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Phase Behavior and Thermal Properties for Binary Blends of Bacterial Poly(3‐hydroxybutyrate‐ co ‐3‐hydroxyhexanoate)s with Narrow‐Comonomer‐Unit Compositional Distribution
Author(s) -
Feng Lidan,
Watanabe Takumi,
He Yong,
Wang Yi,
Kichise Tomoyasu,
Fukuchi Takeshi,
Chen GuoQiang,
Doi Yoshiharu,
Inoue Yoshio
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.200390040
Subject(s) - comonomer , miscibility , differential scanning calorimetry , glass transition , polymer blend , materials science , polymer chemistry , solvent , polymer , phase (matter) , chemical engineering , chemistry , copolymer , organic chemistry , composite material , thermodynamics , engineering , physics
The miscibility and the effect of compositional distribution on physical properties were investigated for binary blends of biosynthesized poly(3‐hydroxybutyrate) [P(3HB)] and comonomer compositionally fractionated poly(3‐hydroxybutyrate‐ co ‐3‐hydroxyhexanoate)s [P(3HB‐ co ‐3HH)] with narrow compositional distribution. Biosynthesized P(3HB‐ co ‐3HH) samples were compositionally fractionated using solvent (chloroform)/nonsolvent ( n ‐heptane) mixtures. The binary blends of fractionated P(3HB‐ co ‐3HH)s with different 3HH unit content were prepared by casting from solution in chloroform. The miscibility and the thermal properties of these blends were analyzed by differential scanning calorimetry (DSC). It was found that the two components are miscible in the amorphous phase when the difference in 3HH unit content between the two component polymers of these blends is less than 20 mol‐%, subsequently they are immiscible when the difference is larger than 30 mol‐%. By comparing the thermal properties of the binary blends of fractions, with those for the fractions themselves, and with those for the bacterially as‐produced unfractionated copolyesters, the effects of compositional distribution on the properties of copolyesters were discussed.Glass transition temperatures of blends PHB/H10, H10/H20, and PHB/H20 versus total 3HH unit content in the blends. The solid lines are the best fits of the experimental results of the P(3HB‐ co ‐3HH) fractions with narrow compositional distribution.