PREPARATION OF PLASTICS BASED ON STARCH AND POLYVINYL ALCOHOL BLENDS AS BIODEGRADABLE PLASTIC MATERIALS

• Main Author: Angeline, Charmenita
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/87530
• Institution: Institut Teknologi Bandung

Plastic are generally made from synthetic polymers commonly used in packaging due to its flexibility, lightweight, and water resistance. However, the production and use of plastics significantly impact environmental balance and human health due to their resistance to natural degradation. An alternative approach to mitigating these negative effects of conventional plastics is the development of bioplastics derived from renewable resources, such as starch. This research aims to determine the optimal composition for producing plastics made from a starch-fumaric acid complex and polyvinyl alcohol (PVA), as well as to evaluate the effect of the composition variations on the mechanical properties, swelling degree, contact angle, moisture absorption, and soil burial degradatioin test. In this research, cassava was used as the source of starch. The isolated starch (yield 5.8%) was complexed with fumaric acid and combined with PVA. The mass ratios between the starch complex and PVA were set at 3:1; 1:1; and 1:3. The addition of PVA formed intermolecular bonds with the starch, thereby enhancing the mechanical properties of the plastic. Plastics based on starch-fumaric acid complex and PVA were produced with fumaric acid concentrations of 3, 5, 7, and 9% (w/w based on the total complex mass). Increasing the amount of fumaric acid improved the starch’s crystallinity, which enhanced the tensile strength of the plastic. The plastic was further modified by adding plasticizers variations of 15, 20, 25, and 30% (variations of citric acid 1, 3, and 5%) (w/w based on the total film mass). The addition of plasticizers increase the distance between polymer chain, resulting in greater polymer chain mobility and elongation of the plastic. The addition of fumaric acid, PVA, sorbitol, and citric acid in the plastic films resulted in tensile strength values ranging from 1.8 to 24.3 MPa, elongation from 7.9% to 548.8%, and Young's modulus from 7.2 to 47.3 MPa. The optimal composition of the plastic film was determined based on its mechanical properties and used for further testing. Swelling degree tests showed values ranging from 109 to 191.2%, while contact angle showed values ranging from 48.9 to 61.4°, indicating that the plastic is hydrophilic. The moisture absorption test conducted over 21 days showed a decrease in mass gain due to degradation, with an average mass increase of 7.5% (day 7), 6.4% (day 14), and 6.7% (day 21). The plastic burial test in soil indicated that the remaining plastic mass after degradation was 44.9% (day 3), 40.1% (day 7), and 36.7% (day 14). The average of these data suggests that this plastic has the potential to be used as a biodegradable plastic.