Thermal Behavior and Molecular Interaction of Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) Studied by Wide-Angle X-ray Diffraction

• DOI: 10.1021/ma049863t
• Publication Date: 2004-05-11T13:20:49Z
• Authors: Harumi Sato; Masayuki Nakamura; Adchara Padermshoke; Hiroshi Yamaguchi; Hikaru Terauchi; Sanong Ekgasit; Isao Noda; Yukihiro Ozaki
• Keywords: Orthorhombic crystal system

The thermal behavior and molecular interaction of a new type bacterial copolyester, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), P(HB-co-HHx) (HHx = 12 mol %), was investigated by using wide-angle X-ray diffraction (WAXD) differential scanning calorimetry (DSC). WAXD measurements were carried out over temperature range from 25 to 110 °C in the scattering angle 2θ 5−13°. pattern at room shows that copolymer has an orthorhombic system (α β γ 90°) with 5.76 Å, b 13.20 c 5.96 Å (fiber repeat), which is identical crystal poly(3-hydroxybutyrate) (PHB) homopolymer. However, temperature-dependent variations lattice parameters, b, are quite different those PHB. Only parameter increases temperature, while changes very little case crystalline P(HB-co-HHx). It seems intermolecular intramolecular interactions between CO group CH3 decrease along axis temperature. (110) peak area starts decreasing around 50 PHB least until 140 °C, indicating crystallinity remains almost unchanged but decreases gradually fairly low (∼50 °C). DSC measurement chloroform solution cast recrystallization 51 °C. maximum value 54 demonstrates process result good agreement measurement.