Addition polymers copolymerisation with

Ethylene has also been copolymerised with a number of non-olefinic monomers and of the copolymers produced those with vinyl acetate have so far proved the most significant commercially . The presence of vinyl acetate residues in the chain reduces the polymer regularity and hence by the vinyl acetate content the amount of crystallinity may be controlled. Copolymers based on 45% vinyl acetate are rubbery and may be vulcanised with peroxides. They are commercially available (Levapren). Copolymers with about 30% vinyl acetate residues (Elvax-Du Pont) are flexible resins soluble in toluene and benezene at room temperature and with a tensile strength of about lOOOlbf/in (6.9 MPa) and a density of about 0.95 g/cm. Their main uses are as wax additives and as adhesive ingredients. 

As already shown, it is technically possible to incorporate additive functional groups within the structure of a polymer itself, thus dispensing with easily extractable small-molecular additives. However, the various attempts of incorporation of additive functionalities into the polymer chain, by copolymerisation or free radical initiated grafting, have not yet led to widespread practical use, mainly for economical reasons. Many macromolecular stabiliser-functionalised systems and reactive stabiliser-functionalised monomers have been described (cf. ref. [576]). Examples are bound-in chromophores, e.g. the benzotriazole moiety incorporated into polymers [577,578], but also copolymerisation with special monomers containing an inhibitor structural unit, leading to the incorporation of the antioxidant into the polymer chain. Copolymers of styrene and benzophenone-type UV stabilisers have been described [579]. Chemical combination of an antioxidant with the polymer leads to a high degree of resistance to (oil) extraction. 

Blending, Grafting and Copolymerisation with Biodegradable Polymers and Additives... 

Other trialkyltin-containing monomers such as 3-tributyltinstyrene (84), tributyltin methacrylate (85) and 4-[bis(trimethylstannyl)methyl]styrene (86) were also reported to homo- and copolymerise with styrene under radical conditions175-177. In addition, 3-tributyltinstyrene (84) was copolymerised under radical conditions with ethyl acrylate, methyl methacrylate, vinyl acetate and acrylonitrile175. A functional methacrylate-based polymer was prepared by the copolymerization of the triorganotin methacrylate monomer 87 with styrene and divinylbenzene178,179. 

The syndiospecific polymerisation of propylene with soluble vanadium-based Ziegler Natta catalysts is not completely regiospecific [389 392], i.e. the monomer unit enchainment is not entirely head-to-tail. In addition to syndiotactic stereoblocks, the polymer also contains sterically irregular stereoblocks. The whole polymerisation can be thus described as a copolymerisation with four head-to-tail and tail-to-tail stages [2,379]. 

Polyesters derived from maleic anhydride and 2,2-di(4-hydroxyphenyl)pro-pane were copolymerised with styrene and then studied by CP/MAS NMR [39] spectroscopy. The three dimensional-crosslinked network formed by the polymerisation was examined using spin-lattice relaxation times in the rotating frame. A correlation between reaction conditions and the structure of the resulting material was found. The degree of residual unsaturation was determined by subtraction of two relaxation times from a linear additivity model used for erosslinked polymer systems. 

Addition polymers are of great importance and are obtained from olefin monomers by sequential covalent addition, as discussed in Chapter 1. It was observed in Chapter 2 that many vegetable oils may be heated with other vinyl monomers to modify their surface coating properties. The modification of triglyceride oils by the copolymerisation of drying and semi-drying oils with vinyl monomers such as styrene, a-methylstyrene or cyclopenta-diene, is one of the oldest methods used in vegetable oil-based chemistry. The products obtained by this technique possess improved film properties and styrene has been found to be the most important monomer for this purpose. 

In recent years, crosslinkable polymers have found a wide demand in the areas of interpenetrating polymer networks, non-linear optical materials, macro- and microlithography, and the formation of more thermally and chemically resistant materials. With this in mind, the controlled ROMP of 5-methacryloyl-l-cyclooctene (Scheme 8) was investigated to produce a linear polymer with cross-linkable methacrylate side chains. In addition, the copolymerisation of this monomer with cyclooctadiene (Scheme 9) allowed for the incorporation of a varying number of methacrylate side chains on the polymer backbone [23]. These copolymers were crosslinked through the methacrylate side chains with either thermal or photochemical initiation. Reaction of this multifunctionalised methacrylate polymer with methyl methacrylate under free radical polymerisation conditions led to the formation of AB crosslinked systems of poly(methyl methacrylate). A comparison of the... 

In some cases, certain properties of a polymer can be enhanced by blending it with another polymer or by copolymerisation with a suitable monomer pair. Additives may be mixed with the polymer before processing by a variety of techniques, such as dry blending, extrusion, compounding, and other methods discussed in Chapter 8. 

PVC is also copolymerised with other monomers such as vinyl acetate, vinylidene chloride propylene and acrylonitrile. Copolymerisation with vinyl acetate tends to soften the polymer to the point that plasticiser addition may be unnecessary. For low temperature applications, plasticiser addition may still be desirable and in this form the copolymer is used in the fabrication of refrigerator trays. 

The earliest synthetic resin to be used in commerce seems to have been a polyester then termed ester gum, which was made by esterifying rosin (essentially an unsaturated monocarboxylic terpenoid acid, abietic acid) with glycerol. When cooked with tung oil (a glycerol ester of 9,11,13-octadecatrienoic acid), this provided varnishes that dried overnight. In this case, the polymer is formed by an addition copolymerisation process, but the product is nevertheless also a polyester. 

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