不同分子量的聚氧化乙烯对聚乳酸结晶和力学性能的影响研究

Influence of poly(ethylene oxide)with different molecular weight on crystallization behavior and mechanical property of poly(lactic acid)

聚乳酸(PLA)和其他可降解高分子材料熔融共混被认为是增韧PLA而不损失其可降解特性的最经济有效的方法。通过熔融共混法制备了PLA与聚氧化乙烯(PEO)的共混物,并采用DSC、XRD、SEM以及万能试验机等方法系统研究了不同分子量以及不同比例PEO对PLA微观结构和力学性能的影响。结果表明:在相同比例条件下,低分子量PEO与PLA的相容性要优于高分子量PEO,且对PLA结晶速率的提高更显著;PEO的加入提高了共混物的断裂伸长率,但伴随着拉伸强度的下降,且随PEO含量的增加,拉伸强度下降越明显。当PEO的分子量超过10万时,对PLA的增韧效果更加显著,且共混物的拉伸强度下降幅度较小。

Melt blending of poly（lactic acid）（PLA）with other biodegradable polymers has been considered to be the effective way to tough PLA without compromising its biodegradability.PLA/poly（ethylene oxide）（PEO）blends were prepared by melt processing.Effect of PEO with different molecular weight on microstructure and mechanical properties of PLA were systematically studied with the combination of differential scanning calorimetry（DSC）,X-ray scattering（XRD）,scanning electron microscope（SEM）and universal testing machine.The results suggested that the compatibility of low molecular weight PEO with PLA was better than that of high molecular weight PEO at the same composition,and the addition of PEO with low molecular weight can more significantly enhanced the crystallization rate of PLA.The results of mechanical properties showed that the addition of PEO significantly increased the breaking elongation,while the tensile strength decreased.When the molecular weight of PEO was more than 100 KDa,the effect of toughing on PLA was more remarkable,and the tensile strength of blends slightly decreased.