Abstract

The effect of poly (vinyl methyl ether) (PVME) on the miscibility, crystallization and rheological behavior of a 50/50 poly(L-lactide) (PLLA)/poly (methyl methacrylate) (PMMA) blend was investigated. The PLLA/PMMA blend, with compositional symmetry, was immiscible at room temperature when prepared by solution casting. However, it became miscible when heated to a high temperature, indicating an upper critical solution temperature (UCST) behavior. With the addition of PVME, whose glass transition temperature was much lower than those of PMMA and PLLA, the thermodynamic miscibility was improved for the PLLA/PMMA/PVME blend, all components being miscible at a low temperature. The crystallization kinetics of the blends was studied by observing the PLLA spherulite growth with annealing time at 100 °C via polarized optical microscopy; the addition of PVME accelerated the crystallization kinetics of the PLLA. Rheological sweep results confirmed this conclusion. The reason for this acceleration effect on the crystallization was explored by etching the PVME in the PLLA/PMMA/PVME blends. The participation of PVME in the crystallization of PLLA played a crucial role in the crystallization process.

摘要

研究了聚（乙烯基甲基醚）（PVME）对50/50聚（L-丙交酯）（PLLA）/聚（甲基丙烯酸甲酯）（PMMA）共混物的混溶性，结晶性和流变行为的影响。通过溶液流延制备时，具有组成对称性的PLLA / PMMA共混物在室温下不混溶。但是，当加热到高温时，它变得混溶，表明临界溶液温度（UCST）较高。通过添加玻璃化转变温度远低于PMMA和PLLA的PVME，可以改善PLLA / PMMA / PVME共混物的热力学混溶性，所有组分都可以在低温下混溶。共混物的结晶动力学研究是通过偏振光学显微镜观察100°C退火时间下PLLA球晶的生长情况。PVME的加入加速了PLLA的结晶动力学。流变扫描结果证实了这一结论。通过蚀刻PLLA / PMMA / PVME共混物中的PVME，探索了这种促进结晶作用的原因。PVME参与PLLA的结晶过程在结晶过程中起着至关重要的作用。