杜仲胶对聚乳酸的增韧改性

通过熔融共混的方法,采用生物基高分子材料杜仲胶(EUG)对聚乳酸(PLA)进行增韧改性,并制备了PLA/EUG共混物。采用扫描电子显微镜、广角X射线衍射、差示扫描量热分析、动态力学性能测试和旋转流变仪表征了PLA/EUG共混物的相结构、结晶性能、热性能、动态力学性能和流变性能。实验结果表明,聚乳酸与杜仲胶为典型的热力学不相容体系;EUG以微米及亚微米的尺寸分散在聚乳酸中。通过对PLA/EUG共混物的拉伸性能和力学性能研究,发现EUG的加入明显地改变了共混物的拉伸行为,由纯PLA的脆性断裂向韧性断裂转变。当PLA/EUG共混物中PLA/EUG的质量比为90/10时,共混物的断裂伸长率较纯PLA提高了14倍,缺口冲击强度提高了5.8倍。共混物拉伸断面照片表明基体在断裂前发生了明显的塑性变形,在断裂过程中吸收了相当大的能量,从而使得共混物的韧性得以提高。EUG能有效地改善PLA的韧性,可以作为新型的聚乳酸增韧改性剂。

Highly Toughened Polylactide by Eucommia Ulmoides Gum

Eucommia ulmoides gum (EUG) was employedto toughen brittle polylactide(PLA) by melt blending.The phase structures,thermal properties,crystallization behav ior,dynamic properties and rheological properties of PLA/EUG blends were characterized by SEM,DSC,WAXD,DMTA and rheological experiments.The results indicate that PLA/EUG blend is typically thermodynamic incompatible systems,and EUG is dispersed in PLA with the size of micrometer and submicron.The tensile and impact properties indicate that EUG changes the failure behavior of PLA from brittle to ductile.When the mass ratio of PLA to EUG of PLA/EUG blend is 90 to 10,the elongation at break and notch impact strength increase 14 times and 5.8 times,respectively.SEM micrographs of tensile-fractured surface reveal that the toughness improvement is caused by a large-scale matrix deformation which would absorb much energy.All the results demonstrate that EUG can effectively toughen PLA and can be adopted as a new type of PLA toughener.