Investigation of sequences in a poly(butadiene‐co‐trimethylvinylsilane) by metathesis degradation

Poly(butadiene‐co‐trimethylvinylsilane) with a mole fraction of 13% trimethylvinylsilane was prepared with butyllithium as initiator. It was degraded by cross‐metathesis with (E)‐4‐octene or (Z)‐2‐butene in the presence of the catalyst WCl6/Sn(CH3)4. The mixtures of the degradation products were investigated by means of gas chromatography (GC)/mass spectrometry (MS) coupling; mass spectra of degradation products with 4‐octene are depicted and discussed. Sequences of up to six trimethylvinylsilane units inserted between 1,4‐linked butadiene were identified after degradation with 2‐butene. Trimethylvinylsilane inserted between 1,4‐ and 1,2‐linked butadiene was also found. Cyclohexenyl and cyclopentenyl compounds were the preferred cyclic metathesis products.