Achieving a Smooth Surface Polystyrene Waste Recyclate in Hot-Melt Processing

Abstract

Polystyrene is an aromatic hydrocarbon plastic material with applications in the packaging, food, and construction industries. As a packaging material, it protects items against shocks and acts as an insulator in the construction of buildings and food preservation. The polystyrene bowl for food packaging has become a convention in the food and pastries industry in Ghana due to its clean, lightweight, and insulation properties. However, the corresponding waste litters its environment, chocks gutters, and does not decompose. For this reason, we explored the hot melt recycling technique to convert the PS wastes into valuable plastic plates that finds application in the artifact and souvenir industry. The incorporation of a 20% v/w lauric fatty acid (LFA) into the material matrix blocked micro holes in the finished product and induced a smooth surface. Characterizations included experiments such as Fourier Transform-Infra Red spectroscopy, melting point determination, tensile testing, and scanning electron microscopy (SEM). Generated data displayed the absence of a chemical bond between the PS molecules and the LFA additive. However, the methyl chains of the PS molecules were miscible with the saturated dodecyl chains of the LFA additive. Hence, the LFA additive was held in place by weak intermolecular forces between its chains and that of the PS molecules. The measured melting point of the recycled plastic with LFA content (rPS20) fell between 84-142 °C. Mechanically, the tensile strength dropped with the addition of LFA. The LFA induced a smooth surface morphology finishing in rPS20.