Other Unsaturated Copolymers

Ethylene-co-allene polymers, as prepared with (iso-Bu)3Al-VCl3 catalyst, have side-chain methylene, side-chain vinyl, in-chain cis, and in-chain trans unsaturation.The side-chain methylene moiety appears to predominate in the copolymer. The copolymer is easily grafted with MA via the Diels-Alder reaction. Films of the grafted material, in comparison to ungrafted copolymer, exhibited greatly enhanced printability, due to the increased polarity. Polyal-lene has also been treated with MA and maleimides to obtain Diels-Alder type grafting and new polymers for possible use in coatings. Little is known about the properties of these modified polymers and copolymers. 

It is well known that MA has a stabilizing influence on poly(vinyl chloride) in the mill. ° The presence of only 1-3% free MA inhibits thermal degradation of PVC. The effects of MA on the dehydrochlorination reaction of PVC has received substantial study. Retardation of dehydrochlori- 

The surface of poly(tetrafluoroethylene) materials may be etched with potassium or liquid ammonia to produce double bonds.These double bonds are usable as grafting sites for MA. Grafting is achieved with free-radical initiators, using neat polymerization conditions. Grafted tubes were tested for thrombogenetic activity by exposure to animal blood. Thrombogenicity of the poly(tetrafluoroethylene) surface was improved, but carboxyl groups were inferior to sulfonic acid residues. 

Polymers with pendent furfuryl residues readily undergo Diels-Alder reaction with MA and maleimides. The polymers are potentially useful in ion-exchange resins and thermoset coatings. The poly(furfuryl methacrylate) or furfuryl methacrylate copolymers may be treated with MA to obtain a Diels-Alder product shown as follows  

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Uses Production of isooctane, butyl rubber, polyisobutene resins, high octane aviation fuels, tert-butyl chloride, ferf-butyl methacrylates copolymer resins with acrylonitrile, butadiene, and other unsaturated hydrocarbons organic synthesis. 

Butyl rubber is a copolymer of 1 -butene, (CH3)2C = CH2, and small amounts (about 2%-3%) of isoprene or other unsaturated compounds. The unsaturation allows subsequent cross-linking of the material. 

Pharmaceutical research has to date been focused on polyanhydrides derived from sebacic acid (SA) and its copolymers with bis(p-carboxyphenoxy)propane (CPP) [75,113,115,119]. More recently, a new class of polyanhydrides was presented, containing fatty acid dimers (FAD) [ 116,118,258]. Erosion characteristics, microsphere preparation, pH-dependence, release rates, morphology, and in vivo performance of polyanhydrides from SA, CPP, and FAD have been intensely studied [75, 111-115,117, 119, 258-260]. Other unsaturated polyanhydrides have been derived from ricinoleic acid [261] and ricinoleic acid half-es-... 

A large variety of monomers and their mixtures were successfully polymerized with functional silicones to die corre nding copolymers, e.g., vinyl acetate, styrene, mediyl methacrylate, butyl acrylate, acryl amide, acrylic acid, and other unsaturated monomers with special residues. 

Polybutadiene, CAS 9003-17-2, is a common synthetic polymer with the formula (-CH2CH=CHCH2-)n- The cis form (CAS 40022-03-5) of the polymer can be obtained by coordination or anionic polymerization. It is used mainly in tires blended with natural rubber and synthetic copolymers. The trans form is less common. 1,4-Polyisoprene in cis form, CAS 9003-31-0, is commonly found in large quantities as natural rubber, but also can be obtained synthetically, for example, using the coordination or anionic polymerization of 2-methyl-1,3-butadiene. Stereoregular synthetic cis-polyisoprene has properties practically identical to natural rubber, but this material is not highly competitive in price with natural rubber, and its industrial production is lower than that of other unsaturated polyhydrocarbons. Synthetic frans-polyisoprene, CAS 104389-31-3, also is known. Pyrolysis and the thermal decomposition of these polymers has been studied frequently [1-18]. Some reports on thermal decomposition products of polybutadiene and polyisoprene reported in literature are summarized in Table 7.1.1 [19]. 

This chapter will cover the chemistry and technology of poly(vinyl chloride) (PVC) homopolymers having a repeating unit of -CH2-CHCI-as well as copolymers of vinyl chloride with smaller amounts of other unsaturated monomers such as vinyl acetate, ethylene, propylene, acrylates, and vinylidene chloride. 

Polyacrylates as binders consist of copolymers of acrylate and methacrylate esters. Other unsaturated monomers (e.g., styrene and vinyltoluene) may also be incorporated, but usually to a lesser extent. Copolymers formed exclusively from acrylates and/or methacrylates are termed straight acrylics. The comonomers differ as regards the alcohol residues of the ester group, which also allow incorporation of additional functional groups. Choice of suitable monomers allows wide variation of the physical and chemical properties of the resulting polymer. Hydrophilicity, hydrophobic-ity, acid base properties as well as can be adjusted resins containing hydroxyl, amine, epoxy, or isocyanate groups can also be produced. 

Acrylonitrile Copolymer A thermoplastic prepared by copolymerization of acrylonitrile with small amounts of other unsaturated monomers. Has good gas barrier properties and chemical resistance. Processed by extrusion, inj ection molding, and thermo forming. Used in food packaging. 

Ethylene Polymers Ethylene polymers include ethylene homopolymers and copolymers with other unsaturated monomers, most importantly, olefins such as propylene and polar substances such as vinyl acetate. The properties and uses of ethylene polymers depend on the... 

Thus, the hybrid dimers can be formed from the block copolymer if the ordinary or deuterated benzyl radical attacks the other unsaturated chain ends formed during pyrolysis as follows (Eq. 3.7). 

All monomers impart certain characteristic properties to polymers of which they form a part, but some have a particularly marked effect and can bring about significant changes in polymer behaviour even when present as only a few percent of the total monomer mix. As examples, acrylic, methacrylic acids and other unsaturated acids are used to give alkali-soluble copolymers in conjunction with methacrylic acid and acrylic esters. N-methyl acrylamide and other polyfunctional monomers produce reactive copolymers capable of secondary polymerisation or cross-linking by etherification or ionic bonding, usually after the watery portion of the emulsion has dried off. 

ABS is considerably more thermally sensitive than other styrene copolymers because of its butadiene phase with unsaturated monomer units. Damage occurs mainly in the butadiene phase, while the styrene phase remains comparatively stable. Double bonds are cleaved and subsequently crosslinking or functional group formation is detected. 

Pb(C2H5)4 is used as a catalyst for side-chain alkylation of toluene with ethene [731], for the reaction of alkenes with SO2 [635], for the halogenation of alkanes such as ethane, propane, or pentane in the gas and liquid phase [123, 650], for vulcanizing a mixture of acetaldehyde copolymers with acrolein or other unsaturated compounds, and a natural rubber [858], for curing caoutchouc [629], and for the polymerization of rosin or rosin acid derivatives [493, 704]. Pb(C2H5)4 is part of room-temperature, light-vulcanizable silicone rubber compositions [875]. 

DADC may be polymerised industrially with small amounts of other miscible Hquid monomers. Some acryflc ester monomers and maleic anhydride may accelerate polymerisation. Copolymerisation with methacrylates, diaHyl phthalates, triaHyl isocyanurate, maleates, maleimides, and unsaturated polyesters are among the examples in the early Hterature. Copolymers of DADC with poly-functional unsaturated esters give castings of high clarity for eyeglass lenses and other optical appHcations (20). 

Photopolymerizable compositions based on monomeric acryflc or other ethylenicaHy unsaturated acid derivatives are becoming increasingly popular. When multiftmctional derivatives are employed, three-dimensional networks having high strength and abrasion resistance are possible on exposure to light. A typical composition may contain an ethoxylated trimethylolpropane triacrylate monomer, a perester phenacjhdene initiator (69), and an acryflc acid—alkyl methacrylate copolymer as binder. 

Polymers ndResins. / fZ-Butyl peroxyneopentanoate and other peroxyesters of neopentanoic acid can be used as free-radical initiators for the polymeri2ation of vinyl chloride [75-01-4] (38) or of ethylene [74-85-1]. These peresters have also been used in the preparation of ethylene—vinyl acetate copolymers [24937-78-8] (39), modified polyester granules (40), graft polymers of arninoalkyl acrylates with vinyl chloride resins (41), and copolymers of A/-vinyl-pyrrohdinone [88-12-0] and vinyl acetate [108-05-4] (42). They can also be used as curing agents for unsaturated polyesters (43). 

Butyl rubber and other isobutylene polymers of technological importance iaclude various homopolymers and isobutylene copolymers containing unsaturation achieved by copolymerization with isoprene. Bromination or chlorination of the unsaturated site is practiced commercially, and other modifications are beiag iavestigated. 

This combination of monomers is unique in that the two are very different chemically, and in thek character in a polymer. Polybutadiene homopolymer has a low glass-transition temperature, remaining mbbery as low as —85° C, and is a very nonpolar substance with Htde resistance to hydrocarbon fluids such as oil or gasoline. Polyacrylonitrile, on the other hand, has a glass temperature of about 110°C, and is very polar and resistant to hydrocarbon fluids (see Acrylonitrile polymers). As a result, copolymerization of the two monomers at different ratios provides a wide choice of combinations of properties. In addition to providing the mbbery nature to the copolymer, butadiene also provides residual unsaturation, both in the main chain in the case of 1,4, or in a side chain in the case of 1,2 polymerization. This residual unsaturation is useful as a cure site for vulcanization by sulfur or by peroxides, but is also a weak point for chemical attack, such as oxidation, especially at elevated temperatures. As a result, all commercial NBR products contain small amounts ( 0.5-2.5%) of antioxidant to protect the polymer during its manufacture, storage, and use. 

Vinyl plastics Group of plastics composed of resins derived from vinyl monomers, excluding those that are covered by other classifications (i.e., acrylics and styrene plastics). Examples include PVC, poly(vinyl acetate), poly(vinyl butyral), and various copolymers of vinyl monomers with unsaturated compounds. 

Depending on the choice of transfer agent, mono- or di-cnd-functional polymers may be produced. Addition-fragmentation transfer agents such as functional allyl sulfides (Scheme 7.16), benzyl ethers and macromonomers have application in this context (Section 6.2.3).212 216 The synthesis of PEG-block copolymers by making use of PEO functional allyl peroxides (and other transfer agents has been described by Businelli et al. Boutevin et al. have described the telomerization of unsaturated alcohols with mercaptoethanol or dithiols to produce telechelic diols in high yield. 

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