PLA/PBS/DCP反应共混体系的结晶行为研究

通过熔融共混法制备了一系列聚乳酸(PLA)/聚丁二酸丁二醇酯(PBS)物理共混试样及PLA/PBS/过氧化二异丙苯(DCP)反应共混试样,采用示差扫描量热分析(DSC)法研究了物理共混试样结晶行为及反应共混试样的特殊结晶行为.结果发现,PLA与PBS的物理共混并未改善PLA的结晶性,而PLA/PBS/DCP反应共混时生成的交联/支化结构可起到异相成核作用,从而明显改善了反应共混体系的结晶性能,且随着DCP含量的增加,共混体系中两相结晶行为出现交替变化.

STUDY ON THE CRYSTALLIZATION BEHAVIOR OF PLA/PBS/DCP REACTIVE BLENDS

The poly(lactic acid)/poly(butylene succinate)(PLA/PBS) blends with and without dicumyl peroxide(DCP) were prepared by melt mixing and the crystallization behaviors of the blends were investigated using a differential scanning calorimeter(DSC).The results showed that the crystallization ability of PLA was not improved when it was blended with PBS because of the higher molecular weight of PBS than that of PLA in this research,which was not in accord with results of some other researchers.However,the crystallization ability of PLA in the reactive blends(PLA/PBS/DCP) was promoted after the addition of different amount of DCP,because some crosslinked(or grafted) structures were generated in this matrix,and the crosslinked(or grafted) structures acted as nucleating points.It is found that when the content of DCP was from 0.1 phr to 0.3 phr,the crystallization was mostly caused by PBS,and this crystallization reduced with increasing the DCP content.When the content of DCP was above 0.3 phr,that is to say,PLA began to crystallize when the DCP content was 0.4 phr.The crystallization of PLA was enhanced with further increasing the content of DCP,while the crystallization of PBS was weakened in the same situation.In other words,the crystallization behavior of PLA and PBS in the PLA/PBS/DCP reactive blends was mostly depended on the DCP content.