Degradation behaviors, thermostability and mechanical properties of poly (ethylene terephthalate)/polylactic acid blends

XIA Xue-lian(夏学莲)¹, LIU Wen-tao(刘文涛)^{1, 2}, TANG Xin-ying(唐新颖)¹, SHI Xiang-yang(史向阳)³, WANG Li-na(王丽娜)^{1, 4}, HE Su-qin(何素芹)¹, ZHU Cheng-shen(朱诚身)¹

(1. School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450052, China;
2. Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and
Technology, Daejeon 305-701, Korea;
3. Department of Quality Assurance, Citic Heavy Industries Co., LTD., Luoyang 471039, China;
4. Department of Materials and Chemical Engineering, Henan Institute of Engineering, Zhengzhou 450007, China)

Abstract:It is difficult for polyethylene terephthalate (PET) to degrade, which caused severe pollution. In this work, polylactic acid (PLA) was introduced to improve the degradation of PET. PET/PLA was synthesized by extrusion blending. The thermal, crystalline and mechanical properties of blends were investigated with TGA, DSC, WAXD and universal testing machine. The degradation of the blends in soil, acid and alkaline buffer solutions was assessed, respectively. It was found that the introduction of a little PLA promoted crystallization of PET during injection molding process. The starting decomposition temperature lowered from 412.1 °C of pure PET to 330.4 °C at 50% PLA content, tensile and bending strength of blends gradually decreased with the PLA content increasing, while the degradation rate improved. Alkaline environment was most beneficial for blends to degrade. The degradation mechanism was discussed.

Key words:degradation; polyester; polylactic acid; mechanical property