Co-crystallization phenomena in biosynthesized isotactic poly[(R)-lactate-co-(R)-2-hydroxybutyrate]s with various lactate unit ratios

Taizo Kabe, Ken'ichiro Matsumoto, Satsuki Terai, Takaaki Hikima, Masaki Takata, Masahiro Miyake, Seiichi Taguchi, Tadahisa Iwata

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

Poly[(R)-lactate-co-(R)-2-hydroxybutyrate], which is biosynthesized as a random co-polyester by microbial organisms, with various ratios of lactic acid (LA) to hydroxybutyrate monomers has been isothermally crystallized to investigate its thermal properties and crystal structure changes. Differential scanning calorimetry on the isothermally crystallized samples detected endothermic peaks due to the melting of the crystals at all LA unit ratios. Melting temperatures of the copolymers increased from ca. 107 °C–146 °C as the LA unit ratio increased. Glass transition temperatures also increased from 24 °C to 44 °C with increasing LA unit ratio. A melting temperature was observed even at LA unit ratios around 50%. Wide-angle X-ray measurements also revealed that co-crystallization occurred at all samples, including at LA unit ratios of ca. 50%. Despite of “jumping” phenomena many co-crystallizable random copolymers having, the lattice constants changed “linearly” from resembling poly[(R)-lactate] to poly[(R)-2-hydroxybutyrate] depending on the LA unit ratio. This unique co-crystallization behavior is discussed in detail.

Original languageEnglish
Pages (from-to)137-144
Number of pages8
JournalPolymer Degradation and Stability
Volume132
DOIs
Publication statusPublished - 2016 Oct 1
Externally publishedYes

Keywords

  • Co-crystallization
  • Microbial polyester
  • Random copolymer

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Polymers and Plastics
  • Materials Chemistry

Fingerprint

Dive into the research topics of 'Co-crystallization phenomena in biosynthesized isotactic poly[(R)-lactate-co-(R)-2-hydroxybutyrate]s with various lactate unit ratios'. Together they form a unique fingerprint.

Cite this