MXPA06007309A - Free-radical initiation in the presence of a stable organic free radical and related compositions - Google Patents

Abstract

The present invention is an improved polymeric composition comprising a free-radical reactive polymer, an organic peroxide, and a graftable stable organic free radical. The present invention permits suppression of an undesirable degradation or carbon-carbon crosslinking reaction while permitting the polymer to undergo the desirable grafting reaction.

Description

INITIATION OF FREE RADICAL IN THE PRESENCE OF A STABLE ORGANIC RADICAL LI BRE, AND COMPOSITION IS RELATED FIELD OF THE I NVENTION This invention relates to polymeric systems that are subjected to free-radical reactions, where organic peroxides are used to generate the free radicals, and a stable, free organic radical mediates free-radical reactions.

DESCRIPTION OF THE PREVIOUS TECHNIQUE Many polymers can be subjected to free radical reactions. Some of these reactions are harmful, such as degradation, premature carbon-to-carbon entanglement or general carbon-to-carbon entanglement. Stable organic free radicals, which are described in patent applications filed concurrently with the present, can be used to mediate such free radical reactions. An additional control in these free radical reactions is desired, so as to increase the efficiency of the desired reactions. It is convenient to select an organic peroxide that facilitates better control of free radical reactions. It is particularly convenient that the organic peroxide be useful when grafting the stable organic free radical into the polymer. That way you can set various functional groups (hydroxyl, amine, carboxyl, urethane, etc.), to the free organic radical, stable and, in such a way, it can be used to functionalize a variety of polymers, such as polyethylene, polypropylene and polystyrene, using conventional chemistries of free radical.

BRIEF DESCRIPTION OF THE INVENTION The present invention is an improved polymer composition comprising a polymer reactive with free radical, an organic peroxide and an organic, stable, graft-free radical. The present invention allows the suppression of an undesirable carbon-to-carbon undesirable degradation or crosslinking reaction, while allowing the polymer to be subjected to the desirable grafting reaction. The present invention is useful in wire and cable, footwear, film (e.g., greenhouse, shrinkable and elastic), engineering thermoplastic, high load reactive, flame retardant, thermoplastic elastomer, thermoplastic vulcanized, replacement of vulcanized automotive rubber, construction, automotive, furniture, foam, moistening, adhesive, paintable substrates, dyeable polyolefin, moisture cure, nanocompositions, compatibilization, wax, calendered sheet, medical, dispersion, coextrusion, cement / plastic reinforcement, packaging for food, non-woven fabrics, paper modification, various containers layers, sports articles, oriented structure and applications for surface treatment.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows MDR torque data for polymeric compositions grafted with 4-hydroxy-TEMPO, which have varying amounts of Luperox 130 organic peroxide and dicumyl peroxide. Figure 2 shows the percentage of grafted 4-hydroxy-TEMPO, as determined by nuclear magnetic resonance data for polymeric compositions grafted with 4-hydroxy-TEMPO. Figure 3 shows the amount of methylation, as determined by nuclear magnetic resonance data for polymeric compositions grafted with 4-hydroxy-TEMPO.

DESCRIPTION OF THE INVENTION "Catalyzed polymer with restricted geometry catalyst", "CGC catalyzed polymer" or a similar term, when used herein, means any polymer that is made in the presence of a constrained geometry catalyst. "Restricted geometry catalyst" or "CGC", when used herein, has the same meaning as this term when it was defined and described in U.S. Patent Nos. 5,272,236 and 5,278,272.

"Long chain branching (LBC)", when used herein, means, for example, co ethylene / alpha-olefin copolymers, a chain length greater than the short chain branching resulting from the incorporation of the alpha-olefin (s) in the polymer backbone. Each long chain branch has the same comonomer distribution as the polymer backbone, and can be as long as the backbone of the polymer to which it is attached. "Metallocene", when used herein, means a metal-containing compound, having at least one substituted or unsubstituted cyclopentadienyl group, attached to the metal. "Metallocene catalyzed polymer", or a similar term, means any polymer that is made in the presence of a metallocene catalyst. "Polydispersity", "molecular weight distribution" and similar terms, when used herein, mean a ratio (Mw / Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn). "Polymer", when used herein, means a macromolecular compound prepared by polymerizing monomers of the same type or of a different type. "Polymer includes homopolymers, copolymers, terpolymers, interpolymers, etc. The term" interpolymer "means a polymer prepared by the polymerization of at least two types of monomers or comonomers, including, but not limited to: copolymers (to which is usually referred to as polymers prepared from two different types of monomers or comonomers; although it is frequently used interchangeably with "ether polymer" to refer to polymers made from three or more different types of monomers or comonomers), terpolymers (which usually refers to polymers prepared from three different types of monomers or comonomers), tetrapolymers (referred to usually to polymers prepared from four different types of monomers or comonomers), and the like. The terms "monomer" or "comonomer" are used interchangeably, and refer to any compound with a polymerizable portion, which is added to a reactor in order to produce a polymer. In those cases in which a polymer comprising one or more monomers is described, for example, a polymer comprising propylene and ethylene, the polymer, of course, comprises units derived from the monomers, for example, -CH2-CH2- and not the monomer itself, for example, CH2 = CH2. "P / E * copolymer" and similar terms, when used herein, mean an unsaturated propylene / comonomer copolymer, characterized in that it has at least one of the following properties: (1) 13 C NMR peaks corresponding to a regio -ror to around 14.6 and around 15.7 ppm; the peaks being of approximately the same intensity; and (ii) a differential scanning calorimetry (DSC) curve with a Tmc that remains essentially the same and a Tpc that decreases as the amount of comonomer increases, i.e. the units derived from ethylene and / or the comonomer or the unsaturated comonomers, in the copolymer. "Tme" means the temperature at which the fusion ends. "Tpic" means the peak melting temperature. Typically, copolymers are characterized of this modality by these two properties. Each of these properties and their respective measurements are described in U.S. Patent Application Serial No. 1 0 / 139,786, filed May 5, 2002 (WO 200/040442), which is incorporated herein by way of this reference. . These copolymers can additionally be characterized by having an asymmetry index Si x of more than about -1.20. The asymmetry index is calculated from the data obtained from fractionation by elution with temperature rise (TREF). The data is expressed as a standardized diagram of the weight fraction, as a function of the elution temperature. The molar content of the isotactic propylene units determines primarily the elution temperature. A prominent feature of the shape of the curve is the excessive prolongation at the lowest elution temperature, compared to the sharpness or inclination of the curve at the highest elution temperatures. A statistic that reflects this type of asymmetry is asymmetry. Equation 1 mathematically represents the asymmetry index, Sx as a measure of this asymmetry.

Equation 1 The Tmax value is defined as the temperature of the maximum weight fraction that elutes between 60 and 90 ° C in the TREF curve. Tj and wj are the elution temperature and the weight fraction, respectively, of a arbitrary fraction in the distribution of TREF. The distributions had been normalized (the sum of wi is equal to 100 percent) with respect to the total area of the curve eluting above 30 ° C. Thus, the index reflects only the shape of the crystallized polymer. Any non-crystallized polymer (polymer still in solution at 30 ° C or less) is omitted from the calculation shown in equation 1. The unsaturated comonomers for the P / E * copolymers include alpha-olefins of 4 to 20 carbon atoms, especially alpha-olefins of 4 to 12 carbon atoms, such as 1-butene, 1-pentene, 1 -hexene, 4-methyl-1-pentene, 1-heptene, 1-ketene, 1 -decene, 1 -dodecene and the like; diolefins of 4 to 20 carbon atoms, preferably 1,3-butadiene, 1,3-pentadiene, norbornadiene, 5-ethylidene-2-norbornene (ENB) and dicyclopentadiene; vinyl aromatic compounds of 8 to 40 carbon atoms, including styrene, o-, m-, and p-methylstyrene, divinylbenzene, vinylbiphenyl, vinylnaphthalene; and vinyl aromatic compounds of 8 to 40 carbon atoms, substituted with halogen, such as chlorostyrene and fluorostyrene. Ethylene and alpha-olefins of 4 to 12 carbon atoms are the preferred comonomers; and ethylene is an especially preferred comonomer. The P / E * copolymers are a unique subset of the P / E copolymers. The P / E copolymers include all copolymers of propylene and an unsaturated comonomer, not just the P / E * copolymers. P / E copolymers that are not P / E * copolymers include metallocene catalyzed copolymers, catalyzed copolymers with restricted geometry and Z-catalyzed copolymers N-. For the purposes of this invention, the P / E copolymers comprise 50 weight percent or more of propylene; while the EP (ethylene-propylene) copolymers comprise 51 weight percent or more of ethylene. As used herein, "comprise ... propylene", "comprise ... ethylene" and similar terms, mean that the polymer comprises units derived from propylene, ethylene or the like, as opposed to the compounds themselves. "Propylene homopolymer" and similar terms mean a polymer consisting solely or essentially of units derived from propylene. "Polypropylene copolymer" and similar terms mean a polymer comprising units derived from propylene and ethylene and / or one or more unsaturated comonomers. "Ziegler-Natta-catalyzed polymer", "Z-N catalyzed polymer" or similar terms, mean any polymer that is formed in the presence of a Ziegler-Natta catalyst. In one embodiment, the present invention is a polymer composition comprising a polymer reactive with free radical, an organic peroxide having a half-life measured at 130 ° C or more, greater than that of dicumyl peroxide and an organic free radical, stable , injectable. Free-radical-reactive polymers include free radically degradable polymers and free radical crosslinkable polymers. When the free radical reactive polymer is a free radical degradable polymer, the polymer undergoes a degradation reaction in the absence of a stable organic free radical, and when induces by organic peroxide. The degradation reaction can be a chain split or a dehydrohalogenation. The stable organic free radical substantially suppresses the degradation reaction and is grafted onto the polymer, after the polymer forms a free radical. When the free radical-reactive polymer is a crosslinkable polymer with free radical, the polymer undergoes a carbon-to-carbon crosslinking reaction in the absence of a stable organic free radical, and when induced by the organic peroxide. The species that traps the free radical substantially suppresses the carbon-to-carbon crosslinking reaction, and is grafted onto the polymer after the polymer forms a free radical. A variety of free radical degradable polymers is useful in the present invention as a polymer. The free radical degradable polymer may be hydrocarbon based. Suitable free-radical degradable hydrocarbon-based polymers include butyl rubber, polyacrylate rubber, polyisobutene, propylene homopolymers, propylene copolymers, styrene / butadiene / styrene block copolymers, styrene / ethylene / butadiene copolymers / styrene; polymers of vinyl aromatic monomers, vinyl chloride polymers, and mixtures thereof Preferably the hydrocarbon-based polymer, degradable with free radical, is selected from the group consisting of polymers of isobutene, propylene and styrene. Preferably the butyl rubber of the present invention is a copolymer of isobutylene and isoprene. Isoprene is typically used in an amount of between about 1.0 percent by weight and about 3.0 percent by weight. Examples of propylene polymers useful in the present invention include propylene homopolymers and P / E copolymers. In particular, these propylene polymers include polypropylene elastomers. The propylene polymers can be made by any process and can be made by Ziegler-Natta catalysis, CGC, metallocene and metallocene-free, metal-centered, with heteroaryl ligand. Useful propylene copolymers include random, block and graft copolymers. Examples of propylene copolymers include VISTAMAX from Exxon-Mobil, TAFMER from Mitsui and VERSIFY ™ from The Dow Chemical Company. The density of these copolymers is typically at least about 0.850, preferably at least about 0.860 and, more preferably, at least about 0.865 grams per cubic centimeter (g / cm3). Typically, the maximum density of these propylene copolymers is about 0.915, preferably the maximum is about 0.900 and, most preferably, the maximum is about 0.890 g / cm3. The weight average molecular weight (Mw) of these propylene copolymers can vary widely; but typically it is between about 10,000 and 1,000,000. The polydispersity of these copolymers is typically between about 2 and about 4. These propylene copolymers typically have a melt flow rate (MFR) of at least about 0. 01, preferably at least about 0.05 and, more preferably, at least about 0.1. The maximum MFR typically does not exceed about 2,000; preferably, it does not exceed about 1,000; more preferably, it does not exceed about 500; still more preferable, it does not exceed about 80 and, most preferred, does not exceed about 50. The MFR for the copolymers of propylene and ethylene and / or one or more alpha-olefins of 4 to 20 carbon atoms is measured in accordance with ASTM D-1238, condition L (2.16 kg, 230 ° C). The styrene / butadiene / styrene block copolymers useful in the present invention are a separate phase system. The styrene / ethylene / butadiene / styrene copolymers are also useful in the present invention. Vinyl aromatic polymers are useful in the present invention. Suitable vinyl aromatic monomers include, but are not limited to, those vinyl aromatic monomers known for use in polymerization processes, such as those described in U.S. Patent Nos. 4,666,987, 4,572.81 9 and 4,585,825. Preferably, the monomer has the formula: K Ar -C = CH2 wherein R 'is hydrogen or an alkyl radical containing three carbon atoms or less; Ar is an aromatic ring structure having from 1 to 3 aromatic rings, with or without substitution with alkyl, halo or haloalkyl; where any alkyl group contains 1 to 6 atoms of carbon and haloalkyl refers to an alkyl group substituted with halo. Preferably Ar is phenyl or alkylphenyl; wherein alkylphenyl refers to a phenyl group substituted with alkyl; phenyl being the most preferred. Typical vinyl aromatic monomers, which may be used, include: styrene, alpha-methylstyrene, all isomers of vinyltoluene, especially para-vinyltoluene; all the isomers of ethylstyrene, propylstyrene, vinylbiphenyl, vinylnaphthalene, vinylanthracene and the like, and mixtures thereof. The vinyl aromatic monomers can also be combined with other copolymerizable monomers. Examples of such monomers include, but are not limited to: acrylic monomers, such as acrylonitrile, methacrylonitrile, methacrylic acid, methyl methacrylate, acrylic acid and methyl acrylate; maleimide, phenylmaleimide and maleic anhydride. In addition, polymerization can be carried out in the presence of predisposed elastomer to prepare products containing fied or grafted impact rubber; examples of which can be found in U.S. Patent Nos. 3, 123,655, 3,346,520, 3,639,522 and 4,409,369. The present invention is also applicable to rigid polymer, matrix or continuous phase, polymeric monovinylidene aromatic compositions, fied with rubber. A variety of free-radical, carbon-to-carbon crosslinkable polymers is useful in the present invention as a polymer. The polymer can be hydrocarbon based. Suitable polymers, based on hydrocarbon, crosslinkable from carbon to carbon, radical free, include: acrylonitrile-butadiene-styrene rubber; chloroprene rubber; chlorosulfonated polyethylene rubber; ethylene / alpha-olefin copolymers; ethylene / diene copolymer; ethylene homopolymers, ethylene / propylene / diene monomers; ethylene / propylene rubbers; ethylene / styrene interpolymers; ethylene / unsaturated ester copolymers; fluoropolymers, halogenated polyethylenes, hydrogenated nitrile-butadiene rubber, natural rubber, nitrile rubber, polybutadiene rubber, silicone rubber, styrene / butadiene rubber, styrene / butadiene / styrene block copolymers, styrene / ethylene / butadiene copolymers / styrene, and mixtures of them. For the present invention, the chloroprene rubbers are generally 2-chloro-1,3-butadiene polymers. Preferably, the rubber is produced by an emulsion polymerization. Additionally, polymerization in the presence of sulfur can occur to incorporate the entanglement in the polymer. It is preferred that the free-radical, carbon-to-carbon crosslinkable hydrocarbon polymer be an ethylene polymer. With respect to the appropriate ethylene polymers, polymers generally fall into four main classifications: (1) highly branched; (2) heterogeneous linear; (3) linear with homogeneous branching; and (4) substantially linear with homogeneous branching. These polymers can be prepared with Ziegler-Natta catalysts, with single-site catalysts, based on metallocene or vanadium, or with single-site catalysts, restricted geometry. The highly branched ethylene polymers include low density polyethylene (LDPE). These polymers can be prepared with a free radical initiator at high temperatures and high pressure. Alternatively, they can be prepared with a coordination catalyst at high temperatures and relatively low pressures. These polymers have a density of between about 0.910 grams per cubic centimeter and about 0.940 grams per cubic centimeter when measured by ASTM D-792. Linear, heterogeneous ethylene polymers include linear low density polyethylene (LLDPE), ultra low density polyethylene (U LDPE), very low density polyethylene (VLDPE) and high density polyethylene (HDPE). The linear low density ethylene polymers have a density between about 0.850 grams per cubic centimeter and about 0.940 grams per cubic centimeter, and a melt index between about 0.01 and about 100 grams per 10 minutes, when measured by ASTM 1238, condition I. Preferably the melt index is between about 0.1 and about 50 grams per 10 minutes. Also preferably the LLDPE is an interpolymer of ethylene and one or more other alpha-olefins having from 3 to 18 carbon atoms, more preferably, from 3 to 8 carbon atoms. Preferred comonomers include: 1-butene, 4-methyl-1-pentene, 1 -hexene and 1-ketene. Ultra low density polyethylene and very low density polyethylene are known interchangeably. These polymers have a density of between about 0.870 grams per centimeter cubic and around 0.91 0 grams per cubic centimeter. High density ethylene polymers are generally homopolymers with a density between about 0.941 grams per cubic centimeter and about 0.965 grams per cubic centimeter. Linear ethylene polymers, branched homogeneously, include homogeneous LLDPE. The uniformly branched / homogeneous polymers are those polymers in which the comonomer is randomly distributed within a given interpolymer molecule; and where the interpolymer molecules have a similar proportion of ethylene / comonomer, within that interpolymer. Homogeneously branched, substantially linear ethylene polymers include: (a) olefin homopolymers of 2 to 20 carbon atoms, such as ethylene, propylene and 4-methyl-1-pentene; (b) interpolymers of ethylene with at least one alpha-olefin of 3 to 20 carbon atoms, monomer of 2 to 20 acetylenically unsaturated carbon atoms, diolefin of 4 to 18 carbon atoms, or combinations of the monomers; and (c) interpolymers of ethylene with at least one of the alpha-olefins of 3 to 20 carbon atoms, diolefins or acetylenically unsaturated monomers, in combination with other unsaturated monomers. These polymers generally have a density of between about 0.850 grams per cubic centimeter and about 0.970 grams per cubic centimeter. Preferably the density is between about 0.85 grams per cubic centimeter and about 0.955 grams per cubic centimeter; more preferable, between about 0.850 grams per cubic centimeter and 0.920 grams per cubic centimeter.

The ethylene / styrene interpolymers useful in the present invention include substantially random interpolymers, prepared by polymerizing an olefin monomer (i.e., ethylene, propylene or alpha-olefin monomer) with a vinylidene aromatic monomer, hindered aliphatic vinylidene monomer, or cycloaliphatic vinylidene monomer. Suitable olefin monomers contain from 2 to 20 carbon atoms, preferably from 2 to 12 carbon atoms, more preferably from 2 to 8 carbon atoms. Preferred among said monomers include: ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1 -hexene and 1-ketene. The most preferred with ethylene and a combination of ethylene with propylene or with alpha-olefins of 4 to 8 carbon atoms. Optionally, the polymerization components of ethylene / styrene interpolymers may also include ethylenically unsaturated monomers, such as enforced ring olefins. Examples of enforced ring olefins include: norbornene and the alkyl-substituted norbornenes of 1 to 10 carbon atoms or with aryl of 6 to 10 carbon atoms. The ethylene / unsaturated ester copolymers useful in the present invention can be prepared by conventional high pressure techniques. The unsaturated esters may be alkyl acrylates, alkyl methacrylates or vinyl carboxylates. The alkyl groups may have from 1 to 8 carbon atoms, and preferably have from 1 to 4 carbon atoms. The carboxylate groups can have from 2 to 8 carbon atoms and, preferably, have from 2 to 5 carbon atoms. The portion of the copolymer attributed to the ester comonomer may be on the approximate scale of about 5 to about 50 percent by weight, based on the weight of the copolymer; and it is preferred that it be on the scale of about 15 weight percent to about 40 weight percent. Examples of acrylates and methacrylates are: ethyl acrylate, methyl acrylate, methyl methacrylate, tertbutyl acrylate, n-butyl acrylate, n-butyl methacrylate and 2-ethylhexyl acrylate. Examples of the vinyl carboxylates are: vinyl acetate, vinyl propionate and vinyl butanoate. The melt index of the ethylene / unsaturated ester copolymers can be in the range of about 0.5 grams per 10 minutes to about 50 grams per 10 minutes. The halogenated ethylene polymers useful in the present invention include fluorinated, chlorinated and brominated olefin polymers. The base olefin polymer can be a homopolymer or an interpolymer of olefins having from 2 to 18 carbon atoms. Preferably the olefin polymer will be an interpolymer of ethylene with propylene or an alpha-olefin monomer having from 4 to 8 carbon atoms. Preferred alpha-olefin comonomers include: 1-butene, 4-methyl-1-pentene, 1 -hexene and 1-ketene. Preferably the halogenated olefin polymer is a chlorinated polyethylene. Natural rubbers suitable in the present invention include polymers of isoprene of high molecular weight. Preferably the natural rubber will have an average degree of polymerization of about 5,000 and a broad molecular weight distribution. It is preferable that the nitrile rubber of the present invention be a random copolymer of butadiene and acrylonitrile. The polybutadiene rubber useful in the present invention is preferably a 1,4-butadiene homopolymer. Useful styrene / butadiene rubbers include the random copolymers of styrene and butadiene. These rubbers are typically produced by polymerization with free radical. The styrene / butadiene / styrene block copolymers of the present invention are a separate phase system. The styrene / ethylene / butadiene / styrene copolymers are also useful in the present invention. Examples of organic peroxides useful in the present invention include dialkyl peroxides. It is preferable that the organic peroxide be a dialkyl peroxide, selected from the group consisting of 2,5-bis (terbutylperoxy) -2,5-dimethylhexane and 2,5-bis (terbutylperoxy) -2,5-dimethyl-3- Hex. It is more preferable that the organic peroxide be 2,5-bis (tert-butylperoxy) -2,5-dimethyl-3-hexyne. Organic peroxide can be added through direct injection. Preferably the free radical-inducing species is present in an amount between about 0.005 weight percent and about 20.0 weight percent; more preferably, between about 0.01 weight percent and about 10.0 weight percent; and what is most preferred, between about 0.03 weight percent and about 5.0 weight percent. Stable organic free radicals, useful for use in the present invention, include stable organic free radicals, hindered amine derivatives. When the stable organic free radical is a stable organic free radical, derived from hindered amine, is preferably a hydroxy derivative of 2,2,6,6-tetramethyl-piperidinyl-oxy (TEMPO). It is more preferred that the free radical scavenger species be 4-hydroxy-TEMPO or a bis-TEMPO. An example of a bis-TEMPO bis (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) sebacate. In addition, the stable organic free radical can be a multifunctional molecule having at least two nitroxyl groups derived from oxo-TEMPO, 4-hydroxy-TEMPO, an ester of 4-hydroxy-TEMPO, TEMPO, PROXYL, DOXYL attached to polymer, diterbutyl-n-oxyl, dimethyl-diphenyl-pyrrolidin-1-oxoyl, or 4-phosphonooxy-TEMPO. Various functional groups (eg, hydroxyl, amine, carboxyl, urethane, etc.) can be connected to the stable organic free radical, and in such a way, it can be used to functionalize a variety of polymer, such as polyethylene, polypropylene and polystyrene, using conventional free radical chemistries. This functionality can be used to impart the desired performance benefits, such as (but not limited to): possibility to paint them, possibility of dyeing them, possibility of interlacing them, etc. Preferably, the stable organic free radical is present in an amount between about 0.005 weight percent and about 20.0 weight percent; more preferably, between about 0.01 weight percent and about 10.0 weight percent; and most preferred, between about 0.03 weight percent and about 5.0 weight percent. Preferably the ratio of organic peroxide to stable organic free radical, and the concentration of stable organic free radical promote the desired graft reaction. More preferably, the organic peroxide, relative to the stable organic free radical, is present in a ratio of more than about 1, more preferable, between about 20: 1 and about 1: 1. Organic peroxide and stable organic free radical can be combined with the polymer, in a variety of ways, including direct compound formation, direct soaking and direct injection. In an alternate embodiment, the present invention is a polymeric composition comprising a free radical reactive polymer, an organic peroxide subject to methyl radical formation to a lesser extent than dicumyl peroxide, at the free radical reaction temperature, and a stable organic free radical, grafting. Examples of organic peroxides useful in the present invention include dialkyl peroxides. Preferably the organic peroxide is a dialkyl peroxide, selected from the group consisting of 2,5-bis (tert-butylperoxy) -2,5-dimethylhexane and 2,5-bis (tert-butylperoxy) -2,5-dimethyl-3-hexyne . It is more preferable that the organic peroxide be 2,5-bis (tert-butylperoxy) -2,5-dimethyl-3-hexyne. Organic peroxide can be added by direct injection. It is preferable that the free radical-inducing species be present in an amount between about 0.005 weight percent and about 20.0 weight percent; more preferably, between about 0.01 weight percent and about 1 0.0 weight percent; and what is most preferred, between about 0.03 weight percent and about 5.0 weight percent. In a preferred embodiment, the present invention is an article of manufacture prepared from the polymer composition. Any number of processes can be used to prepare the articles of manufacture. The specifically useful processes include: injection molding, extrusion, compression molding, rotational molding, thermoforming, blow molding, powder coating, intermittent Banbury mixers, fiber spinning and calendering. Suitable articles of manufacture include: insulation for wire and cable, wire and cable semiconductor articles, wire and cable liners and liners, cable accessories, shoe soles, multi-component shoe soles (including polymers of different densities and of different types), weather stripping, packaging, profiles, durable articles, rigid stretch tape, inserts for deflated tires, construction panels, mixed structures (for example, mixed wooden structures), pipes, foams, blown films and fibers (including binder fibers and elastic fibers).

EXAMPLES The following non-restrictive examples illustrate the present invention.

COMPARATIVE EXAMPLE 1 AND EXAMPLE A comparative example and an example of the present invention were prepared, with a low density polyethylene having a melt index of 2.4 grams per 10 minutes, 121/12 of 52, a density of 0.9200 grams per cubic centimeter and a polydispersity ( Mw / Mn) of 3.54, and a melting point of 10.2 ° C. The goal was the preparation of a LDPE grafted with 2.0 weight percent 4-hydroxy-TEMPO. Before mixing, the polyethylene was vacuum dried to remove any residual moisture. Each of the formulations shown in Table I, excluding peroxide, were prepared in a Brabender mixer to form samples of 40 grams at 125 ° C for three minutes. The peroxide was subsequently added. The composition was formed for an additional four minutes. The mixing bowl was purged with nitrogen. The low density polyethylene DXM-446 was obtained commercially from The Dow Chemical Company. The 4-hydroxy-TEMPO was commercially obtained from A. H. Marks. Luperox ™, 2,5-bis (tert-butylperoxy) -2,5-dimethyl-3-hexyne, an organic peroxide, was obtained commercially from Atofina. The Dicup R ™ dicumyl peroxide commercially available from Geo Specialty Chemicals was commercially available. Test specimens were interlaced by processing the samples for fifteen minutes on a movable die rheometer (MDR) at 200 ° C, at a frequency of 1 00 cycles per minute, and with an arc of 0.5 degrees.

TABLE 1 Figure 1 shows the MDR torque data for various amounts of the compositions containing organic peroxide Luperox 130 and dicumyl peroxide. Figure 2 shows the nuclear magnetic resonance data that refer to the percentage of grafted 4-hydroxy-TEMPO. Figure 3 shows the NMR data that refer to the amount of methylation.

Claims (6)

1 .- A polymeric composition, characterized in that it comprises: (a) a polymer reactive with free radical; (b) an organic peroxide having a half-life, measured at least 130 ° C, greater than that of dicumyl peroxide; and (c) an organic, stable, graft-free radical; wherein the stable, organic free radical: (i) substantially suppresses the degradation of the polymer in the presence of the free radical-inducing species; and (ii) it is grafted onto the polymer after the polymer forms a free radical.

2. A polymeric composition, characterized in that it comprises: (a) a polymer reactive with free radical; (b) an organic peroxide having a half-life, measured at 130 ° C, greater than that of dicumyl peroxide; and (c) a stable, graft-free organic radical; wherein the stable, free organic radical: (i) substantially suppresses the carbon-carbon entanglement in the polymer, in the presence of the free radical-inducing species; and (ii) it is grafted onto the polymer after the polymer forms a free radical.

3. A polymeric composition, characterized in that it comprises: (a) a polymer reactive with free radical; (b) an organic peroxide subject to methyl radical formation to a lesser degree than dicumyl peroxide, at the free radical reaction temperature; and (c) an organic, stable, graft-free radical; wherein the stable, organic free radical: (i) substantially suppresses the degradation of the polymer in the presence of the free radical-inducing species; and (ii) it is grafted onto the polymer after the polymer forms a free radical.

4. A polymeric composition, characterized in that it comprises: (a) a polymer reactive with free radical; (b) an organic peroxide subject to methyl radical formation, to a lesser degree than dicumyl peroxide, at the temperature of the free radical reaction; and (c) an organic, stable, graft-free radical; where the stable organic free radical: (i) substantially suppresses the carbon-carbon entanglement of the polymer, in the presence of the free radical-inducing species; and (ii) it is grafted onto the polymer after the polymer forms a free radical.

5. The polymer composition according to any of claims 1 to 4, further characterized in that the stable, graft-free organic radical has a functional group.

6. The composition according to claim 5, further characterized in that the functional group is selected from the group consisting of a hydroxyl group, amino groups, carboxyl groups and urethane groups.