PET分子量对PET/PC共混体系高压结晶行为的影响

Effect of PET molecular weight on high-pressure crystallization behaviours of PET/PC blends

以往高压合成的聚合物伸直链晶体尺寸较小且合成时间过长,不能满足单晶应用的要求。加入10wt%PC于不同分子量的PET中,采用自制高压装置,制备共混体系,用WAXD,SEM,DSC等表征手段,研究了PET/PC共混体系在高压下的结晶行为。研究结果表明:通过PET/PC体系在高压下化学反应诱导的自组装,不同分子量PET的PET/PC共混体系均在较短的时间内生成了尺寸较大的聚酯伸直链晶体,对应于三斜晶系,其中PET/PC体系最适于大尺寸伸直链晶体的合成,仅需6hr时间即生成PE需200hr方可合成的40μm厚度的伸直链晶体。同时提出了PET1/PC体系中伸直链晶体高温下缺陷自我修复模型。

The small size of polymer extended -chain crystals ,which were formerly obtained through a long time under high -pressure confined their application effect. Adding 10wt - % PC to PET of different viscosity - average molecular weight,we carried out experiments with a self- made high - pressure apparatus to investigate the crystallization behaviors of PET/PC blends under high pressure. Samples were analyzed hy the characterzation method such as WAXD ,SEM and DSC. The experimental results showed that large polyester extended - chain crystals with triclinic structure could be found in PET/PC blend samples of different PET by a self - assembly procedure induced by chemical reactions at high pressure. The most suitable system to form large extended - chain crystals was found to be a PET1/PC blend,among samples of which crystallized for 6hr extended - chain crystals with thickness up to 40μm were found while the same size had to be obtained through 200hr for PE. Furthermore, a high - pressure defect - mending model of polyester extended - chain crystals in a PET1/PC blend samples was put forward. The study.above indicates a completely new methodology for the growth of polymer crystals that is different from conventional one for crystals consisting of small molecules.