Synthesis and characterization of a biodegradable polymer prepared via radical copolymerization of 2-(acetoacetoxy)ethyl methacrylate and molecular oxygen

2-(Acetoacetoxy)ethyl methacrylate and oxygen react at 50 degrees C under high pressure in the presence of a radical initiator to give poly[2-(acetoacetoxy)ethyl methacrylate] peroxide (PAEMAP). Elemental analysis, mass spectral fragmentation analysis, FTIR and NMR spectroscopy have been used to confirm the alternating copolymer structure with peroxy (-O-O-) bonds in the copolymer main chain. Thermal degradation studies of PAEMAP by using differential scanning calorimetry (DSC) reveal that PAEMAP degrades highly exothermically and the heat of degradation, -40.5 kcal mol(-1), is of the same order as that reported for other vinyl polyperoxides. The thermal degradation of PAEMAP is also investigated by thermogravimetric analysis (TGA). The mechanism of the primary exothermic degradation has been supported by thermochemical calculations. Biodegradation using horseradish peroxidase enzyme and in vitro biocompatibility to HeLa cells have been studied for PAEMAP. These results indicate that incorporation of -O-O- links in the main chain favours enzymatic degradation of PAEMAP.