Polymers and Polymer Composites

Miscibility and isothermal crystallization behavior of poly-(l-lactideco-glycolide)/ poly(rho-dioxanone) blends

August 1, 2014 By: Xiaojin Zhang; Chi Ma; Wei Bai; Chengdong Xiong; Dongliang Chen Research article

Title: Miscibility and isothermal crystallization behavior of poly-(l-lactideco-glycolide)/ poly(rho-dioxanone) blends
Page Range: p.705-712
Author(s): Xiaojin Zhang; Chi Ma; Wei Bai; Chengdong Xiong; Dongliang Chen
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Journal: Polymers and Polymer Composites
Issue Year: ppc
Volume: 22
Issue No: No.8

Abstract
We prepared a series of blends from solution co-precipitation of poly-(L-lactide-co-glycolide) (PLGA) and poly (p-dioxanone) (PPDO) at various mass ratios. Using a scanning electron microscopy (SEM), PLGA and PPDO were revealed to be immiscible. The crystallisation behaviour of PLGA/PPDO blends was investigated by differential scanning calorimetry (DSC) under isothermal conditions. Through comparing the crystallisation exothermic peak location and the PLGA/PPDO blends’ shape, the crystallisation rate was determined to slow as the temperature increased. We applied the Avrami equation to analyze the primary stage of the isothermal crystallisation and obtained relevant crystallisation kinetic parameters. The data revealed that the PPDO component acted as nucleation sites in blends and accelerated the PLGA crystallisation rate by increasing the crystallisation rate constant k and decreasing the half-crystallization time (t1/2). The Arrhenius equation was used to analyze the crystallization’s activation energy. Our analysis confirmed that blending with PPDO accelerates PLGA crystallisation. Our micrograph imaging of the spherulites via a polarizing optical microscopy (POM) revealed that the PLGA/PPDO blends’ crystals were smaller in size but greater in number than that of pure PLGA. This finding indicated that PPDO is a good nucleation agent for PLGA. All these results suggest that it is possible to control the PLGA crystallisation rate by adding a PPDO component. 36 Refs.


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