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Highly Enhanced Nucleating Effect of Melt‐Recrystallized Stereocomplex Crystallites on Poly( L ‐lactic acid) Crystallization
Author(s) -
Narita Junichi,
Katagiri Mikio,
Tsuji Hideto
Publication year - 2011
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/mame.201100024
Subject(s) - crystallite , materials science , crystallinity , crystallization , nucleation , lactic acid , atmospheric temperature range , chemical engineering , composite material , metallurgy , organic chemistry , bacteria , chemistry , physics , biology , engineering , genetics , meteorology
In the general processing temperature range of poly( L ‐lactic acid) (PLLA) articles (210–240 °C), PLLA/poly( D ‐lactic acid) (PDLA) stereocomplex (SC) crystallites melted just above the endset temperature of SC melting (228–238 °C) and recrystallized during cooling were found to act as the most effective nucleating agents for enhancing the crystallization of PLLA compared to partially melted SC crystallites (211–227 °C) or those melted far above the endset temperature of SC melting (240 and 250 °C) and recrystallized during cooling. The high nucleating effect of the SC crystallites melted in the temperature range of 228–238 °C was found to be caused by their smaller sizes or the larger number of SC crystallites per unit mass. The incorporation of such SC crystallites facilitates the processing of PLLA articles having high crystallinity and, therefore, high heat‐resistance in a shorter period to reduce the production cost.