COMPOSITES OF STARCH ? COUMARIN COMPLEX/MICROCRYSTALLINE CELLULOSE/BIOPOLYMER AS SCENTED PLASTIC MATERIALS

• Main Author: Sita Permatasari, Amaliya
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/75538
• Institution: Institut Teknologi Bandung

Starch has not been able to fully replace non-biodegradable plastic materials because it has weaknesses, especially related to low mechanical properties. Therefore, to improve the mechanical properties of starch, it is necessary to mix it with other polymers that have a high compatibility with starch. Microcrystalline cellulose (MCC) is a polymer with a high potential to improve the mechanical properties of thermoplastic starch. In addition, the mechanical properties of starch can be enhanced by increasing the crystallinity of starch, including through the formation of complexes between starch and a guest molecule. This study chose coumarin as a guest molecule because it offered additional properties, especially for producing scented plastics. Scented plastics are widely used, in the children's toy industry, aroma therapy packaging, and scented waste plastics. This research consisted of the isolation of cassava starch and its characterizations, the preparation of composite films by the casting method, and the characterizations of the resulting and composite films. The starch ? coumarin complexes blended with microcrystalline cellulose were mixed with other biopolymers, such as poly(vinyl alcohol), xanthan gum, and karaya gum. Optimization in this study included variations in the added biopolymers, the concentration of guest molecules in the complexes, and the amount of plasticizer used. The characterizations of the sample included FTIR, XRD, mechanical test, contact angle, moisture content, microbial biodegradation test, and soil burial test. This study isolated the starch from cassava, yielding 14,05% (w/w). Cassava starch had a water content of 8,03% (w/w) and an amylose content of 19,67% (w/w). Starch ? .? coumarin complexes with 5%, 7%, and 10% (w/w) coumarin content were successfully prepared. Iodine assays showed that within these complexes, the relative percentage of amylose channels not occupied by coumarins ranged from 40 ? 60% for dried samples and 50 ? 70% for non-dried samples. The UV-Vis spectroscopy test of the starch ? .? coumarin complex solution showed a change in absorbance at a wavelength of 258 nm and the appearance of peaks at 277 nm and 315 nm originating from coumarin. This data indicated that coumarins were possibly not only in the amylose channels but also between the amylose helices. Based on the mechanical test data, the most optimum results were obtained for plastics containing double plasticizers, namely PEG200 and glycerol, with a mass ratio of 1:1, with a content of 20% (w/w), with a duration of stirring and sonication for 30 minutes and 50 minutes, and a mass ratio of support polymer and complex at 1:2. The best mechanical properties of the resulting starch composite films were obtained for 5% starch ? .? coumarin /PVA material, which resulted in an elongation percent of 189,7±83,7% and a tensile strength of 3,9±2,3 MPa. Moisture content data showed that 10% MXG was the most hydrophilic to water vapor, while the effect of starch .coumarin complex concentration on the resulting contact angle showed that it was directly proportional to the hydrophilicity of MXG. The optical properties of films with whiteness index (WI) were closest to the standards, MCC/complex/xanthan gum (MXG) 5% and 10% (w/w) with values of 19,31 and 18,17, ?L* values of 0,57 and 0,02, while ?E were 0 respectively 0,74 and 0,81. ?b* values of MCC/complex/karaya gum (MKG) 7% and 10% (w/w) of 5,36 and 5,19 indicated that the sample was yellower, while ?a* of 1,13 and 0,99 indicated that the sample was more reddish than the standard. The XRD data indicated that the starch ? .? coumarin complexes and the starch ? .? coumarin/MCC/polymer composite films were successfully obtained at an angle of 2? 18º and 22º for MCC/complex/poly(vinil alcohol) (MPVA 5% (w/w)), 16º (MXG 5% (w/w)), and MKG 7%, MKG 10%, MXG 10% (w/w) respectively 21 .? 23º, 12 .? 16º and 20 .? 21º. TGA characterization showed that the decrease in composite film mass due to thermal degradation was around 59,4% .? 61,3%, with MPVA 5% (w/w) were the highest degradation at temperature of 304 ºC. The biodegradation test showed that A. Niger could degrade the starch film composite well. In addition, the 10% starch ? coumarin/xanthan gum complex composite showed the highest resistance to a composer containing Trichoderma sp, Rhizobium sp, Azotobacter sp, Actinomycetes sp, Aspergillus sp, Bacillus sp, Lactobacillus sp, Pseudomonas sp. Microscopy and SEM data confirmed the degradation of the composite films. These data indicated that the starch ? .? coumarin complex/MCC/biopolymer composite films had a high potential as a biodegradable scented plastic material.