyamides. The dicarboxylic acid can be used in the form of a functional derivative, for example, an ester or hydrochloric acid.

Examples of the mentioned monoamino monocarboxylic acids and lactams which are useful in the preparation of polyamides include those compounds containing from 2 to 16 carbon atoms between the amino groups and dicarboxylic acid, such carbon atoms form a ring containing the group CO (NH) in the case of a lactam. As particular examples of aminocarboxylic acids and lactams there may be mentioned -aminocaproic acid, butyrolactam, pivalolactam, -caprolactam, capryllactam, enantholactam, undecanolactam, dodecanolactam and 3- and 4-aminobenzoic acids.

Suitable diamines for use in the preparation of polyamides include the straight chain and branched diamines with alkyl, aryl and alkaryl groups. Examples of these are trimethylenediamine, tetramethylenediamine, pentamethylenediamine, octamethylenediamine, hexamethylenediamine (which is often preferred), trimethylhexamethylenediamine, m-phenylenediamine and m-xylylenediamine.

Dicarboxylic acids can be represented by the formula HOOC-B-COOH (V) where B is an aliphatic or aromatic divalent group containing at least 2 carbon atoms. Examples of aliphatic acids are sebacic acid, octadecanedioic acid, suberic acid, glutaric acid, pimelic acid and adipic acid.

Both amorphous and crystalline polyamides can be employed, crystalline species often being preferred because of their resistance to solvents. Typical examples of polyamides or nylons, as they are often called, include, for example, polyamide-6 (polycaprolactam), 6,6 (poly examethylene adipamide), 11, 12, 4.6, 6.10 and 6.12. as well as polyamides of terephthalic acid and / or isophthalic acid and trimethylhexamethylenediamine; of adipic acid and m-xylylenediamines; of adipic acid, acelaic acid and 2,2-bis (p-aminophenyl) propane or 2,2-bis (p-aminociclohexyl) propane and of terephthalic acid and 4,4'-diaminodicyclohexylmethane. Mixtures and / or copolymers of two or more of the above polyamides or their prepolymers, respectively, are also within the scope of the present invention. Preferred polyamides are polyamide-6,6,6,6,6,6,9,16,12 and 12, more preferably polyamide-6,6. Commercially available thermoplastic polyamides can be advantageously used in the practice of this invention, preferring linear crystalline polyamides with a melting point between 165 and 230 ° C.

The polyesters that can be used as a component of the compositions of this invention are, in general, of relatively high molecular weight and can be linear or branched. Polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycyclohexane-bis-methylene terephthalate (PCT) and thermoplastic elastomers, or combinations of these thermoplastic elastomer polyesters with the polyesters mentioned above as PBT are included. Suitable polyesters for the compositions of the present invention include, in general, linear products saturated with the condensation of diols and dicarboxylic acids, or reactive derivatives therefrom. Preferably they are polymeric glycol esters of terephthalic acid and isophthalic acid. These polymers are commercially available or can be prepared by known techniques, such as alcoholysis of esters of italic acid with a glycol and the subsequent polymerization, heating glycols with free acids or with halide derivatives, and the like process.

Such polymers and the methods for their preparation are described more extensively in the references cited in U.S. Pat. No. 5, 290, 863 or elsewhere.

Preferred polyesters are from the family comprising glycols terephthalates and polymeric isophthalates having high molecular weight and having repeating units of the formula where n is an integer from two to ten, and more generally from two to four, and mixtures of such esters, including copolyethers of terephthalic and isophthalic acids of up to 30 mol% iso-ionic units.

Especially preferred polyesters are poly (ethylene tereñalate) and poly (1,4-butylene tereñalate).

When high melt strength is important, branched poly (l, 4-butylene tereilalate) resins of high melt viscosity, which include small amounts, for example up to 5% mol base tereñalate units, of a branched component are especially favored. which contains at least three ester groups. The component for branching may be one that provides branching in the acid unit portion of the polyester, or in the glycol unit portion, or it may be a hybrid. Examples of such branching components are tri or tetracarboxylic acids, such as trimesic acid, pyromellitic acid and low alkyl esters, and the like, or preferably, tetraols, such as pentaerythritol, triols, such as trimethylolpropane, or dihydroxycarboxylic acids and hydroxydicarboxylic acids and their derivatives, such as dimethylhydroxytereilalate and the like. The addition of a polyepoxide, such as triglycidyl isocyanurate, which is known to increase the viscosity of the polyester phase through branching can assist in improving the physical properties of the mixtures present.

The branched poly (1,4-butylene tereilalate) resins and their preparation is described in U.S. Pat. No. 3,953,404.

Exemplifying, the high molecular weight polyesters useful in the practice of this invention possess an intrinsic viscosity of at least 0.2 deciliters per gram, and more generally 0.4 to 1.5 deciliters per grams determined in ortho-chlorophenol solution or in a mixture 60/40 phenol / tetrachloroethane at 25-30 ° C.

Linear polyesters include poly (alkylene dicarboxylate) thermoplastics and analogous alicycles. Typically they contain the unitary structure of formula: - O-Re ^ O-C-A ^ -C- (VII) where R8 is a saturated divalent aliphatic or an alicyclic idiocarburo radical containing from 2 to 10 and generally from 2 to 8 carbon atoms, and A2 is a divalent aromatic radical containing between 6 and 20 carbon atoms. They are usually prepared by the reaction of at least one diol such as ethylene glycol, 1,4-butanediol or 1,4-cyclohexanedimethanol with at least one aromatic dicarboxylic acid such as isophthalic or terephthalic acid, or a low alkyl ester. Among the polyalkylene tereilalates, polyethylene and polybutylene ternarylate, and especially the latter, are particularly preferred. Such polyesters are known in the art, for example in the references cited in U.S. Pat. No. 5,290,863.

Linear polyesters generally have average molecular weights in the range of 20,000 to 70,000, determined by intrinsic viscosity (IV) at 30 ° C in a mixture of 60% (by weight) of phenol and 40% of 1,1,2,2 -tetrachloroethane. When resistance to heat deformation is an important factor, the molecular weight of the polyester must be relatively high, typically above 40,000.

Polycarbonates suitable for use in the present compositions include aliphatic and aromatic polycarbonates.

The raw materials for the aliphatic polycarbonates are diols and carbonates, for example diethyl or diphenyl carbonate which are obtained by phosgenation of hydroxy compounds or 1,3-dioxolan-2-ones formed from C02 and oxiranes. The aliphatic polycarbonates can also be prepared from l, 3-dioxan-2-ones obtained by thermal depolymerization of the corresponding polycarbonates.

Current methods for the preparation of aliphatic polycarbonates include the transesterification of diols with dialkyl carbonates, dioxolanones or diphenyl carbonate in the presence of catalyst such as alkali metal, tin compounds or titanium. The ring-opening polymerization of 6-membered cyclic carbonates (1, 3-dioxan-2-ones), in the presence of bicyclic carbonates which act as crosslinking agents, leads to hard and resistant thermosetting. Crosslinked polycarbonates with outstanding properties can also be obtained with free radical polymerization of diethylene glycol bis (allyl carbonate). Based on ethylene glycol carbonate other phosgene routes have been found, starting from C02 with urea or a dialkyl carbonate as an intermediate, or from CO. Other routes involve cationic or free radical polymerization by ring opening of orthocyclic carbonic acid esters. These reactions produce polyether polycarbonates.

The molecular weights of linear aliphatic polycarbonates are process dependent and range from 500 to 5000. Polycarbonates with molecular weights of up to about 30,000 are obtained by transesterification, and those of molecular weight greater than 50,000 are prepared by polymerization of carbonates with 6 members Among the preferred polycarbonates are aromatic homopolymer polycarbonates. The structural unit of such homopolymers generally has the formula (VIII) O II - 0-A3-0-C - where A3 is an aromatic radical. Suitable A3 radicals include m-phenylene, p-phenylene, 4,4'-biphenylene, 2,2-bis (4-phenylene) propane, 2,2-bis (3, 5-dimethyl-4-phenylene) propane and similar radicals such as those corresponding to the dihydroxyaromatic compounds described by name or formula, generally or specifically in U.S. Pat. No. 4,217,438. Radicals containing non-hydrocarbon groups are also included. These may be substituents such as chlorine, nitro, alkoxy or the like, and also binding radicals such as thio, sulfoxy, sulfone, ester, amide, ether and carbonyl. More frequently, however, all radicals A3 are hydrocarbon radicals.

The A3 radicals preferably have the formula - A4 - Y - A5 - (IX) where each A4 and A5 are a divalent radical of a single ring and Y is a bridging radical in which one or two atoms separate A4 from A5. The three free valence bonds in formula IX are generally meta or para positions of A4 and A5 in relation to Y. Such values of A3 can be considered as derivatives of bisphenols of the formula HO - - Y - A5 - OH. Frequent reference will be made to bisphenols, but it should be understood that A3 values derived from suitable compounds other than bisphenols can be used appropriately.

In the formula G ?, the values of A4 and A5 may be unsubstituted phenylene or substituted derivatives, examples of substituents are one or more alkyls, alkenyls (for example crosslinkable-grafting groups such as vinyl or allyl), halo (especially chloro) and / or bromine), nitro, alkoxy and the like. Phenylene radicals without substituents are preferred. Both A4 and A5 are preferably p-phenylene, although both may be o- or m-phenylene, or one may be o-phenylene or m-phenylene and the other p-phenylene.

The bridge type radical, Y, is such that one or two atoms, preferably one, separate A4 from A5. More frequently it is a hydrocarbon radical, and particularly a saturated radical such as methylene, cyclohexylmethylene, 2- [2.2.1] -bicycloheptylmethylene, ethylene, 2,2-propylene, 1, 1- (2,2-dimethylpropylene), 1, 1-cyclohexylene, 1,1-cyclopentadecylene, 1,1-cyclododecylene or 2,2-adamantylene, especially gemalkylene radical. Also included are, however, unsaturated radicals and radicals that are composed entirely or partially of atoms other than carbon and hydrogen. Examples of such radicals are 2,2-dichloroethylidene, carbonyl, uncle, oxy, and sulfone. For reasons of availability and particular suitability for the purposes of this invention, the radical of formula G? preferred is 2,2-bis (4-phenylene) propane, which is derived from bisphenol A and in which Y is isopropylidene and A4 and A5 are each p-phenylene.

Various methods of preparing polycarbonate homopolymers are known. These include the interfacial method and other methods in which phosgene reacts with bisphenols, transesterification methods in which phenols react with diaryl carbonates, and methods involving the conversion of cyclic polycarbonate oligomers to linear polycarbonates. This latter method is disclosed in U.S. Pat. No. 4,605,731 and No. 4,644,053. Polycarbonate resins suitable for the practice of the present invention can be any commercial polycarbonate resins. The weight average molecular weight of suitable polycarbonate resins (determined by gel permeation chromatography relative to polystyrene standards) can be in the range of 20,000 to 500,000, preferably 40,000 to 400,000. However, compositions in which the polycarbonate has a molecular weight in the range of 80,000 to 200,000 frequently exhibit favorable properties.

It is also possible in the polymer mixture of the present invention to use a mixture of different aromatic polycarbonates as mentioned above.

Generally a minimum of 1% by weight of the styrene-ACI block copolymer of the present invention will be sufficient to observe the effects of compatibilization in the engineering thermoplastic composition in which it is used, such as improvements in mechanical properties. The block copolymer can also be used in amounts greater than the minimum, but limited to a range so as to positively affect the characteristics of the mixture without substantially degrading other desired characteristics. Thus, typical blends will comprise the following: (a) 98-1% by weight of engineering thermoplastic, (b) 1-98% by weight of thermoplastic polymer; and (c) 1-20% by weight of styrene-ACI copolymer. The preferred blends of engineering thermoplastics of this invention comprise from about 40 to about 90% by weight of engineering thermoplastic, 10-60% by weight of miscible or compatible polystyrene thermoplastic, and from about 2 to about 5% by weight. weight of styrene-ACI block copolymer. This range of compositions will generally lead to materials with improved impact and mechanical strength properties.

In general, the compositions of the invention can be prepared by mixing the engineering thermoplastic, the thermoplastic miscible or compatible with polystyrene and the block copolymer of the invention (styrene-ACI), in any order and subjecting the mixture to temperatures high enough to melt it, for example 180 ° C or higher. Mixing and heating can be carried out using conventional polymer processing equipment known in the art, such as batch mixer, single or multiple screw extruder, continuous kneader, etc. Additionally, the compatibilized compositions of the present invention may contain various additives, for example stabilizers, flame retardants, antioxidants, fillers, processing agents and pigments in normal and conventional amounts, depending on the desired end use. Examples of fillers are, for example, metal oxides such as iron and nickel oxide, non-metals such as carbon fiber, silicates (for example mica, aluminum silicate (clay)), titanium dioxide, glass flakes, glass spheres , fiberglass, polymer fibers, etc. If conventional additives and fillers are used, they are mechanically mixed, and the compositions of the invention are molded by known methods.

Another aspect of this invention is the use of the unsaturated styrene-cyclic anhydride block copolymer (ACI) as a coupling agent for polystyrene, styrene copolymers and polymers miscible or compatible with the polystyrene block and various fillers containing functional groups that show affinity strong chemistry or that can react with the dicarboxylic group of the ACI units of the styrene-ACI block copolymer. An additional object are the compositions resulting from this method of use. Thus, typical compositions will comprise the following: (a) 40-98% by weight of polystyrene, styrene copolymers or polymers miscible with the polystyrene block of the block copolymer (b) 1-50% by weight fillers; and (c) 1-20% styrene-ACI copolymer. Preferred compositions of this invention will comprise 60-89% by weight of (a), 10-30% of (b) and 2-10% of (c).

The styrene-based polymers miscible or compatible with the polystyrene block of the above-mentioned block copolymer include those which can be described as hydrogenated or partially hydrogenated homopolymers, and random, block and block polymers (copolymers, including terpolymers, tetrapolymers, etc.) of dienes conjugates and / or monovinyl aromatic compounds. Conjugated dienes include isoprene, butadiene, 2,3-dimethyl butadiene and / or mixtures thereof, such as isoprene and butadiene. The monovinyl aromatic compounds include any of the following or mixtures of monovinyl monoaromatic compounds, such as styrene or alkylated styrenes substituted on the alpha carbon atom of the styrene, such as alpha-methylstyrene, or on the ring carbons such as o-, m - and p-methylstyrene, ethylstyrene, propylstyrene, isopropylstyrene, butylstyrene, isobutylstyrene, tert-butylstyrene (for example p-tert-butylstyrene). Also included are vinylxilenes, methylethyl styrenes, and ethyl vinylstyrenes. Specific examples include random copolymers of butadiene and / or isoprene and polymers of isoprene and / or butadiene and styrene, and also stereo-specific polymers such as sidotactic polystyrene. Typical block copolymers include polystyrene-polyisoprene, polystyrene-polybutadiene, polystyrene-polybutadiene-polystyrene, polystyrene-ethylene, butylene-polystyrene, hydroxylated polyvinyl-cyclohexane-polyisoprene, and hydrogenated polyvinyl-cyclohexane-polybutadiene. The gradual polymers include those of the aforementioned monomers prepared by the methods known in the art. Other non-styrenic polymers miscible or compatible with the polystyrene block of the styrene-ACI copolymer include, but are not limited to, polyphenylene ether (PPE), polyvinyl methyl ether and tetramethyl polycarbonate.

Examples of fillers are metal oxides such as iron and nickel oxide, non-metals such as carbon fiber, silicates (for example mica, aluminum silicates (clay)), titanium dioxide, glass flakes, glass beads, fiberglass, polymer fibers, etc. Preferred fillers are glass fibers containing epoxy or amino coating due to the high affinity of this type of compounds for the double carboxylic group of the ACI units. Examples of glass fiber include types E, C, A, S and M in any possible combination of number of filaments per strand, strand configurations and length / weight ratio of the fiber. The preferred form of fiberglass is strands cut into lengths ranging from 1/8 to 1 inch.

The following examples illustrate the invention in greater detail. They should not be construed as limiting the present invention in any way. It is hereby declared that the invention encompasses all the changes and modifications of the specific examples that do not constitute a deviation from the spirit and scope of the invention.

EXAMPLE I Mass polymerization of styrene and maleic anhydride at 120 ° C in 20 mL vials, without agitation. A solution of styrene (Aldrich, 99% purity), and variable amounts (5, 10 and 15% by weight) of maleic anhydride (Aldrich, 99%), benzoyl peroxide (BPO, from Akzo, 99% purified) 0.033M as initiator and 4-hydroxy 2,2,6,2, tetramethyl-piperidin-N-oxyl (HO-TEMPO, 99%, from Ciba, Puebla, Mexico) as stable free radical, were heated in an oil bath at 120 ° C. The HO-TEMPO / BPO molar ratio remained constant. The molar ratio of HO-TEMPO to BPO was 1.3. The maleic anhydride was purified by crystallization from chloroform and the styrene monomer was washed with sodium hydroxide.

The vials with identical formulations were removed from the oil bath at different time intervals as indicated in Table I, and the reaction was turned off by immersing the vials in a water bath maintained at the freezing temperature. The average molecular weights and their distribution were measured using gel permeation chromatography (GPC) [Waters 410 Gel Permeation Chromatograph, IR detector, THF as eluent, 1.0 mL / min, at 40 ° C; with linear columns Styragel HR 5, HR 4, HR 3, using polystyrene as standard].

The conversion, molecular weight and its distribution were compiled in Table I. High molecular weights were achieved even at moderate conversions, and the molecular weight shows stable growth as the conversion increases .. The final polydispersity (PD) is less than 3, even for high content (15%) of maleic anhydride.

TABLE I.

Key Anhydride Time of the maleic reaction% Mn M PD sample% weight (hr) Conversion 1 5 0.333 27.53 42 885 94 902 2.21 2 5 1 30.41 44 835 101 449 2.26 3 5 3 42.96 55 596 112 657 2.03 4 5 5 56.76 66 482 152 832 2.30 5 10 0.333 40.77 53 182 255 176 4.80 6 10 1 44.40 60 305 327 216 5.43 7 10 3 54.47 58 468 232 586 3.98 8 10 5 65.75 68 201 190 687 2.80 9 15 0.333 54.33 55 666 211 853 3.81 10 15 1 58.53 57 084 241 962 4.24 11 15 3 66.32 68 556 351 502 5.13 12 15 5 74.66 73 459 213 474 2.91 EXAMPLE II Styrene (PEMEX, industrial grade) was copolymerized with maleic anhydride (Aldrich, 95% purity) in the presence of 4-oxo-2,2,6,6-tetramethyl-piperidin-N-oxyl (oxo-TEMPO from Crompton Corp., Middlebury , CT) as stable free radical agent and BPO (Akzo, 75%) as initiator, at 120 ° and 130 ° C to prepare a poly (styrene-random-AM) -co-styrene copolymer) in a Parallel Polymerization Reactor (PPR, Symyx ™). The reaction volume in each mini-reactor was 3 mL. Table II shows the change in average molecular weight over time. The molar ratio of stable free radical to initiator used was [oxo-TEMPO] / [BPO] = 1.3 and the initial amount of [BPO] = 0.003M TABLE II.

Sample Time Mn Mw PD reaction (hr) 13a 1 17,400 44,700 2.57 13b 3 55,500 107,500 1.93 13c 5 55,100 123,100 2.23 13d 9 75,600 142,700 1.89 13e 12 98,200 168,900 1.72 Table II shows the molecular weight distribution data obtained at different reaction times for an AM content of 0.5% by weight. The molecular weight distributions were measured in an HP series 1100 GPC, with UV detector, THF as eluent, flow rate of 1 mL / min, 40 ° C; Plgel columns ?? and 5μ ?? mixed-B. Note the increase in molecular weight and the general decrease in polydispersity, which is typical of polymerizations controlled by nitroxides.

The resulting styrene / AM copolymer was characterized by 1 H NMR spectroscopy, recorded at room temperature on a Bruker AC-250 TF NMR spectrometer. 10 milligrams of the copolymer were dissolved in 0.5 mL of CDCL3 (20% w / v) and the solution was subjected to 1 H NMR determination.

Table III shows the composition of the copolymer determined by α-NMR spectroscopy of the styrene / AM copolymers produced by reaction 13 (120 ° C, 0.5% by weight of AM, samples 13a-13e in Table II), as well as by reactions 14 (120 ° C, 0.3% by weight of AM) and 15 (130 ° C, 0.3% by weight of AM). Note how each reaction proceeds, the composition of AM decreases, indicating the consumption of AM in the early stage of the reaction. The compositions calculated with NMR below 1% by weight are not quantitatively reliable, but can be used to indicate trends. The most reliable value (sample 13a, 1 h) is close to the expected theoretical value.

TABLE ??.

Sample Time in% in mol Temperature reaction Anh M (hr) 13a 1 5.69 120 ° C (10 maleic groups (9.4 units / chain) * AM measurements) 13b 3 0.74 120 ° C (10 maleic groups (4.4 units / chain) * AM measurements) 14a 1 0.84 120 ° C (3 maleic / chain groups) * 14b 3 0.33 120 ° C (3 maleic / chain groups) * 15a 1 2.59 130 ° C (3 maleic / chain groups) * 15b 3 0.57 130 ° C (3 maleic / chain groups) * * Theoretical calculation based on the feed to the reaction EXAMPLE III Copolymerization of styrene (PEMEX, industrial grade for samples 16-19 and Aldrich, 99% for samples 20-23) with maleic anhydride (Aldrich,> 95% by weight) in the presence of HO-TEMPO (Ciba, 99% , Puebla, Mexico) or oxo-TEMPO (Crompton Corp., Middlebury, CT) as stable free radical agent and BPO (Akzo,> 75%) as initiator at 120 ° C. The reaction proceeded to 20-30% conversion in a 2 L jacketed glass reactor with agitation (106 rpm) connected to a recirculating bath with oil, and subsequently the molasses was emptied into stainless steel (SS) cylindrical reactors. L without stirring placed in a bath with oil at constant temperature to prepare the poly (styrene-random-MA) -co-styrene copolymer in a quasi-live process. The final conversions after 24 h were close to 100% in all cases. Table IV shows the final average molecular weight after 24 hours of reaction in the stainless steel reactors, for 8 different reactions which were directed to obtain different total lengths and different levels of functionalization. The samples were characterized using GPC [Waters 410, IR detector, THF as eluent, 1.0 mL / min, at 40 ° C; linear columns Styragel HR 5, HR 4, HR 3]. The interrelation of low levels of initiator concentration combined with high levels of AM tends to increase polydispersity.

TABLE IV.

Key Weight% Anh [BPO], M [Nitroxide], M Type Mn Mw PD Sample Maleic Controller 16 0.9429 0.0335 0.0436 oxoTEMPO 22 100 30 685 1.39 17 0.1885 0.0067 0.0087 oxoTEMPO 58 614 78 664 1.34 18 4.7300 0.0336 0.0437 oxoTEMPO 22 505 29 959 1.33 19 0.9429 0.0044 0.0057 oxoTEMPO 74 526 102 377 1.37 20 4.7300 0.0030 0.0039 HO-TEMPO 77 566 202424 2.70 21 8.0000 0.0030 0.0039 HO-TEMPO 76361 172708 2.26 22 4.7300 0.0030 0.0075 HO-TEMPO 72270 180526 2.50 23 6.0000 0.0030 0.0105 HO-TEMPO 55 251 136005 2.46 EXAMPLE IV Extensive experimentation was carried out to determine the influence of the initial concentration of initiator (benzoyl peroxide, Akzo purified at 99%) on the final molecular weight and polydispersity in the controlled copolymerization of styrene (Aldrich, 99%) and maleic anhydride. (Aldrich, 99% »). All experiments ran for 24 hr, controlled by HO-TEMPO (Ciba, Puebla, Mexico, 99%), by mass, in a parallel polymerization combinatorial reactor (PPR Symyx ™) at 120 ° C and 100 rpm stirring, until that it was possible to maintain the agitation due to the increasing viscosity of the reaction medium. Table V shows the results of the concentration variation of benzoyl peroxide (BPO) and of two different initial concentrations of maleic anhydride. The results of Table V correspond to a molar ratio of HO-TEMPO to initiator of 1.3. Tables VI and VII correspond to similar results but for molar ratios of HO-TEMPO to initiator from 1.6 to 1.9, respectively. The molecular weight distributions were determined in a fast Symyx GPC kit, with evaporative light scattering detector, THF as eluent, at 40 ° C and with three Plgel series columns of ?? μp? mixed-B from Polymer Labs.

TABLE V.

Key of% Weight [10], M Mw Mn PD AM shows 24a 0.001 0.1885 2.525E + 05 1.962E + 05 1.29 24b 0.002 0.1885 1.549E + 05 1.301E + 05 1.19 24c 0.003 0.1885 1.208E + 05 1.027E + 05 1.18 24d 0.005 0.1885 7.987E + 04 6.881E + 04 1.16 24e 0.0067 0.1885 6.534E + 04 5.472E + 04 1.19 24f 0.0075 0.1885 5.386E + 04 4.725E + 04 1.14 24g 0.01 0.1885 4.916E + 04 4.369E + 04 1.13 24h 0.0168 0.1885 2.180E + 04 1.934E + 04 1.13 24i 0.001 0.9429 1.453E + 05 1.171E + 05 1.24 24j 0.002 0.9429 1.244E + 05 1.011E + 05 1.23 24k 0.003 0.9429 1.324E + 05 1.112E + 05 1.19 241 0.005 0.9429 8.098E + 04 7.020E + 04 1.15 24m 0.0067 0.9429 6.576E + 04 5.354E + 04 1.23 24n 0.0075 0.9429 8.606E + 04 7.302E + 04 1.18 24o 0.01 0.9429 5.135E + 04 3.967E + 04 1.29 24p 0.0168 0.9429 2.831E + 04 2.480E + 04 1.14 TABLE VI.

Key of% weight [10], M Mw Mn PD AM shows 25a 0.001 0.1885 1.581E + 05 1.304E + 05 1.21 25b 0.002 0.1885 1.252E + 05 9.914E + 04 1.26 25c 0.003 0.1885 8.796E + 04 7.754E + 04 1.13 25d 0.005 0.1885 6.487E + 04 5.612E + 04 1.16 25e 0.0067 0.1885 5.689E + 04 5.057E + 04 1.12 25f 0.0075 0.1885 6.587E + 04 5.918E + 04 1.11 25g 0.01 0.1885 2.928E + 04 2.625E + 04 1.12 25h 0.0168 0.1885 1.146E + 04 1.016E + 04 1.13 25i 0.001 0.9429 1.958E + 05 1.594E + 05 1.23 25j 0.002 0.9429 1.295E + 05 1.080E + 05 1.20 25k 0.003 0.9429 1.366E + 05 9.889E + 04 1.38 251 0.005 0.9429 8.737E + 04 7.250E + 04 1.21 25m 0.0067 0.9429 7.181E + 04 5.986E + 04 1.20 25n 0.0075 0.9429 6.660E + 04 5.700E + 04 1.17 25o 0.01 0.9429 5.706E + 04 4.297E + 04 1.33 25p 0.0168 0.9429 4.418E + 04 2.741E + 04 1.61 TABLE VII.

The polydispersity is lower at low contents of maleic anhydride, at high levels of HO-Tempo and at high levels of initiator (for a constant ratio of HO-TEMPO / initiator).

EXAMPLE V Solution polymerization was performed using styrene (Aldrich, 99%) and maleic anhydride (Aldrich, 95%) as monomers in the presence of solvent (toluene, see Table VIII and xylene, see Table IX), hydroxy-TEMPO (Ciba, Puebla, Mexico, 99%) as stable free radical agent and BPO (Akzo, 75%) as initiator (0.0065 M) at 120 ° C. The reactions were run in a parallel polymerization combinatorial reactor (PPR Symyx ™). For each solvent, a factorial experiment of 2x2x3 was run, varying the monomer / solvent ratio (two levels), the nitroxide to initiator ratio ([NOx] / [I0]) (two levels), and the percentage by weight of maleic anhydride (3). levels). Three samples were extracted at different reaction times for each factorial combination, the reaction was inhibited and the resulting polymer was determined by gravimetry and molecular weight by GPC (Symyx ™ rapid analysis GPC equipment, with dispersion detector evaporative light, THF as eluent, at 60 ° C, with Plgel columns of 10um mixed-B). The results are shown in Tables VIII and IX for toluene and xylene, respectively. TABLE VIII.

Time Ratio% weight of monomer / [NOx] / [I0] Anhydride Mw Mn PD Reaction key,% solvent Maleic sample hr Conversion 27a 50-50 1.3 0.5 1 5.36 38511 22205 1.73 27b 50-50 1.3 0.5 10 16.78 58688 60676 1.66 27c 50-50 1.3 0.5 17 20.81 66272 66785 1.68 28a 50-50 1.9 0.5 1 3.70 26763 11968 2.07 28b 50-50 1.9 0.5 10 11.67 60802 30506 1.36 28c 50-50 1.9 0.5 17 17.72 50728 36507 1.39 29a 50-50 1.3 2 1 6.65 60028 23666 1.71 29b 50-50 1.3 2 10 13.85 60852 63337 1.60 29c 50-50 1.3 2 17 22.22 65580 62862 1.53 30a 50-50 1.9 2 1 6.96 32612 15713 2.06 30b 50-50 1.9 2 10 13.03 65156 31637 1.66 30c 50-50 1.9 2 17 17.15 55682 39932 1.39 31a 50-50 1.3 5 1 5.78 62052 22585 1.86 31b 50-50 1.3 5 10 16.86 62517 63062 1.65 31c 50-50 1.3 5 17 20.02 72159 65801 1.58 32a 50-50 1.9 5 1 5.35 38699 19902 1.96 32b 50-50 1.9 5 10 16.02 56150 35036 1.55 32c 50-50 1.9 5 17 22.23 63602 60670 1.56 33a 75-25 1.3 0.5 1 16.03 67363 27517 1.72 33b 75-25 1.3 0.5 10 61.51 76286 51850 1.67 33c 75-25 1.3 0.5 17 59.06 86220 59663 1.65 36a 75-25 1.9 0.5 1 9.26 33080 17273 1.92 36b 75-25 1.9 0.5 10 35.98 57977 61237 1.61 36c 75-25 1.9 0.5 17 53.90 70197 51103 1.37 35a 75-25 1.3 2 1 16.28 65167 25612 1.78 35b 75-25 1.3 2 10 65.01 78058 52656 1.69 35c 75-25 1.3 2 17 61.63 91528 60630 1.51 36a 75-25 1.9 2 1 12.61 66820 22009 2.06 36b 75-25 1.9 2 10 60.51 61662 61282 1.69 36c 75-25 1.9 2 17 56.86 75826 50672 1.50 37a 75-25 1.3 5 1 18.78 56169 33899 1.66 37b 75-25 1.3 5 10 52.63 85797 53513 1.60 37c 75-25 1.3 5 17 63.21 96609 60667 1.60 38a 75-25 1.9 5 1 16.37 53120 27028 1.97 38b 75-25 1.9 5 10 67.76 70721 65572 1.55 38c 75-25 1.9 5 17 65.39 86065 56312 1.55 TABLE IX.

Time Ratio% weight of monomer / [NOx] / [I0] Anhydride Mw Mn PD Key to the reaction,% solvent Maleic sample hr Conversion 39a 50-50 1.3 0.5 1 6.62 63379 25216 1.72 50a 75-25 1.9 5 1 18.32 52756 25533 2.07 50b 75-25 1.9 5 10 57.35 86899 38189 2.22 50c 75-25 1.9 5 17 65.69 99526 60311 2.67 EXAMPLE VI Copolymers of styrene (Aldrich, 99%) and maleic anhydride (Aldrich, 95%) were prepared by mass polymerization at 120 ° C, in the presence of a stable free radical type nitroxide type (3,3-dimethyl-1, 1- diphenyl azabutane-N-oxide, 99%) which was synthesized by the Profa group. Martha Albores of the Faculty of Chemistry (School of Chemistry) of the National Autonomous University of Mexico. BPO (Akzo, 75%) 0.0065M was used as initiator. A factorial of 2x2 with some replicates varying the concentration of maleic anhydride (2 levels) and the nitroxide-to-initiator ratio ([NOx] / [I0]) (two levels) was run in a combinatorial parallel polymerization reactor (PPR Symyx ™) . Table X shows the results of conversion and molecular weight at different reaction times for different factorial experiments. The samples were characterized by gravimetry for conversion and by GPC for rapid analysis (Symyx, evaporative light scattering detector, THF as eluent, 60 ° C, Plgel columns B mixed? Μp?).

TABLE X.

Key Time% weight Ratio of% Mw Mn PD of the Anhydride [NOx] / [I0] reaction Conversion sample Maleic (hr) 51a 2 1.3 0.3333 26.16 16620 9738 1.68 51b 2 1.3 1 36.38 17810 12170 1.66 51c 2 1.3 3 53.92 22910 15760 1.65 51d 2 1.3 5 63.85 28580 20030 1.63 51e 2 1.3 7 96.66 33660 23090 1.66 52a 2 1.3 0.3333 31.50 17920 12060 1.69 52b 2 1.3 1 36.56 19000 12880 1.68 52c 2 1.3 3 68.62 23180 15560 1.69 52d 2 1.3 5 69.51 29710 20360 1.66 52e 2 1.3 7 96.07 35660 23930 1.68 53a 2 1.9 0.3333 20.05 15270 10170 1.50 53b 2 1.9 1 30.76 16060 10860 1.68 53c 2 1.9 3 53.88 22330 15660 1.63 53d 2 1.9 5 56.09 25080 17210 1.66 56a 5 1.3 0.3333 30.06 22270 16510 1 .53 56b 5 1.3 1 51.29 26530 17650 1.50 56c 5 1.3 3 62.33 33200 21000 1.58 56d 5 1.3 5 17.18 61720 26510 1.57 56e 5 1.3 7 37.65 51680 31870 1.62 55a 5 1.3 0.3333 32.35 25260 16370 1.56 55b 5 1.3 1 68.89 36670 23680 1.56 55c 5 1.3 3 60.23 67350 31680 1.50 55d 5 1.3 5 86.50 65790 62010 1.57 55e 5 1.3 7 96.59 68360 636 80 1.57 56a 5 1.9 0.3333 29.62 26920 16260 1.53 56b 5 1.9 1 60.27 29120 18960 1.56 56c 5 1.9 3 73.16 62970 27950 1.56 56d 5 1.9 5 82.16 66000 30360 1.52 56e 5 1.9 7 93.81 92080 65660 2.02 EXAMPLE VII Styrene (Aldrich, 99%) was copolymerized with 5% maleic anhydride (Aldrich, 99%) with benzoyl peroxide (BPO, Akzo, 99% purified), 0.005 M as initiator and 6 hydroxy, 2,2,6, 6-tetramethyl-piperidine-N-oxyl (HO-TEMPO, 99%, Ciba, Puebla, Mexico) as a stable free radical. The HO-TEMPO to BPO molar ratio was 2.5. The polymerizations were carried out in a Parallel Polymerization Reactor (PPR Symyx). The reaction proceeded at 120 ° C. By gravimetry, the monomer conversion was determined at different reaction times. The molecular weight of the polymer was determined by GPC (Waters model 610, IR detector, THF as eluent, 1 ml / min, at 60 ° C, with linear columns Styragel HR5, HR6, HR3). The results are presented in Table XI. Polydispersities below 2 were obtained using the HO-TEMPO to BPO ratio of 2.5.

TABLE XI.

Name of the Anhydride Time Conversion sample Maleic (%) (min) (%) Mn Mw PD 57a 5 30 23.86 21591 36082 1.58 57b 5 60 36.02 30007 50086 1.67 57c 5 120 65.67 32160 55396 1.72 57d 5 300 62.83 60165 77219 1.92 EXAMPLE VIII The polycarbonate Bisphenol-A (BPA) that was used in the following examples was Lexan 141 obtained from General Electric Plastics. Polyethylene terephthalate (PET) was a recycled resin with characteristics equivalent to grade 1101 of KOSA. High-impact polystyrene (HEPS) was HIPS 4220, a half-impact, half-flow grade (Izod slotted impact = 1.3 ft-lb / in, MFI "G" = 8.0 g / 10 min.) Obtained from Resirene. The polyamide (PA-6) was commercial polyamide-6 ZYTEL 7300 NC010 from Dupont. Two grades of polyphenylene ether, PPE (Blendex HPP820 and HPP830) which were used in the following examples were obtained from General Electric Specialty Chemicals and have intrinsic viscosity in chloroform at 25 ° C of 0.40 dl / g. Blendex HPP830 is a mixture of polyphenylene ether and polystyrene. The impact modifier was a linear hydrogenated triblock copolymer (SEBS) Calprene CH 6110 from Dynasol which contains 30% styrene and has a Brookfield viscosity (at 20% solids in toluene) of 400 cPs. Polystyrene (PS) was HH104, a degree of medium flow (MFI "G" = 4.2 g / 10 min) obtained from Resirene. The fiberglass was type E cut into 5 mm long strands with an amine-type coating.

The styrene-ACI block copolymers used in the following examples correspond to samples 17,18,19,20,22,23 synthesized in Example III All blends were prepared by dry blending the component followed by extrusion in a fully spliced 30mm double spindle WP ZSK, co-rotating at 150 rpm. The temperatures of the segments of the barrel were dependent on the system to be evaluated, in the case of the polycarbonate and polyester mixtures the profile was 260 ° C (in the throat), 270 ° C, 270 ° C, 275 ° C. For the PA6 mixtures, the profile was 220 ° C (in the throat), 230 ° C, 230 ° C, 240 ° C. For the polystyrene-fiberglass compositions the profile was 160 ° C (throat), 180 ° C, 190 ° C, 195 ° C. The extrusion product was cooled in water, pelleted and dried in an air circulating oven at 100-110 ° C prior to the molding of test specimens using a Demag Ergotech 80/240 fuel transfer with fixed barrel temperatures of 275 ° C for polycarbonate and polyester blends, 240 ° C for blends of polyamide 6, and 210 ° C for polystyrene-fiberglass compositions. The temperature of the mold was 50 ° C in all cases. The Izod impact values were determined according to ASTM # D256. The tensile properties were determined according to ASTM # D638. The flexural properties were determined according to standard # D790. The deflection temperature under load (HDT) was determined with the ASTM # D648 standard. TABLE XII.

Sample Samples 59-60 and comparative sample 58 show that there is an improvement in the yield strength and the elongation at break for the mixtures containing the SAM copolymer, this improvement apparently varies with the amount of SAM present in the mixture polycarbonate / HIPS. Samples 62-63 and comparative sample 61 show a similar tendency to PET and HIPS mixtures. In this case, the degree of improvement is also correlated with the type of SAM used in the mixture. Sample 65 also shows improvements in the same properties with respect to comparative sample 64 for mixtures of PA6 and HIPS.

TABLE XIII.

Sample * indicates that the specimens did not break during the test.

The sample 67 and the comparative sample 66 show that there is an improvement in the flexural strength, in the flexural modulus and in the ungrooved Izod impact of the PPE and HIPS mixtures containing the SAM copolymer, this improvement is also observed in impact properties without grooving. Samples 69-70 and comparative sample 68 show a similar trend to mixtures of PPE and HIPS containing an impact modifier (SEBS). In this case, the improvement in properties can be along all the properties, but it is extremely evident in the elongation at break. The improvement in properties is also dependent on the type of SAM used in the mixture.

Even more evidence of the compatibilizing effect of the block copolymer SAM is these mixtures can be seen in Figures 4 A and 4B. In these figures, an unaccompanied mixture of PPE, SEBS and PA (50/10/50) (Fig. 4A) is compared against a mixture containing the SAM block copolymer (Fig. 4B). The drastic change in the morphology provides an indication of the increase in the interfacial adhesion, the reduction in the interfacial tension and the stabilization of the mosrphology that are obtained with the use of the compatibilizer, this change in the morphology in turn correlates with the improvement in mechanical properties shown in Table XIII.

TABLE XIV. Sample Samples 72-75 and comparative sample 71 show that there is a considerable improvement in flexural strength, flexural modulus, tensile strength and deflection temperature under load for the polystyrene and fiberglass compositions that contain the SAM block copolymer. Apparently, the improvement in properties is independent of the type of SAM block copolymer used in the composition.

Claims (88)

CLAIMS What is claimed is:

1. A process for producing a block copolymer comprising: The heating of styrene and an unsaturated cyclic anhydride (ACI) in the presence of a free radical initiator and a stable free radical at temperatures between about 110 and about 200 ° C, adjusting or adjusting the ratio of initiator to monomer with In order to control the total length of the chain, cooling the reaction mixture; and recovering a block copolymer by isolating it from the unreacted monomer, wherein the composition of the block copolymer comprises: a first block containing a random copolymer of styrene and an unsaturated cyclic anhydride, and having a total length between about 1 and about 720 monomer units; Y a second block containing a block of basically pure polystyrene having a length of between about 100 to about 2000 monomer units, in which the polydispersity is between about 1.2 to about 3.

2. The process of claim 1, wherein the first block has some degree of alternating character given by the reactivity ratios of the monomers.

3. The process of claim 1, wherein the number average molecular weight of the chain is controlled by adjusting or adjusting the molar concentration of the initiator to a value of about A - (5x10"8 Mn) if the desired molecular weight is greater than about 61500, and B - (3.33x10" 7 Mn) if the desired molecular weight is less than about 61500, wherein Mn is a target value for the number average molecular weight; A is between about 0.005 and about 0.01; and B is between about 0.016 and about 0.042.

4. The process of claim 1, wherein the value of the molar ratio of stable free radical to initiator is at least about: 1. 3 + 0.10 * (percentage by weight of ACI with respect to total monomers)

5. The process of claim 1, wherein the ACI is maleic anhydride.

6. The process of claim 1, wherein the ACI is itaconic anhydride.

7. The process of claim 1, wherein the temperature range is between about 120 and about 170 ° C

8. The process of claim 1, wherein the temperature range is between about 120 and about 150 ° C

9. The process of claim 1, wherein the proportion of ACI in the styrene mixture - ACI is in the range of about 0.09 to about 18% by weight.

10. The process of claim 1, wherein the proportion of ACI in the styrene mixture - ACI is in the range of about 0.3 to about 10% by weight.

11. The process of claim 1, wherein the proportion of ACI in the styrene -ACI mixture is in the range of from about 0.9 to about 8% by weight.

12. The process of claim 1, wherein the stable free radical is a nitroxyl free radical

13. The process of claim 12, wherein the nitroxyl free radical is selected from the group consisting of:

14. The process of claim 1, wherein the free radical initiator is selected from the group consisting of: 2,2'-Azobis (2-methylpropanonitrile), 2,2'-azobis (2-methylbutanonitrile), dibenzoyl peroxide (BPO), ter-amyl peroxy-2-ethylhexanoate, ter-butyl peroxy-2-ethylhexanoate, , 5-Bis (2-ethylhexanoylperoxy) -2,5-dimethylhexane and tert-Butyl peroxydiethyl acetate.

15. A process for producing a block copolymer comprising: heating of styrene and an unsaturated cyclic anhydride in the presence of a free radical initiator and of 6-hydroxy-2,2,6,6-tetramethyl-piperidin-N-oxyl and / or 6-oxo 2,2,6,6 tetramethyl-piperidin-N-oxyl as stable free radical at temperatures between about 110 and about 200 ° C; cooling the reaction mixture; and the recovery of a block copolymer by isolation of the unreacted monomer from the same

16. The process of claim 15, wherein the number average molecular weight of the chain is controlled by manipulating the molar concentration of initiator to have a value of about A - (5x10"8 Mn) if the desired molecular weight is greater than around 615,000, and B - (3.33xl0"7 Mn) if the desired molecular weight is less than about 61500, wherein Mn is an objective value for the number average molecular weight; A is between about 0.005 and about 0.01 and B is between about 0.016 and about 0.042.

17. A process for producing a block copolymer comprising: the heating of styrene monomer and an unsaturated cyclic anhydride in a reactor at a temperature range between about 110 and about 200 ° C; adding a free radical initiator to the reactor; adding a stable free radical to the reactor; Y recovery of a block copolymer, wherein the range for the desired average molecular weight for the block copolymer is obtained by adjusting or adjusting the molar ratio of free radical initiator to monomer.

18. The process of claim 17, wherein the process is continuous.

19. The process of claim 17, further comprising providing a molar ratio of stable free radical to initiator of about 1. 3 + 0.10 * (percentage by weight of ACI with respect to total monomers).

20. The process of claim 17, wherein the number average molecular weight of the chain is controlled by adjusting the molar concentration of initiator to about At least (5x10") times Mn, if the desired molecular weight is greater than about 615,000, and B minus (3.33xl0-7) times Mn, if the desired molecular weight is less than about 61500 wherein Mn is a desired number average molecular weight; A is between about 0.005 and about 0.01; and B is between about 0.016 and about 0.042.

21. A process that includes: heating of styrene and an unsaturated cyclic anhydride monomer in the presence of a solvent, a free radical initiator and a stable free radical at a temperature range between about 110 and about 200 ° C for more than about two hours.

22. The process of claim 21, wherein the process pressure is adjusted above the vapor pressure of the reaction mixture.

23. The process of claim 21, wherein the process pressure is about equal to or above that obtained by the formula: 2. 5 Po s, if xs is less than about 0.2 or 1.4 Po xs, if xs is equal to or greater than about 0.2, where P0 is the vapor pressure of the solvent at the reaction temperature, and xs is the mole fraction of the solvent in the mixture of solvent and monomer.

24. The process of claim 21, wherein the solvent is ethyl acetate, toluene, chloroform, xylene, acetone and / or ethylbenzene.

25. The process of claim 21, wherein the solvent is present in an amount of 10-95% by weight based on the mixture of monomers and solvent.

26. The process of claim 21, wherein the solvent is present in an amount of 10-30% by weight based on the mixture of monomers and solvent.

27. The process of claim 21, wherein the solvent is present in an amount of 15-25% by weight based on the mixture of monomers and solvent.

28. The process of claim 21, wherein the solvent is present in an amount of 60-95% by weight based on the mixture of monomers and solvent.

29. The process of claim 21, wherein the solvent is present in an amount of 70-90% by weight based on the mixture of monomers and solvent.

30. The process of claim 21, wherein the solvent is present in an amount of 75-88% by weight based on the mixture of monomers and solvent.

31. A process for producing a block copolymer comprising: heating in a styrene monomer reactor and the unsaturated cyclic anhydride monomer at a temperature range between about 110 and about 200 ° C; wherein the proportion of the unsaturated cyclic anhydride monomer in the mixture of styrene-unsaturated cyclic anhydride is in the range of about 0.09 to about 18% by weight; adding a free radical initiator to the reactor at a molar ratio of monomer to initiator of about 100 to about 12,000; adding TEMPO or a TEMPO derivative to provide a stable free radical resulting in a stable free radical to initiator ratio of about 1.0 to about 3.0; cooling the reaction mixture; Y recovering a block copolymer by isolating it from unreacted monomer, where the block copolymer has a molecular weight greater than about 25,000.

32. The process of claim 31, wherein the molecular weight of the block copolymer is between about 50,000 and about 100,000.

33. The process of claim 31, wherein a solvent is added to the reaction mixture.

34. A process for producing a block copolymer comprising the steps of: the mixing of styrene and an unsaturated cyclic anhydride in the presence of a solvent; addition of a free radical initiator to the mixture, at a molar ratio of monomer to initiator of about 100 to about 12,000; addition as stable free radical of 6-hydroxy-2,2,6,6-tetramethyl-piperidin-N-oxyl and / or 6-oxo-2,2,6,6-tetramethyl-piperidin-N-oxyl; using a molar ratio of stable free radical to initiator around 1. 3 more about 0.10 times (percentage by weight of ACI with respect to total monomers), wherein the percentage of ACI with respect to the total monomers is between about 0.1 and about 16%.

35. The process of claim 34, further comprising cooling the reaction mixture and recovering a block copolymer having a molecular weight greater than about 35,000.

36. A process for producing in a controlled manner a block copolymer having a molecular weight of greater than about 30,000 using living free radical polymerization, comprising the steps of: maintaining styrene and unsaturated cyclic anhydride (UCA) in a reactor at temperatures between about 110 and about 200 ° C; addition to the reactor of a free radical initiator at a molar ratio of monomer to initiator of about 100 to about 12,000; Y addition of a stable free radical at a molar ratio of stable free radical to initiator of about: 1.3 plus 0.25 times (percentage by weight of ACI with respect to total monomers), the percentage of ACI with respect to the total monomers being between about 0.1 and about 6%;

37. The process of claim 36, wherein the stable free radical comprises 6-bidroxy-2,2,6,6-tetramethyl-piperidin-N-oxyl and / or 6-oxo-2,2,6,6-tetramethyl-piperidin-N -oxyl.

38. A process for producing a block copolymer, comprising: the reaction of styrene monomer and an unsaturated cyclic anhydride monomer in the presence of a free radical initiator and a stable nitroxyl free radical and with (or without) a solvent with some polarity temperatures between about 110 and about 200 ° C; Y recovery of a block copolymer, wherein the composition of the block copolymer comprises: a first block containing a random copolymer of styrene and an unsaturated cyclic anhydride, with some degree of alternating character given by the reactive ratios of the monomers, and a total length between about 1 and about 720 monomer units; Y a second block comprising a block of substantially pure polystyrene having a length of between 100 to 2000 monomer units, wherein Polydispersity is between about 1.2 to about 3.0.

39. The process of claim 38, wherein the ratio of nitroxyl radical to initiator is between about 1.3 and about 3.0.

40. The process of claim 38, wherein the molar ratio of nitroxyl radical to initiator is between about 1.6 and about 2.5.

41. The process of claim 38, wherein the molar ratio of nitroxyl radical to initiator is between about 1.9 and about 2.5.

42. The process of claim 38, wherein the molar ratio of total monomer to initiator is in the range of about 100 to about 12,000.

43. The process of claim 38, wherein the molar ratio of total monomer to initiator is in the range of from about 200 to about 3,000.

44. The process of claim 38, wherein the molar ratio of total monomer to initiator is in the range of about 600 to about 1,500.

45. A process for producing a block copolymer comprising: the heating of styrene and an unsaturated cyclic anhydride in the presence of a free radical initiator and a stable free radical at temperatures between about 110 and about 200 ° C; agitation of the reactants in a first reactor until obtaining a conversion of about 10 to about 50%; maintaining the reactants in the first or second reactor without agitation until a conversion of about 90% to about 100% is achieved; Y recovery of a block copolymer, wherein the block copolymer composition comprises: a first block comprising a random copolymer of styrene and an unsaturated cyclic anhydride, having a total length between about 1 and about 720 monomer units; Y a second block comprising an almost pure polystyrene block having a total length between about 100 and about 2000 monomer units.

46. The process of claim 45 wherein the block copolymer has a polydispersity between about 1.2 and about 3.0.

47. The process of claim 45 wherein the unsaturated cyclic anhydride is maleic anhydride.

48. The process of claim 45, wherein the unsaturated cyclic anhydride is itaconic anhydride.

49. A process for producing a block copolymer comprising: the reaction of styrene and an unsaturated cyclic anhydride in the presence of a free radical initiator and a stable free radical to form a reaction mixture; Y recovery of a block copolymer, wherein the composition of the block copolymer comprises: a first block containing a random copolymer of styrene and an unsaturated cyclic anhydride, having a total length between about 1 and about 720 monomer units; Y a second block of mostly polystyrene having a length of between 100 to 2000 monomeric units, further comprising: a) the heating and passage of the reaction mixture through a tubular type reactor in which the fractional conversion of monomer to the outlet is numerically about twice or greater than the mass fraction of the ACI in the feed (with respect to to the total monomer) to form a first intermediate; b) passing the first intermediate into a continuous stirred tank reactor with outlet conversion between about 10 and about 50% by weight to form a second intermediate; and c) passing the second intermediate through a tubular type reactor in which the final conversion is between about 60 and about 100% by weight.

50. The process of claim 49, wherein step (a) is omitted and the first intermediary referred to in step (b) is fresh feed.

51. The process of claim 49, wherein the cyclic unsaturated anhydride is maleic anhydride.

52. The process of claim 49, further comprising recovering and recirculating unreacted monomer.

53. A process comprising: the formation of a reaction mixture by heating styrene and an unsaturated cyclic anhydride in the presence of a solvent, a free radical initiator and a stable free radical at a temperature in the range of about 110 to about 200 ° C in the steps that include: a) heating and passing the reaction mixture through a first tubular type reactor in which the fractional conversion of leaving monomer is numerically about twice or greater than the mass fraction of ACI in the feed (with respect to the total monomer) to form a first intermediate; and b) heating the reaction mixture in a continuous stirred tank reactor with output monomer conversion between about 10 and about 50% to form a second intermediate, and c) passing the second intermediate through a second tubular type reactor. in order to achieve a monomer conversion at the outlet of between about 60 and about 100% by weight.

54. The process of claim 53, wherein step (a) is omitted and the reaction mixture referred to in step (b) is fresh feed.

55. The process of claim 53, wherein the second tubular type reactor is a vertical plug flow reactor fed from the bottom.

56. The process of claim 53, wherein the solvent is toluene, acetone, ethyl acetate, xylene and / or ethyl benzene.

57. The process of claim 53, wherein the unsaturated cyclic anhydride is maleic anhydride.

58. The process of claim 53, wherein the unsaturated cyclic anhydride is itaconic anhydride.

59. A block copolymer composition, comprising: a) a first block comprising a random copolymer of styrene and an unsaturated cyclic anhydride having a total length between about 1 and about 720 monomer units; and b) a second block comprising a block of substantially pure polystyrene having a total length between about 100 and about 2000 monomer units, wherein c) the polydispersity is between about 1.2 and about 3.0.

60. The composition of claim 59, wherein the first block has some degree of alternating character given by the reactivity ratios of the monomers.

61. The composition of claim 59, wherein the polystyrene block contains a terminal nitroxide of a single chemical type covalently linked.

62. The block copolymer of claim 59, wherein the cyclic unsaturated anhydride is maleic anhydride.

63. The block copolymer of claim 59, wherein the cyclic unsaturated anhydride is itaconic anhydride.

64. A block copolymer comprising: a block of a styrene copolymer and a cyclic unsaturated anhydride; Y a block of polystyrene having a length between about 100 and about 2000 monomer units, in which the polydispersity is between about 1.2 and about 3.0.

65. The block copolymer of claim 64, wherein the block of a copolymer of styrene and an unsaturated cyclic anhydride has a length between about 1 and about 720 monomer units.

66. A method for compatibilizing an engineered thermoplastic with a thermoplastic polymer that is compatible or miscible with polystyrene, comprising: mixing the two polymers together in relative proportions with a block copolymer of styrene and an unsaturated cyclic anhydride monomer in a reactor , wherein the block copolymer is made by a process comprising the heating of styrene and a cyclic unsaturated anhydride monomer at a temperature range between about 110 and about 200 ° C in a reactor, addition of a radical initiator free to the reactor; addition of a stable free radical; manipulating or adjusting or adjusting the molar ratio of free radical initiator to total monomer; and the recovery of a block copolymer.

67. The method of claim 66, wherein the reactor is an extruder.

68. A thermoplastic polymer composition, comprising: (a) 1-98% by weight of an engineering thermoplastic having functional groups capable of reacting with or being compatible with the styrene block copolymer and an unsaturated cyclic anhydride monomer. (b) 1-98% by weight of a thermoplastic polymer with polymeric segments compatible or miscible with the polystyrene block of the block copolymer; and (c) 1-20% by weight of the block copolymer.

69. The composition of claim 68, wherein the block copolymer is made by the process of claim 1.

70. A thermoplastic polymer composition, comprising: (a) 1-98% by weight of an engineering thermoplastic having functional groups selected from the group consisting of amine (NH2), amide (NH), carboxyl (COOH) and hydroxyl (OH ) (b) 1-20% by weight of styrene-maleic anhydride block copolymer, and (c) 1-98% by weight of thermoplastic polymer miscible or compatible with the polystyrene block of the maleic anhydride block copolymer.

71. The composition of claim 70 ,. wherein the block copolymer is made by the process of claim 1.

72. The thermoplastic polymer of claim 70, wherein the molecular weight of the styrene-maleic anhydride block copolymer is in the range of about 10,000 and about 200,000.

73. The thermoplastic polymer of claim 70, wherein the styrene-maleic anhydride block copolymer comprises between about 0.1 and about 18 weight percent maleic anhydride.

74. The composition according to claim 70, wherein the engineered thermoplastic polymer is selected from the group consisting of: aliphatic or aromatic polycarbonates, polyesters, polyamides, polyphenylene ether, and mixtures thereof.

75. The composition according to claim 70, wherein the thermoplastic polymer is high impact polystyrene.

76. The composition according to claim 70, wherein the thermoplastic polymer is a block copolymer of styrene and butadiene.

77. The composition according to claim 70, wherein the engineering thermoplastic is a polyamide and the thermoplastic polymer is polyphenylene ether, alone or in mixtures with polystyrene and / or high impact polystyrene and / or styrene-butadiene block copolymer .

78. The composition according to claim 70, wherein the engineering thermoplastic is a polyamide and the thermoplastic polymer is high impact polystyrene and / or styrene-butadiene block copolymer.

79. The composition according to claim 70, wherein the thermoplastic polymer is a styrene-methyl methacrylate copolymer.

80. The composition according to claim 70, wherein the engineering thermoplastic is an aromatic polycarbonate and the thermoplastic polymer is polystyrene and / or high impact polystyrene and / or styrene-butadiene block copolymer.

81. The composition according to claim 70, wherein the engineering thermoplastic is a polyethylene terephthalate and the thermoplastic polymer is polystyrene and / or high impact polystyrene and / or styrene-butadiene block copolymer.

82. The composition according to claim 70, wherein the engineering thermoplastic is a polybutylene terephthalate and the thermoplastic polymer is polystyrene and / or high impact polystyrene and / or styrene-butadiene block copolymer.

83. A method for making a polymer composition, comprising: blending a thermoplastic polymer compatible or miscible with polystyrene together with a filler in relative proportions with a block copolymer of styrene and an unsaturated cyclic anhydride monomer in a reactor, wherein the copolymer block is made by a process comprising the heating of styrene and a cyclic unsaturated anhydride monomer at a temperature range between about 110 and about 200 ° C in a reactor, addition of a free radical initiator to the reactor; addition of a stable free radical; manipulating or adjusting or adjusting the molar ratio of free radical initiator to total monomer; and recovery of a block copolymer.

84. The method of claim 83, wherein the reactor is an extruder.

85. A thermoplastic polymer composition, comprising: (a) 40-98% by weight of a thermoplastic polymer with polymer segments compatible or miscible with the polystyrene block of a styrene-maleic anhydride block copolymer; (b) 1-40% by weight of a filler containing functional groups that exhibit strong chemical affinity or that can react with the dicarboxylic group of the styrene-maleic anhydride block copolymer; and (c) 1-20% by weight of styrene-unsaturated cyclic anhydride block copolymer.

86. The composition of claim 85, wherein the unsaturated styrene-cyclic anhydride block copolymer is made by the process of claim 1.

87. The composition according to claim 85, wherein the thermoplastic polymer is polystyrene and / or high impact polystyrene and / or a styrene-butadiene copolymer.

88. The composition according to claim 87, wherein the filler is glass fiber.