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Biobased Copolymers Composed of l ‐Lactic Acid and Side‐Chain‐Substituted Lactic Acids: Synthesis, Properties, and Solid‐State Structure
Author(s) -
Marubayashi Hironori,
Asai Shigeo,
Hikima Takaaki,
Takata Masaki,
Iwata Tadahisa
Publication year - 2013
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.201300406
Subject(s) - lactic acid , substituent , small angle x ray scattering , copolymer , chemistry , lactide , polymer chemistry , side chain , ultimate tensile strength , organic chemistry , materials science , polymer , scattering , bacteria , genetics , physics , optics , biology , metallurgy
Various biobased copolyesters composed of l ‐lactic acid (LLA) and side‐chain‐substituted lactic acids (SLAs) with high molecular weight and LLA‐rich composition are synthesized by direct solution polycondensation. Glycolic acid, 2‐hydroxyisobutyric acid, ( S )‐2‐hydroxy‐3‐methylbutanoic acid (LVOH), and ( S )‐2‐hydroxy‐4‐methylpentanoic acid (LLOH) are chosen as SLAs. Wide‐angle X‐ray diffraction (WAXD) and small‐angle X‐ray scattering (SAXS) reveal that the substituent size of the SLAs determines whether or not SLA units are included in crystallites of the LLA sequences. Unlike poly( l ‐lactic acid), tensile necking is seen in the copolymers with 2 mol% LVOH and with 6 mol% LLOH. Enzymatic degradation is accelerated with increasing SLA content. Especially for 6 mol% LLOH, the SLA introduction improves both the mechanical properties and the enzymatic degradability.