| Poly(N -isopropylacrylamide)-stabilized gold nanoparticles in combination with tricationic branched phenylene-ethynylene fluorophore for protein identification | |
| Kusolkamabot K., Sae-Ung P., Niamnont N., Wongravee K., Sukwattanasinitt M., Hoven V.P. | |
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| Abstract | |
| Gold nanoparticles stabilized by thermoresponsive polymer, poly(N-isopropylacrylamide) (PNIPAM-AuNPs) were prepared by surface grafting of thiol-terminated PNIPAM onto citrate-stabilized AuNPs. The color change of the PNIPAM-AuNPs solution from red to blue-purple without precipitation when the solution was heated to 40 C, above the lower critical solution temperature (LCST) of PNIPAM, indicated the thermoresponsive property of the synthesized AuNPs. PNIPAM-AuNPs were used to detect proteins by chemical nose approach based on fluorescence quenching of fluorophore by AuNPs. An array-based sensing platform for detection of six proteins, namely bovine serum albumin, lysozyme, fibrinogen, concanavalin A, hemoglobin, holo-transferrin human can be successfully developed from the PNIPAM-AuNPs having different molecular weights (4 and 8 kDa) and conformation (varied heat treatment from 25 to 40 C) in combination with a tricationic branched phenylene-ethynylene fluorophore. From principal component analysis (PCA) followed by linear discriminant analysis (LDA), 100% accuracy of protein classification using a leave-one-out (LOO) approach can be achieved by using only two types of PNIPAM-AuNPs. © 2013 American Chemical Society. | |
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| Fluorescence quenching; Linear discriminant analysis; Lower critical solution temperature; N- isopropylacrylamide; Poly (n isopropylacrylamide); Protein Classification; Protein identification; Thermoresponsive polymer; Acrylic monomers; Aromatic compounds; Fluorophores; Gold; Grafting (chemical); Metal nanoparticles; Principal component analysis; Proteins; acrylic acid resin; alkyne; bovine serum albumin; cation; concanavalin A; fibrinogen; gold; hemoglobin; lysozyme; metal nanoparticle; poly N isopropylacrylamide; poly-N-isopropylacrylamide; transferrin; animal; article; cattle; chemical structure; chemistry; human; metabolism; particle size; surface property; temperature; Acrylic Resins; Alkynes; Animals; Cations; Cattle; Concanavalin A; Fibrinogen; Gold; Hemoglobins; Humans; Metal Nanoparticles; Molecular Structure; Muramidase; Particle Size; Serum Albumin, Bovine; Surface Properties; Temperature; Transferrin | |
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| On the potential of porphyrin-spiked triarylamine stars for bulk heterojunction solar cells | |
| Kengthanomma T., Thamyongkit P., Gasiorowski J., Ramil A.M., Sariciftci N.S. | |
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| A novel porphyrin-triarylamine compound was synthesized to serve as a photosensitizer in bulk heterojunction solar cells (BHJ-OSCs). Based on cyclic voltammetric analysis, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the target porphyrin trimer were determined to be at -5.4 and -3.5 eV versus vacuum, respectively, and compared with those of other materials used for the construction of the BHJ-OSCs. Absorption and emission spectra of the film of the target porphyrin trimer were in good agreement with those of its solution. The charge transfer in a blended film of the porphyrin-triarylamine compound with phenyl-C 61-butyric acid methyl ester (PCBM) was proven possible by photoluminescence measurements. The energy conversion efficiency of the BHJ-OSCs based on the target compound depended strongly on the donor:acceptor weight ratio and the thickness of the organic layer. Surface nanomorphologies of the films with different donor:acceptor ratios and thickness were investigated by atomic force microscopy (AFM). The short circuit current density (J SC) up to 2.06 mA cm-2 was obtained from the BHJ-OSC fabricated herein. © 2013 The Royal Society of Chemistry. | |
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| Absorption and emission spectra; Bulk heterojunction solar cells; Cyclic voltammetric; Highest occupied molecular orbital; Lowest unoccupied molecular orbital; Nanomorphologies; Photoluminescence measurements; Target compound; Atomic force microscopy; Electron energy levels; Emission spectroscopy; Energy conversion; Heterojunctions; Nanostructured materials; Oligomers; Photosensitizers; Solar cells; Vacuum applications; Porphyrins | |
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| Hydrothermolysis of carbohydrates to levulinic acid using metal supported on porous aluminosilicate | |
| Suacharoen S., Tungasmita D.N. | |
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| BACKGROUND: Aluminosilicate catalysts have the potential to promote the formation of oxygenated derivatives from carbohydrates in a hydrothermolysis reaction. Levulinic acid (LA) can be obtained from glucose, sucrose and starch hydrothermolysis reactions, and is a very versatile building block for diverse organic synthetic compounds. In this work, the catalytic performance of Ni- or Ru-doped aluminum-loaded SBA-15 (Al-SBA-15) was compared with ZSM-5 catalyst in order to achieve high LA selectivity. RESULTS: All catalytic hydrothermolysis reactions tested gave remarkably higher LA selectivity than non-catalytic reactions for every carbohydrate substrate used. The acid contents and porous properties are important keys to control yield and selectivity of LA. The highest selectivity of LA (44%) was attained from glucose hydrothermolysis at 200°C (for 1h) using a 15wt% loading of the 20wt% Ru-doped ZSM-5 catalyst. CONCLUSION: Moderately raising Ru in ZSM-5 and Al-SBA-15 catalysts increased the levels of LA. The MFI structure of ZSM-5 is suitable for hydrothermolysis of glucose monosaccharide, while the hexagonal mesoporous structure of Al-SBA-15 is preferred for starch polysaccharide hydrothermolysis at the optimum condition. © 2012 Society of Chemical Industry. | |
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| Aluminosilicate catalysts; Catalytic performance; Hydrothermolysis; Levulinic acid; Mesoporous structures; Non-catalytic reactions; Oxygenated derivatives; Synthetic compounds; Aluminosilicates; Aluminum; Carbohydrates; Catalysis; Glucose; Organic acids; Starch; Catalyst selectivity; aluminosilicate calcium; carbohydrate; glucose; levulinic acid; nickel; ruthenium; article; catalysis; chemical reaction; hydrothermolysis; temperature; thermal conductivity; transmission electron microscopy; X ray diffraction | |
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| ABS modified with hydrogenated polystyrene-grafted-natural rubber | |
| Pisuttisap A., Hinchiranan N., Rempel G.L., Prasassarakich P. | |
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| Natural rubber (NR) latex was grafted by emulsion polymerization with styrene monomer, using cumene hydroperoxide/tetraethylene pentamene as redox initiator system. The polystyrene-grafted NR (PS-g-NR) was hydrogenated by diimide reduction in the latex form using hydrazine and hydrogen peroxide with boric acid as a promoter. At the optimum condition for graft copolymerization, a grafting efficiency of 81.5% was obtained. In addition, the highest hydrogenation level of 47.2% was achieved using a hydrazine:hydrogen peroxide molar ratio of 1:1.1. Hydrogenation of the PS-g-NR (H(PS-g-NR)) increased the thermal stability. Transmission electron microscopy analysis of the H(PS-g-NR) particles revealed a nonhydrogenated rubber core and hydrogenated outer rubber layer, in accordance with the layer model. The addition of H(PS-g-NR) at 10 wt % as modifier in an acrylonitrile-butadiene-styrene (ABS) copolymer increased the tensile and impact strengths and the thermal resistance of the ABS blends, and to a greater extent than that provided by blending with NR or PS-g-NR. Copyright © 2012 Wiley Periodicals, Inc. | |
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| Acrylonitrile-butadiene-styrene; Cumene hydroperoxide; Graft co polymerizations; Grafting efficiency; Optimum conditions; Redox initiator systems; Styrene monomer; Transmission electron; ABS resins; Blending; Copolymers; Elastomers; Emulsion polymerization; Grafting (chemical); Hydrazine; Hydrogen peroxide; Hydrogenation; Latexes; Mechanical properties; Peroxides; Polystyrenes; Styrene; Transmission electron microscopy; Rubber | |
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| Rapidly stopping hemorrhage by enhancing blood clotting at an opened wound using chitosan/polylactic acid/polycaprolactone wound dressing device | |
| Boonkong W., Petsom A., Thongchul N. | |
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| Doxycycline and monosodium glutamate (MSG) loaded chitosan (CHI)/polylactic acid (PLA)/polycaprolactone (PCL) blend film was studied as a model device to deliver drug to targeted human organ which in this case was the skin with opened wound. The CHI/PLA/PCL blend film containing 60 % CHI, 28 % PLA, and 12 % PCL exhibited the good properties for making the dressing device. It was observed that doxycycline/MSG loaded CHI/PLA/PCL blend film could rapidly deliver both doxycycline and MSG at the high release percentage approaching 100 % loaded. MSG accelerated blood clotting and fibrin formation; thus, it exhibited the good hemostatic activity. The antibacterial activity of doxycycline loaded CHI/PLA/PCL blend film against Staphylococcus aureus and Escherichia coli as model bacteria was investigated. Doxycycline release played the crucial role in bacterial inhibition as observed from the lowest bacterial cell dry weight observed when compared with the control bacterial culture or the bacterial cultures with the presence of other films studied. © 2013 Springer Science+Business Media New York. | |
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| Anti-bacterial activity; Bacterial cells; Bacterial cultures; Bacterial inhibition; Fibrin formation; Monosodium glutamate; Staphylococcus aureus; Wound dressings; Bacteria; Escherichia coli; Polycaprolactone; Blood; chitosan; doxycycline hyclate; polycaprolactone; polylactic acid; antibacterial activity; article; bacterial cell; bacterium culture; bleeding; controlled study; dry weight; Escherichia coli; fibrin formation; hemostasis; nonhuman; priority journal; Staphylococcus aureus; water vapor; wound dressing; Anti-Bacterial Agents; Bacterial Infections; Bandages; Blood Coagulation; Chitosan; Doxycycline; Drug Carriers; Equipment Design; Hemostatics; Humans; Lactic Acid; Polyesters; Polymers; Postoperative Hemorrhage; Sodium Glutamate; Surgical Wound Infection; Treatment Outcome; Wound Closure Techniques; Bacteria (microorganisms); Escherichia coli; Staphylococcus aureus | |
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| Mixed oxides of Ca, Mg and Zn as heterogeneous base catalysts for the synthesis of palm kernel oil methyl esters | |
| Limmanee S., Naree T., Bunyakiat K., Ngamcharussrivichai C. | |
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| A series of mixed oxides of Ca, Mg and Zn were investigated as heterogeneous catalysts for the synthesis of palm kernel oil methyl esters (FAME) via the transesterification of palm kernel oil with methanol. The mixed oxides with different elemental compositions were prepared via the pH-controlled co-precipitation using Na2CO3 as a precipitant. The effects of the precipitation conditions on the physicochemical and catalytic properties of the resulting mixed metal precipitates and oxides were studied. The structural analyses indicated that the atomic ratio of Ca:Mg:Zn, the pH, the concentration of CO32-, and the molar ratio of CO32-/metal ions essentially determined the types of metal hydroxides and carbonates in the CaMgZn mixed precipitates. The substitution of Mg2+ and Zn2+ into the CaCO3 lattice as CaMg(CO3)2 and CaZn(CO3)2, respectively, resulted in highly dispersed metal oxide crystallites in the catalysts and enhanced the base properties of the mixed oxides. The initial rate of FAME formation was well correlated with the total basicity of the oxide catalysts. The FAME yield of 97.5wt.% was achieved over the CaMgZn mixed oxide, prepared with the Ca:Mg:Zn ratio of 3:1:1 under the Na2CO3 concentration of 0.75molL-1 and the CO32-/metal ions ratio of 1.0, when the reaction conditions were the methanol/oil molar ratio of 20, catalyst amount of 6wt.% and temperature of 60°C. © 2013 Elsevier B.V. | |
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| Base catalyst; Catalytic properties; Elemental compositions; Fatty acid methyl ester; Heterogeneous base catalyst; Heterogeneous catalyst; Mixed oxide; Reaction conditions; Alkalinity; Calcium; Calcium carbonate; Catalysts; Esterification; Esters; Lasers; Lime; Metal ions; Precipitation (chemical); Sodium; Transesterification; Zinc; Palm oil | |
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| 2,2,2-Trifluoroethyl methacrylate-graft-natural rubber: Synthesis and application as compatibilizer in natural rubber/fluoroelastomer blends | |
| Hinchiranan N., Wannako P., Paosawatyanyong B., Prasassarakich P. | |
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| The incompatibility and immiscibility of natural rubber (NR)/fluoroelastomers (FKM) blends were improved by incorporation of a graft copolymer synthesized from the free radical graft copolymerization of 2,2,2-trifluoroethyl methacrylate (TFEM) onto NR initiated by benzoyl peroxide via a melt-mixing process. The grafting properties were investigated as functions of the initiator and monomer concentrations, reaction temperature and time. At the optimal conditions, the obtained graft NR (GNR) purified by Soxhlet extraction contained a maximum grafting efficiency of 1.34% with 49.1% monomer conversion. The structure of the purified GNR was analyzed using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and nuclear magnetic resonance spectroscopy (1H NMR and 19F NMR). The gross GNR was then applied as the compatibilizer for NR/FKM vulcanizates (20/80 (w/w)) cured by peroxide vulcanization. The addition of GNR at 15 parts per hundred of rubber (phr) gave a vulcanizate with the highest tensile strength (9.93 MPa), some 5.31-fold higher than that of the incompatibilized one (1.87 MPa). This is likely to be due to the higher degree of homogeneity of the constituent phases in the GNR-compatibilized blends, as observed by scanning electron microscopy (SEM). The GNR-compatibilized NR/FKM vulcanizates were also resistant to gasohol E85 (85% (w/w) of ethanol). © 2013 Elsevier B.V. All rights reserved. | |
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| Attenuated total reflectance Fourier transform infrared spectroscopy; Chemical synthesis; Constituent phasis; Graft co polymerizations; Grafting efficiency; Monomer concentration; Monomer conversions; Reaction temperature; Elastomers; Fourier transform infrared spectroscopy; Free radicals; Graft copolymers; Grafting (chemical); Mechanical properties; Microstructure; Monomers; Nuclear magnetic resonance spectroscopy; Peroxides; Purification; Scanning electron microscopy; Synthesis (chemical); Tensile strength; Thermodynamic properties; Rubber | |
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| Hydrogenated polyisoprene-silica nanoparticles and their applications for nanocomposites with enhanced mechanical properties and thermal stability | |
| Kongsinlark A., Rempel G.L., Prasassarakich P. | |
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| Hydrogenated polyisoprene (HPIP)-SiO2 nanocomposites were synthesized via differential microemulsiion polymerization followed by diimide hydrogenation. First, the isoprene monomer was polymerized on the silane treated nanosilica by differential microemulsion polymerization to obtain polyisoprene (PIP)-SiO2 nanoparticles with a particle size of 43 nm. PIP-SiO 2 latex was subsequently hydrogenated at the carbon-carbon double bonds by diimide reduction in the presence of hydrazine and hydrogen peroxide with boric acid as promotor to provide HPIP-SiO2 nanocomposites. Core-shell morphology consisting of silica as the nano-core encapsulated by HPIP as the nano-shell was formed. The highest hydrogenation degree of 98 % was achieved at a ratio of hydrogen peroxide to hydrazine of 1.5:1. The nanosized HPIP-SiO2 at 98 % hydrogenation showed a maximum degradation temperature of 521 C resulting in excellent thermal stability, compared with unfilled PIP (387 C). A new nanocomposite of HPIP-SiO2 could be used as a novel nanofiller in natural rubber. Consequently, HPIP-SiO2/NR composites had improved mechanical properties and exhibited a good retention of tensile strength after thermal aging and good resistance toward ozone exposure. © 2013 Springer Science+Business Media Dordrecht. | |
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| Boric acid; Carbon; Hydrazine; Hydrogen bonds; Hydrogen peroxide; Hydrogenation; Mechanical properties; Microemulsions; Nanocomposites; Nanoparticles; Oxidation; Ozone resistance; Particle size; Peroxides; Polyisoprenes; Polymerization; Silica; Silicon; SiO2 nanoparticles; Tensile strength; Thermal aging; Thermodynamic stability; Carbon-carbon double bonds; Core-shell morphologies; Degradation temperatures; Diimide; Hydrogenation degree; Isoprene monomers; Microemulsion polymerization; Nano-silica; Silica nanoparticles; boric acid; carbon; hydrazine; nanocomposite; nanoshell; ozone; polyisoprene; silicon dioxide; unclassified drug; article; catalysis; hydrogenation; microemulsion; particle size; polymerization; priority journal; reduction kinetics; tensile strength; thermostability | |
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| Synthesis of nanosized ethylene-propylene rubber latex via polyisoprene hydrogenation | |
| Kongsinlark A., Rempel G.L., Prasassarakich P. | |
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| Nanosized ethylene-propylene rubber (EPM) latex with a particle size of 47 nm was synthesized via an alternative route consisting of isoprene (IP) polymerization followed by hydrogenation. First, the IP monomer was polymerized by differential microemulsion polymerization to obtain polyisoprene (PIP) rubber latex with a particle size of 42 nm. The structure of synthetic PIP was hydrogenated at the carbon-carbon double bonds to produce an ethylene-propylene copolymer by diimide reduction in the presence of hydrazine and hydrogen peroxide using boric acid as promotor. The degree of hydrogenation was determined by proton nuclear magnetic resonance (1H-NMR) spectroscopy and the structure of the ethylene-propylene copolymer was identified by 13C-NMR spectroscopy. In nanosized PIP hydrogenation, the hydrogenation level was found to be increased by boric acid addition. An EPM yield of 94% was achieved using a hydrogen peroxide: hydrazine ratio of 1.5: 1. The EPM produced from PIP has high thermal stability with the maximum decomposition temperature of 510°C and a glass transition temperature of -42.4°C close to commercial ethylene-propylene diene rubber. Dynamic mechanical analysis indicated that EPM had a maximum storage modulus due to the saturated carbons domains of the ethylene segments in the polymer chains. Copyright © 2012 Wiley Periodicals, Inc. | |
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| Alternative routes; Boric acids; Carbon-carbon double bonds; Decomposition temperature; Diene rubbers; Diimide; Ethylene propylene copolymers; Ethylene-propylene rubber; High thermal stability; Microemulsion polymerization; Polymer chains; Proton nuclear magnetic resonance; Rubber latexes; Saturated carbon; Boride coatings; Copolymers; Ethylene; Hydrazine; Hydrogen peroxide; Inorganic acids; Latexes; Microemulsions; Nanoparticles; Nuclear magnetic resonance spectroscopy; Partial discharges; Particle size; Polyisoprenes; Polymerization; Propylene; Rubber; Hydrogenation | |
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| Enhanced UV-protection and antibacterial properties of natural rubber/rutile-TiO2 nanocomposites | |
| Seentrakoon B., Junhasavasdikul B., Chavasiri W. | |
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| Natural rubber/rutile-TiO2 nanocomposites (NR/n-TiO 2(R) composites) with different n-TiO2(R) contents were prepared. The n-TiO2(R) with median particle size (d50) of 73 nm was successfully prepared from commercial micron-TiO2(R) by ultrasonication. NR incorporated with n-TiO2(R) shows the good performance in mechanical properties as well as UV-protection and antibacterial properties. The mechanical performance of NR/n-TiO2(R) composites was enhanced with an increase of n-TiO2(R) content up to the optimum content at 5 phr (parts per hundred parts of rubber) and then declined. In addition, the prepared NR/n-TiO2(R) composites possess the UV-protection material. The UV-protection property of NR nanocomposites was evaluated by measuring the evolution of carbonyl absorption band from ATR-FTIR spectra, surface cracking, and mechanical properties after UV irradiation. The presence of n-TiO2(R) exhibits significant improvement in photo-degradation by UV irradiation compared to the unfilled NR. More importantly, the obtained NR/n-TiO2(R) composites demonstrate effective antibacterial property against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), the strong antibacterial property of the prepared NR nanocomposites was obtained at the only loading level of 1 phr of n-TiO2(R). The prepared NR/n-TiO2(R) composites could be used as a novel antibacterial material. © 2012 Elsevier Ltd. All rights reserved. | |
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| Antibacterial materials; Antibacterial properties; ATR FTIR; Escherichia coli (E. coli); Loading level; Mechanical performance; Median particle size; S. aureus; Staphylococcus aureus; Surface cracking; Titanium dioxide nanoparticles; Ultra-sonication; UV irradiation; UV-protection; Bacteria; Escherichia coli; Fourier transform infrared spectroscopy; Mechanical properties; Nanocomposites; Photodegradation; Rubber; Surface defects; Titanium dioxide | |
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| Shell-derived heterogeneous base catalyst for transesterification of palm oil | |
| Jindapon W., Jaiyen S., Winitsorn A., Butnark S., Ngamcharussrivichai C. | |
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| In the present work, shell, which is available in abundance, low cost and non-toxicity, was used as a source of calcium for preparation of heterogeneous base catalysts. The catalyst was prepared by dissolution-precipitation method in which a calcined shell was mixed with Zn(NO3)2 and Al2O3 under acidic conditions, followed by calcination at 300-700 °C. ZSA-I was referred to as the catalyst attained under the suitable synthesis conditions. Physicochemical properties of ZSA-I were studied by using X-ray fluorescence spectroscopy (XRF), powder X-ray diffraction (XRD), thermogravimetric/ differential thermal analysis (TG/DTA) and CO2-pulse chemisorption analysis. ZSA-I gave the highest fatty acid methyl ester yield of 99 wt.% in the transesterification of palm oil with methanol and can be reused at least 5 times with a retention of the methyl ester yield higher than 96 wt.%. © (2013) Trans Tech Publications, Switzerland. | |
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| Acidic conditions; Calcined shells; Fatty acid methyl ester; Heterogeneous base catalyst; Heterogeneous catalyst; Low costs; Methyl esters; Non-toxicity; Palm oil; Physicochemical property; Powder X ray diffraction; Shell; Synthesis conditions; Thermogravimetric; X-ray fluorescence spectroscopy; Calcination; Carbon dioxide; Chemisorption; Differential thermal analysis; Esterification; Esters; Fluorescence spectroscopy; Lime; Manufacture; Methanol; Precipitation (chemical); Shells (structures); Technology; Transesterification; Vegetable oils; X ray diffraction; Catalysts | |
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