材料期刊网

利用差示扫描量热仪(DSC)研究了碳酸钙、滑石粉等无机填料对PET等温和非等温结晶行为的影响,并与适于PET用的有机钠盐类成核剂NA作了对照。结果表明,滑石粉比碳酸钙更有利于PET结晶速率的提高,当滑石粉用量为5%(质量 ),其对PET等温结晶速率的贡献接近1%(质量)有机成核剂NA的贡献。而且,滑石粉的加入明显 提高了PET拉伸强度和弯曲模量,而成核剂NA的使用虽然有助于PET弯曲模量的提高,却使PET 拉伸强度、弯曲强度,特别是冲击强度减小。这可能是由于碳酸钙和滑石粉对PET是异相成核 ,对PET分子量影响不太大;而成核剂NA却是通过与PET反应生成PET钠盐而促进结晶的,其副作用是导致PET分子降解,表现为PET／NA体系的熔体粘度最低。

Effects of inorganic fillers on isothermal and non-isothermal crystallization kinetics of polyethylene terephthalate(PET) were studied by using DSC in comparison with an organic uncleating agent(NA). T he results indicate that Talc has a better nucleating effect on PET crystallizat ion rate than CaCO3, 5 mass% Talc has a similar effect on PET isothermal cryst allizatio rate to 1 mass% nucleating agent NA. Moreover, the presence of Talc can improve the tensile strength and flexural modulus of PET. Although nucleating agent NA increase the flexural modulus of PET, it decreases the tensile strength and flexural strength, especially Izod impact strength of PET. The reasons are probably that CaCO3 and Talc have heterogeneous nucleation effects on the PET crystallization and little influence on the molecular weight of PET; however, the nucleating agent NA reacts with PET, causes the degradation of PET molecules and decreases the viscosity of PET／NA system.