Glycerol and Urea Plasticized Green Composites from Microalgae Biomass and Bioplastic

This work explored the potential use of residual microalgae biomass (RMB) obtained from the production of biodiesel as a new filler for compostable biocomposites. Nannochloropsis gaditana, the microalgae studied, was cultivated in the Microbial Ecology Laboratory of the University of Antofagasta, Chile. The RMB was obtained after transesterification of the microalgae biomass. Proximate analysis determined that the protein content of the RMB was 42%. The bioplastic used was poly(butylene adipate-co-terephtalate) (PBAT). Processing experiments were carried out in a micro twin-screw extruder at 140 ⁰C for 2 min, with an injection molding system. The compositions (in  wt%) of the blends were fixed at PBAT/RMB (90/10; 80/20; 70/30). The green composites and neat polymer samples were evaluated for tensile, flexural and impact properties after processing. In the second part of this work, RMB was modified with glycerol (20% and 30%), water with glycerol (30%), and urea (7.5 and 15%), which were used as plasticizers. The effect of plasticizers on the blend PBAT/RMB (80/20) was compared based on mechanical performance, and the optimal formulation was determined. 

Acknowledgements: This work was financially co-supported by 1) Desert Bioenergy S.A. from Innova-CORFO, 2) the chilean projects “Inserción de Capital Humano Avanzado en el Sector Productivo Chileno” No 78110106 and FONDECYT, Chile (Grant 11121591), 3) the Ontario Ministry of Economic Development and Innovation (MEDI), Ontario Research Fund - Research Excellence Round 4 program and 4) Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) New Directions & Alternative Renewable Fuels ‘Plus’ Research Program.