Toughening of polylactic acid using styrene ethylene butylene styrene: Mechanical, thermal, and morphological studies

Abstract

Polylactic acid, PLA, derived from renewable resources has gained great attention nowadays owing to their sustainability, biodegradability, superior property, and transparency. However, intrinsic brittleness and low toughness severely limits its variety of applications. Blending of PLA with other polymers is more economical and more flexible technique for the property improvement of PLA. In this study, Styrene Ethylene Butylene Styrene (SEBS) and Maleic Anhydride grafted SEBS (MA-g-SEBS) are used as toughening agents to study their effect for its toughness, high strength and heat resistance on PLA. PLA/SEBS and PLA/Maleic Anhydride grafted SEBS blends were prepared under four different compositions by melt mixing technique using a corotating twin–screw extruder after optimizing the mixing conditions. The mechanical properties of the blends such as tensile, flexural, and impact strengths were investigated using specimens prepared by injection molding process. The percentage elongation and impact strength of PLA/MA-g-SEBS blends were found to be increased significantly by 540 and 135%, respectively in comparison with virgin PLA and PLA/SEBS blends. However, tensile strength and modulus of PLA/SEBS and PLA/MA-g-SEBS blends decreased compared with pristine PLA. SEM behaviour supported the higher impact property of PLA with the incorporation of modified SEBS via multiple crazing and cavitation mechanisms. DSC study also supported greater compatibility between maleated SEBS and PLA. POLYM. ENG. SCI., 2016. © 2016 Society of Plastics Engineers