低密度聚乙烯/聚乳酸共混物性能的研究

Study on Properties of PE–LD/PLA Blends

利用熔融成型法制得不同聚乳酸(PLA)质量分数的低密度聚乙烯/聚乳酸(PE–LD/PLA)共混物,并对PE–LD/PLA共混物的结构和性能进行研究。结果表明,共混物中PLA相与PE–LD相之间没有发生化学反应,它是PLA与PE–LD的一种简单混合物。共混物中的PLA含量对其力学性能和亲水性均有很大影响。随着PLA含量的增加,共混物的断裂伸长率逐渐降低而拉伸强度和拉伸弹性模量逐渐增大,共混物的亲水性增加,且随着降解时间的增加,共混物的断裂伸长率轻微增加而拉伸强度和拉伸弹性模量小幅度降低,这些现象均与PLA是一种强度高但柔韧性较差的亲水性高分子材料有关。

The low-density polyethylene / polylactic acid（PE-LD / PLA） blends with various contents of PLA were prepared by using melt-blending method firstly, then the structure of the blends and the influences of PLA content on the mechanical properties and hydrophilicity of these prepared samples were investigated. The results show that the blends is a simple hybrid of pure PE-LD and PLA. The PLA content influences on the mechanical properties and hydrophilicity of the blends, with the increasing of PLA content, the elongation at break decreases gradually, the tensile strength and the tensile modulus of elasticity increase, and the hydrophilicity increases. With the increasing of degradation time, the elongation at break increases slightly, but the tensile strength and the tensile modulus of elasticity decrease slightly. All these changes are attributed to the high strength, low ductibility and well hydrophilicity of the PLA.