Using Olive Stone Powder for Biodegradation of Bio-Based Polyamide 5.6

Abstract

Polymers are extensively used advanced materials since plastics meet a wide variety of needs in many applications and sectors. The most commonly used polymers in industry are non-biodegradable and petroleum derived. The increasing demand for these types of polymers brings along the problem of accumulation of plastic waste in the environment and depletion of fossil resources. At this point, biodegradability of polymers gains great importance as well as bio-based polymers produced from renewable resources. In this study, bio-based polyamide 5.6 polymer (PA56) was incorporated with olive stone powder (OSP) in order to manufacture a biodegradable polyamide compound, and its degradability was investigated under environmental conditions for 6 months. Bio-based polyamide 5.6, which is recently introduced to the plastics world, was chosen for this study, since bio-based polymers have many advantages over petroleum derived polymers in respect to environmental concerns. Olive stone powder was used as a biodegradation additive. Utilization of olive stone is important not only for being renewable source for bio-polyols, but also for the valorization of the solid waste from the olive-oil industry. The olive stone powder was incorporated into polyamide 5.6 at 10% (w/w) with a twin screw extruder by extrusion compounding method in order to manufacture the biodegradable polyamide compound, PA56/OSP10. The characterization of the manufactured PA56/OSP10 compound was done using Fourier transform infrared (FTIR) spectroscopy. The biodegradability of the PA56/OSP10 compound was examined through a natural soil burial test which lasted for 180 days. The sign of degradation was assessed by both visual observation and weight loss measurements. At the end of 6 months, 5.24% weight loss and surface deformation were determined for the PA56/OSP10 compound. These results suggest that olive stone powder can be considered as a green alternative to conventional biodegradation additives for polymer compounding.