Styrene fumaronitrile copolymers

Koppers produced SMA moulding powders under the tradename Dylark . Arco has since acquired this business and continues to produce these SMA resins today under the Dylark tradename. Another styrene copolymer with better heat resistance than regular polystyrene is the copolymer of styrene and fumaronitrile which was reported in 1948 [27]. Both of these styrene copolymers are based on nonpolymerizable monomers - that is, fumaronitrile, like its corresponding anhydride (maleic anhydride), does not form homopolymers but readily copolymerizes with styrene at levels of up to 40%. Monsanto attempted to commercialize the styrene-fumaronitrile copolymer under the tradename Cerex , but residual fumaronitrile was a powerful vesicant (an irritant which causes blisters) and the project was shelved [28]. 

There exist many alternating copolymerizations ethylene or propene with alkyl acrylates [244], vinyl acetate with maleic anhydride [245], styrene with acrylonitrile [246], styrene with fumaronitrile [247], vinyl carbazol with fumaronitrile, vinyl ferrocenne with diethylfumarate [248], and further pairs or systems of three monomers [238, 249-253]. External conditions can support or hinder alternation. At not too high temperatures, vinyl acetate forms a donor—acceptor complex with maleic anhydride. Under these conditions (and in the presence of a radical initiator), an alternating copolymer is formed. The concentration of the complex decreases with increasing temperature above 363 K the complex cannot exist. Under these conditions, copolymerization yields a statistical copolymer whose composition depends on the composition of the monomer mixture [245]. 

Warakomski, J and Dion R (1992) The effect of chemical composition on the miscibility of styrene/acrylonitrile/fumaronitrile terpolymers with styrene/acryloni-trile copolymers. J Appl Polym Sci 46 1057-63. 

The copolymerization data for the styrene(Mi)-fumaronitrile(M2) system indicate that there are also effects due to remote monomer units preceding the penultimate unit. The effect of remote units has been treated by further expansion of the copolymer composition equation by the use of greater number of monomer reactivity ratios for each monomer [34]. However, the utility of the resulting expression is limited due to the large number of variables involved. 

Only a small percent of styrene copolymers reported in the literature achieved industrial importance. Some of the interesting copolymers of styrene that were reported but not utilized commercially are copolymers with various unsaturated nitriles. This includes vinvlidine cyanide, fumaronitrile, malononitrile, methacrylonitrile, acrylonitrile, and cinnamonitrile. Often, copolymerization of styrene with nitriles yields copolymers with higher heat distortion temperature, higher tensiles, better craze resistance, and higher percent elongation. 

Another styrene copolymer with heat resistance superior to polystyrene, is a copolymer of styrene and furaaronitrile (12). Fumaronitrile, like the corresponding anhydride (maleic anhydride), does not form homopolymers but copolymerizes with styrene to produce a copolymer with as much as 40 percent fumaronitrile. Because of the bulky groups present, this copolymer is only partially alternating i.e., the sequence is not BABA but BABAA where B represents the fumaronitrile monomer and A represents styrene. 

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