Polymers and Polymer Composites

CONCENTRATION DEPENDENCE OF CRYSTALLINE POLY(L-LACTIDE) PREPARED BY FREEZE-DRYING SOLUTIONS

January 1, 2009 By: Hao Hong; Liu Rongjie; Zhao Yaling Research article

Title: CONCENTRATION DEPENDENCE OF CRYSTALLINE POLY(L-LACTIDE) PREPARED BY FREEZE-DRYING SOLUTIONS
Page Range: p.31-35
Author(s): Hao Hong; Liu Rongjie; Zhao Yaling
File size: 155K
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Journal: Polymers and Polymer Composites
Issue Year: ppc
Volume: 17
Issue No: No.1

Abstract
Poly(L-lactide) was freeze dried from p-xylene solutions of varying concentrations and the molecular conformation and thermal properties of the freeze-dried poly(L-lactide) investigated by DSC and X-ray diffraction. It was found that the molecular conformation of the polymer in solution changed with solvent and temperature and that samples produced from dilute solution exhibited higher non-isothermal crystallisation temperatures and faster crystallisation rates. A critical concentration corresponding to De Gennes critical overlap concentration was detected and polymer chains were isolated from each other in solutions below the critical concentration, resulting in accelerated melt crystallisation of recovered samples. 14 refs.


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