Copolyesters of 3-hydroxybutyrate (3HB) and 3-hydroxypropionate (3HP) with a wide range of compositions varying from 0 to 88 mol % 3HP were produced by Alcaligenes latus from the mixed carbon substrates of 3-hydroxypropionic acid with sucrose or 3-hydroxybutyric acid. The copolyesters were shown to have a random sequence distribution of 3HB and 3HP monomeric units by analysis of 13C NMR spectra. The number-average molecular weights of the copolymers were in the range (1.1-3.5) X 10s. The structure and physical properties of P(3HB-co-3HP) copolymers were characterized by 'H and 13C NMR spectroscopy, X-ray diffraction, gel permeation chromatography, differential scanning calorimetry, dynamic mechanical spectroscopy, and dielectric spectroscopy. The crystallographic parameters of copolymers with compositions up to 43 mol % 3HP were little influenced by the presence of the 3HP unit, but the X-ray crystallinities decreased with the 3HP fraction. The isothermal radial growth rates of spherulites of P(3HB-co-ll % 3HP) were slower by 2 orders of magnitude than the rate of P(3HB). The rate of enzymatic degradation of P(3HBco-3HP) films increased with an increase in the 3HP fraction.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.