Polyolefins vinyl monomers

Peroxidic groups in oxidized polyolefins have frequently been employed as sources of free radicals to allow grafting of vinyl monomers to polyolefins (2f[). Some of the products from the gas reactions also have interesting potential as reactive sites. For example, chloroformate groups are well known to react with alcohols, and amines 2J[). Thus chloroformate groups could be useful for example in coupling highly oriented polyolefin fibres to resins such as epoxy based systems. 

Most general purpose linear polymers, such as polyolefins, PS, PVC, and polymethyl methacrylate (PMMA), are not suitable for use at temperatures above 100 °C. PMMA and other polymers of 1,1-substituted vinyl monomers, such as poly-a-methylstyrene, decompose almost quantitatively to their monomers at elevated temperatures. However, the Tg and Tm values of these polymers are greater than those of polymers from 1-substituted vinyl monomers. For example, the Tg values of polymethyl acrylate (PMA) and PMMA are 276 and 381 K, respectively. 

They are able to polymerize a large variety of vinyl monomers. The polymer microstructure can be controlled by the symmetry of the catalyst precursor. Prochiral alkenes such as propylene can be polymerized to give stereospecific polymers,554 572-574 allowing production of polyolefin elastomers. They can give polyolefins with regularly distributed short- and long-chain branches which are new materials for new applications. 

T his paper presents a polymerization reaction, as yet unreported in the literature, wherein block polymerization of a free radical type can be caused to take place onto an actively growing chain which had proceeded by an anionic mechanism. Specifically, a Ziegler type of polymerization, such as that of propylene or ethylene, can be interrupted by adding vinylic monomers and an organic peroxide, and a vinyl polymer grown on the end of the polyolefin. For simplicity we will refer to these types as anionic free radical (AFR) polymerizations. 

A major objective of our research has been to introduce polar groups into polyolefin molecules. With the anionic type of catalysts, copolymerization is very difficult because most nonhydrocarbon vinylic monomers deactivate the catalyst system and stop olefinic polymerization. However, by the AFR route, the desired olefin is completely polymerized before polar monomers are introduced so that high yields of product are possible. 

Polyolefins and Modified Polyolefins Weather-Resistant Grafts of Vinyl Monomers to EPDM and Polyacrylates... 

During the past 20 years, there has been much interest in understanding the grafting of polar vinyl monomers to polyolefins (PO). The grafting process can be performed in an inert solvent or in a PO melt. A direct grafting of a monomer to chains in molten PO that follows the free-radical mechanism appears more preferable, and it has been studied more widely. It is most often done by means of reactive extrusion (RE), where an extruder is used as a reactor of continuous action. This technology permits the production of a variety of functionalized PO (1-8). 

Vainio et al. (27) have studied the grafting of ricinoloxazoline maleate to PP and reported that the use of styrene did not increase the reaction efficiency in some instances it decreased the latter while the degradation of polypropylene decreased markedly. The copolymerization constant value could be the basic point in explaining the effect of styrene on the grafting of vinyl monomers to polyolefins and concurrent secondary reactions (27). 

Modern electron processors offer high speed (high dose-rate) curing of low viscosity liquid coatings so that surface modification of films becomes practicable. A process has been developed for grafting vinyl monomers to polyolefin film surfaces with the aid of functional silane primers using electron initiated polymerization. 

Useful film-forming resin adhesives include polyvinyl esters and ethers and their copolymers and interpolymers with ethylene and vinyl monomers, acrylic resins and their copolymers, polyvinyl alcohol, water dispersion of polyolefin resins, polystyrene copolymers such as polystyrene butadiene, polyamide resins, natural rubber dispersions, and natural and modified carbohydrates (starch or carboxycellulose). Particularly preferred for use are aqueous dispersions of polyvinyl acetate and vinyl acetate-ethylene copolymers. 

Numerous nylon blends prepared by compatibilization or reactive blending are commercially successful. The modifiers fiequenfly utilized in commercial nylon blends include polyolefin, thermoplastic polyolefin, thermoplastic polyunethane, ionomer, elastomer, ethylene-propylene rubber, nitrile mbber, polyftetrafluoroethylene), poly (phenylene ether), poly(ether amide), silicone, glass fiber, and carbon fiber. The nonpolar modifiers such as polyolefin, maleic anhydride or a polar vinyl monomer such as acrylic acid, methaciylic acid and fimiaric acid is fiequently incorporated to introduce reactive sites in nylon. 

To prepare polyolefin blends, PO (e.g., EVAc, PE, PP, EPR), with vinyl polymers, 10-200 parts of vinyl monomer [e.g., (meth)acrylates, styrenics, vinyl chloride, glycidyl methacrylate, maleic anhydride, acrylonitrile, divinylbenzene] and 0.01-4.0 parts of a free radical initiator were used to impregnate 100 parts of PO particles at T = 20-130 °C. After 50-99 wt% of the monomer was absorbed, the particles were dispersed in water and the free radical polymerization initiated. Good adhesion between the components in the extruded or molded articles was achieved... 

LRP is a powerful tool for the synthesis of complex polymer architectures as was shown above. However, in some cases it is desirable to combine structures that are hardly or not at all accessible via radical polymerization techniques. In such cases it may be beneficial to combine LRP with another polymerization mechanism. Many examples have been reported so far. A few examples will be listed here. Polystyrene-6-pol3risobutylene-6-polystyrene was synthesized via a combination of living cationic polymerization and ATRP (98). Polyolefin Graft Copolymers (qv) were synthesized by first polymerizing alkoxyamine-substituted olefins via metallocene catalysis, and subsequent polymerization of vinyl monomers via... 

Vinyl fibers are those man-made fibers spun from polymers or copolymers of substituted vinyl monomers and include vinyon, vinal, vinyon-vinal matrix (polychlal), saran, and polytetrafluoroethylene fibers. Acrylic, modacrylic and polyolefin—considered in Chapters 8 and 9—are also formed from vinyl monomers, but because of their wide usage and particular properties they are usually considered as separate classes of fibers. The vinyl fibers are generally specialty fibers due to their unique properties and uses. AH of these fibers have a polyethylene hydrocarbon backbone with substituted functional groups that determine the basic physical and chemical properties of the fiber. 

Synthetic polymers with conformational chirality have become a research field of widespread interest in recent years, and a wide range of polymers with conformational chirality have been synthesized from various types of monomers including vinyl monomers [9, 61-63, 128-136]. The existing examples of optically active vinyl polymers with conformational chirality include isotactic, helical polyolefins bearing asymmetric side chains [133-135] and isotactic, hehcal polymethacrylates bearing bulky, achiral side chains [61-63,136]. These polymers have stereocenters in the main and/or side chains. Optically active poly(PDBS) is the first vinyl polymer with conformational chirality bearing no stereocenters in the main and side chains whose chiroptical properties arise only from a chiral conformation. 

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