端羧基聚乳酸共聚物的合成及表征

Abstract: The carboxyl-terminated modified polylactic acid copolymers of P (LA / SA), P (LA / CA) and P (LA /AC) were synthesized via directly melt polycondensation with D, L-racemic lactic acid (D,L-LA) as raw material and stannous octoate as catalyst. The copolymerization reaction was performed at the temperature of 168 ℃ and the pressure of 0.098 MPa using linear heating method. The copolymers were characterized by viscosity-average molecular weight, FT-IR, 1H-NMR , DSC, TGA and XRD. The results demonstrate that Tg of the carboxyl-terminated copolymers is lower than PLA, reducing the rigidity of PLA; The copolymers have good thermal stability for one-step thermal decomposition; Compared with PLA, the crystallinity of P(LA/SA) and P(LA/AC) decreased, While the P(LA/CA) slightly decreased, so that, by adjusting the ratio of lactic acid and modifier to adjust the mechanical properties