Premium
Synthesis and Characterization of Stereo Multiblock Poly(lactic acid)s with Different Block Lengths by Melt Polycondensation of Poly( L ‐lactic acid)/Poly( D ‐lactic acid) Blends
Author(s) -
Rahaman Md. Hafezur,
Tsuji Hideto
Publication year - 2012
Publication title -
macromolecular reaction engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.37
H-Index - 32
eISSN - 1862-8338
pISSN - 1862-832X
DOI - 10.1002/mren.201200032
Subject(s) - lactic acid , crystallinity , condensation polymer , materials science , block (permutation group theory) , polymer chemistry , crystallite , melting temperature , chemical engineering , composite material , polymer , mathematics , combinatorics , metallurgy , genetics , bacteria , engineering , biology
Stereo multiblock PLAs with different block lengths are synthesized by melt polycondensation of low‐molecular‐weight poly( L ‐lactic acid)/poly( D ‐lactic acid) blends with a wide variety of $\overline {M} _{{\rm w}} $ in the range of 1.1–5.2 × 10 3 g · mol –1 . The average block length (ν av ) of the stereo multiblock PLAs increases with increasing $\overline {M} _{{\rm w}} $ of the blend and with the reaction temperature, whereas $\overline {M} _{{\rm w}} $ and PDI of the stereo multiblock PLAs increases with increasing $\overline {M} _{{\rm w}} $ of the blend, the reaction time, and the temperature. Stereo multiblock PLAs with ν av > 7 are crystallizable to form stereocomplex crystallites, and the crystallinity and melting temperature of the stereo multiblock PLAs increases with increasing ν av and $\overline {M} _{{\rm w}} $ of the stereo multiblock PLAs.