Preparation of telechelic oligomers by controlled thermal degradation of isotactic poly(l-butene) and poly(propylene-ran-1-butene)

摘要

It was found that telechelic isotactic oligo(l-butene) and telechelic oligo(propylene-ran-1-butene) could be isolated as nonvolatile oligomers from polymer residues resulting from the thermal degradation of isotactic poly(l-butene) and poly(propylene-ran-1-butene), respectively. Their structures were determined by ~1H and ~(13)C NMR with attention being paid to their reactive end groups. The maximum average number of terminal vinylidene groups per molecule (f_(tvd)) was 1.8, indicating that about 80 mol% were α,ω-diene oligomers having two terminal vinylidene groups. This useful new telechelic oligomer had a lower polydispersity than the original polymer, in spite of its lower molecular weight and T_m. The composition of end groups of nonvolatile oligomers obtained by thermal degradation of poly(propylene-ran-1 -butene) could be explained by the differences in bond dissociation energy and activation energy of elementary reactions during thermal degradation, based on the monomer composition of the original polymer.