多面体低聚倍半硅氧烷晶粒诱导的聚乳酸结晶行为及性能

The crystal structure and mechanical properties of polylactide induced by polyhedral oligomeric silsesquioxane

通过溶液及熔融两步共混方法,用带有环氧基的多面体低聚倍半硅氧烷(EVOS)对聚乳酸(PLA)进行改性,并对复合材料的力学性能、结晶性能和相态等方面进行了表征。实验结果表明,随着EVOS的加入,PLA冷结晶温度降低,结晶和熔融温度变化不大,结晶热和熔融热下降。1%的EVOS在PLA中实现了纳米尺度的分散,随着EVOS含量增加,球晶尺寸明显增加。当EVOS的添加量为5%时,材料的拉伸强度比纯PLA增加26.2%,达到最大值。

Polylactide（PLA） was modified with hybrid epoxied polyhedral oligomerie silsesquioxane（EVOS） by so- lution and melting blending. The morphology, crystallization properities and mechanical properties were studied. It sug- gested that the cold crystal temperature decreased with the increase of the weight fraction of EVOS, while the crystal and melting point was almost as same as the pure PLA. The crystal and melting enthalpies decreased with the increase of EVOS. EVOS（1 ~） dispersed well in the PLA matrix, and the EVOS tended to enter its own crystal structure when its a- mount increased. EVOS acted as a nuclear agent during the crystallization of PLA. EVOS of large amount provided less nuclear points for PLA, thus the sphere grew bigger than well-dispersed EVOS. The tensile strength of the composite reached its maximum with 5% EVOS, which was 26. 2% larger than the tensile strength of pure PLA.