Structure and thermal degradation of poly(vinyl chloride) synthesized by various polymerization catalyst

Relationship between the structure and the thermal stability of poly(vinyl chloride) synthesized by various polymerization catalysts was investigated. The Cp∗Ti(OPh)/MAO catalyst, n-butyllithium (n-BuLi), the Cu(0)/TREN/CHBr₃/DMSO catalyst, benzoyl peroxide/N,N-dimethylaniline (BPO/DMA), 2,2’-azobis(2.4-dimethylvaleronitrile) (V-65) was used as the polymerization catalyst. The temperature of 5% weight loss was in the following order; Cp∗Ti(OPh)₃/MAO (280 °C) > n-BuLi (264 °C) > V-65 (249 °C) > Cu(0)/TREN/CHBr₃/DMSO (215 °C) > BPO/DMA (209 °C), and the rate of weight loss was the reverse order of T_−5% in the isothermal degradation of the polymer from 160 °C to 220 °C. The T_−5% value of the polymer obtained from the polymerization with Cp∗Ti(OPh)₃/MAO catalyst increased with an increase of the molecular weight of PVC, in contrast to that PVC obtained with the radical initiator did not depend on the molecular weight of the polymer. The T_−5% value of PVC macromonomer was 285 °C, while the temperature of non-functionalized PVC was 262 °C, respectively. It is clear that the PVC macromonomer had a good thermal stability regardless of low-molecular weight.