Designing and Characterization of Poly(L-Lactide)/Poly(ϵ-Caprolactone) Multiblock Copolymers

Abstract

Abstract A series of poly(L-lactide)/poly(ϵ-caprolactone) (PLA/PCL) biodegradable multiblock copolymers was synthesized by a two-step process and characterized. Ring-opening polymerization was used to prepare a series of HO-PLA-PCL-PLA-OH copolymers initiated by hydroxyl-terminated PCL. Then the triblock copolymers and 1,6-hexamethylene diisocyanate (HDI) were reacted with different copolymer/HDI weight ratios. Consequently, a series of PLA/PCL multiblock copolymers with designed molecular chain structure was obtained. Gel permeation chromatography (GPC), Fourier transform infrared (FTIR) spectroscopy, and 1H NMR were used to characterize these copolymers and the results showed that the designed PLA/PCL copolymers had been synthesized. Dynamic mechanical analysis (DMA) was applied to characterize their thermal properties. Stress–strain curves showed that a PLA/PCL copolymer with adjustable mechanical properties had been achieved. Keywords: block copolymermechanical propertiespoly(ϵ-caprolactone)poly(L-lactide)ring-opening polymerizationsynthesis Funding This work was largely supported by a Sci-tech Project of China National Textile and Apparel Council (Program No. 2010003) and a Science and Technology Key Projects of Henan Province (Program No. 112102210006).