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Structural Characterization and Degradability of Poly( L ‐lactic acid)s Incorporating Phenyl‐Substituted α ‐Hydroxy Acids as Comonomers
Author(s) -
Moon SungIl,
Urayama Hiroshi,
Kimura Yoshiharu
Publication year - 2003
Publication title -
macromolecular bioscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.924
H-Index - 105
eISSN - 1616-5195
pISSN - 1616-5187
DOI - 10.1002/mabi.200390038
Subject(s) - mandelic acid , lactic acid , copolymer , chemistry , polymer chemistry , condensation polymer , organic chemistry , nuclear chemistry , catalysis , polymer , bacteria , genetics , biology
Three types of copolymers of poly( L ‐lactic acid) (PLLA) were synthesized by direct polycondensation of L ‐lactic acid and phenyl‐substituted α ‐hydroxy acids ( L ‐phenyllactic acid and D ‐ and L ‐mandelic acids). It was found that the glass transition temperature of the copolymers comprising L ‐mandelic acid became significantly higher (from 58 to 69 °C) with increasing content of L ‐mandelic acid (from 0 to 50 mol‐%) although the M w decreased (from 87 000 to 4 000 Da). The cast films of the L ‐mandelic acid containing copolymers showed improved tensile properties compared with those of the PLLA film. This may be due to a pinning effect of the L ‐mandelic acid units on the helix formation of PLLA, although 30% of the units were racemized. The enzymatic degradability of the L ‐mandelic acid containing copolymers was much higher than that of PLLA, as analyzed with Proteinase K® originating from Tritirachium album .Synthesis of copolymers of L ‐lactic acid and phenyl‐substituted α ‐hydroxy acids.