Triene Copolymers

The novelty of isobutene-triene copolymers does not allow us to present a complete series of results since further work is in progr However, some interesting features shown by these copolymers, e. g. radical and Diels-Alder curing, hi efficiency in radical grafting, possibility of easy and controlled halogenation, allow us to expect a parallel behavior in terpol3nners containing similar unsaturations and hence permit us to draw some conclusions which comjdete thc obtained from the terpolymers study. 

Other recants and details ccmceming the isobutene-triene copolym synthesis and structural characterization were reported elsewhere 2,4-Hexadiene (HD, a mixture of 30/70 cis-tram and trans-tram isomers) and 2,5-dimethyl-2,4-hexadiene (DMHD) were used as model compounds of isobutene-triene ccipolyn rs and were pure grade cxjmmercdal products, distilled before use. 

In the case of peroxide-cured EPTMs or EPDMs, the cross-linking density (vt) was obtained throu swelling measurements (in n-heptane at 30 °C) and using the interaction parameter proposed in Ref whereas in the case of isobutene-triene copolymers the interaction parameter suggested by Sheenan and Bisio was adopted. 

The presence in polyisobutene chains of conjugated unsaturations highly reactive toward free radicals, as it occurs in tire case of isobutene-triene copolymers, induced us to investigate radical crc sdinking of these copolymers. 

As EPTMs containir dienic unsaturations easily undergo Diels-Alder reactions, i butene-triene copolymers are also subjected to viscosity increase on prolonged storage as a consequence of a slow but progressive self-curing occuring even at room temperature. 

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