This study aimed to enhance the properties of CaCl2 crosslinked sodium alginate/k-carrageenan (SA/KC) incorporated with clove essential oil (CEO). An evaluation of the modification effects on physicochemical, morphological, antioxidant, and antibacterial properties was performed. The properties were observed at various SA/KC ratios (10/0 to 1.5/1), CEO (1.5% to 3%), and CaCl2 (0% to 2%). The surface morphology was improved by addition of KC and CaCl2. The Fourier transform infrared (FTIR) result showed insignificant alteration of film chemical structure. The X-ray diffraction (XRD) result confirmed the increased crystallinity index of the film by CaCl2 addition. On physicochemical properties, a higher proportion of SA/KC showed the declined tensile strength, meanwhile both elongation at break and water solubility were increased. The incorporated CEO film reduced both tensile strength and water solubility; however, the elongation at break was significantly increased. The presence of Ca2+ ions remarkably increased the tensile strength despite decreased water solubility. Overall, the addition of KC and CaCl2 helped in repairing the mechanical properties and flexibility. CEO incorporation showed the effectiveness of profiling the antioxidant and antimicrobial activity indicated by high 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity up to 90.32% and inhibition zone of E. coli growth up to 113.14 mm2.

Glycerol is a by-product of biodiesel production. So far, glycerol has not been used optimally. An alternative product that can be produced from glycerol is triacetin through the esterification process. Research on the review of reaction kinetics to determine the optimum conditions of the reaction still limited. Previous study also reported that the esterification process requires quite a long reaction time. Therefore, in this study ultrasonic technology will be used to accelerate the reaction of glycerol esterification with acetic acid using sulfuric acid catalyst. The purpose of this study is to study the effect of ultrasonic technology on the conversion of esterification of glycerol/acetic acid, and to observe the kinetic study of triacetin production. To answer this goal, this study uses a set of ultrasonic devices as a substitute for the esterification of conventional models. The greatest conversion results are obtained when the reaction temperature is 1000C with a mole ratio of glycerol/mole of acetic acid 1/8. The use of ultrasonic technology in theory should have a greater impact on conversion results. The reaction order obtained is order 2 with the largest k value in the mole ratio of glycerol: acetic acid 1: 8 which is 0.0006 (l.mol−1menit−1). Due to the variation of moles ratio, the ratio at 1/6 and 1/4 did not show significant changes of reaction rate, the changes are constant for both first and second order reaction. But at the mole ratio of 1/8, the reaction rate constant shows a significant different for temperature changes.

The hydrogel is superabsorbent polymers (SAP) that are biodegradable and can be obtained from polysaccharides, lipids, and proteins. Polysaccharides include cellulose, starch and their derivatives, seaweed extracts such as carrageenan, alginate, pectin, and chitosan. Carrageenan is the result of the extraction of red seaweed sap with an alkaline solution. The main objective of this study was to simultaneously increase the strength and properties of κ-carrageenan SAP film with the addition of glyoxal and acrylamide as crosslinkers. The addition of acrylamide (variated from 1 to 7 % b/v) into the k-Carrageenan based SAP hydrogel compound and the presence of glyoxal as crosslink agent (variated from 0 to 1,0 % v/v). The physical properties of the SAP films were analyze using swelling degree and tensile strength. The structural and morphological properties of composite films were analyzed using Fourier Transform Infrared (FTIR) and Scanning Electron Microscopy (SEM). In addition, the effect of pHs on the releasing drug Poly(vinylpyrrolidone)-Iodine was investigated. This research shows that the addition of acrylamide and glyoxal can improve the physical properties of the modified κ-carrageenan film. Characterization using SEM shows that the addition of glyoxal causes the formation of tissue fibers in SAP. FTIR spectra indicated the formation of cross bonds in modified SAP film at 3294.42 cm-1 (carboxylic acid). The treatment under alkaline conditions will increase drug release ability.Keywords: κ-carrageenan; hydrogels; acrylamide; glyoxal; drug delivery