Rubber cassava is a plant that underutilized due to toxic HCN that contained in it and it has very high carbohydrate content that is 98.47%. Peel of rubber cassava also has high enough carbohydrate content of about 70%. Rubber cassava and its peel can be as basic material of manufacturing of biodegradable plastic. This research was did to determine the effect of composition of sorbitol and glycerol plasticizer and obtained an optimum composition with using other materials such as chitosan, acetic acid, and aquadest. Sorbitol and glycerol plasticizer varied with the number two at 40% by weight starch with 5% of each sample interval. The results obtained in the form of a edible film of biodegradable plastic that has been tested mechanical properties. Based on analysis of the tensile strength test, biodegradable plastics obtained from starch cassava rubber and its peel that optimum in 6 sample (25% sorbitol and 15% glycerol) by0.00613 MPa and 0.00429 MPa. Based on analysis of elongation test, biodegradable plastics obtainedfrom starch cassava rubber and its peel that optimum in 4 sample (15% sorbitol and 25% glycerol) by 5% and 4%. Based on analysis of biodegradation test showed that biodegradable plastics are tested with the land medium has been degraded perfect for 60 days while with the aqueous medium takes longer time for biodegradable plastics can be degraded perfect
