Effects of UV Irradiation and Soil Burial Treatment on Mechanical Properties and Surface Morphology of Starch-Based Plastic

Abstract

Starch-based plastics are gaining attention as eco-friendly alternatives to their petroleum-based counterparts due to their biodegradable and renewable characteristics. However, a comprehensive evaluation of their mechanical performance and durability under varying environmental conditions is lacking. Thus, this study investigates the impact of UV irradiation and soil burial on the mechanical properties and surface morphology of starch-based plastics. The weight loss and important mechanical parameters, including tensile strength and elongation at break, were analysed using standard testing procedures on starch-based plastic samples that were subjected to varying durations of UV irradiation and soil burial. Furthermore, the surface morphology of these samples was examined using scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) analysis to analyse composite degradation. There was a 64.7% reduction in elongation at break for the soil burial treatment and a 92.1% reduction for the UV irradiation treatment, indicating significant deterioration in the mechanical properties of the plastic. Weight loss was used as an indicator of degradation, showing a 55.1% weight loss in the soil burial treatment and a 9.1% weight loss in the UV irradiation treatment after 100 days. FTIR analysis revealed structural changes during degradation, with both treatments showing the formation of new peaks. This suggests that degradation occurred over the treatment period, likely due to chain scission of the polymer. SEM analysis of the surface morphology of the samples showed more pronounced changes with the soil burial treatment, where numerous small holes were observed. These findings contribute to a comprehensive understanding of the behaviour of starch-based plastics under UV irradiation and soil burial treatment conditions, offering valuable insights into their potential applications and limitations across industries, including packaging and agriculture.