Preparation of Biobased Monofunctional Compatibilizer from Cardanol To Fabricate Polylactide/Starch Blends with Superior Tensile Properties

A biobased monofunctional compatibilizer (called Epicard) is first synthesized by the reaction of cardanol with epichlorohydrin as confirmed by Fourier transform infrared and 1H NMR. Subsequently, biosourced polymers, polylactide (PLA) and starch, are melt-blended by a twin-screw extruder with Epicard. Confirmed by the measurements of contact angle and 1H nuclear magnetic resonance of the extracted starches from PLA/starch/Epicard blends, the Epicard only possesses a monoepoxy group to mainly react with starch and then increased the hydrophobicity of the starches during the melt-blending process. As a result, an obvious improvement to the interfacial adhesion between starch and PLA is observed by the scanning electron microscopy. Furthermore, the tensile properties of PLA/starch blends are effectively improved with the addition of Epicard. This study suggests a simple but effective material technique by utilizing a novel plant oil modifier to increase interfacial adhesion in fabricating fully biobased PLA/starch blends with superior tensile properties.