JPS6116762B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to chemically bonded, phase separated, self-cured hydrophilic thermoplastic graft copolymers and methods of making the same. This hydrophilic copolymer has excellent wet strength and has wide utility in a variety of applications, particularly in the field of biomedics such as contact lenses and prosthetics. A considerable amount of research and development has been undertaken to obtain hydrophilic polymers with sufficient wet strength to be considered virtually water-insoluble. For example, certain types of hydrophilic polymers with improved wet strength are
U.S. patent of Otto Wichterle et al.
No. 2976576 and No. 3220960 and M.
MF Refojo et al., Journal of Applied Polymer Science, No. 9, pp. 2425-2435 (1965). These polymers are known for their ester moieties (ester
moiety) polymerizes a water-soluble monoester of acrylic acid or methacrylic acid containing at least one hydrophilic group, such as a hydroxyl group, and simultaneously cross-links the monomer with a polyunsaturated cross-linking agent such as ethylene glycol dimethacrylate. Manufactured by The amount of cross-linking agent is usually less than about 1 mole percent of the monoester. This polymerization is generally carried out in the presence of a redox initiator. Hydrophilic polymers with improved wet strength derived from polymers obtained by copolymerizing water-soluble vinyl monomers containing at least one nitrogen atom with small amounts of difunctional monomers have also been disclosed. These polymers have been suggested to be useful in a variety of biomedical applications due to their affinity for body tissues and/or mucosa. Some of these polymers were developed by Maurice Seidaman.
Seiderman) U.S. Pat. No. 3,639,524 and No.
It is disclosed in specification No. 3767731. One of the factors necessary for the production of these prior art hydrophilic polymers with improved wet strength is the use of small amounts of polyunsaturated crosslinkers. The amount of cross-linking agent used is generally so small that it can be varied only slightly. Therefore, the final properties of the hydrophilic polymer cannot be effectively adjusted by varying the amount of cross-linking agent. Various attempts to circumvent this problem have been made by Seidaman, US Pat.
Stamberger, U.S. Pat. No. 3,758,448. Pending U.S. Patent Application No. 282099 dated August 21, 1972
There is a disclosure in the patent application, the description of which is hereby incorporated by reference, of the outstanding pioneering discovery of the production of chemically bonded, phase separated thermoplastic graft copolymers. These copolymers are essentially physically cross-linked (as opposed to chemically cross-linked) polymers and have been referred to as "naturally cured" or "naturally reinforced" thermoplastic graft copolymers. This phenomenon is observed during the controlled dispersion of large molecular weight side chains of a single phase (domain) into a backbone polymer phase (matrix). Since all large molecular weight monomer side chain domains are integral parts (i.e. inserted between large segments of the main chain polymer), the resulting graft copolymer is Segment Tg or Tm
If there is a large difference in , it has the properties of a cross-linked polymer. This fact is true until the temperature required to break the thermodynamic cross-links of the dispersed phase is reached. In order to impart the desired cross-linking or "self-curing" effect to the domains of the dispersed phase of the graft copolymer, the macromolecular monomers that make up the domains of the dispersed phase must have substantially the same molecular weight; It is important that the molecular weight monomers should have a Mw/Mn ratio of substantially no greater than about 1.1. Large molecular weight monomers with even broader molecular weight distributions, i.e. ratios of about 1.5 or 2 or higher, usually have very low molecular weight polymeric species that are "copolymerizable" with very high molecular weight backbone polymers. “Gives an effect,
This backbone polymer will form a secondary dispersed phase or domains of different size than the primary dispersed phase. The end result is an opaque polymer of inferior quality with respect to the desired physical properties of the backbone polymer. The present invention relates to a process for producing chemically bonded, phase separated and self-curing hydrophilic thermoplastic graft copolymers that are water-insoluble and water-swellable. This new copolymer comprises at least one hydrophilic (water-soluble) ethylenically unsaturated monomer or mixture thereof (or hydrophilized compound) and a copolymerizable hydrophobic monomer having at least one copolymerizable end group. This copolymerizable hydrophobic large molecular weight monomer can be copolymerized with the above hydrophilic monomer based on the relative reactivity ratio of each copolymerizable moiety, and its characteristics are Mw /Mn ratio substantially not exceeding about 1.1, and a molecular weight of at least about 2,000. The novel copolymer according to the invention is water-dispersible and water-swellable, with suspension stabilizers and flocculants (flocculants).
It finds use in a variety of applications such as hydrogels (i.e. biomedical hydrogels such as contact lenses, prosthetics, etc.), industrial thickeners, ion exchange resins and drilling muds. This new copolymer provides hygroscopic, water permeable (useful for dialysis tube manufacturing) and anti-static properties in a variety of products.
properties). More specifically, the present invention relates to a chemically bonded, phase separated and naturally cured hydrophilic thermoplastic graft copolymer, which copolymer is comprised of the following various copolymers: (1) at least one copolymerizable, usually hydrophobic, large molecular weight monomer with a substantially uniform molecular weight distribution;
and (2) at least one species forming the polymer backbone of the copolymer, such that the copolymerizable, typically hydrophobic, large molecular weight monomers described above form the linear polymer side chains of the graft copolymer. Hydrophilic (water soluble)
copolymerizable comonomer or hydrophilized compound,
However, a. The polymer main chain of the graft copolymer consists of polymer units of the above copolymerizable comonomer,
the copolymerizable comonomer is at least one ethylenically unsaturated monomer consisting of a hydrophilic or water-soluble compound and mixtures thereof, and b the linear polymer side chains of the graft copolymer are predominantly polymerized hydrophobic from a linear polymer or copolymer consisting of molecular weight monomers having a substantially uniform molecular weight distribution such that the hydrophobic large molecular weight monomers have a molecular weight of at least about 2000 and the Mw/Mn ratio is substantially less than about 1.1; Furthermore, the large molecular weight monomer is characterized by having one or less copolymerizable moieties per linear polymer chain or copolymer chain, and the copolymerization is a copolymerization of a hydrophobic large molecular weight monomer and a copolymerizable hydrophilic comonomer. (c) the linear polymer side chains of the graft copolymer copolymerized into the copolymer backbone form at least 20 consecutive monomeric repeat units of the hydrophilic polymer backbone; The side chain distribution and copolymerization along the main chain are controlled by the reactivity ratio of the copolymerizable end groups of the hydrophobic large molecular weight monomer and the copolymerizable hydrophilic comonomer. It is something that The graft copolymer according to the invention assumes a "T" configuration when its only side chain is copolymerized into the hydrophilic copolymer backbone. However, when one or more side chains are copolymerized with a hydrophilic main chain polymer, the graft copolymer has a comb-shaped structure as shown in the following example. (wherein "a" represents a generally hydrophobic polymer or copolymer of substantially linear, uniform molecular weight with a molecular weight that exhibits the physical properties of at least one substantially linear hydrophobic polymer, and "b" ” represents the copolymerized terminal group after completing the reaction that is chemically bonded to the side chain “a” and also represents the copolymerized end group that has been completely copolymerized into the main chain polymer, and “c” represents its hydrophilicity. It is characterized by having a hydrophilic main chain polymer (representing a hydrophilic main chain polymer with continuous segments having a molecular weight sufficient to exhibit the physical properties of the polymer). The backbone of the graft copolymer according to the invention preferably contains at least about 20, more preferably at least about 30 consecutive monomeric repeat units in each segment. However, it has been found that particularly favorable physical properties are provided when there are at least about 100 consecutive monomeric repeat units in each segment. This condition was found to give a graft copolymer with the properties of a hydrophilic polymer in the main chain. In other words, the presence of segments containing at least about 20 consecutive monomeric repeat units provides the graft copolymer with physical properties ascribed to the polymer backbone, such as water affinity and water swellability. The backbone polymer segments of the chemically bonded, phase separated, naturally cured hydrophilic thermoplastic graft copolymers according to the invention are derived from copolymerizable comonomers, preferably low molecular weight comonomers. These comonomers include polycarboxylic acids, their anhydrides and amides, polyisocyanates, organic epoxides (including thioepoxides), urea-formaldehyde,
Included are siloxanes and ethylenically unsaturated monomers. A particularly preferred group of copolymerizable polymers includes ethylenically unsaturated monomers, especially monomeric vinylidene type compounds, i.e. at least one vinylidene monomer.
Monomers containing CH ₂ =C'H groups are included. general formula
Vinyl-type compounds of the formula CH ₂ =C'H, where hydrogen is attached to one of the free valences of the vinylidene group, are intended to fall within the general scope of vinylidene compounds described above. Copolymerizable comonomers useful in the practice of this invention are not limited to the exemplified compounds set forth above. A slight constraint on the particular comonomers used is their ability to copolymerize with the end groups of the side chain prepolymer under free radical, ionic, condensation or coordination polymerization (Ziegra or Ziegler-Nata catalysts) reactions. Another limitation on low molecular weight comonomers is that they have a functional moiety that becomes hydrophilic or that can be rendered hydrophilic by subsequent reactions. Particularly preferred examples of this latter group of compounds consist of vinyl esters such as vinyl acetate.
This vinyl ester is copolymerized with a copolymerizable hydrophobic large molecular weight monomer having a copolymerizable double bond at the position of its molecular chain, and following the copolymerization, the resulting graft copolymer is saponified and the polymer main chain Make it hydrophilic. In other words, the polymer backbone consists of polyvinyl alcohol. As is clear from the description of copolymerizable large molecular weight monomers below, the selection of copolymerizable end groups includes all commercially available copolymerizable comonomers. Thus, the selection of the respective copolymerizable end groups for the large molecular weight monomer and the copolymerizable comonomer can be selected based on the ratio of relative reactivities under the respective copolymerization reaction conditions suitable for copolymerization. Thus, a simple examination of the reactivity of various comonomer pairs in the literature can provide the appropriate end groups for large molecular weight monomers and copolymerizable comonomers. Preferably, the r of each copolymerizable moiety is
Set this value as close to 1 as possible. For example, large molecular weight monomers with acrylate or methacrylate ends copolymerize with acrylates and methacrylates under free radical conditions in a manner governed by the ratio of the respective reactivities of the comonomers. As explained below, the advantageous properties of the graft copolymers of the present invention are due to the combination of large segments of the hydrophilic backbone of the continuous copolymer;
Due to fully copolymerized linear hydrophobic polymer side chains with controlled molecular weight and narrow molecular weight distribution. The term "linear" above is used in its conventional sense and refers to a polymer backbone without cross-linking. The term "hydrophilic" above is used in its conventional sense to refer to a polymeric or monomeric substance or system that absorbs or adsorbs water. The term "hydrophobic" above is used in its conventional sense to describe polymeric materials that repel water. Side-chain polymers of substantially uniform molecular weight consist of substantially linear hydrophobic polymers and copolymers formed by anionic polymerization of any anionically polymerizable monomer or mixture thereof to produce a hydrophobic polymer. This side chain polymer will clearly be different from the hydrophilic main chain polymer. Preferably, at least one segment of the side chain polymers of the graft copolymers according to the invention has a molecular weight sufficient to exhibit the beneficial properties of each polymer. In other words, side chain physical properties such as glass transition temperature (Tg) should be expressed. The molecular weight of the polymer side chains is generally at least about 2000;
Preferably the polymer has a molecular weight of about 5,000 to about 50,000.
is within the range of Particularly favorable results have been observed when the molecular weight of the polymer side chains ranges from about 10,000 to about 35,000, more preferably from about 12,000 to about 25,000. In view of the unusually improved physical properties of the thermoplastic graft copolymers of the present invention, polymer side chains bonded by a single functional group of substantially uniform molecular weight have small dispersions precipitated in the matrix of the polymer backbone. It is thought to be what is known as a "domain" that becomes a droplet. The domains or droplets are microscopic in size and generally below the wavelength of light of the backbone polymer. The finished graft copolymer is clear or transparent. Hydrophobic polymer side chains that provide a natural hardening or reinforcing effect to the hydrophilic polymer backbone improve the wet strength of the finished polymer. Copolymerizable Hydrophobic Large Molecular Weight Monomer The hydrophobic polymer side chains of the chemically bonded, phase separated, naturally cured hydrophilic graft copolymer described above are preferably produced by anionic polymerization of a polymerizable monomer or combination of monomers. In many cases this monomer is a compound with olefin groups, such as a vinyl-containing compound. The olefin group-containing monomer can also be used in conjunction with epoxy- or thioepoxy-containing compounds. The first step in producing copolymerizable hydrophobic large molecular weight monomers is to create a living polymer. The living polymer is conveniently prepared by contacting the monomer with an alkali metal hydrocarbon or alkoxide salt in the presence of an inert organic diluent that does not precipitate or inhibit the polymerization reaction. These monomers that are susceptible to anionic polymerization are well known and the present invention encompasses the use of all anionically polymerizable monomers that yield substantially hydrophobic polymers of molecular weight of at least about 2000. Non-limiting exemplary reactants include vinyl aromatic compounds such as styrene, alpha-methylstyrene, vinyltoluene and its isomers; acenaphthalene;
acrylonitrile and methacrylonitrile; organic isocyanates including lower alkyl, phenyl, lower alkyl phenyl and halophenyl isocyanates; organic diisocyanates including lower alkylene, phenylene and tolylene diisocyanates; lower alkyl and allyl acrylates and methacrylates (methyl, t- (including butyl acrylate and methacrylate); lower olefins such as ethylene, propylene, butylene, isobutylene, pentene, hexene, etc.; vinyl acetate, vinyl propionate, vinyl octoate, vinyl oleate, vinyl stearate, vinyl benzoate, vinyl Included are vinyl esters of aliphatic carboxylic acids such as lower alkyl ethers; conjugated dienes including isoprene and butadiene. The term "lower" is used to denote organic groups containing eight or fewer carbon atoms. Preferred olefin group-containing monomers useful in preparing this hydrophobic large molecular weight monomer are conjugated dienes containing from 4 to 12 carbon atoms per molecule and vinyl substituted aromatic hydrocarbons containing up to about 12 carbon atoms. Particularly preferred monomers include styrene, alpha-methylstyrene, butadiene and isoprene. Many other monomers suitable for the production of side chains by anionic polymerization are Macromolecular Reviews, Vol. 2, No. 74-83.
Monomers Polymerized by Anionic Initiators, published by Interscience Publishers, Inc. (1967).
by Anionic Initiators)”.
The description thereof is cited herein. These initiators for anionic polymerization are all alkali metal hydrocarbon and alkoxide salts that yield monofunctional living polymers (ie, only one end of the polymer contains a reactive anion). Suitable catalysts have the general formula RMe, where Me is an alkali metal such as sodium, lithium and potassium, and R is a hydrocarbon radical, such as up to about 20 or more, preferably about 8
lithium, sodium or potassium hydrocarbons with alkyl, aryl, alkaryl or aralkyl radicals containing up to 1 carbon atoms. Exemplary alkali metal hydrocarbons include ethyl sodium, n-propyl sodium, n-butyl potassium, n-octyl potassium, phenyl sodium, ethyl lithium, sec-butyl lithium, t
-butyllithium and 2-ethylhexyllithium. sec-butyllithium is a preferred initiator because of its rapid initiation properties, which is important for producing narrow molecular weight distribution polymers. When the polymerizable monomer has nitrile or carbonyl functionality, the use of alkali metal salts of tertiary alcohols, such as potassium t-butyl alkoxylate, is preferred. Both alkali metal hydrocarbons and alkoxylates are commercially available or can be prepared and used by known methods such as reaction of halohydrocarbons, halobenzenes or alcohols with the appropriate alkali metal. Generally, an inert solvent is used to facilitate heat transfer and proper mixing of the initiator and monomer. Hydrocarbons and ethers are preferred solvents. Solvents useful in anionic polymerization include benzene,
Included are aromatic hydrocarbons such as toluene, xylene, ethylbenzene, t-butylbenzene, and the like. Saturated aliphatic and cycloaliphatic hydrocarbons such as n-hexane, n-heptane, n-octane, cyclohexane and the like are also suitable. Additionally, aliphatic and cyclic ether solvents may be used, such as, for example, dimethyl ether, diethyl ether, dibutyl ether, tetrahydrofuran, dioxane, anisole, tetrahydropyran, diglyme, glyme. The rate of polymerization is faster in ether solvents than in hydrocarbon solvents, and the addition of small amounts of ether to hydrocarbon solvents increases the rate of polymerization. The amount of initiator used is an important factor in anionic polymerization because it determines the molecular weight of the living polymer.
When a small amount of initiator is used relative to the amount of monomer, the molecular weight of the living polymer is higher than when a large amount of initiator is used. It is generally desirable to add the initiator dropwise to the monomer (if that is the selected order of addition) until the characteristic color of the organic anion persists, adding the calculated amount of initiator for the desired molecular weight. Pre-dropwise addition helps to destroy contaminants and therefore allows better control of the polymerization. To produce polymers with narrow molecular weight distributions, it is generally advantageous to introduce all reactants into the system simultaneously.
In this method, polymer growth by continuous addition of monomers occurs at the same rate at the active end groups without chain transfer or termination reactions. Once this is done, the molecular weight of the polymer is controlled by the monomer/initiator ratio as seen from the following equation: Living polymer molecular weight = moles of monomer/moles of initiator x molecular weight of monomer. A high concentration of initiator will produce a low molecular weight polymer, whereas a low concentration of initiator will give a high molecular weight polymer. The concentration of monomer added to the reaction vessel can vary widely, but is limited by the ability of the reactor to dissipate the heat of polymerization and to adequately mix the resulting viscous solution of living polymer. High concentrations of monomers of 50% or more by weight based on the weight of the reaction mixture may be used. However, preferred monomer concentrations are from about 5% to about 25% to provide proper incorporation. As is clear from the above formula and the above limitations on monomer concentration, the initiator concentration is critical but can be varied depending on the desired molecular weight of the living polymer and the relative concentrations of the monomers. Generally, initiator concentrations can range from about 0.001 to about 0.1 mole of active alkali metal per mole of monomer or more.
Preferably the initiator concentration is from about 0.01 per mole of monomer.
There will be approximately 0.004 moles of active alkali metal. Polymerization temperature depends on the monomer. Generally, this reaction may be conducted at a temperature of about -100 to about 100°C. With aliphatic and hydrocarbon solvents, the preferred temperature range is from about -10°C to about 100°C. Using ether as the solvent, the preferred temperature range is from about -100°C to about 100°C. Polymerization of styrene is generally carried out slightly above room temperature. Polymerization of alpha methylstyrene is preferably carried out at low temperatures, such as -80°C. Living polymers are produced by adding a solution of an alkali metal hydrocarbon initiator in an inert organic solvent to a mixture of monomers and diluent at a desired polymerization temperature, and leaving the mixture with or without stirring until polymerization is complete. It can be done. In another method, monomer is added to a diluent solution of catalyst at the desired polymerization temperature at the same rate as the polymerization rate. In either method, the monomer is quantitatively converted to living polymer as long as the system does not contain impurities that would inactivate the anionic reactant. However, as already indicated, it is important to add all reaction components together quickly to ensure polymer formation with uniform molecular weight distribution. Anionic polymerizations must be carried out under carefully controlled conditions to exclude substances that would destroy the catalytic effect of the catalyst or initiator. For example, water
Impurities such as oxygen, carbon monoxide, and carbon dioxide. That is, the polymerization is generally carried out using anhydrous reactants in a drying apparatus under an atmosphere of an inert gas such as nitrogen, helium, argon, methane, and the like. The living polymers described above are susceptible to subsequent reactions, including subsequent polymerization. That is, when an additional monomer, such as styrene, is added to this living polymer, the polymerization is reformed and the chains grow until no more styrene monomer is present. Alternatively, upon addition of other different anionically polymerizable monomers (e.g., butadiene or ethylene oxide), the living polymer described above will initiate polymerization of butadiene or ethylene oxide, and the resulting final living polymer will contain polystyrene segments and polybutadiene or polyoxyethylene segments. Consisting of diblock hydrophobic copolymer is the first
A living polymer of a vinyl aromatic compound, such as living polystyrene or living poly(alpha-methylstyrene), is contacted with another anionically polymerizable monomer, such as a conjugated diene such as butadiene or isoprene. sell. Thus, according to the method of carrying out the present invention, the reaction is completed and a living block polymer is obtained. Using this method, a living block polymer having the following general formula AB is obtained, where A is a vinyl aromatic compound polymer block and B is a conjugated diene polymer block.
A copolymerizable large molecular weight monomer having a diblock structure is disclosed in pending U.S. Patent Application No. 347,116,
The description thereof is cited herein. As mentioned above, the living polymer used in the present invention is characterized by a relatively uniform molecular weight. That is, the molecular weight distribution of the living polymer mixture is extremely narrow. This is in sharp contrast to typical polymers, which have a very broad molecular weight distribution. The difference in molecular weight distribution is very evident in gel permeation chromatogram analysis of commercial polystyrene produced by free radical polymerization (Dow 666u) and polystyrene produced by the anionic polymerization method used in accordance with the present invention. . That is, the characteristics of living polymers made in accordance with the teachings of the present invention do not substantially exceed about 1.1
It also has a Mw/Mn ratio. Here, M is the weight average molecular weight of the living polymer, and Mn is its number average molecular weight, which can be determined by a conventional analytical method such as gel permeation chromatography (GPC). This living polymer is terminated by reaction with a halogen-containing compound that also contains polymerizable moieties such as olefin groups or epoxy or thioepoxy groups. Suitable halogen-containing terminators include vinyl haloalkyl ethers in which the alkyl group contains up to 6 carbon atoms such as methyl, ethyl, propyl, butyl, isobutyl, sec-butyl, amyl or hexyl; vinyl esters of haloalkanoic acids containing up to 6 carbon atoms, such as butyric acid, pentanoic acid, or hexanoic acid; 6 carbon atoms, such as vinyl halide, allyl halide, methallyl halide, 6-halo-1-hexene, etc. Olefinic halides with carbon atoms; halides of dienes such as 2-halomethyl-1,3-butadiene, epihalohydrin, acrylyl and methacrylyl halides, haloalkylmaleic anhydrides, haloalkylmaleic esters; vinylhaloalkylsilanes; vinyl Included are haloaryls; vinylhaloakarlyls such as vinylbenzyl chloride (VBC); haloalkylnorbornenes such as bromomethylnorbornene, bromonorbornane; and epoxy compounds such as ethylene or propylene oxide. The halogen group is chloro, fluoro, bromo, or iodo, preferably chloro. Anhydrides of compounds having olefin groups or epoxy or thioepoxy groups, such as maleic, acrylic or methacrylic anhydride, may also be used. Termination of the living polymer is accomplished by simply adding the terminator to the living polymer solution at the temperature at which the living polymer is produced. The reaction is instantaneous and the yield is consistent with the theoretical value. Although the reaction proceeds on a mole-mole basis, a slight molar excess of terminator relative to the amount of anionic initiator may be used. This termination reaction can be carried out in any suitable inert solvent. It is generally recommended to use the same solvent system used for living polymer production. In a preferred embodiment of the invention, the termination reaction is carried out in a hydrocarbon solvent rather than a polar ether type solvent such as tetrahydrofuran. It has been found that hydrocarbon solvents such as aromatic hydrocarbons, saturated aliphatic and cycloaliphatic hydrocarbons produce some differences in reaction conditions and products obtained. For example, termination reactions can be carried out at higher temperatures in hydrocarbon solvents as opposed to ethereal solvents. In some cases, due to the nature of the living polymer and the monomers from which it is made, or due to the nature of the terminating agent, certain deleterious side reactions may occur resulting in impure products. For example, the carbanions of some living polymers tend to react with the functional groups of the terminator or with any active hydrogens. Thus, for example, crylyl chloride or methacrylyl chloride, due to the presence of a chlorine atom in its structure, acts as a terminating agent while providing a carbonyl group in the terminated polymer chain, which is a second highly reactive carbonyl group. It can become the center of attack from living polymers with The resulting polymer has twice the expected molecular weight or contains some chlorine, some of the living polymer being removed by reaction with a second living polymer or an activated hydrocarbon of one of the acrylyl chloride or methacrylyl chloride. This indicates that the engine has started and stopped. It has been found that one means of overcoming the above problems is to make the reactive carbanion less susceptible to reaction with the functional group of the terminator or any active hydrogen. A preferred method of making the living polymer less susceptible to adverse reactions is to "cap" the highly reactive living polymer with a less reactive reactant. Examples of some suitable "capping agents" include lower alkylene oxides, ie, those having eight or fewer carbon atoms, such as ethylene and propylene oxide; diphenylethylene, and the like. This "cap and cap" reaction gives a product that is still a living polymer, but subsequent reaction with a terminator containing a functional group or active hydrogen gives a purer product. Diphenylethylene has been found to be an excellent "cap agent" when using stoppers such as vinyl chloroalkanoate. Particularly preferred "capsules" are alkylene oxides such as ethylene oxide. This breaks its oxirane ring and reacts with the living polymer. The following is a typical example of a "cap reaction", which shows the reaction of ethylene oxide as a cap agent with a "living polymer prepared by the polymerization of styrene and the initiator sec-butyllithium": The cap reaction, like the termination reaction, is carried out very simply by adding the cap reactant to the living polymer at the polymerization temperature. This reaction occurs immediately. As in the termination reaction, a slight molar excess of cap reactant compared to the amount of initiator may be used. This reaction occurs on a mole-mole basis. It will be appreciated that reacting a large molar excess of alkylene oxide with a living polymer will result in a living polymer with two polymer blocks. Typical examples with polystyrene segments and polyoxyalkylene segments are shown below: (However, X is a positive integer). Any of the ethylene oxide "cap" polymers described above may be conveniently terminated with a compound having a moiety capable of reacting with the anion of the cap polymer and a polymerizable end group. Typical examples of this compound include: acrylyl chloride, methacrylyl chloride, vinyl-2-chloroethyl ether, vinyl chloroacetate, chloromethylmaleic anhydride and its esters, maleic anhydride (water proton formation followed by half esters of maleic acid), allyl chloride and methachloride and vinylbenzyl chloride. The reaction of the above “cap” living polymer with acrylyl or methacrylyl chloride can be represented by the following reaction: (However, in the formula, n is a positive integer of at least about 50,
is 0 or a positive integer, and R ⁴ is hydrogen or methyl. ) When epihalohydrin is used as a terminator, the resulting polymer contains terminal epoxy groups. This terminal epoxy can be used as the polymerizable group itself, as in the preparation of polypropylene oxide backbone graft copolymers, or it can be converted to a variety of other useful polymerizable end groups using any one of several known reactions. It can be transformed. In one aspect of the invention, a terminated living polymer containing epoxy or thioepoxy end groups is reacted with a polymerizable carboxylic acid halide, such as acrylic, methacrylic or maleic acid halide, as a polymerizable end moiety in a substantially uniform molecular weight polymer. Beta-hydroxyalkyl acrylate, methacrylate or maleate esters can be made. These same polymerizable esters are prepared from this terminated epoxy polymer by first converting the epoxy groups to the corresponding glycols by heating the polymer with an aqueous sodium hydroxide solution, and then converting the glycol end groups to the appropriate polymerizable carboxylic acid. Alternatively, it can be produced by esterification with an acid halide in a conventional manner. Glycols obtained by aqueous hydrolysis of epoxy groups in the presence of a base are referred to as "high molecular weight dicarboxylic acids that can be produced, for example, by polymerizing glycols or diamines with molar excess of phthalic anhydride, maleic anhydride, succinic anhydride, etc." It can be reacted and converted into a copolymer. These reactions can be modified to yield polystyrene blocks and polyamide blocks (nylon). This glycol terminated polymer can also be reacted with diisocyanates to form polyurethanes. The diisocyanate can be, for example, the reaction product of polyethylene glycol with an average molecular weight of 400 and a molar excess of phenylene diisocyanate. In another embodiment of the invention, an organic epoxide is copolymerized with a terminal polymer containing epoxy or thioepoxy terminal groups. The resulting graft copolymer is characterized by a backbone having at least about 20, preferably at least about 30, consecutive segments of organic epoxide. Suitable organic epoxides include ethylene oxide, cyclohexene epoxide and styrene oxide, ie, those having 8 or fewer carbon atoms. This backbone polymer can be made hydrophilic by simple hydrolysis. If the large molecular weight monomer is to be separated from the solvent in which it was produced and further purified, any known technique used by those skilled in the art for recovering polymeric materials may be used. These techniques include (1)
Solvent-nonsolvent precipitation; (2) evaporation of the solvent in an aqueous medium;
(3) evaporation of the solvent by methods such as vacuum roll drying, spray drying, and freeze drying; (4) steam jet coagulation. Separation and recovery of large molecular weight monomers is not a limiting aspect of the invention. There is actually no need to recover large molecular weight monomers. In other words, once the large molecular weight monomer is produced, it can be graft copolymerized by introducing it into the system in which the large molecular weight monomer was made together with the appropriate monomer and polymerization catalyst. This is the case where the solvent and raw materials in the polymer production reactor do not poison the catalyst or adversely affect the graft copolymerization process). Therefore, judicious selection of reactor system solvents and purification during the production of large molecular weight monomers can ultimately result in significant savings in the production of the graft copolymers of the present invention. As mentioned above, the large molecular weight monomers that are completely polymerized into the backbone polymer and ultimately become the side chains of the graft copolymer must have a narrow molecular weight distribution.
Methods for determining the molecular weight distribution of polymers such as this large molecular weight monomer are known in the art. These known methods can be used to ascertain the weight average molecular weight () and number average molecular weight () and determine the molecular weight distribution (/) of the large molecular weight monomer.
The large molecular weight monomer must have a near Poisson distribution of molecular weights or be substantially monodisperse in order to have the highest degree of functionality. That is, the /ratio is not substantially greater than about 1.1. Preferably, the novel large molecular weight monomer/ratio is about 1.1 or less. The large molecular weight monomers according to the invention have the narrow molecular weight and purity described above due to the above-described production method. It is therefore important that the order of the large molecular weight monomer manufacturing steps is followed to best impart beneficial properties to the graft copolymer. As is clear from the above description, the hydrophobic copolymerizable large molecular weight monomer considered in the present invention is generally represented by the following structural formula: However, in the formula, 1 is the residue of a monofunctional anionic initiator, P ₁ is at least one anionically polymerized monomer, and P ₂ is at least one anionically polymerized monomer, which may be the same as P ₁ . may be different; R is hydrogen or lower alkyl, R' is hydrogen or where X is hydrogen, lower alkyl, or a monovalent metal; n is a positive integer of at least about 20; m is 0 or a positive integer; 2000, preferably
The value is from 5000 to approximately 50000, and o, q,
r and s are 0 or 1, p is 0 or 1
A positive integer within the range of ~8, and o and p are 1
If so, q is 0, r is 0 or 1, s is 0 or 1, t is 1, and if o is 0, p is a positive integer and q, r, s, and t are 0 or 1. If o, q, r, s and t are 0, then p is a positive integer and s can be 0 or 1;
u and v are 0 or 1, if u is 1 then v is 0,
If v is 1, u is 0. This large molecular weight monomer is meant to have a substantially uniform molecular weight distribution such that the ratio is substantially less than about 1.1. The weight average molecular weight of the monomer is
is the number average molecular weight of the monomer. As mentioned above, P ₁ and P ₂ are preferably polymers of vinyl aromatics and conjugated dienes. Copolymerizable hydrophilic (water-soluble) compounds Copolymerizable comonomers suitable for obtaining the hydrophilic polymer backbone of the graft copolymers according to the invention must not be water-soluble or capable of being made water-soluble after copolymerization. Must not be. These compounds must be copolymerized into water-soluble materials or those that can be made water-soluble. The term "water soluble" is used herein to mean at least about 10% by weight, preferably at least about 10% by weight.
30% by weight is used to encompass compositions that are homogeneously miscible in water at room temperature. Suitable copolymerizable monomers contemplated for use in preparing the hydrophilic polymer chains of the graft copolymers according to the invention include: Acrylic and methacrylic acids Water-soluble monoesters of acrylic and methacrylic acids. The ester moiety contains at least one hydrophilic group such as a hydroxyl group. That is, typical hydroxy lower alkyl acrylates or methacrylates are as follows: 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, diethylene glycol monomethacrylate, diethylene glycol monoacrylate, dipropylene glycol monomethacrylate, and dipropylene glycol monoacrylate. Water-soluble vinyl monomers with at least one nitrogen atom in the molecule, examples of which are: acrylamide, methacrylamide, methylol acrylamide, methylol methacrylamide, diacetone acrylamide, N-methyl acrylamide, N-ethyl acrylamide, N-hydroxyethylacrylamide, N,N disubstituted acrylamide (e.g. N,N
-dimethylacrylamide; N,N-diethylacrylamide; N-ethyl-methylacrylamide; N,N-dimethylol-acrylamide and N,N-dihydroxyethylacrylamide), heterocyclic nitrogen-containing compounds (e.g. N-pyrrolidone, N-vinylpiperidone) , N-acryloylpyrrolidone, N-acryloylpiperidine and N
-acryloylmorpholene), monomers with cationic functionality may also be used (e.g. vinylpylidene quaternary ammonium salts, and dimethylaminoethyl methacrylate quaternary ammonium salts and the trade name Sipomer Q- 1). A particularly preferred group of compositions includes those that can be rendered hydrophilic in a post-polymerization reaction. For example, carboxylic acid vinyl esters such as vinyl formate, vinyl acetate, vinyl monochloroacetate, and vinyl butyrate are copolymerized with the copolymerizable large molecular weight monomers described above, and subsequent to the copolymerization reaction, the carboxylic acid vinyl ester monomeric The polymer main chain containing repeating units can be hydrolyzed to make it hydrophilic as polyvinyl alcohol. In other words, this polymer backbone consists of polyvinyl alcohol. The above-mentioned hydrophilic monomers can be made hydrophilic by a subsequent reaction and can be used alone or in combination, or as an interpolymer with other comonomers. The copolymerizable monomer used in admixture or combination with the hydrophilic monomer or those capable of being hydrophilized can be any ethylenically unsaturated monomer, including the hydrophilic monomer or the hydrophobic monomer and the hydrophobic copolymerizable large molecular weight monomer. This includes combinations with "Monoma". Suitable hydrophobic copolymerizable monomers that can be interpolymerized with the above-mentioned "hydrophobic copolymerizable large molecular weight monomers" and the above-mentioned "hydrophilic comonomers" include alkyl acrylates and methacrylates such as methyl acrylate or methacrylate. , ethyl acrylate or methacrylate, propyl acrylate or methacrylate, butyl acrylate or methacrylate, with butyl acrylate being preferred. Other suitable hydrophobic comonomers include vinyl chloride, vinylidene chloride, acrylonitrile, methacrylonitrile, vinylidene cyanide,
Included are vinyl acetate, vinyl propionate and vinyl aromatics such as styrene and alpha-methylstyrene, and maleic anhydride. Suitable comonomers useful for preparing the hydrophilic polymer backbone of the graft copolymers according to the invention include monoesters of acrylic and/or methacrylic acid with polyhydric alcohols (e.g., 2-hydroxyethyl acrylate and methacrylate); ，
N-disubstituted acrylamides (e.g. N,N-dimethylacrylamide, especially when butyl acrylate is used together as another comonomer); and monocarboxylic acid vinyl esters such as vinyl acetate (which can be saponified with alkali after the copolymerization reaction); ) is included. The amount of the above-mentioned "copolymerizable hydrophobic large molecular weight monomer" to be copolymerized with the copolymerizable comonomer forming the hydrophilic copolymer main chain is about 1 to about Must be within 95% by weight. Stated differently, a chemically bonded, phase-separated thermoplastic graft copolymer with a hydrophilic polymer backbone is composed of (1) copolymerizable hydrophobic large molecular weight monomers with a narrow molecular weight distribution of about 1 to about 95% by weight; , (2) about 99 to about 5% by weight of a copolymerizable comonomer forming a hydrophilic polymer backbone. Preferably, the graft copolymer contains up to about 60% by weight, more preferably from about 2 to about 40% by weight, of the hydrophobic large molecular weight monomers described above to achieve the final mechanical strength of the polymer. The copolymerizable hydrophobic large molecular weight monomer and the copolymerizable comonomer forming the hydrophilic polymer backbone of the graft copolymer (and in some cases a small amount of a suitable small amount, referred to as a modifier monomer by those skilled in the art). The copolymerization with the comonomer) can be carried out by solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and non-aqueous suspension polymerization. In general, it is preferable to remove all copolymerizable hydrophobic large molecular weight monomers remaining in the polymerization system after completion of the copolymerization reaction. Removal of this large molecular weight monomer may be accomplished using any suitable means, such as solvent extraction. If desired, especially during bulk polymerization, the copolymerization can be carried out in a mold, such as a contact lens mold. In this case, cross-linking agents can be added to the copolymerization reaction in order to further improve the wet strength of the graft copolymer. Cross-linking agents suitable for this purpose include ethylene glycol dimethacrylate, diethylene glycol methacrylate, divinylbenzene and N,N-methylene-bis-methacrylamide. The amount of crosslinking agent used generally depends on the degree of crosslinking desired. A suitable amount of crosslinking agent is from about 0.1 to about 2% by weight, or generally about 1 mole%, based on the weight of the monomers forming the hydrophilic polymer backbone.
It can be: When using a polymerization reaction catalyst for a copolymerization reaction, a suitable polymerization reaction environment for the catalyst should be used. For example, oil- or solvent-soluble
Oxides such as benzoyl peroxide are used when copolymerizable, hydrophobic, large molecular weight monomers and ethylenically unsaturated comonomers are copolymerized in bulk in solution in organic solvents such as benzene, cyclohexane, toluene, xylene, etc. or in aqueous solution. Generally effective. Water-soluble peroxides such as persulfate sodium, potassium,
Lithium and ammonium salts and the like are useful in aqueous suspension and emulsion systems. Many copolymerizable and hydrophobic large molecular weight monomers such as ethylenically unsaturated end groups and polystyrene,
In the copolymerization reaction of monomers having polyisoprene or polybutadiene repeating units, emulsifiers or dispersants may be used in the aqueous suspension.
Particular advantages can be achieved in these systems by dissolving the water-insoluble large molecular weight monomers in small amounts of suitable solvents such as hydrocarbons. This novel technique copolymerizes monomers in a solvent with polymerizable large molecular weight monomers in an aqueous system surrounding the solvent-polymer system. Of course, the polymerization reaction catalyst is chosen so that it is soluble in the organic system of the polymerization reaction system. The polymerization reaction catalyst used can be any catalyst suitable for polymerizing compounds having ethylenically unsaturated bonds (but meeting the above criteria), but is preferably a free radical catalyst. Catalysts of particular interest are, for example, azobisisobutyronitrile and peroxide catalysts. Some examples of suitable peroxide catalysts include hydrogen peroxide, benzoyl peroxide, t-butyl peroctoate, phthalic peroxide, and succinic peroxide.
oxide, benzoylacetic peroxide,
Coco acid peroxide, lauric peroxide, stearic peroxide, malic peroxide
oxide, t-butyl hydroperoxide, di-
Includes t-butyl peroxide and its analogs. Suitable catalysts are those that are effective at moderately low temperatures, such as about 45-85°C. In addition to free radical polymerization reaction catalysts, catalysts include materials that polymerize primarily by cleavage of epoxide groups, such as copolymerizable hydrophobic large molecular weight monomers having epoxy-terminated groups. Such catalysts include p-toluenesulfonic acid, sulfuric acid, phosphoric acid, aluminum chloride, stannic chloride, ferric chloride, boron trifluoride, boron trifluoride-ethyl ether complex, and iodine. It may be desirable to use a multi-step polymerization method. The amount of catalyst used will depend on the type of catalyst system used and will generally range from about 0.1 to about 10 parts by weight per 100 parts of comonomer mixture, preferably from about 0.1 to about 10 parts by weight per 100 parts of comonomer mixture. It is about 1 part by weight. The copolymerization reaction is generally conducted at a temperature of about room temperature to about 165°C. Generally, however, the polymerization reaction is initiated at a relatively low temperature, such as from about 40°C to about 85°C, and then the temperature is increased to a temperature of from about 90°C to about 165°C as long as the reaction continues, preferably after most of the reaction is complete. It is preferable that The optimum polymerization reaction initiation temperature range is between about 45 and 70°C. This polymerization reaction is usually carried out under autogenous pressure in a closed reactor. However, any suitable means may be used to prevent significant evaporation of any of the monomers. The copolymerization reaction is generally completed in about 4 to about 48 hours, but preferably in about 6 to about 24 hours. Of course, time and temperature are in an inversely proportional relationship. That is, temperatures used at the upper end of the temperature range provide a polymerization process that can be completed in times near the lower end of the time range. Following the copolymerization reaction, the graft copolymer can optionally be post-cured by any suitable means. However, since the graft copolymers of the present invention have natural reinforcing and self-curing properties, such post-curing is generally not required, except for applications where significant strength is required. If post-curing is desired, it can be done in a mold or cast that fits the approximate or exact shape and/or size of the desired product. After the polymer is completed, including post-curing, a solid, hard and transparent copolymer is obtained. The manufactured product can then be swollen in a suitable liquid until equilibrium is reached or a hydrogel containing the desired amount of liquid, such as an aqueous liquid. In addition, it should be noted that for hydrogels it is also possible to swell the polymers according to the invention with water-soluble swelling agents instead of with aqueous liquids. Water-soluble swelling agents include ethylene glycol, liquid polyethylene glycol, glycol esters of lactic acid, formamide, dimethylformamide,
Includes dimethyl sulfoxide and its analogs. In addition to being molded as is, the copolymers according to the invention can be processed by pressing, extrusion or injection molding. It is also within the scope of this invention that the copolymer be coated onto other substrate materials. In this example, the graft copolymer according to the invention is particularly useful as it has both hydrophilic and hydrophobic groups. One or the other or both of these groups may be compatible with the coated substrate. Copolymerizability with a hydrophobic large molecular weight monomer that is copolymerizable with a second monomer as indicated in pending U.S. Patent Application No. 282,099, the disclosure of which is herein incorporated by reference. Alternatively, the reactive end groups are specifically selected based on the relative reactivity ratio of the second comonomer selected to form the hydrophilic polymer backbone. That is, the present invention provides a means for controlling the backbone of a graft copolymer. More specifically, control of the graft copolymer backbone may be achieved by any one or all of the following means. (1) By measuring the reactivity ratio of a copolymerizable hydrophobic large molecular weight monomer and a second monomer during the copolymerization reaction, a pure graft copolymer not contaminated by homopolymers can be produced ( 2) the distance between side chains in the polymer structure can be controlled by controlling the monomer addition rate during the copolymerization reaction of the copolymerizable hydrophobic large molecular weight monomer and the second comonomer: and (3) ) The size of the grafted chains can be planned and controlled in anionic polymerization reaction steps to produce copolymerizable hydrophobic large molecular weight monomers. It will be apparent to those skilled in the art that all copolymerization reaction mechanisms can be used in the preparation of controlled phase separated graft copolymers by appropriate selection of the terminating agent. Of fundamental importance is the fact that the positioning of the side chains in the polymer backbone is based on the end groups of the large molecular weight monomer and the second copolymerizable comonomer.
That is, the distribution of side chain polymers along the main chain polymer is controlled by the reactivity ratio of each comonomer. As indicated above, the copolymerizable hydrophobic large molecular weight monomers according to the invention interact with the monomers that form the hydrophilic polymer backbone in a predictable manner as measured by relative reactivity ratios. Copolymerize. Copolymer equation in the present invention: (1) It can be shown that when M ₁ has an extremely low molecular concentration, it easily transforms into the approximate formula: (2) dM ₁ /dM ₂ ~M ₁ /r ₂ M ₂ . Thus, the copolymerization reaction of a large molecular weight monomer (M ₁ ) with another monomer (M ₂ ) is described solely by the r ₂ value and the feed composition of the monomers. Rearranging equation (2): (3) r ₂ = dM ₂ /M ₂ /dM ₁ /M ₁ =% polymerization rate M ₂
/% polymerization rate M ₁ is given. The reactivity ratio r ₂ can be estimated from a relatively low conversion sample of a single copolymerization reaction experiment. This concept of predictable and controllable reactivity of copolymerizable hydrophobic large molecular weight monomers can thereby be established. The reactivity of commercially available monomers with the copolymerizable hydrophobic large molecular weight monomers according to the invention having various end groups has been shown to be related to the available literature values for the reactivity ratio of r ₂ . Graft copolymers with unique combinations of properties are produced according to the methods outlined above. These unique combinations of properties are made possible by the novel methods described herein that enhance the miscibility of otherwise immiscible segments. These immiscible segments separate into their own kind of phase. Thus, in the case of the graft copolymers according to the invention having a hydrophilic polymer main chain and hydrophobic polymer side chains, separate phases of the respective polymers are formed. The structure of this product consists of hydrophobic regions dispersed within a hydrophilic polymer matrix. The hydrophobic regions are interconnected by water-soluble linking segments. The hydrophobic regions act as cross-links and provide wet strength to the water-swollen polymer backbone. The degree of swelling in water can be controlled by the amount and molecular weight of the copolymerized hydrophobic large molecular weight monomers and by the organization of the water-soluble or hydrophilic polymer backbone. An example of one type has a hydrophilic backbone of 5/95~
Compositions consisting of 100/0 acrylic acid/ethyl acrylate and methacrylate terminated polystyrene having a molecular weight within the range of about 10,000 to about 35,000 and a weight range of 20 to 80% of the total product are included. This product is swollen with water to provide a useful hydrogel. Because graft copolymers consist of hydrophilic and hydrophobic segments, they are particularly useful as protective colloids or suspension stabilizers for pigments, polymer suspensions, emulsions, and the like. They are also useful in the production of protective coatings in which the rheology of the paint can be controlled and adhesives where the side chains of the paint or hydrophobic polymer serve as stabilizers and adhesion promoters. The novel graft copolymers of this invention are also useful as flocculants, particularly when the hydrophilic polymer backbone contains some monomer functionality. Polymeric materials with these types of backbones are also useful as wet end additives.
These copolymers can also be used as thickening agents or defoamers. The dual nature of the novel copolymers according to the invention also makes them useful as wetting and coupling agents for hydrophilic surfaces in applications as adhesives and binders. The high wet strength of the novel copolymers of the present invention makes the polymer compositions of the present invention useful as water permeable membranes, sponges, hydrogels, ion exchange resins, and conductive polymers. Water-permeable and water-absorbing compositions can also be made by incorporating copolymers according to the invention into films and the like. When copolymerizable hydrophobic large molecular weight monomers are used in low concentrations, the product has antistatic properties, especially when the hydrophilic polymer backbone contains cationic functional moieties. The copolymers according to the invention are also useful for their antistatic properties when deposited in packaging films and for their ability to provide a fog-free surface. Grafted polymers containing both hydrophilic and hydrophobic polymer chains in a single molecule have enhanced thickening properties over conventional industrial thickening agents. The solubility of the graft copolymers according to the invention differs from that of random copolymers.
Even if the solubility of the random copolymers allows them to be treated as if they were novel polymers composed of single monomer units, the graft copolymers according to the invention contain elements that constitute homopolymer chains. Immiscibility and phase separation usually occur as soon as the interaction of two different polymer chains becomes significant. For example, when a graft copolymer consisting of water-soluble and water-insoluble component chains is added to a compounded latex, interactions between the polymer thickener and the latex particles or pigments and clays occur and the molecules of the polymer thickener disintegrate. do. Since the two homopolymer chains are incompatible, the hydrophobic chains combine to form microgel particles. Agglomeration proceeds quickly to form large aggregates and finally all the particles are bound together by the latex thickening agent molecules where the microgel particles of the hydrophobic portion of the thickening agent molecules act as cross-linking points. Combined to form a network. In the application of polymeric materials as industrial thickeners, flocculants, etc., the most effective structures contain two incompatible homopolymer chains, one of which is hydrophilic and the other hydrophobic. It is a block copolymer or a graft copolymer. The hydrophilic portion of the molecule makes the hydrophobic portion soluble, making the entire molecule water (or alkali) soluble. However, when adding a thickening agent to a compounded latex, the thickening agent and latex particles,
Graft copolymer interaction between clay and pigment reduces its water solubility. The hydrophobic part of the molecule becomes insoluble in water and is incompatible with other parts of the molecule, so it aggregates into a microgel. The novel graft copolymers according to the invention are also adapted as carriers for pharmaceutically active substances and for natural and synthetic flavours, essences, fragrances, spices, food colours, sweeteners, dyes and the like. Ru. That is, various additives may be incorporated into the graft copolymer according to the present invention in the manner disclosed in U.S. Pat. No. 3,520,949, given by Thomas H. Sheppard et al. can be done. The invention is further illustrated by the following examples, which are not intended to limit the invention in any respect. Care should be taken in each case to keep all materials pure and the reacted mixture dry and free of contaminants.
All parts and percentages are by weight unless otherwise specified. Example 1 Production of polystyrene terminated with allyl chloride. ACS grade benzene (thiophene-free) pre-dried with Linde molecular sieves and calcium hydride in a stainless steel reactor. ) 76.56 copies were prepared. The reactor was heated to 40°C and 0.015 parts of diphenylethylene was added using a hypodermic syringe.
Dissolved sec-butyllithium in hexane
The 12.1% solution was added in portions to the reactor to maintain a permanent orange-yellow color, at which point an additional 0.885 parts (1.67 moles) of the sec-butyllithium solution was added followed by 22.7 parts (218 moles) of styrene. 44
Added in minutes. The reactor temperature was maintained at 36-42°C. The polymerizing polystyrene was quenched by adding 0.127 parts of allyl chloride to the reaction mixture. α to precipitate the resulting polymer
A -olefin terminated polystyrene-benzene solution was added in methanol, thus precipitating the polymer. The α-olefin terminated polystyrene was dried at 40-45° C. in an air circulating hot air dryer and then traces of methanol were removed in a fluidized bed. The methanol content after purification was 10 ppm. The molecular weight of the polymer is 15,400 (theoretical: 13,000) as measured by a membrane osmometer.
The molecular weight distribution was extremely narrow, that is, / was 1.05 or less. The large molecular weight monomer has the following structural formula: (However, n has a value such that the molecular weight of the polymer is 15,400.) Example 2 Poly(α) terminated by allyl chloride
-Production of methylstyrene) 472g in a volume of 2500ml of tetrahydrofuran
A 12% hexane solution of n-butyllithium was added dropwise to this solution to maintain a pale red color. Further addition of 30 ml (0.383 mol) of this n-butyllithium solution produced a bright red color. The temperature of the mixture was then lowered to -80 DEG C. and held at this temperature for 30 minutes before 4.5 g (0.06 mole) of allyl chloride was added. The red color disappeared almost instantly, indicating that the living polymer had stopped. The resulting colorless solution was poured into methanol to precipitate the α-olefin terminated poly(α-methylstyrene), which was determined by vapor phase osmometry.
It was shown to have an average molecular weight of 11,000 (theory: 12,300), and its molecular weight distribution was extremely narrow, ie, / was less than 1.05. The resulting large molecular weight monomer has the following structural formula: (However, n is a value such that the molecular weight of the polymer is 11,000.) Example 3 Preparation of polystyrene terminated with vinyl chloroacetate Dissolve one drop of diphenylethylene in 2500 ml of cyclohexane and treat this solution dropwise at 40°C with a 12% solution of sec-butyllithium in cyclohexane. 18ml more to maintain red color
(0.024 mol) of the sec-butyllithium solution was added followed by 312 g (3.0 mol) of styrene. After keeping the temperature of the polymerization reaction mixture at 40℃ for 30 minutes,
The living polystyrene was capped by treatment with ml (0.040 mol) of diphenylethylene and end-terminated by treatment with 6 ml (0.05 mol) of vinyl chloroacetate. This cyclohexane solution was added to methanol to precipitate the resulting polymer, which was then filtered to separate the polymer. The average molecular weight measured by vapor phase osmotic pressure is 12000 (theory: 13265), and the molecular weight distribution is extremely narrow, i.e.
It was below 1.06. The produced large molecular weight monomer has the following structural formula: (However, n has a value such that the molecular weight of the polymer is 12,000.) Example 4 Preparation of poly(α-methylstyrene) terminated with vinylchloroacetate 357 g in a volume of 2500 ml of tetrahydrofuran
(3.0 mol) of α-methylstyrene was dissolved and treated by dropping a 12% solution of t-butyllithium in pentane to this solution to maintain a pale red color. An additional 15.0 ml (0.03 mole) of the t-butyllithium solution was then added and a bright red color developed.
The temperature of this mixture is then lowered to -80°C.
After holding for 30 minutes, 5.6 ml of diphenylethylene was added. The resulting mixture was poured into 5.0 ml (0.04 mol) of vinyl chloroacetate and the poly(α-methylstyrene) thus terminated was isolated by precipitation with methanol and filtration. Its average molecular weight as measured by vapor phase osmotic pressure is
14280 (theoretical value: 12065), and the molecular weight distribution was extremely narrow. The produced large molecular weight monomer has the following structural formula: (However, n has a value such that the molecular weight of the polymer is 14,280.) Example 5 Preparation of polystyrene terminated with vinyl-2-chloroethyl ether A 12% solution of t-butyllithium in pentane was added dropwise to a solution of one drop of diphenylethylene at 40°C to give a pale red color. At that point an additional 30 ml (0.04 mol) of t-butyllithium solution was added followed by 312 g (3.0 mol) of styrene. After maintaining the temperature of the polymerization reaction mixture at 40 DEG C. for 30 minutes, the living polystyrene was end-terminated by treatment with 8 ml (0.08 mole) of vinyl-2-chloroethyl ether. The polymer was separated by precipitating the resulting polymer by adding a benzene solution to methanol and filtering.
The average molecular weight measured by vapor phase osmotic pressure was 7200 (theoretical: 7870), and the molecular weight distribution was extremely narrow, ie, / was less than 1.06. The produced large molecular weight monomer has the following structural formula: (However, n has a value such that the molecular weight of the polymer is 7200.) Example 6 Preparation of polystyrene terminated with epichlorohydrin A solution of living polystyrene in benzene was prepared by the method described in Example 5 and terminated by treatment with 10 g (0.10 mol) of epichlorohydrin. The resulting terminated polystyrene was separated by precipitation with methanol and filtration. Its molecular weight as indicated by vapor phase osmotic pressure is 8660
(Theory: 7.757), and the distribution of the average molecular weight was extremely narrow. The produced large molecular weight monomer has the following structural formula: (However, n has a value such that the molecular weight of the polymer is 8660.) Example 7 Preparation of polystyrene terminated with methacrylic chloride Dissolve 0.2 ml of diphenylethylene in a volume of 2500 ml of benzene and add dropwise a 12% solution of n-butyllithium in hexane to maintain a pale reddish-brown color. reached it. 24 of the n-butyllithium solution
ml (0.031 mol) was added followed by 416 g (4.0 mol) of styrene, an orange color developed. A temperature of 40°C was maintained throughout by external cooling and controlled styrene addition rate. After all the styrene has been added, maintain this temperature for another 30 minutes and then 20°C.
4.4 g (0.1 mole) of ethylene oxide was added and the solution became colorless. The living polymer was end-terminated by reacting with 10 ml (0.1 mol) of methacryl chloride. The average molecular weight of the obtained polymer is according to the vapor phase osmotic pressure.
It was 10,000. This large molecular weight monomer has the following structural formula: (However, n has a value such that the molecular weight of the polymer is 10,000.) Example 8 Preparation of polystyrene terminated with methacrylyl chloride 121.12 (32 gallons) of ACS grade benzene (thiophene) predried with Linde molecular sieves and calcium hydride in a stainless steel reactor. (not included) was prepared. The reactor was heated to a temperature between 38-40°C and 10 ml of diphenylethylene was added to the reactor via hypodermic syringe. A 11.4% hexane solution of sec-butyllithium was added dropwise into the reactor (60 ml) until it retained a persistent orange-yellow color, and 1.56176 Kg (3.44 lb) of the sec-butyllithium benzene solution was then added to the reactor. 37.455 kg (82.5 lb) of purified styrene was added over a period of 1 hour and 40 minutes. The reactor temperature was maintained at 38-40°C. When 0.12712 kg (0.28 lb) of ethylene oxide was added to the living polystyrene and capped, the reaction solution turned from red-orange to yellow. The resulting capped living polystyrene was then reacted with 260 ml of methacryl chloride and the solution turned very pale yellow. The polymer precipitated out of solution by adding a benzene solution of the polymer to methanol to precipitate the methacrylate-terminated polystyrene. The polymer was dried at 40-45° C. in an air circulating hot air dryer and then traces of methanol were removed on a fluidized bed.
The molecular weight of the polymer measured by membrane phase osmotic pressure is
13,400, and the molecular weight distribution was extremely narrow, that is, / was 1.05 or less. Example 9 Preparation of polystyrene terminated with maleic anhydride. ACS grade benzene (thiophene free) pre-dried with Linde molecular sieves and calcium hydride in a stainless steel reactor. I installed 2.5. 40 reactors
C. and added 0.2 ml of diphenylethylene to the reactor via hypodermic syringe. A 12.1% hexane solution of sec-butyllithium was added in portions to the reactor until it retained a permanent orange-yellow color (0.7
ml) Then, further add the sec-butyllithium solution.
22.3 ml was added followed by 421.7 g of styrene over a period of 16 minutes. The reactor temperature was maintained at 40-45°C.
Ethylene oxide was added subsurface intermittently from a lecture bottle until the solution became clear and colorless 5 minutes after the styrene addition was complete. One hour after the addition of ethylene oxide is complete, add 20.55 ml of a benzene solution of maleic anhydride (the maleic anhydride solution contains 84 g of maleic anhydride).
(prepared by dissolving in 550 g of purified benzene) was added to the capped living polymer. One hour after addition of the maleic anhydride, the contents of the reactor were discharged into methanol and precipitated. The polystyrene terminated maleic acid half ester was approximately 14,000 as determined by Gel Permeation Chromatography. This copolymerizable large molecular weight monomer has the following structural formula: It had Example 10 Production of polybutadiene terminated with allyl chloride CP grade 1,3-butadiene (99.0% purity) was
Condensed and collected in 0.568 (1 pint) soda bottle. These bottles are heated in an oven to 150° C. for 4 hours, passed through nitrogen during cooling, and capped with a perforated metal crown using a butyl rubber and polyethylene film backing. These bottles containing butadiene were stored in a laboratory refrigerator at −10°C before use.
Stored at 0.7 Kg/cm ² (10 psi) nitrogen pressure. The reactor was charged with hexasolvent and heated to 50°C, and then 0.2ml of diphenylethylene was added using a syringe. The sec-butyllithium was dripped into the reactor via syringe until the red diphenylethylene anion color persisted for at least 10-15 minutes. The temperature of the reactor was lowered to 0°C, 328.0 g of butadiene was charged into the polymerization reactor, and when half of the butadiene charge was added, 17.4 ml (0.02187 mol) was added.
A 12% hexane solution of sec-butyllithium was added. Butadiene was polymerized in hexane at 50°C for 18 hours. Following the polymerization reaction, the anionic polybutadiene solution in the reactor was divided into 400 ml portions and transferred to capped bottles under nitrogen pressure. Allyl chloride (0.48 ml, 0.00588 mol) was poured into each bottle. These bottles were fixed in a water bath at a temperature of 50-70°C for up to 24 hours. Samples in each bottle were quickly stopped with methanol and ionol solutions and analyzed by gel permeation chromatography. Each sample was clear and colorless, and analysis by gel permeation chromatography analysis showed that the sample had a narrow molecular weight distribution. 2 as a terminal stopper
- Termination of several control samples was carried out in bottles from the same lot of living polybutadiene capped with chlorobutane (0.4 ml, 0.00376 mol). The 2-chlorobutane-terminated polymer was yellow in color, and examination by gel permeation chromatography after 24 hours at 70°C showed a broad molecular weight distribution. It is clear that the reaction and reaction products of 2-chlorobutadiene and anionic polybutadiene are different from the reaction and reaction products of allyl chloride and anionic polybutadiene. Example 11 Production of methacrylate-terminated polyisoprene Chemco with a capacity of 3.785 (1 gallon)
2.5 g of purified heptane, previously dried with Linde molecular sieves and calcium hydride, in a glass-bowl reactor.
Then add 0.2 ml of diphenyethylene as an indicator and add a solution of t-butyllithium (12% in hexane) until the characteristic light yellow color persists.
The reactor was sterilized by adding dropwise. Heat the reactor to 40℃ and
19.9 ml (0.025 mol) of t-butyllithium 12
% hexane solution by hypodermic syringe and then
331.4 g (4.86 moles) of isoprene was added. The mixture was allowed to stand at 40°C for 1 hour, then 0.13 moles of ethylene oxide was charged to the reactor and the living polyisoprene was capped. After keeping the capped living polyisoprene at 40° C. for 40 minutes, 0.041 mole of methacrylic chloride was charged into the reactor to terminate the capped living polymer. The mixture was kept at 40° C. for 13 minutes and then the heptane solvent was removed by stripping under vacuum. Based on gel permeation chromatography examination of polystyrene, the gel permeation chromatography molecular weight of methacrylate-terminated polyisoprene was approximately 10,000 (theoretical: 13,000).
The high molecular weight monomer of methacrylate-terminated polyisoprene has the following structural formula: It had Example 12 Preparation of alpha-olefin terminated polyisoprene. 2.5 ml of purified heptane was charged, and then 0.2 ml of diphenylethylene was added as an indicator. Sterilization was carried out by dropping a solution of t-butyllithium (12% in hexane) until a pale yellow color, characteristic of the reactor and solvent, persisted. Heat the reactor to 40℃ and add 19.03ml to it.
(0.02426 moles) of t-butyllithium solution was injected via hypodermic syringe and then 315.5 g (4.63 moles) of isoprene was added. After the polymerization reaction proceeded at 50° C. for 66 minutes, 2.0 ml (0.02451 mol) of allyl chloride was added to the living polyisoprene. The end-stopped polyisoprene was held at 50° C. for 38 minutes before the polymer was removed from the reactor for use in the copolymerization reaction. This polymer had a very narrow molecular weight distribution when analyzed by gel permeation chromatography, ie, a / of less than about 1.06. The theoretical molecular weight of this polymer was 13,000. The copolymerizable large molecular weight monomer has the following structural formula: It had Example 13 Preparation of high molecular weight monomers of polystyrene capped by butadiene and terminated by allyl chloride 2.5 volumes of benzene (without thiophene) were charged to a reactor and heated to 40°C, and 0.2 volumes of this was added as an indicator. The reactor was sterilized by adding ml of diphenylethylene and then adding dropwise a 12% solution of sec-butyllithium until the orange-red color persisted. Now add another 18ml (0.024
sec-butyllithium solution (mol) in hexane
12%) was added followed by 416 g (4.0 moles) of styrene. The temperature of the polymerization reaction mixture was maintained at 40°C for 5 minutes. The living polystyrene was then capped by passing butadiene gas into the reactor until the color of the solution changed from dark red to orange. This living polymer was end-terminated with 4.1 ml (0.05 moles) of allyl chloride. The large molecular weight monomer thus produced was separated by precipitation with methanol. Its average molecular weight estimated by gel permeation chromatography was 25,000 (theory: 18,000), and its molecular weight distribution was extremely narrow. The produced large molecular weight monomer has the following structural formula: (where m is equal to 1 or 2). Example 14 Preparation of a Gukuft Copolymer Having a Hydrophilic Polymer Backbone of Polyacrylic Acid and a Hydrophobic Polymer Side Chain of Polystyrene A Very Narrow Molecular Weight Copolymer Made in Example 5 Above with a Molecular Weight of about 8000 and a Ratio of about 1.06 or Less Vinyl, which has a distribution
60 g of polystyrene end-terminated with 2-chloroethyl ether were placed in two resin flasks.
It was dissolved in 240 g of acrylic acid and 50 g of tetrahydrofuran (THF). An additional 500 g of THF was placed in the second resin flask and 0.6 g of benzoyl peroxide was added. The flask was heated to 65°C and the polymerization reaction was allowed to proceed for 2 hours.
After the polymerization reaction was completed, 300 g of distilled water was added to the resin flask to distill off THF. This aqueous copolymer system was then used as a latex thickener. Example 15 Preparation of a graft copolymer with a hydrophilic polymer backbone of polyacrylic acid and a hydrophobic polymer side chain of polystyrene 4 g of Triton X-100 was dissolved in 500 g of distilled water and mixed in a waring mixer. (blender) put it inside. A stable dispersion is obtained by dissolving 30 g of t-butyl polystyrene vinyl ether prepared in Example 5 above in 60 g of benzene and adding this solution to a Walling mixer containing a solution of Triton X-100 under high shear rate. I made it. This dispersion was charged into a second resin flask equipped with a stirrer and a condenser, and nitrogen was passed through the flask for 1 hour. Heat the reactor to 65℃ and 240℃.
g of acrylic acid was added (pH neutralized to 8.0 with ammonium hydroxide). 69 Add 1 g of benzoyl peroxide to the resin flask to start the polymerization reaction.
℃ for 3 hours. The polymer was recovered as described in Example 14 and further evaluated and tested as an industrial latex thickening agent. Example 16 Preparation of a graft copolymer with a hydrophilic polymer backbone of polyacrylic acid and a hydrophobic polymer side chain of polystyrene 18 g of Triton X-405 (or 26 g of 70% solids Triton X-405) are dissolved in 300 g of water. The pH was adjusted to 8 with ammonium hydroxide and the solution was placed in a wall mixer. 30 g of t-butyl polystyrene vinyl ether made as described in Example 5 are dissolved in 70 g of ethyl acrylate and this solution is stabilized by adding it to a Walling mixer containing a solution of Triton X-405 under high shear rate. A dispersion was created. This dispersion was placed in a second resin flask equipped with a stirrer and a condenser, and nitrogen was passed through the flask for 1 hour. 65 reactor
0.1 g of ammonium persulfate was added to the mixture. 200g ethyl acrylate and 2%
The ammonium persulfate solution was added to the polymerization reactor over a period of 3 hours and the polymerization reaction was carried out at 65-67°C. Hydrophilicity was imparted to the polymer main chain by hydrolyzing the acrylic acid groups with alkali under heating.
The resulting hydrophilic and hydrophobic polymers were recovered in the manner described above. Example 17 Polyacrylic Acid Hydrophilicity - Latex Thickening Effect of Polystyrene Polymer Side Chains Three graft copolymers consisting of 80% polyacrylic acid polymer backbone and 20% polymer polystyrene side chains prepared as described in the previous example. was tested as a latex thickening agent. The sizes of polystyrene side chains were as follows: Sample A (G30)
is equal to 1000: Sample B (G32) is
4000 and sample C (G33) is 8000
It was a long time ago. These graft copolymers were tested in the following manner. 0.3 in 300g Wica Latex 7035 (50% solids)
g, 0.6 g and 1.2 g of hydrophilic graft copolymer (solid based) and its viscosity was determined by a Brookfield LVT viscometer (No. 3 weight, 12 revolutions per minute). It was measured. The results of this test are shown in Table 1.

Table 1 As is known from the above data, the graft copolymer according to the invention acts as an excellent thickening agent for latexes due to the presence of both hydrophilic and hydrophobic polymer segments. It was clear that the polymer side chains with uniform molecular weight distribution contributed to the overall ability to form a stable latex. It was also evident that higher molecular weight polymer side chains improved the overall thickening ability. This is because polymer side chains at high molecular weights, ie, above about 2000, resemble the properties of polystyrene polymers and result in better phase separation when the polymer side chains have a high molecular weight. Example 18 Preparation of a hydrophilic polymer backbone graft copolymer of polyvinyl alcohol with hydrophobic polymer side chains of polystyrene A purified copolymerizable large molecular weight monomer ( In producing this large molecular weight monomer, sec-butyllithium is used as a reaction initiator, and the polymer has a molecular weight of 2080 and a /
60 g of the monomer (in which the monomer was prepared in the same manner but with the same ratio) were copolymerized with 240 g of vinyl acetate in benzene using benzoyl peroxide as a catalyst. The polyvinyl acetate-styrene graft copolymer (G26) thus produced was hydrolyzed to a polyvinyl alcohol-styrene graft copolymer in a 50/50 methanol/benzene mixture using sodium methoxide as a catalyst. The obtained polymer was washed with methanol, vacuum dried, and then extracted with benzene. Analysis of the extracted copolymer showed that a copolymer was produced. The saponified product was formed into a film and compared with commercially available polyvinyl alcohol to confirm its water resistance. Each film was coated onto glass and soaked in water overnight at room temperature. Even by mere visual observation, it was clear that the water resistance of the copolymers of the present invention was much improved over that of the control polyvinyl alcohol. Example 19 Preparation of a hydrophilic polymer backbone graft copolymer of polyvinyl alcohol with hydrophobic polymer side chains of polystyrene Sodium dodecyl sulfate (0.4 g) was added to 85 g of water with stirring to which 15 g of the methacrylate prepared in Example 8 was added. A latex copolymerization reaction was carried out by adding polystyrene terminated with , followed by 30 g of vinyl acetate. 0.15g
of benzoyl peroxide and heated at 40-50℃ for 6 hours.
A polymerization reaction was carried out. When the polymerization reaction was completed, the copolymer was poured into 100 ml of methanol under stirring, and 10 g of sodium methoxide was added to this solution over a period of 20 minutes. The solution was refluxed for 10 minutes and the polymer was washed twice with isopropanol and dried under vacuum at 70°C. The solubility of the hydrolyzed product was tested using various solvents. This copolymer was slightly soluble in DMSO but insoluble in toluene, tetrahydrofuran, benzene and cresol. Films made from this copolymer were transparent and exhibited good extensibility and excellent wet strength. Example 20 Preparation of a hydrophilic polymer backbone graft copolymer of polyhydroxyethyl methacrylate with hydrophobic polymer side chains of polystyrene. 75 parts were mixed with 125 parts of hydroxyethyl methacrylate to form a polymerization reaction catalyst.
The polymerization reaction was initiated with 0.4 parts of t-butyl peroctoate. The polymerization reaction of this material was carried out by first heating the mixture at about 50°C for 8 hours. The polymerization reaction was then completed by heating to 90°C for about 1 hour and then to 120°C for 1 hour. After the polymerization reaction was completed, a transparent, firm and hard copolymer was obtained. The polymer was contacted with a physiological saline solution and brought into osmotic equilibrium with the saline. The hydrogel film thus produced was transparent, flexible, and elastic. Example 21 Preparation of a Graft Copolymer Having a Hydrophilic Polymer Backbone of Poly(N,N-dimethylacrylamide) and a Hydrophobic Polymer Side Chain of Polystyrene The purified highly functional methacrylate-terminated polystyrene prepared in Example 8 40 g and 60 g of N,N-dimethylacrylamide (having a molecular weight of 13400 and a / ratio of 1.5 or less) were dissolved in 150 g of benzene. This mixture was mixed on a shaker to obtain a homogeneous solution. 0.12 g of AIBN (VAZO) polymerization initiator was added and the contents were transferred to a 0.95 (1 quart) polymerization reactor. After the contents were flushed with nitrogen, the reactor was sealed and continued to be flushed with nitrogen. The polymerization reactor was placed on a shaker in a 60°C water bath for 19.5 hours and then brought to 85°C for 2 hours to complete the polymerization reaction.
The resulting copolymer was a clear, highly viscous liquid. 250 g of benzene was added to this viscous liquid copolymer to reduce its viscosity. The weight of the solvent and copolymer was 465 g, 20.9% solids (95.4 g solids), and the yield of copolymer was 95.4%. A copolymer film was formed by stretching the benzene-copolymer solution onto a glass plate with a drawing rod. This film was optically clear. The wet films obtained by immersing these coated plates in distilled water were tough and transparent. The swelling ratio of this film was 2.2 g water to 1 g copolymer. The tensile strength of the wet film is 60.9Kg/cm ² (870psi) and the stretching ratio is 100
It was %. The film was tested for its water vapor permeability (WVT) using ASTM test method E96-63T(B) and the WVT of the wet film was
It was 1.100g/24 hours/ ^m2 . Gel permeation chromatography analysis of this copolymer showed the absence of unreacted hydrophobic large molecular weight monomers. The insolubility of this copolymer when immersed in water and the high strength of the wet film are due to the hydrophobic polymer side chains acting as physical cross-links to the normally water-soluble poly(N,N-dimethylacrylamide). It was shown that
The above copolymers were softened in water and tested for their water vapor permeability. The wet copolymer film was measured for its WVT of 2000 g/24 hours/ ^m2 , indicating its use as a semipermeable membrane. Example 22 Preparation of a graft copolymer having a hydrophilic polymer backbone of poly(N,N-dimethylacrylamide) and a hydrophobic polymer side chain of polystyrene. The methacrylate-terminated polystyrene has a molecular weight of 12,100 as determined by gel permeation chromatography analysis and a ratio of less than or equal to about 1.06), 10 parts of N,N-dimethylacrylamide and 900 parts of N,N-dimethylacrylamide. of benzene. This mixture was placed on a shaker until a homogeneous solution was obtained. Thereafter, 0.1 part of AIBN was added, and the solution was charged into a 0.95 (1 quart) polymerization reactor, which was then bubbled with nitrogen and sealed tightly. After passing nitrogen through this tightly closed system, the polymerization reaction mixture was poured for 60 min.
The polymerization reaction was continued for 12 hours by placing on a shaker in a water bath at °C. After the polymerization reaction was completed, the copolymer was recovered by precipitation in hexane, filtered, and dried. This copolymer had excellent wet strength properties when immersed in water as a clear, viscous solution. Example 23 Preparation of a graft copolymer having a hydrophilic polymer backbone of poly(N,N-dimethylacrylamide) and a hydrophobic polymer side chain of polystyrene. 10 parts of methacrylate-terminated polystyrene (having a molecular weight of 12,700 and a ratio of about 1.05 or less as determined by gel permeation chromatography analysis) was dissolved in 90 min of N,N-dimethylacrylamide. I let it happen. 5 parts of calcium styphosphate were dispersed in the comonomer mixture and 200 parts of heptane and 0.1 part of AIBN were added to the comonomer mixture under rapid stirring. This system is 0.95
The mixture was charged into a 1 quart polymerization reactor, and nitrogen was passed through the reactor and the reactor was tightly stoppered. Nitrogen was further flushed through the capped system to clean it. This polymerization reactor was placed on a shaker in a water bath at 67°C to carry out the polymerization reaction.
It lasted for 12 hours. The copolymer was obtained in the form of a fine powder and was easily filtered and dried. Recovery of the copolymer was very successful due to the use of non-aqueous emulsion polymerization techniques. Analysis of the product by gel permeation chromatography showed the absence of unreacted methacrylate-terminated polystyrene. This copolymer had excellent wet strength when immersed in water.
This copolymer was also useful in making polyblends with polyvinyl chloride. In this embodiment, various polyblends were prepared by dry blending 40-60 parts by weight of copolymer and 60-40 parts by weight of polyvinyl chloride. Shearing this dry blend on a mill at elevated temperature resulted in a film with excellent water vapor permeability. A detailed description of the blending of N,N-dialkyl acrylamide polymers with polyvinyl chloride resins can be found in copending U.S. Patent Application No. 359,284, which is incorporated herein by reference.
It is stated in the specification of the issue. In a specific example of a polyblend, 33.3 parts of the above copolymer were dry blended with 70 parts of polyvinyl chloride (Vygen 110) and 70 parts of dioctyl phthalate (DOP). The dry compounded mixture was placed on a rubber mill for 8 minutes at 148.89°C (300°C). The blended ingredients melted extremely easily to form a smooth, transparent film. After compounding and subjecting the mixture to high shear, 10 mil films were evaluated for water vapor permeability and water absorption. This polyblend had a water vapor permeability of 200 g/24 hours/m ² and absorbed 5.8% water in 18 hours at 85% specific humidity. In comparison, a similar blend made from a homopolymer of N,N-dimethylacrylamide and a plasticized polymer of vinyl chloride had a water vapor transmission rate of 75 g/24 hours/m ² and 85%. for 18 hours under specific humidity of
Absorbed 4.5% moisture. It was quite evident that besides the improved physical properties, the hydrophobic polystyrene side chains improved the processing of the polyblend and this contributed to the solubility of the polystyrene side chains in dioctyl phthalate. In other words, the side chains improved the melt rheology imparted to poly(N,N-dimethylacrylamide) by these grafted chains. Example 24 Preparation of a graft terpolymer of a hydrophilic polymer backbone of poly(N,N-dimethylacrylamide)/butyl acrylate and a hydrophobic polymer side chain of polystyrene. The methacrylate-terminated polystyrene has a molecular weight of 20,000 and a ratio of less than or equal to about 1.06 as determined by gel permeation chromatography.
10 parts were dissolved in 85 g of N,N-dimethylacrylamide by means of an air mixer.
Then add 5 parts of butyl acrylate, 5 parts of calcium stearate and 0.1 part of AIBN and 200 parts of heptane to the comonomer mixture and stir.
(1 quart) polymerization reactor. The polymerization reaction mixture was bubbled with nitrogen and capped tightly. The reactor was placed on a shaker in a hot water bath at 67°C for 16 hours to carry out the polymerization reaction. The terpolymer was filtered and dried. The yield of terpolymer was 105 g and the yield was 100% based on the added "solid material". Example 25 Preparation of a graft terpolymer of a hydrophilic polymer backbone of a maleic acid half ester and a hydrophobic polymer side chain of polystyrene by first condensing maleic anhydride with Carbowax 750.
A maleic acid half ester of methoxypolyethylene oxide ether (Carbowax 750) with a molecular weight of 750 was prepared. Seven parts of Carbowax 750 maleic acid half ester and 250 parts of isooctane (Soltrol 10, available from Phillips Petroleum) were charged to the reactor. The temperature of the reactor was increased to 73° C. and 135 parts of N,N-dimethylacrylamide and 7.5 parts of maleic acid half ester terminated polystyrene high molecular weight monomer (this maleic acid half ester terminated polyester was prepared as described in Example 9). The polymer had a molecular weight of 7000 and had a ratio of 1.05 or less as determined by gel permeation chromatography). 53/47N,N- to the reactor containing the polymerizable monomer.
A mixture of 20 parts of a 20% solution of dimethyl acrylamide/lauryl methacrylate copolymer dispersion in isooctane and 0.3 parts of AIBN as polymerization initiator was added over a period of 5 hours, after which time more isooctane was added. After continuing the polymerization reaction for an additional 12 hours, a fine dispersion of terpolymer was recovered by filtration. This terpolymer had excellent wet strength when immersed in water. Example 26 Preparation of a graft copolymer of a hydrophilic polymer backbone of poly(hydroxyethyl methacrylate) and a hydrophobic polymer side chain of polyisoprene. Polyisoprene has a molecular weight of 10,000 and a molecular weight of less than 1,1 as determined by gel permeation chromatography.
(on a solid dry basis) and 100 parts of hydroxyethyl methacrylate were mixed in a 0.95 (1 quart) polymerization reactor. 0.2 parts AIBN by passing nitrogen into the comonomer mixture
The mixture was copolymerized for 16 hours at 67° C. by adding a polymerization initiator. The resulting copolymer was a clear, viscous solution. This clear copolymer solution was placed in a mold and irradiated with gamma rays for 20 minutes. The copolymer was then physiologically immersed in saline. Wet copolymers have excellent wet strength due to the fact that the hydrophilic backbones are held together by hydrophobic side chains, which are linked to each other by cross-linking upon irradiation. It was hot. That is, the copolymer was reinforced by a structure of cross-linked hydrophobic regions that were chemically bonded to a hydrophilic host phase. The hydrophilic-hydrophobic graft copolymers according to the invention unexpectedly exhibit improved properties in their hydrated state, such as tensile strength,
wet strength, stretching ratio, etc.). Generally, hydrophilic polymers must be cross-linked by chemical cross-linking agents to improve their physical properties. However, the novel graft copolymers of the present invention uniquely provide thermally labile physical cross-links that serve to anchor the polymer backbone portions and also provide a "filling effect" so that the modulus of elasticity of the final product ( modulus) and tensile strength. This graft copolymer is
Temperatures above Tg (90~ for polystyrene
When heated to 100℃), the region becomes a fluid and flows under pressure. That is, they are truly thermoplastic. When the graft copolymer cools, the regions are regenerated and the graft copolymer regains the properties of the cross-linked hydrophilic polymer. Adding an aqueous liquid merely acts as a plasticizer for the hydrophilic polymer and does not dissolve the entire copolymer material. Graft copolymers can be turned into hydrogels by soaking them in an aqueous liquid (such as water or saline). The amount of aqueous liquid can vary widely depending on the composition of the graft copolymer, ie, the amount of polymer side chains in the graft copolymer. Generally, the amount of aqueous liquid will range from about 10% to about 95%, preferably 45% to 80% of the graft copolymer. Contact lenses, since they can retain their form even when there is a high level of aqueous liquid in the graft copolymers according to the invention,
Useful in making internal implants and the like. The formation of a hydrogel by immersing the copolymer according to the present invention in an aqueous liquid results in the formation of a hydrogel in the form of microscopic droplets that fill the microscopic pores or voids distributed throughout the hydrogel matrix in the copolymer. Retention is enhanced by the covalent forces of the hydrophilic polymers, which are held together by thermally labile cross-links of the hydrophobic polymer side chains. Water can be removed from the graft copolymer if desired by applying pressure on the polymeric material. After the pressure is relieved, air cannot enter the voids and the overall volume of the product remains small until it is brought into contact with water or an aqueous solution, after which it swells to its original size and shape. Return to
In such products, some of the water is retained by capillary suction in the voids and some as a component of the colloidal system of the hydrogel. In the embodiments described here, the hydrogels according to the invention have hygroscopic properties which can be advantageously used, for example, in adhesive bands or layers in medicated bandages. The product can also be used as an ultrafiltration semipermeable membrane. Regarding the latter, it is desirable to impart porosity to the hydrophilic graft copolymer by incorporating agents or blowing agents into the polymer structure during the polymerization reaction or by using them as a post-treatment. Other unique variations of the invention include preparing hydrophilic-hydrophobic graft copolymers as emulsions useful in paper coatings. These copolymers share polyvinyl aromatic (eg, polystyrene) or polyvinyl aromatic/polybutadiene in the polyvinyl acetate polymer backbone.
The following reaction scheme characterizes the unique process for making emulsion graft copolymers. The graft copolymer is prepared by first copolymerizing the copolymerizable large molecular weight monomer a or b with vinyl acetate under free radical conditions. This emulsion has excellent physical properties suitable for use in paper coatings. For example, it is known that polystyrene-butadiene latex is most widely used as a pigment binder in the paper industry. Although polyvinyl acetate latex has better adhesion, whiteness and low odor, its poor wet pick resistance and wet abrasion resistance limit its use. This is because polyvinyl acetate is more hydrophilic than the hydrocarbon resin polystyrene-butadiene (the solubility of vinyl acetate monomer in water is 2.8 g/100 g water). Since the r ₁ value for styrene is 0.01 and the r ₂ value for vinyl acetate is 55, it is not possible to copolymerize styrene and vinyl acetate. The unique copolymerizable high molecular weight monomers of this invention combine the properties of polyvinyl acetate and polystyrene and polystyrene-butadiene with the superior adhesion and whiteness of polyvinyl acetate and the superior properties of polystyrene or polystyrene-butadiene latex. Good wet pick resistance and wet friction resistance can be provided. Yet another unique aspect of the present invention is the production of a wet end additive from a graft copolymer.
is to manufacture. For example, treatment of the graft copolymer according to Example 18 with a cationic reagent can yield a wet end additive useful in the paper industry. The process is illustrated by the following reaction scheme starting from the product according to Example 18. The graft copolymer described above is unique because the phase separation of the polyvinyl alcohol moieties incorporates the cationic graft copolymer therein to enhance both the wet and dry strength of the paper. Although the invention has been described with respect to particular embodiments, it will be obvious that it may be further modified and this application is not intended in its broadest scope to cover any variations, uses, or adaptations of the invention in accordance with its principles. Even if such deviations from the present disclosure are included, they are known or customary in the art to which the present invention pertains and can be applied to the essential characteristics described herein, and It is within the scope of the present invention.

Claims (1)

[Claims] 1. A method for producing a hydrogel-like hydrophilic thermoplastic graft copolymer that is chemically bonded, phase separated, and naturally cured, including the following two steps: (1) (a) within the range of about 5,000 to about 50,000; a linear polymer or copolymer with a substantially uniform molecular weight distribution such that the Mw/Mn ratio is less than about 1.1; of a polymerizable hydrophobic large molecular weight monomer which has only a moiety and whose polymerizable moiety is identified as being at the end of its chain.
and (b) forming the polymer backbone of the graft copolymer;
The copolymerizable hydrophobic large molecular weight monomers form the linear polymer side chains of the graft copolymer, and the linear polymer side chains of the graft copolymer are linked to the main chain by the polymerizable end groups on the large molecular weight monomers. At least one hydrophilic (water-soluble) ethylenically unsaturated monomer or an ethylenically unsaturated monomer capable of imparting hydrophilic or water-soluble properties is copolymerized into the polymer, the main chain being copolymerized in the polymer.
polymer units, and the linear polymer side chains of the graft copolymer copolymerized into the copolymer backbone have at least about 20
separated by consecutive monomeric repeating units, and the copolymerization and distribution of side chains along the backbone polymer is relative to the copolymerizable end groups of the hydrophobic large molecular weight monomer and the hydrophilic copolymerizable comonomer. (2) copolymerizing the hydrophilic graft copolymer with from about 99 to about 5% by weight of at least one hydrophilic copolymerizable comonomer, as controlled by the ratio of reactivity of the hydrophilic copolymer; A method as described above comprising the step of contacting with an aqueous liquid to form a hydrogel containing from about 10 to about 95 weight percent aqueous liquid based on the weight of the graft copolymer.