Fractionation and thermal characteristics of biosynthesized polyhydoxyalkanoates bearing aromatic groups as side chains

摘要: Two polyhydroxyalkanoate (PHA) copolymers, poly(3-hydroxybutyrate-co-3-hydroxy-3-phenylpropioate) [P(3HB-co-3H3PhP)] and poly(3-hydroxybutyrate-co-3-hydroxy-4-phenylbutyrate) [P(3HB-co-3H4PhB)], both bearing aromatic side chains, were biosynthesized by recombinant Ralstonia eutropha fed with a respective precursor for the unit. As bacterial PHA copolymers generally exhibit broad comonomer compositional distribution, as-biosynthesized samples, P(3HB-co-18 mol% 3H3PhP) P(3HB-co-11 3H4PhB), fractionated into several fractions narrow distribution using chloroform/n-hexane mixed solvent. When samples aged under ambient conditions, P(3HB-co-3H3PhP) fraction 12 3H3PhP exhibited melting temperature (Tm) of 132–148 °C, whereas 15–21 did not behavior. P(3HB-co-3H4PhB), all range 4–15 3H4PhB Tm in 105–151 °C. The glass transition (Tg) these increased increasing unit content, highest Tg 20 °C was observed 21 3H3PhP. On basis results presented here, effects comonomers on thermal properties resulting are discussed. [P(3HB-co-3H4PhB)] biosynthesized. polymers Using fractions, investigated.