Degradability of plastic sheeting prepared from esterified sago residue

Abstract

 In this report, plastic sheeting prepared from esterified sago residue was investigated for its degradability in soil or on fungi and for its insolubility in various solvents.
 The esterification conditions for the residue, as adopted in the previous study, were reaction at 140°C for 4 hours or at 160°C for 2 hours. The reaction products were mixed with glycerol (0, 10, 15 and 20wt%) as a plasticizer and then molded into a plastic sheet by a hot-press. Samples of the plastic sheeting were buried in soil for 60 days. After this period, all samples showed a decreasing modulus of elasticity (MOE) and loss of mass. Other plastic sheet samples were placed on a fungus medium. The resulting samples were remarkably biodegraded, regardless of the esterification conditions or the glycerol contents. The results of insolubility tests with various solvents showed clearly that plastic sheeting had low insolubility in acid and alkali solutions. A comparison of insolubility between polar and non-polar solvents, revealed higher insolubility in the non-polar. In addition, the insolubility of the polar solvent decreased with increasing glycerol content.