Biography
Biography: Rangrong Yoksan
Abstract
Polylactic acid (PLA) is one of the most promising bio-based and biodegradable polyester, which can be converted into packaging and utensils; for example, cutlery, cup, tray, etc.; however it is brittle and expensive. Blending with thermoplastic starch (TPS) is a way to reduce the price of the final PLA-based products and to improve their flexibility. Although TPS/PLA blend is a biodegradable thermoplastic material, its recyclability is also important to meet sustainability. Until now, there is no any report relevant to the recyclability of TPS/PLA blend. Therefore, the aim of this research is to demonstrate the effect of injection-molded TPS/PLA blend scrap concentration on properties of the reformed TPS/PLA blend. TPS/PLA blend was prepared by a twin-screw extruder using a weight ratio of TPS:PLA of 60:40 and various concentrations of injection-molded TPS/PLA (60/40) blend scrap, i.e. 0, 20, 40, 60, 80 and 100 wt%. The blends were then converted into dumbbell-shaped specimens using an injection molding machine. The increased amount of scrap caused slightly increased tensile strength and elongation at break; however TPS/PLA blend with scrap concentration of 20 wt% had the highest tensile strength (24.2% improved). In addition, Young’s modulus and Izod impact strength of the blend decreased with increasing scrap content. Glass transition temperature of TPS/PLA blend decreased from 59.7°C to 52.4-57.5°C when scrap concentration was increased. The results suggest that TPS/PLA blend can be recycled and suitably used for making injection-molded products, especially for the ones without food contact such as jardiniere, flowerpot, shovel, basket, stationary box, etc.