Segmented Poly(L-lactic acid)-Co-polyamides Synthesized through Polycondensation and Chain Extension

By : Yanping Zhao, Suqing Li, Xiaokai Yuan, Jingbo Zhao, Zhiyuan Zhang, Junying Zhang, Wantai Yang

Page No: 127-144

Abstract
Two poly(L-lactic acid) prepolymers (PrePLLAs) terminated with HO- and HOOC- groups were synthesized via melt polycondensation from L-lactic acid with or without adipic acid under the catalysis of stannous chloride and p-toluenesulfonic acid. Chain extension of them was carried out at 180 ºC using 2,2’-(1,4-phenylene)-bis(2-oxazoline) (PBOX) and adipoyl biscaprolactamate (ABC) as combination chain extenders. High molecular weight chain extended PLLAs were obtained. To improve crystallization, a nylon-610 oligomer (PrePA) was prepared from the reaction of nylon 610 salt with sebacic acid. Polycondensation of a PrePLLA with PrePA was conducted, and several segmented poly(L-lactic acid)-b-polyamide (PLLA-PA) prepolymers were synthesized. Chain extension of them was conducted at 190 ºC with PBOX and ABC. Chain extended PLLA[1]PAs (ExtPLLA-PAs) with Mn above 70500 g/mol were synthesized. The ExtPLLA-PAs were characterized by FT-IR, 1 H-NMR, DSC, TGA, and wide angle X-ray scattering. ExtPLLA-PAs exhibit Tm up to 154.7 ºC and initial decomposition temperature over 270.5 ºC. Their crystallization and thermal stability are obviously improved.

Authors :
Yanping Zhao, Suqing Li, Xiaokai Yuan, Jingbo Zhao, Zhiyuan Zhang, Junying Zhang and Wantai Yang : Key Laboratory of Carbon Fiber and Functional Polymers (Beijing University of Chemical Technology), Ministry of Education; State Key Laboratory of Chemical Resource Engineering, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China.