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New Complex Crystals of Chiral Poly( L ‐lactic acid) and Different Tactic Poly(methyl methacrylate)
Author(s) -
Woo Eamor M.,
Wang YuHsiang
Publication year - 2012
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.201200111
Subject(s) - differential scanning calorimetry , tacticity , polymer chemistry , fourier transform infrared spectroscopy , methyl methacrylate , materials science , poly(methyl methacrylate) , crystal (programming language) , crystallography , polymer , copolymer , chemical engineering , chemistry , polymerization , composite material , physics , computer science , engineering , thermodynamics , programming language
Based on evidence from differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WAXD), and Fourier‐transform infrared (FTIR) spectroscopy, a new stereocomplex crystal (DSC T m = 175 °C, with WAXD 2 θ = 10.0° and 12.5°) is proven for the first time between structurally dissimilar chiral poly( L ‐lactic acid) (PLLA) and syndiotactic poly(methyl methacrylate) (sPMMA). There is a strong complexing capacity only between low molecular weight PLLA and sPMMA, in miscible state, at specific weight fractions (70:30). The complexing capacity is more significant when the mixtures are melt‐crystallized at T c = 110 °C or lower, and the intensity of this complex can be further enhanced if it is annealed between 100 and 160 °C, below its T m = 175 °C. The new complex crystal can be formed only between PLLA and sPMMA, but not with isotactic or atactic PMMA.