Improving the Properties of Biodegradable PLA via Blending with Polyesters for Industrial Applications

Abstract

Polylactic acid (PLA) is a biodegradable polymer obtained from the fermentation of renewable resources, which can also be used in industrial areas. The employment of PLA is restricted by its brittle nature at room temperature. This study, it is aimed to prepare PLA blends with PBT (Polybutylene terephthalate) to overcome this drawback. Thus, it can be provided new raw materials to many sectors, especially textile, automotive and electronic products, by preparing biodegradable, environmentally friendly materials with better performance properties. PLA/PBT blends containing 5%, 10%, and 15% PBT by weight were produced in a twin screw extruder using with using maleic anhydride grafted ethylene/butyl acrylate (EBA-g-MAH) as a compatibilizer. For comparison studies, blends of PLA/PBT without compatibilizer were also prepared. Examinations on the flow, viscoelastic properties, and rheologic characteristics of prepared samples were carried out by using Melt Flow Index values and Rotational Rheometer measurements. Mechanical and impact resistance characteristics were identified in accordance with the relevant standards. Physical properties of blends such as molding shrinkage, density, and hardness values were also determined. Degradation or cross-linking-induced changes in the chain structure was not observed during the investigation via using a rotational rheometer for PBT samples at 240 °C /15 min., and PLA samples at 260 °C /15 min. Notched izod impact test results show that adding compatibilizer increases 16% impact resistance of PLA/PBT blends. The tensile modulus values of the blends containing compatibilizer decreased by 2% approximately. These results show the transition from brittle to ductile behavior of PLA for compatibilized blends.

Poly(Lactic Acid) / Polyester Blends: Review of Current and Future Applications

“…Aside from issues with energy and the environment, this trend is fueled by lower prices for commercial PLAs, initiatives to make up for or circumvent PLA's flaws, and the introduction of PLA-based goods with superior functionality and desirable attributes. But in order to create PLA-based blends with better performance, fewer defects, reduced cost, and desirable multifunctional properties, extensive study is needed [55,56].…”

“…While the izod value of PLA/PET blend containing 15% PET prepared without compatibilizer or chain extender is 2.69 kJ/m 2 increased to 5.49 kJ/m 2 when a chain extender is used. Thus, it is thought that PLA can be used more easily and successfully instead of using PLA alone in applications requiring low viscosity such as PLA/PET blends, injection molding, and 3D printing [55,56].…”

“…The EBA-g-MAH compatibilizers' interface compatibility is responsible for the blends' noticeable improvement in notched izod impact strength. The EBA-g-MAH adapters' interface compatibility is what led to the blends' notched izod impact strength significantly increasing[55,56].PET is a significant engineering thermoplastic used in commerce that has strong thermal and mechanical characteristics as well as low permeability and chemical resistance. Girija et al examined the thermal and mechanical properties of blends of PLA and PET[57].…”