Biodegradation of poly(ethylene terephthalate) modified with polyester "Bionolle®" by Penicillium funiculosum

The purpose of the study was to determine the degree of biodegradation of poly(ethylene terephthalate) films modified with "Bionolle (R)" polyester in comparison with films made of neat commercial poly(ethylene terephthalate). After 84-day incubation in the presence of filamentous fungi Penicillium funiculosum or their extracellular hydrolytic enzymes secreted by "Bionolle (R)" weight loss of the films was measured. The texture of the polymeric samples was observed with a scanning electron microscope. Important chemical changes of polymeric chains were detected by FT-IR and XPS analysis. Significant reduction in quantity of aromatic rings derived from terephthalic acid indicated that decomposition of films by fungi occurred not only due to hydrolytic enzymes but also oxidative ones. Moreover, we observed rather unilateral influence of poly(ethylene terephthalate) on biodegradation: addition of "Bionolle (R)" didn't accelerate significantly degradation of modified films and - what is more important - the presence of PET inhibited decomposition of easily biodegradable "Bionolle (R)".