An approach for the compatibility of thermoplastic starch/poly (lactic acid) blends using an ester obtained from glycerol and tall oil fatty acids

Abstract

AbstractThis work reports the compatibilization of thermoplastic starch (TPS)/polylactic acid (PLA) blends with a glycerol ester (GE), obtained by modifying glycerol with tall oil fatty acids. The proportions of TPS/PLA studied were 50/50 and 70/30, with the GE amounts from 0 (control sample), 5, 10, 15, and 20 wt%. The effect of the compatibilizer on the structural, thermal, rheological, morphological, mechanical and biodegradation properties of the blends was evaluated. Ultraviolet visible (UV–Vis) analysis of the blends showed that GE improved the light transmission resistance of the materials. The presence of GE resulted in decreased glass transition temperature (Tg) and complex viscosity (η*) values for the blends as opposed to the control sample. Furthermore, η* decreased with the increase in GE content and the η* values were lower than 105 Pa.s. Scanning electronic microscopy analysis revealed that GE improved the interfacial adhesion between TPS and PLA. The tensile modulus (149–414 MPa), tensile strength (5.60–11.6 MPa) and the biodegradability of the blends decreased with GE content, but the water resistance showed an opposite behavior. The GE acted as a plasticizer, compatibilizer and antioxidant for TPS/PLA blends.