Preparation of Highly Flexible PLLA/P(LA-BF) Membranes and Their Thermal, Mechanical, and Rheological Properties

Poly(L- lactic acid- butyrate fumarate) copolymers(P(LA- BF)) were synthesized by melt polycondensation. Further, PLLA/P(LA-BF) membranes with different component ratios were prepared by co-blending P(LA-BF) with PLLA. The polymerization of P(LA-BF) was analyzed by NMR and FT-IR. Studies show the synthesis of P(LA-BF) copolymer in amorphous state. Crystallization, thermal, and mechanical properties of PLLA/P(LA-BF) membranes were evaluated by WAXD, DSC and tensile testing machines. Results show that the addition of P(LA-BF) does not change the crystallization ability of PLLA, and the membranes remain in amorphous state. Meanwhile, PLLA and P(LA-BF) exhibit excellent compatibility. The addition of P(LA-BF) improves the motility and flexibility of PLLA chain segments, and thus PLLA/P(LA-BF) membranes exhibit high flexibility. With the increase of P(LA-BF) content, the elongation at break increases up to 352.5% of PLLA/P(LA-BF)60, which is about 104 times of pure PLLA; the plastic deformation of the membrane before fracture becomes more pronounced, showing a bundle-like drawing shape with tough nest when the content of P(LA-BF) is 80%. In addition, the rheological properties show that PLLA/P(LA-BF) 40, PLLA/P(LA-BF)60, and PLLA/P(LA-BF)80 all exhibit Newtonian fluid characteristics, effectively improving the flowability of PLLA melt during processing. © 2023 Chengdu University of Science and Technology. All rights reserved.