利用气相色谱(GC)仪、热重分析(TG)仪、旋转流变仪和熔融指数仪等,研究了工业级聚碳酸亚丙酯(PPC)的溶剂残留、热稳定性能和动态流变性能。Gc结果表明,工业级PPC含有质量分数为1.281%的残留环氧丙烷单体;TG及旋转流变测试结果表明,材料的加工热稳定性能较差。同时,加工过程中分子链之间的摩擦内耗能极大,产热量极大,更易加剧其降解。因此,加工的剪切速率不可太大,否则降解严重。熔融指数测试结果表明:从常规加工的要求看,加工温度需要达到180℃才有合适的流动性。基于所得研究结果,建议生产厂商考虑适当减小PPC的分子量,并使其相对分子量分布变窄,以提高材料的流动性。这样可极大降低PPC的加工难度。
The solvent residue, thermal stability and dynamic rheological properties of industrial grade poly(propylene carbonate) (PPC) were characterized by gas chromatography (GC), thermal gravimetric analysis (TG), rotational rheometer and melt index meter. The GC results showed that PPC contained 1.281% residual monomer propylene oxide. The TG results indicated poor processing thermal stability of PPC. The rotation rheological results further revealed poor processing thermal stability of PPC. The degradation of PPC was mrre intensified for great heat because of huge amounts of energy consumed in the friction processing of between the molecular chain. Therefore, the shear rate should not be too great for preventing serious degradation in characterization. The results of melt index indicated that under the requirements of the conventional processing, PPC had proper fluidity when the processing temperature reached 180 ℃. PPC manufacturers should reduce the molecular weight with the narrowing of molecular weight distribution to improve material flow and thus greatly reduce the difficulty in processing.