Biodegradation of the films of polyethylene modified with starch. Studies on changes
of supermolecular structure of polyethylene
Polimery 2004, No 6, 424
Decompositions of the films made of low-density polyethylene (PE-LD) modified with oxidized potato starch (PESZ) or corn starch (PESK), after 6, 12 or 16 months (e.g. PESZ-6, PESZ-12 etc.) of mixed bacteria action have been investigated. Bacteria population consisted of Bacillus type bacteria, Actinomycetales and mildew fungi isolated from the soil. The results of the film biodegradation process were estimated on the basis of a degree of microorganisms' growth, surface changes observed using a microscope as well as structural changes determined by WAXS or SAXS. Significant adhesion of microorganisms colonies to the film surface as well as morphology changes and numerous losses of starch grains were found after 16 months of biodegradation. There were also found the changes in polyethylene supermolecular structure, manifested as a decrease in PE lamellar structure long period dimensions. The demonstrated effect of biodegradation did not depend on the kind of a starch applied. Biodegradation does not influence the ratio of crystalline and amorphic phases in the polymer.
Keywords: biodegradation, low-density polyethylene, starch, modification, supermolecular structure
Biodegradation of the films of polyethylene modified with starch. Studies on changes of supermolecular structure of polyethylene