Avaliação da degradação biótica do poli(ácido lático), do polipropileno e suas misturas pela ação de fungos basidiomicetos

Abstract

Polymeric wastes when intended improperly, associated with its resistance to degradation may promote environmental pollution. Therefore, studies involving the degradation of some polymers are considered as an alternative to current environmental pollution problems. Another alternative that allows changing the characteristics of interest of the polymers is through the development of polyblends, and their physical and chemical properties can be changed to a wide range of applications, providing desirable performance to the final product. In this work were used polypropylene (PP), synthetic polymer, and polylactic acid (PLA), biodegradable polymer with and without the presence of compatibilizer (AC) based maleic anhydride modified PP. The objective of this study was to evaluate the properties of the blend of PLA and PP with and without the presence of compatibilizer as well the action of 10 basidiomycete fungi isolated from biomes, rainforest and pampa in as individually degradation polymers and the blends of PLA/PP. Polyblends of PP and PLA with and without the presence of a compatibilizer were produced by extrusion and injection process and morphological analysis, thermal, chemical and mechanical properties. For the process of biological degradation in solid culture in vitro were produced films of PP, PLA and their blend by compression molding. The pure polymers were subjected to exposure to the ten basidiomycete fungi for a period of 14, 28 and 75 days at 28°C, being the fungi Trametes villosa (Sw.) Kreisel 82I.6, Schizophyllum cf. commune (Fr.) 85E.16 and Auricularia bull Ex. Juss. 551.9B those who have provided evidence of degradation in the films of PLA and the fungus T. villosa (Sw.) Kreisel 82I.6 in the films of PP. A blend of PLA/AC/PP 75/3/25 selected due to its higher hydrophilic character, was subjected to exposure to the fungus T. villosa (Sw.) Kreisel 82I.6 during 14, 28 and 60 days at 28°C. After the evaluation period the physical properties (weight loss), morphological (light microscopy and scanning lectron microscopy) and chemical characteristics (infrared spectroscopy with Fourier transform) were observed. As a result of the properties of the blends, these proved to be immiscible, and the mechanical properties were lower than those of the PLA, without change in thermal stability and change in hydrophilicity with PP increasing. PLA decreased crystallinity after processing and PP increased. The solutions produced in liquid culture of the PLA with fungi T. villosa (Sw.) Kreisel 82I.6, S. cf. commune (Fr.) 85E.16 and A. bull Ex Juss. 551.9B and PP with the fungus T. villosa (Sw.) Kreisel 82I.6, however, the enzymes were not as efficient biological degradation in the broth. The fungi that showed higher degradation potential in solid culture of PLA were the T. villosa (Sw.) Kreisel 82I.6, S. cf. commune (Fr.) 85E.16 and A. bull Ex. Juss 551.9B below those reported in the literature time and the PP, the fungus T. villosa (Sw.) Kreisel 82I.6.; it promoted surface changes with removal of material after 28 and 75 days of incubation. The fungus T. villosa (Sw.) Kreisel 82I.6 used in the process of degradation in solid culture blend PLA/AC/PP (75/3/25), was identified that provided evidence of degradation during periods of exposure this study.