No abstract

PP/clay nanocomposites samples of 1st and 2nd cycles (recycle) and different nanoclay loadings (i.e. 0, 5, 10, 15 wt%) samples were made by utilizing twin-screw extruder and injection molding machine. The samples were then characterized using a tensile test machine. The tensile tests results showed that modulus of elasticity and tensile strength of the nanocomposites samples for both 1st and 2nd cycles were all higher than the neat PP, and increased with increasing nanoclay loadings. The enhancements of modulus of elasticity (as compared to the neat PP) for 1st cycle of the nanocomposites were about 38.08%, 49.33%, and 78.65% for NC-5-I, NC-10-I, and NC-15-I, respectively. Whereas, for the 2nd cycle of the nanocomposites were about 44.33%, 59.59%, and 84.69% for NC-5-II, NC-10-II, and NC-15-I, respectively. This indicated that the incorporation of nanoclay in the PP matrix significantly increased mechanical properties, especially modulus of elasticity and tensile strength of the nanocomposites. Additionally, values of modulus of elasticity and tensile strength of 1st cycle and 2nd cycle of PP/clay nanocomposites were compared by plotting them in two graphs. The plots revealed that reprocessing of the nanocomposites did not significantly influence the mechanical properties of the nancomposites.

Chitosan is a polysaccharide compound in the form of a linear polysaccharide consisting of N-acetyl glucosamine (GlcNAc) and D-glucosamine (GlcN) monomer, which is a derivative of deacetylization of chitin polymer. Chitin is one of common type of polysaccharide on earth after the excess cellulose from inveterbrata skeletons. Chitosan has anti-microbial properties. Based on this properties, chitosan is potentially used to be an edible film as drug delivery system membrane. Edible film was made by dissolving chitosan in 100 mL acetic acid 1%, then the plasticizer and crosslinker was added while heated at 60° C. It was molded and dried in oven at 50°C for 48 hours. Drug loading in the edible film could be controlled by remodeling membrane characteristics in the presence of crosslinker additions. The purpose of this study was to estimate the mass transfer coefficient (kCa) of drug loading in various concentrations of ascorbic acid in the edible film. The characteristics of ascorbic acid in chitosan edible film could be seen from the number of drugs that could be loaded through the uv-vis spectrophotometric analysis. The higher concentration of ascorbic acid was added, the drug would be loaded more into edible film.

Special Region of Yogyakarta is one of the regions that has high potential for natural disasters. Food is the most consumable material which is needed when natural disasters occur. An alternative form of food preservative is needed to maintain nutritious foods that will be distributed to the victims of natural disasters. The foods must still appropriate to eat. In this research, watermelon rind was chosen as an ingredient to make natural preservatives because they contain flavonoids and anthocyanins. This research aims were to determine the total content of anthocyanins, flavonoids and phenolics in the red watermelon rind and yellow watermelon rind, also to determine the effect of chitosan composition to the ability of flavonoids and phenolics release in the food. This research was carried out by extraction and encapsulation methods. The analysis included the content of Total Anthocyanin (TA), Total Flavonoids (TF) and Total Phenolic (TPC) in the supernatant. The other analysis was in vitro tests that was done to know the ability of flavonoids and phenolics release in the food. The total anthocyanin content in the red watermelon rind was 0.0334 mg L-1 while in the yellow watermelon rind was 0.0668 mg L-1. The total content of flavonoids in the red watermelon rind was 0.7369 g mL-1, while in the yellow watermelon rind was 0.3296 g mL-1. The total phenolic content of red watermelon rind was 0.3669 g mL-1, while in the yellow watermelon rind was 0.2273 g mL-1. In both of red and yellow watermelon rind, the highest release of flavonoid and phenolic levels showed in the variations of chitosan mass 0.4 grams. The highest flavonoid content released was 0.0638 g mL-1 in red watermelon rind and 0.0702 g mL-1 in yellow watermelon rind. The highest phenolic content released was 0.0321 g mL-1 in red watermelon rind and 0.0408 g mL-1 in yellow watermelon rind.

Cation and industrial pollutant anions are removed from wastewater using organic cation and anion exchange resin. "Extracellular Polymeric Substance" (EPS) from bacterial extraction can accumulate cation and anion elements through biosorption by adsorption mechanism, ion exchange, formation of complex compounds and hydrogen bonds. EPS can be used as an biosorbent and ion exchange bioresin replacing organic resins, because EPS contains organic functional groups that are negatively charged (RCOOH, ROPO3H, ROPO3Na, ROSO3H, ROSO3Na, etc.) cation absorbers and positively charged (ROH, RCNH2HCOOH, etc.) anion absorber. EPS consists of 40-95% polysaccharide compounds, protein 1-60%, nucleic acids 1-10%, lipids 1-10% and the remaining amino acid polymers and other compounds. The tannery industry produces trivalent (Cr+3) chromium pollutants at levels of 15.2 ppm and hexavalent (CrO4-2 or Cr2O7-2) levels of 0.77 ppm which exceeds the standard quality for a total Cr of 0.6 ppm. Cr pollutants are very dangerous for human health. Research had been done on the use of immobilized EPS bioresin in epoxy polymers for chromium binding. EPS was extracted from bacterial activated sludge by centrifugation at 9000 rpm for 20 minutes at 4°C, the filtrate was EPS. The analysis showed EPS content were 16% fat, 12% carbohydrate, and 16% protein. The functional group analysis results with infrared ray spectroscopy (FTIR) showed EPS containing chemical bonds such as -CH, -OH, -NH, and -C=O which proved that EPS extraction contained RCOOH, ROH, and RCNH2HCOOH functional components which were exchanging components cations and anions. Epoxy polymers were prepared by mixing bisphenol A monomers and 1: 1 ratio epichlorohydrin. Immobilized EPS double ion exchange biorecin in epoxy polymers was prepared by mixing 200 mg EPS and 1800 mg epoxy. The binding of chromium ions in the resin was carried out by recirculating the chromium solution through a burette column filled with 2 rams of bioresin at pH 5, 6 and 7. The optimum results gave chromium ion absorption efficiency of 89.20% at pH 5. Column operations could be optimized by varied the amount of bioresin used.