马来酸酐接枝聚乳酸增容聚碳酸亚丙酯/聚乳酸共混体系的结构与性能研究

Study on Structure and Properties of Poly(propylene carbonate)/Poly(lactic acid) Blend System Compatibilized by Maleic Anhydride Graft Polylactic Acid

采用熔融接枝技术将马来酸酐(MAH)接枝到聚乳酸(PLA)上,制备不同MAH含量的PLA-g-MAH接枝共聚物,将聚碳酸亚丙酯(PPC)、PLA、PLA-g-MAH熔融共混,制备PPC/PLA/PLA-g-MAH共混物,分析接枝物中MAH含量对PPC/PLA/PLA-g-MAH共混体系的热学性能以及力学性能的影响。结果表明:PLA-g-MAH可以改善PPC与PLA二者的相容性,使PLA在降温过程中更容易结晶。引入接枝物后,共混物的起始分解温度及完全分解温度分别提高30℃和60℃。共混物的力学性能随着接枝物中MAH含量的增加呈现先增加后减小的趋势,当MAH的加入量为3%,共混体系力学性能最佳,冲击断面塑性形变程度更加显著,呈现褶皱状韧性断裂特征,拉伸强度达到42.8 MPa,断裂伸长率为120%左右,同时冲击强度最大。

Melt grafting technology was used to graft maleic anhydride(MAH) onto polylactic acid(PLA) to prepare PLA-g-MAH graft copolymers with different MAH content. Polypropylene carbonate(PPC), PLA and PLA-g-MAH were melt blended to prepare PPC/PLA/PLA-g-MAH blends were analyzed, and the effects of MAH content in the grafts on the thermal and mechanical properties of PPC/PLA/PLA-g-MAH blends. The results show that PLA-g-MAH can improve the compatibility of PPC and PLA, and make PLA easier to crystallize during the cooling process. After introducing the graft,the initial decomposition temperature and complete decomposition temperature of the blend are increased by 30 ℃ and60 ℃ respectively. The mechanical properties of the blend show a trend of first increasing and then decreasing with the increase of the MAH content in the graft. When the content of MAH is 3%, the mechanical properties of the blend system are the best, and the plastic deformation degree of the impact section is more significant. It presents the characteristics of fold-like ductile fracture, the tensile strength reaches 42.8 MPa, the elongation at break is about 120%, and the impact strength is the maximum.