Effect of Gelatinization Temperature and pH and Addition of Sodium Tripolyphosphate on the Characteristics of Biodegradable Plastic from Cassava Starch (Manihot esculenta)

Kristinah Haryani ^[2] | Hargono Hargono ^[3] | Noer Abyor Handayani ^[2] | Ignatia Novita Tanuwidjaja | Mochammad Pasycal Ramadhan

Abstract: Biodegradable plastics have become a good substitute for conventional plastics because it is can be decomposed by microorganism into water, carbon dioxide, and methane. Biodegradable plastic can be made from starch and it have been widely studied and traded. Starch is one of the natural ingredients that has good properties to be formed into biodegradable plastic. However, the use of starch-based biodegradable plastic is limited due to its poor mechanical properties. Cross-linking method is one of the methods for polymer modification that is widely used to improve mechanical properties of starch-based biodegradable plastic by adding an ingredient called a cross-linking agent where it could tie together with carbon atoms from different chains of the polymer. One of the cross-linking agents is Sodium Tripolyphosphate (STTP). STTP is used because it has a low level of toxicity and is by food quality. This research aims to examine the effect of temperature and pH on the tensile strength and water absorption of the biodegradable plastic produced, to examine the effect of the concentration of sodium tripolyphosphate (STTP) on the tensile strength, water absorption, and the level of biodegradability of the biodegradable plastic. The result showed that increasing the temperature in the gelatinization process of biodegradable plastic from cassava starch can increase the tensile strength value and reduce water absorption in the resulting biodegradable plastic. Increasing the pH in the gelatinization process of biodegradable plastic from cassava starch can increase the tensile strength value and increase water absorption in the resulting biodegradable plastic. The addition of STTP levels in the process of making biodegradable plastic from cassava starch does not always increase the tensile strength value of the resulting biodegradable plastic. This can occur due to the residue of the cross-linking agent due to the addition of excess cross-linking agent so that it can interfere with the interaction between starch molecules and result in a decrease in the tensile strength value. The addition of STTP levels in the process of making biodegradable plastic from cassava starch can reduce water absorption and can increase the level of biodegradability of the resulting biodegradable plastic.

Keywords: biodegradable plastic; cassava; cross-link; sodium tripoplyphosphate

Edition: Volume 12 Issue 3, March 2023,

Pages: 1461 - 1468