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A Unique Meta-Form Structure in the Stereocomplex of Poly(D-lactic acid) with Low-Molecular-Weight Poly(L-lactic acid)

✍ Scribed by Ling Chang; Eamor M. Woo

Publisher
John Wiley and Sons
Year
2010
Tongue
English
Weight
350 KB
Volume
212
Category
Article
ISSN
1022-1352

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✦ Synopsis

Abstract

The crystalline structure and crystallization behavior of PLLA crystals in a 1:1 w/w mixture of low‐MW PLLA with high‐MW PDLA were analyzed using WAXD, DSC, and SAXS. Under cold crystallization, homopolymeric PLLA, appearing as a meta crystal, was discovered in the PDLA/LMW‐PLLA blend. The meta__‐__ and α′ crystal forms of PLLA were found to form on crystallization at a T~cc~ of 85–95 °C and the α crystal PLLA formed at 100 ≤ T~cc~ < 120 °C. The meta‐crystal PLLA may be incorporated in the stereocomplexed PDLA/LMW‐PLLA lamellar region. During heating, the meta‐crystal PLLA first partially melted and then repacked directly into the α crystal PLLA without going through the less‐stable α′ form. magnified image

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