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Synthesis of biodegradable polyhydroxyalcanoate copolymer from a renewable source by alternate feeding
Author(s) -
Pereira Silvia M.F.,
Sánchez Rubén J.,
Rieumont Jacques,
Cabrera Jose G.
Publication year - 2008
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.21178
Subject(s) - copolymer , materials science , polymer , crystallinity , crystallization , monomer , tacticity , polymer chemistry , isothermal process , yield (engineering) , chemical engineering , polymerization , composite material , thermodynamics , engineering , physics
Polyhydroxyalcanoates copolymers with 3‐hydroxybutirate (3HB) and 3‐hydroxyvalerate (3HV) co‐monomers, P3(HB‐co‐x%HV), were produced in fed‐batch culture by Ralstonia eutropha DSM428 using fructose as a single carbon source in the first step and adding propionic acid in the second step by alternating feeding. Polymer yield was 0.18 g/L with a content of 24 mol% of the 3HV fraction determined by 1 H NMR. NMR measurements indicated that the polymer obtained is isotactic. The copolymer attained 35% of crystallinity according to X‐ray diffraction measurements, and two (020) planes were observed. Thermal behavior presented melting temperature at 154°C and the crystallization temperature was 65°C. A glass transition temperature was observed at −10°C. Average molecular weight measured by GPC was 4.9 × 10 5 Dalton. Isothermal radial growth rates of spherulites of P3(HB‐co‐24%HV) were studied. All experimental facts and the analysis of the sequence distribution of diads and triads of 3HB and 3HV units led to the conclusion that it is not a completely statistical random copolymer once it contains different types of segments. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers.