Copolymer compounds aromatic copolymerization

In order to increase the solubiUty parameter of CPD-based resins, vinyl aromatic compounds, as well as other polar monomers, have been copolymerized with CPD. Indene and styrene are two common aromatic streams used to modify cyclodiene-based resins. They may be used as pure monomers or contained in aromatic steam cracked petroleum fractions. Addition of indene at the expense of DCPD in a thermal polymerization has been found to lower the yield and softening point of the resin (55). CompatibiUty of a resin with ethylene—vinyl acetate (EVA) copolymers, which are used in hot melt adhesive appHcations, may be improved by the copolymerization of aromatic monomers with CPD. As with other thermally polymerized CPD-based resins, aromatic modified thermal resins may be hydrogenated. 

Attempts to elucidate the polymerization or copolymerization kinetics of ethynyl and maleimide-functionalized monomers have been undertaken via vibrational spectroscopy (137). The thermal polymerization of A-(3-ethynyl-phenyl) maleimide (the structure is given in Fig. 48) was studied via IR and Raman spectroscopy. This model compound is interesting because it carries maleimide and ethynyl groups attached to the same aromatic ring. Kinetic studies indicate that both the acetylene and maleimide group react at the same rate, which strongly suggests the formation of a copolymer rather than a mixture of homopolymers. 

Some of the styrene-vinyl aromatic compound copolymers also demonstrate isomorphism 175). The best examples are styrene-o-F-styrene copolymers, which are highly crystalline products with melting points in the 235-270° C range. The helix bands in the IR spectra of the copolymers disappear, beginning from the 30% content of another comonomer, confirming random copolymerization 175). 

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