Vol.:(0123456789) 1 3 Journal of Polymers and the Environment https://doi.org/10.1007/s10924-020-01762-3 ORIGINAL PAPER Studies on Biodegradability of Cobalt Stearate Filled Polypropylene After Abiotic Treatment Sunil Sable 1  · Sanjeev Ahuja 1  · Haripada Bhunia 1 © Springer Science+Business Media, LLC, part of Springer Nature 2020 Abstract This study aims to investigate the efect of abiotic treatment (accelerated weathering) of cobalt stearate (CoSt) flled polypro- pylene (PP) composite flms on their biodegradability. The PP composite flms, after abiotic treatment, were characterized by diferent techniques and the results were compared with those of untreated flms. After biodegradation (biotic treatment) of abiotically treated composite PP flms, the degradation intermediates were evaluated for their ecotoxicological impact. The presence of oxygen products after degradation of composite PP by abiotic treatment was confrmed by FTIR. The carbonyl index of abiotically treated composite flms was improved with CoSt loading and with the time of abiotic treatment. After abiotic treatment, the thermal stability of the modifed PP sample decreased as shown by thermogravimetric analysis (TGA). The crystallinity of CoSt flled 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 flms was shown to be 36.42% having 2 phr CoSt in it. SEM results of biotically treated flms also showed erosion, several small pits and increased roughness on the modifed PP flms. The overall results indicate that the addition of CoSt and abiotic treatment signifcantly 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 flled PP has high industrial potential to make biodegradable fexible packaging. Keywords Biodegradation · Degradation · Photo-oxidation · Pro-oxidant · UV exposure Introduction Polypropylene (PP) is the thermoplastics that is extensively utilized for manufacturing of grocery bags, flms, sheets, containers, toys, pipes, cable jacketing, etc. for diferent kinds of food packaging, agricultural field, automotive parts, piping industry, medical applications, home appli- ances, adhesives, prosthetic implants, and engineering plas- tics [1–3]. The PP has found several applications due to its lightweight, low cost, durability, better intrinsic properties and low density and performance, like excellent ductility, chemical resistance, water barrier properties, etc. [4]. PP in a flm form is used for fexible packaging applications [2, 5]. Currently, the global production capacity of PP is signifcantly growing because of the increasing global popu- lation, demand for plastics in each aspect of life, although there are signifcant environment-related issues for its reuse, recycling, discarding and/or recovery of energy. To face the environmental pollution, which consistently causes damage to the environment, degradable polymeric materials, even if produced from petroleum, are found as hopeful means to facilitate resolving waste management problems. However, the major drawback of PP is that it is non-biodegradable. In natural conditions, plastics are degraded very slowly [6]. Therefore, biodegradable plastics appear as a promising solution to the growing problem of environmental contami- nation [7–9]. During the previous few decades, most investigations have focused on the blending of PP with degradable natural polymers like starch [10–12], cellulose [13], and poly(lactic * Haripada Bhunia hbhunia@thapar.edu Sunil Sable sunilsable123@gmail.com Sanjeev Ahuja skahuja@thapar.edu 1 Department of Chemical Engineering, Thapar Institute of Engineering & Technology (Deemed to be University), Patiala, India