STARCH? AND MICROCRYSTALLINE CELLULOSE?BASED PLASTICS INCORPORATING INDIGO CARMINE AS BIODEGRADABLE COLORED PLASTIC MATERIALS

• Main Author: Limuel Effendy, Evelyn
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/87516
• Institution: Institut Teknologi Bandung

The high use of petroleum-based plastics, which are difficult to decompose in nature, has a negative impact on the environment. One solution is to make plastics from natural polymers, such as starch. However, the physical and chemical properties of starch are not adequate enough to be processed into plastic, so modifications are needed to strengthen the structure of starch-based plastics. In this experiment, starch was modified by adding cellulose as an additional polymer, sorbitol as a plasticizer, and indigo carmine as a dye. This study aimed to utilize sweet potatoes as a source of starch and cogongrass as a source of cellulose. Additionally, the study was conducted to determine the optimum composition of plastic components and the effect of composition variations on mechanical properties, degree of swelling, plastic storage at a relative humidity of 53%, biodegradation, and contact angle. Plastic films were made by mixing starch with indigo carmine as a dye with concentration variations of 3, 5, 7, and 9% (w/w based on the total mass of starch?indigo carmine) at 85 °C. Subsequently, cellulose was added to the mixture, with variations in cellulose concentration of 2, 4, and 6% (w/w). Afterward, the mixture was plasticized by adding sorbitol with concentration variations of 15, 20, 25, and 30% (w/w). Based on the results, the starch yield was 4,7% (w/w), and the cellulose yield was 37,9% (w/w). The addition of indigo carmine, cellulose, and sorbitol used in the manufacture of plastic films resulted in a tensile strength of 3,2–27,2 MPa and an elongation of 5,6–116%. The degree of swelling test yielded a range of values of 44,8–162,6%. The plastic storage test at a relative humidity of 53% revealed that the plastic film tended to become drier after being stored for 30 days. The plastic burial test in the soil demonstrated plastic degradation, marked by a mass reduction of approximately 28,5– 39,2% (3 days), 28,2–41,5% (7 days), 42,9–57,5% (14 days), and 51,2–61,1% (21 days). The contact angle test yielded a range of values of 22,8–37,7°, indicating that the plastic is hydrophilic. The average data suggests that the plastic has the potential to be applied as a naturally degradable plastic.