Biodegradation of poly(vinylalcohol-co-ethylene) with the fungus Phanerochaete chrysosporium

Under appropriate conditions for lignine peroxidase production in a culture medium that contains spores of Phanerochaete Chrysosporium fungus, the bio degradation of ethylene vinyl alcohol (EVOH) pellets with 27% mole of ethyl ene content was observed after 30 days. The oxidative degradation was detec ted by Fourier Transform Infrared Spectroscopy (FTIR) through the formation of hydroperoxides containing chains which were broken with degradation tim e. Differential Scanning Calorimetry (DSC) initially showed only one meltin g peak and after 30 days two peaks appeared on the thermogram one due to th e remaining copolymer that did not change with degradation time and the oth er due to the polymer degradation sequence. When EVOH film with a similar amount of ethylene was used, the initial melt ing temperature (T-m) decreased during degradation and a second crystalline sequence with a lower T-m was produced, indicating that both copolymer seq uences were degraded. Observed differences in the biodegradative behavior b etween EVOH pellets and EVOH film were mainly due to the changes in crystal linity of the copolymer induced by film processing. The initial EVOH film s howed a lower crystallinity and the presence of double bonds, which favors the degradative process.