Characterization and degradation of poly(vinyl chloride-g-lsobutylene) carrying tertiary chlorine and cyclopentadienyl branch termini

Summary Poly(vinyl chloride-g-isobutylene)s have been synthetized by using PVC backbones containing relatively high concentration of allylic chlorines PVC(A)] in conjunction with BCl₃ coinitiator. Since graft-termination occurs by ion-collapse, graft copolymers with tertiary chlorine branch termini PVC(A)-g-PIB-Cl] were formed. The presence of terminal tertiary chlorines has been demonstrated by degradation and cyclopentadienylation experiments. UV-visible spectra of ungrafted and grafted PVC(A) , molecular weight data, and branching frequency as a function of concentration of allylic chlorines indicate chain transfer to polyenes. Thermal and thermooxidative stability of PVC(A) increases upon grafting due to the replacement of allylic chlorines by PIB branches. The introduction of highly oxidizable Cp groups in PVC(A)-g-PIB-Cl by Me₂CpAl-treatment decreases the thermooxidative stability.