Biopolymers and Bioplastics

Biography

Biography: Manjusri Misra

Abstract

Glycerol is the primary co-product of biodiesel production with an estimated worldwide production of about 6 billion lbs per year by 2020. This biobased molecule is envisioned as a precursor for polymer synthesis among many other chemical syntheses which can be performed using glycerol as starting molecule. Succinic acid is a dicarboxylic acid which can now be commercially obtained from renewable resources through fermentation of biomass derived sugars. When these two monomers are combined, a biobased polymer termed poly glycerol succinate (PGS) is formed which has not yet found applications in the material science field limiting its adoption at commercial scale. In this work we have synthesized and employed PGS as a blending partner for PLA aiming to improve the tensile toughness of the blend system. The influence of the main synthesis parameters for PGS (molar ratio of reactants, monomer type and temperature of synthesis) in the mechanical behavior of PLA/PGS blends was investigated and a preferred set of synthesis conditions leading to an effective PLA toughening has been selected. Moreover, reactive extrusion has been performed utilizing free radical initiators in order to improve the compatibility of the phases in the blend. For this purpose a third monomer, maleic anhydride, was employed in the synthesis to create unsaturated poly glycerol succinate co maleate (PGSMA) polyesters which allows them to react from the unsaturation point in subsequent processing steps. It was seen that the addition of maleic anhydride as a monomer for the synthesis of PGSMA allows for the in situ compatibilization of PLA and PGSMA phases through the formation of PLA-g-PGSMA copolymers. With the in situ compatibilization effect taking place an effective toughening of PLA was achieved increasing the elongation at break of the blend from 3% for neat PLA to 150% for an 80/20 wt% PLA/PGSMA blend created in reactive extrusion mode.