Degradable properties of compositions based on polyethylene and plasticized polyvinyl alcohol.

In the present paper the degradation of polyethylene (PE) compositions with additives of 1-5 wt % polyvinyl alcohol (PVA) plasticized with modified rape (MRo) or soybean oil (MSo) was studied. The degradability of obtained composites was evaluated by changes in physico-mechanical characteristics which take place under the influence of UV irradiation and biological factors of the soil during 120 days. It was found that the initial tensile strength of compositions with additives of plasticized polyvinyl alcohol is increased compared with the pure PE by 50-77 % (11,10-13,10 MPa). Meanwhile, after the UV exposure due to the passage of degradation processes, tensile strength was significantly reduced (up to 2-3 MPa). The action of biological soil factors has a little effect on physico-mechanical characteristics, as the result the tensile strength of the samples is reduced by only 15-24 %. The loss of elongation was similarly influenced by UV irradiation and decreased up to 90 % of the original value, which was within 40-80 %. The pyrolysis mass spectrometry was also used to describe the processes which occur during sample aging. It is shown that the functional additives based on plasticized PVA induce the structural transformations were assessed by the change of quantity and intensity of ion fragments. For instance, the intensity of ion fragments for PE-MSo decreased by 7-96 % after the UV exposure and 9-42 % after the aging of composite in the soil. [ABSTRACT FROM AUTHOR]