Preparation of biodegradable poly(3-hydroxybutyrate) (PHB) and poly(ethylene glycol) (PEG) graft copolymer

Biodegradable poly(3-hydroxybutyrate ) (PHB) and poly(ethylene glycol) (PEG) graft copolymer was prepared using two-step method. The PEG macromer was synthesized and then PHB and PEGM were reacted under the ultraviolet (UV) to prepare PHB?PEG graft coplolymer. Chloroform solutions with different compositions of PEGM/PHB were prepared. The concentrated solutions were poured into TFE molds and irradiated using a 500 W high-pressure UV lamp at room temperature. The obtained copolymer gelations were dried in vacuum at room temperature for 48 hours. The measurement of contact angle was performed at 25°C by a pendant drop method, employing a contact-angle measurement apparatus. Surface energy of the solid was estimated by contact angle measurement together with a theory of intermolecular forces. results show that the biodegradability of the PHB can b improved significantly by grafting a hydrophilic polymer such as PEG.