Structural Characterization and Degradability of Poly(L-lactic acid)s Incorporating Phenyl-Substituted α-Hydroxy Acids as Comonomers
✍ Scribed by Sung-Il Moon; Hiroshi Urayama; Yoshiharu Kimura
- Publisher
- John Wiley and Sons
- Year
- 2003
- Tongue
- English
- Weight
- 157 KB
- Volume
- 3
- Category
- Article
- ISSN
- 1616-5187
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✦ Synopsis
Abstract
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.
magnified imageSynthesis of copolymers of L‐lactic acid and phenyl‐substituted α‐hydroxy acids.