Synthesis of a new hyperbranched, vinyl macromonomer through the use of click chemistry: Synthesis and characterization of copolymer hydrogels with PEG diacrylate

A new biodegradable, water-soluble macromonomer based on the commercial hyperbranched polyester Boltorn (R) H20 has been synthesized through the use of click chemistry. The macromonomer was developed with the aim of being injected with a comacromonomer, poly(ethylene glycol) (PEG) diacrylate, for in situ copolymerization to form biodegradable polymer hydrogels. Copolymer hydrogels were prepared from the macromonomer and PEG diacrylate (FW 700) by free radical copolymerization. A degree of phase separation of the hydrogels was observed during polymerization and with increasing incorporation of the Boltorn macromonomer an increasing tendency for the formation of macropores was observed. The swelling ratios of the gels in water and phosphate buffered saline solution, PBS, all increase with increasing Boltorn macromonomer concentration, as did the penetrant diffusion coefficients and the degradation rate in PBS. (c) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012