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Effect of the melt‐mixing condition on the physical property of poly( l ‐lactic acid)/poly( d ‐lactic acid) blends
Author(s) -
ElKhodary Esraa,
Fukui Yoko,
Yamamoto Masaki,
Yamane Hideki
Publication year - 2017
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.45489
Subject(s) - materials science , lactide , differential scanning calorimetry , copolymer , polymer chemistry , mixing (physics) , chemical engineering , lactic acid , melt flow index , crystal (programming language) , composite material , polymer , thermodynamics , physics , genetics , quantum mechanics , biology , bacteria , computer science , engineering , programming language
The effect of the mixing condition in a mill‐type mixer on the thermal property and the crystal formation of the poly( l ‐lactide)/poly( d ‐lactide) blends is investigated. The blends melt‐mixed at 200 and 210 °C under application of a high shear flow tend to show a single melting peak of the stereocomplex crystal (SC) in the differential scanning calorimetry first and second heating processes without indicating the trace of the melting of homo‐chiral crystal. The mixing at an elevated temperature causes a serious thermal degradation. Further kneading of the blends at an elevated temperature higher than T m of SC causes the transesterification between the same enatiomeric chains forming block copolymers of l ‐ and d ‐chains. This block copolymer acts as a nucleating agent of SC and the compatibilizing agent between poly( l ‐lactide) and poly( d ‐lactide) and promotes the formation of SC. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45489.