Abstract
Biodegradable plastics were fabricated from rice flour by the extrusion method using glycerol and rice husk powder as the plasticizer and filler, respectively. The independent variables were temperature (100(120(C), glycerol (25(45%), and rice husk powder (0(20%). The independent variables were varied at three levels following the Box-Behnken experimental design. Three response surface models describing the effect of the independent variables on the tensile strength, elongation at break, and stiffness of the plastics were proposed. The tensile strength and the elongation at the break of the plastics were significantly affected by glycerol and rice husk, while the stiffness of the plastic was only significantly influenced by glycerol. The response optimizer was applied to estimate the optimum conditions for preparing the plastics, i.e., 100(C for temperature, 25.81% for glycerol, and 0% for rice husk. The tensile strength, elongation at break, and stiffness of the plastic estimated by the optimum conditions were 7.27 MPa, 12.45%, and 10630 N/m, respectively. The biodegradable plastics prepared with the optimum conditions had a tensile strength of 7.13 MPa, elongation at break of 13.05%, and stiffness of 10400 N/m. These values are closely similar to the predicted values.
