Synthesis and Characterization of the Poly ethylene glycol Grafted Unsaturated Microbial Polyesters

Pseudomonas oleovorans was grown with either 10-undecenoic acid alone or the equimolar mixture of octanoic acid and 10-undecenoic acid to obtain unsaturated poly 3- hydroxy alkanoates PHA s; poly 3-hydroxy-10-undecenoate PHU and poly 3-hydroxy- octanoate-co-3-hydroxy-10-undecenoate PHOU , respectively. The addition of bromine to olefinic double bond, by reacting the unsaturated PHA with bromine in homogeneous solution in dark, was readily carried out. The brominated PHA was reacted with polyethylene glycol PEG in the presence of a base to obtain PHA-g-PEG graft copolymers. The polymers were characterized by 1H NMR and FTIR spectroscopy, gel permeation chromatography GPC , differential scanning calorimetry DSC and thermogravimetric analysis TGA .