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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]

Polyelectrolyte complexes (PECs) based on sodium alginate (SA) with polyethyleneimine (PEI) were synthesized at a molar ratio of SA:PEI = 1.00:0.25 (PEC-1) and SA:PEI = 1.0:0.5 (PEC-2). The temperature intervals of thermodegradation for both the initial components and PECs were determined by pyrolytic mass spectrometry. It was shown that the molar ratio in these PECs significantly affects their swelling level in an aqueous environment as well as their mechanical characteristics. For instance, PEC-2 film is stiffer and more brittle compared to PEC-1 film, which retains flexibility. It has been revealed that PEC-2 exhibits a lower total ionic current of volatile components and a smaller number of ionic fragments generated during pyrolysis across the entire temperature range compared to PEC-1. In other words, PEC-2 is more resistant to temperature impact than PEC-1, which can be attributed to the difference in the molecular structure of the PECs. The formation of a greater number of ionic and hydrogen bonds in PEC-2, in our opinion, results in the formation of a stiffer and more ordered structure (compared to PEC-1). It is worth noting that the composition of PEC-2 is closer to stoichiometric, which leads to a decrease in the swelling degree of its film in water, and a decrease in its elasticity. [ABSTRACT FROM AUTHOR]