苯乙烯-丙烯酸甲酯共聚物增容对聚乳酸/SBS共混物结晶行为的影响

Impact of Styrene-co-Methyl Acrylate on the Crystallization Behaviors of Poly(lactic acid)/SBS Blends

研究了苯乙烯-丙烯酸甲酯无规共聚物(SMA)增容剂对聚乳酸(PLA)与苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)共混物的结晶行为的影响。通过熔融共混的方法制备了PLA/SBS(m PLA∶m SBS=95∶5)和PLA/SBS/SMA(m PLA∶m SBS∶m SMA=95∶5∶3)共混物,使用扫描电子显微镜(SEM)、差示扫描量热仪(DSC)和偏光显微镜(POM)研究了SMA增容PLA/SBS共混物的形貌、非等温结晶行为、等温结晶行为和晶体形貌。结果表明,SBS的增塑效应和异相成核效应对PLA的非等温结晶和等温结晶行为有促进作用;而SMA的加入起到了降低SBS分散相尺寸的作用,同时阻碍了SBS对PLA结晶行为的促进作用。增容剂SMA阻碍SBS对PLA基体结晶行为促进作用的可能原因在于SMA在PLA和SBS界面处的阻隔作用导致两者接触面积减少,且SMA对PLA的结晶没有促进或抑制作用。

The effect of poly(styrene-co-methyl acrylate)(SMA)compatibilizer on the crystallization behaviors of poly(lactic acid)(PLA)and styrene-butadiene-styrene(SBS)copolymer blends was studied.The PLA/SBS(m PLA∶m SBS=95∶5)and PLA/SBS/SMA(m PLA∶m SBS∶m SMA=95∶5∶3)blends were prepared by melt blending.The morphology,non-isothermal crystallization behavior,isothermal crystallization behavior and crystal morphology of SMA compatibilized PLA/SBS blends were studied by scanning electron microscope(SEM),differential scanning calorimeter(DSC)and polarizing microscope(POM).The results show that the plasticization effect and heterogeneous nucleation effect of SBS could promote non-isothermal crystallization and isothermal crystallization of PLA.The addition of SMA compatibilizer plays a role in reducing the size of SMA dispersed phase and hinders the promotion of SBS on PLA's crystallization behavior.The reason why the compatibilizer SMA could hinder the promotion of SBS on the crystallization behavior of PLA is that the barrier of SMA at the interface between PLA and SBS could reduce the contact area.And SMA has no promotion or inhibition effect on the crystallization of the PLA.