Multiscale characterization of commercial and landfill-recovered plastics in Songkhla province, Thailand

Abstract

This study provides a comprehensive assessment of five types of plastics: commercial polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyvinyl chloride (PVC), and landfill-derived polyethylene [PE (LF)] from Songkhla Province, Thailand. PE (LF) was naturally exposed to environmental conditions. Through advanced multiscale characterization techniques, including scanning electron microscopy (SEM), thermogravimetric analysis (TGA), tensile testing, and Fourier-Transform Infrared spectroscopy (FTIR), it was found that prolonged exposure to landfill conditions causes substantial physical, mechanical, and chemical degradation in PE (LF), as evidenced by extensive surface cracks, reduced tensile strength (below 10 MPa), and the formation of oxidative functional groups (CO and –OH). In contrast, commercial plastics maintain superior stability and mechanical integrity. Despite this degradation, PE (LF) retains significant potential for energy recovery via pyrolysis, with thermal properties suggesting efficient conversion into hydrocarbon fuels. Our findings highlight the urgent need for innovative waste management strategies and position landfill-derived plastics as a valuable resource for sustainable energy solutions. This research offers actionable insights for waste management authorities and recycling industries, supporting the transition toward a circular economy and the reduction of environmental impact from plastic waste.