Mechanical properties, structure analysis and enzymatic degradation of uniaxially cold-drawn films of poly[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate]

Jiaqi Zhang, Kenichi Kasuya, Takaaki Hikima, Masaki Takata, Akio Takemura, Tadahisa Iwata

Research output: Contribution to journalArticlepeer-review

36 Citations (Scopus)


Poly[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate] (P(3HB-co-4HB)) films were prepared by uniaxial cold-drawing from an amorphous preform at a temperature below, but close to the glass transition temperature. Molecular and highly-ordered structures and physical properties of cold-drawn films were investigated by tensile testing, wide-angle X-ray diffraction and small-angle X-ray scattering. Enzymatic degradation of P(3HB-co-4HB) films was performed using an extracellular polyhydroxybutyrate depolymerase purified from Ralstonia pickettii T1. Tensile strength, elongation to break and Young's modulus of P(3HB-co-4HB) with cold-drawn ratio 1200% reached 290 MPa, 58% and 2.8 GPa, respectively. X-ray fibre diagrams of cold-drawn P(3HB-co-4HB) films showed a strong reflection on the equatorial line, indicating a planar zigzag conformation (β-form) together with 21 helix conformation (α-form). The β-form seems to contribute to the high tensile strength, and a new mechanism of generation of the β-form is proposed. The enzymatic degradation rate increased with increasing draw ratio, and increased greatly with increasing 4HB content.

Original languageEnglish
Pages (from-to)2130-2138
Number of pages9
JournalPolymer Degradation and Stability
Issue number12
Publication statusPublished - 2011 Dec


  • Enzymatic degradation
  • Physical property
  • Poly[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate]
  • Structure analysis
  • Uniaxial cold-drawing


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