聚酯在超临界甲醇中的降解特性

研究在间歇高压反应器中聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)及聚碳酸酯(PC)在超临界甲醇中的降解反应;通过建立聚酯在超临界甲醇中的降解反应模型,探讨了聚酯在甲醇中降解的机理。结果表明:PET、PBT和PC在甲醇溶液中的降解具有共性,均可分为超临界区、非临界区和中间过渡区三个区域。在超临界区聚酯完全溶于甲醇并降解为原料单体,且对苯二甲酸二甲酯(DMT)和碳酸二甲酯(DMC)的收率均大于90%;聚酯的降解是在聚合物分子链的无规断裂和聚酯进行酯交换反应的双重作用下发生的。

Degradation Behaviors of Polyesters in Supercritical Methanol

The degradation of polyethylene terephthalate(PET),polybutylene terephthalate(PBT) and polycarbonate(PC) in supercritical methanol were carried out using a batch-type autoclave reactor in order to study their common characteristics of decomposition in supercritical methanol.In the supercritical region,the degradation reaction carries out in homogeneous phase,and polyester solves quickly with the conversion of polyesters increasing nearly 100%.(Moreover,) polyesters could be degraded completely into monomers,which the yield of DMT or DMC is above 90% in supercritical region.Based on the experiments,a degradation-reaction model was proposed to(explain) the reaction mechanism,i.e.random scission and ester exchange reaction occurred simultaneously during the process of degradation of polyesters.