A study of biodegradation, water uptake and thickness swelling of animal fibers reinforced unsaturated polyester resin composites

Abstract

The ever-increasing quantities of trash produced by the poultry and tannery industries, particularly chicken feathers, cow hairs, and waste leather fibers, pose serious challenges to maintaining a pristine natural environment. In this research, the polymer composites were produced by combining 2, 5, 7, 10, 12, and 15 % (by weight) recycled chicken feather fibers (CFF), cow hair fibers (CHF), and leather fibers (LF) with inorganic materials ZnO, Al2O3, CaCO3, and unsaturated polyester resin (UPR) through a hand lay-up process. After cleaning, a portion of the fibers was subjected to a two-hour soak in 0.20 M KOH at 50 °C, followed by five hours of drying at 60 °C, and the remaining half was not attended. This study successfully reduced environmentally hazardous waste from the poultry and tannery industries. The biodegradation of composites was compared in weather, water, brine, soil and compost over a period of 90 days at 25 °C, suggesting that the composites have potential in a variety of settings. Degradation rates varied among the composites, and the leather fibre-UPR composites (LR + UPR + Al2O3) showed the fastest degradation rate under all media and were especially degraded highest percentages (17.8 %) when buried in compost. Degradation percentages in compost media for (CHF + UPR + Al2O3), (CFF + UPR + Al2O3) and (CHF + CFF + UPR + Al2O3)) composites are 16.3 %, 14.8 %, and 13.5, respectively. The helical structure of the composites disintegrated in thermogravimetric analysis (TGA), losing its chain-linkage skeleton and peptide fiber bridges, and dissolving keratin and collagen into carbon dioxide (CO2), hydrogen sulfide (H2S), and hydrogen cyanide (HCN). The results of the water uptake and thickness swelling study for up to 15 days due to water absorption can have positive effects on the mechanical properties of the composite material and found 8.8 % water uptake and 15.8 % thickness swelling both for (LR + UPR + Al2O3) composite.