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Effects of Solvents on Stereocomplex Crystallization of High‐Molecular‐Weight Polylactic Acid Racemic Blends in the Presence of Carbon Nanotubes
Author(s) -
Yang Su,
Xu JiaZhuang,
Li Yang,
Lei Jun,
Zhong GanJi,
Wang Ruyin,
Li ZhongMing
Publication year - 2017
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201700292
Subject(s) - crystallization , crystallite , differential scanning calorimetry , dimethylformamide , polylactic acid , materials science , solvent , dichloromethane , polymer chemistry , carbon nanotube , chloroform , solubility , lactic acid , chemical engineering , polymer , organic chemistry , chemistry , composite material , physics , genetics , biology , bacteria , engineering , metallurgy , thermodynamics
Abstract Stereocomplex (SC) crystallization of solution‐casted high‐molecular‐weight polylactic acid/carbon nanotube (CNT) composites is investigated under the effects of solvents, including dichloromethane (CH 2 Cl 2 ), chloroform (CHCl 3 ), N , N ‐dimethylformamide (DMF), and 1,4‐dioxane (DIOX). It is found that addition of 0.1 wt% CNTs can promote the SC formation in the equimolar poly( l ‐lactic acid) (PLLA)/poly( d ‐lactic acid) (PDLA) blends. More interestingly, the final content of SC crystallites is mediated by solvent species to a large extent. Results of wide‐angle X‐ray diffraction and differential scanning calorimetry reveal that the capability of solvents for enhancing the SC content in PLLA/PDLA/CNT composites follows the sequence: DMF > DIOX > CHCl 3 > CH 2 Cl 2 . Especially, exclusive SC crystallites are formed in the DMF. Such a disparity is explained in terms of solubility parameter and vapor pressure of the solvents. The above results also provide the possible solution to regulate the crystalline composition of the PLLA/PDLA/CNT blends, by which the expected performance may be obtained.