|IMMOBILIZED LIPASE SYSTEMS FOR MODIFICATION AND PROCESSING OF LIPIDS - A REVIEW |
In principle, immobilized lipase technology facilitates the development of continuous, large-scale commercial processes, which have a high efficiency per unit volume of reactor and a corresponding high rate of return of capital costs. Furthermore, the use of immobilized lipase lead to a decrease in the potential for contamination of the product via residual lipase, thus avoiding the need for downstream thermal treatment. Immobilization also permits multiple use of lipase and enhances its thermal and chemical stability, thus leading to predictable decay rates and enhances opportunities for better coritrol of both the process and product quality. This review focuses on the use of immobilized lipase technology. The various immobilization procedures, reactor configurations, and process consideration are reviewed and discussed.
Nazimah Sheik Abdul Hamid and Uma Devi M. Palanisamy*
|1994||3/14/2017 12:12 PM||1/18/2018 7:35 AM|
|LIQUID STATE 1H AND 13C-NMR STUDIES ON POLYMERISATION REACTION OF 2,2'-DIFURFURYLOXY-2- SILAPROPANE |
The purpose of this study was to prepare the copolymer of 2,2'-difurfuryloxy-2-silapropane (DFS) and 1, 1 '-(methylenedi-4, 1-phenylene) bismaleimide (BM). DFS was prepared at 0°C through the reaction of 2 moles of furfuryl alcohol (FA) with 1 mole of dichlorodimethylsilane (DCMS) in the presence of pyridine and chloroform as a solvent. The formation of this compound was characterized by the 1H and 13C-NMR spectroscopy and mass spectrometry. DFS has the ability to undergo the Diels-Alder reaction. The furan end groups of DFS could react with dienophile groups of other materials. The adduct of DFS-BM was prepared by the reaction of DFS with BM at room temperature (18°C) in chloroform (CDCI). Characterization of the adduct was carried out through a study of the 1H and 13C-NMR spectra of the adduct.
KEYWORDS: Furfuryl alcohol (FA), dichlorodimethylsilane (DCMS), 2,2'-difurfuryloxy-2-silapropane (DFS), 1, 1 '-(methylenedi-4, 1-phenylene) bismaleimide (BM), condensation reaction, Diels-Alder reaction.
|1994||3/14/2017 12:12 PM||1/18/2018 7:33 AM|
|RHEOLOGY STUDY OF RICE HUSK ASH - POLYPROPYLENE COMPOSITE |
The rheological properties of rice husk ash-polypropylene composite was studied using a Br~bender slit capillary rheometer. The melt shear stress and viscosity increased with filler content. The .filler was subsequently treated with a silane-based coupling agent. The silane used was Prosil 2020, a proprietary silane coupling agent containing the peroxide bis(t-butyl peroxy)di-isopropyl benzene. The peroxide induces -scission of the polypropylene molecular chains reducing the shear stress and viscosity. Hence, the filler and the coupling agent (peroxide concentration) have opposing effect on the rheology of the composite's melt. For high filler content melt, the peroxide effect is more prominent lowering the overall stress and viscosity. At higher shear rate, the effect of filler concentration is more dominant. Mixing torque and melt flow index studies support the, rheology measurements by the slit die technique.
KEYWORDS: Polypropylene, rheology, rice husk ash, filler, composite, compounding, Prosil, coupling agent.
M.Y. Ahmad Fuad*, J. Mustafah and M.S. Mansor, Z.A. Mohd Ishak and A.K. Mohd Omar
|1994||3/14/2017 12:12 PM||1/18/2018 7:34 AM|
|RICE HUSK ASH AND OIL PALM AS FILLERS IN POLYPROPYLENE: FILLER CONTENT DETERMINATION BY THERMOGRAVIMETRIC ANALYSIS |
The use of three types of agricultural by-products as fillers in polypropylene has been investigated. The first two were derived from burnt rice husk ash (RHA) while the third, a wood-based filler, was processed from oil palm trunk. One important characterization of the composites involves the checking for the actual filler content and filler distribution within the matrix. An analytical technique is described here for computation of the filler content in the composites based on simple expression derived from thermogravimetric analysis. For filler with volatiles such as the black RHA, the derived expression is p, = 106(m/m0) and for easily burnt fillers (wood-based), the expression is p, = 160 (mime). The technique has shown good agreement (and consistency) between analysed and actual filler contents with. a uniform filler distribution in the polypropylene matrix.
KEYWORDS: Polypropylene, rice husk ash (RHA), oil palm wood flour (OPWF), composite,
compounding, thermogravimetric analysis, filler content.
M.Y. Ahmad Fuad*, M.J. Zaini, J. Mustafah Z.A. Mohd Ishak and A.K. Mohd Omar
|1994||3/14/2017 12:12 PM||1/18/2018 7:33 AM|
|SEPARATION BY SELECTIVE ADSORPTION: PREPARATIVE LIQUID CHROMATOGRAPHY |
An investigation to separate methyl isostearate from a mixture containing methyl esters and methyl isostearates using the isothermal liquid phase selective adsoption technique proved to be successful. The technique may provide the impetus for use ir simulated counter current technology. This particular investigation utilized the method of preparative liquid chromatography using several desorbent materials and separation conditions (temperature and sampling time). The maximum percentage composition of methyl isostearate separated was 81.1 %. This value was obtained using n-heptane + 1 % acetic acid as desorbents at 30°C. The solute desorption rates were found to be influened by both temperature and the percentage of the acetic acid or ethyl acetate added to n-heptane as desorbents.
Wan Mohtar Wan Vusoff, Che Husna Azhar and D. Lonchamp
|1994||3/14/2017 12:13 PM||1/18/2018 7:33 AM|