Bioplastics synthesis based on sorghum–Eucheuma spinosum modified with sorghum stalk powder

In this study, a bioplastic was produced by addition of filler and plasticizer. Sorghum stalk powder was selected as a filler and glycerol as plasticizer. The effects of filler and plasticizer concentration on physical and mechanical characteristics of the bioplastics were observed. In the bioplastic production, the amount of sorghum stalk powder varied from 0.25 to 1 g, and glycerol concentration was varied from 5 to 20%. On the other hand, the amount of Eucheuma spinosum, as a fiber, and sorghum starch as a matrix remained constant. The bioplastic production has conducted by stirring the starch, fiber, filler, and glycerol for 35 minutes at 95°C and 375 rpm. The mixture was dried at 50°C for 8 hours. The best physical and mechanical characteristics of the product were obtained from the formulation consisting 0.5 g of filler and 10% of plasticizer concentration. The bioplastic itself had 21.265 MPa of tensile strength, 4.467% of elongation, 498.463 MPa of Young's Modulus, 0.95 g/cm³ of density, and 21.265% of water uptake which are in the range of commercial HDPE plastic characteristics. (paper)