Studies on Biodegradability of Cobalt Stearate Filled Polypropylene After Abiotic Treatment

Abstract

This study aims to investigate the effect of abiotic treatment (accelerated weathering) of cobalt stearate (CoSt) filled polypropylene (PP) composite films on their biodegradability. The PP composite films, after abiotic treatment, were characterized by different techniques and the results were compared with those of untreated films. After biodegradation (biotic treatment) of abiotically treated composite PP films, the degradation intermediates were evaluated for their ecotoxicological impact. The presence of oxygen products after degradation of composite PP by abiotic treatment was confirmed by FTIR. The carbonyl index of abiotically treated composite films was improved with CoSt loading and with the time of abiotic treatment. After abiotic treatment, the thermal stability of the modified PP sample decreased as shown by thermogravimetric analysis (TGA). The crystallinity of CoSt filled PP decreased with increase in CoSt, as revealed by DSC and XRD, which led to enhanced degradation of PP. The highest biodegradation of abiotically treated composite PP films was shown to be 36.42% having 2 phr CoSt in it. SEM results of biotically treated films also showed erosion, several small pits and increased roughness on the modified PP films. The overall results indicate that the addition of CoSt and abiotic treatment significantly enhanced the biodegradation of PP. Eco-toxicity tests of the degraded material, namely microbial test, plant growth test, and earthworm acute-toxicity test demonstrated that the degradation intermediates were nontoxic. Hence, CoSt filled PP has high industrial potential to make biodegradable flexible packaging.