Jusami | Indonesian Journal of Materials Science
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COMPARATION OF RUBBER MILLING PROCESS TO PRODUCE NATURAL RUBBER COUMPOUNDS USING MODIFIED AND UNMODIFIED LOCAL CLAY FILLER
Get PDFCOMPARISON OF RUBBER MILLING PROCESS TO PRODUCE NATURAL RUBBER COMPOUNDS USING MODIFIED AND UNMODIFIED LOCAL CLAY FILLER. Many researchers have studied the effect of modified clay as filler on rubber compounds for both natural rubber and synthetic rubber. Various chemicals are used as clay modifiers. In the rubber milling process, modified clay is directly used as filler after pretreatment with clay modifier. However, clay modifiers can also be milled together with original clay during the rubber mastication and milling process. Thus both of these methods certainly produce different physical properties, so the comparison of the two rubber milling processes is the focus of this research. The analysis of the curing characteristics and physical properties of vulcanized natural rubber was carried out with a rheometer and physical properties test units. Thermal analysis was carried out using TG/DTA and dispersion of filler on the rubber compound was analyzed by SEM. The results of the curing characteristic of the rubber compound and the physical properties of vulcanization showed that there was an effect due to the comparison of the rubber milling process. Modified clay using JH-S69 is better than JH-S69 milled with original clay and vice versa occurs in PEG 4000 which is used as clay modifier. PEG 4000 which is milled together with original clay produces curing characteristic and physical properties of vulcanization better than pretreatment of clay to be modified clay. This analysis is in line with the analysis using SEM
EFFECT OF ANNEALING CYCLES ON DEEP DRAWABILITY OF LOW CARBON TITANIUM ADDED STEEL
Get PDFEFFECT OF ANNEALING CYCLES ON DEEP DRAWABILITY OF LOW CARBON TITANIUM ADDED STEEL. Maximum mechanical properties and deep drawability of low carbon titanium added steels was obtained after heat treatment with simulation batch annealing cycles in an industrial process. The effect of holding times and holding temperatures on deep drawability were studied using tensile test for measuring normal anisotropy (r-value) and strain hardening exponent (n-value). Scanning electron microscope were employed for observation of microstructure in steel sheets. X-ray diffraction with pole figure techniques were also used for measuring texture of annealing. Results showed that as the temperature was increased up to 900 oC, both r and n values increased gradually and peaked in the temperature of 850 oC. This results showed that formability of sheet materials increased until batch annealing temperature reach 850 oC as increasing the ratio of intensities {111} /{100}. The largest mean r value of almost 2.6 was obtained in slow heating at holding temperature of 850 oC with n value of 0.27
EFFECT OF ULTRASONIC TREATMENT ON THE CONSOLIDATION OF ODS STEEL FeCrY2O3 PROCESSING WITH CAPSULATED SINTERING PROCESS.
Get PDFEFFECT OF ULTRASONIC TREATMENT ON THE CONSOLIDATION OF ODS STEEL FeCrY2O3 PROCESSING WITH CAPSULATED SINTERING PROCESS. A new method on the synthesis of ODS (Oxide Dispersion Strengthened) steel for advanced nuclear material was performed by ultrasonic treatment to improve the consolidation process. The raw material of Fe, Cr and Y2O3powder with the composition of Fe-15 wt% Cr, 0.5 wt% and Ytria (Y2O3) as disperzoid were processed by the powder metallurgy method with the main process of pre-alloying, iso-compaction and sintering process. The pre-alloying process was carried out by mixing the alloying elements using ultrasonically treatment at frquency of 20 kHz with variation of 40, 50 and 60 % amplitude. Iso-compaction process was done using the load of 800 psi to obtain a pellet-shaped sample, then continued by the sintering process for consolidation. The sintering process was done in two stages, 1-step sintering and 2-steps sintering, using the heating furnace by putting the sample in a quartz capsule to prevent oxidation attack. Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS), X-ray Diffraction (XRD), and Micro-hardness tests were carried out to analyze the microstructure and phase formation in relation to the consolidation process. The highest hardness occurred in the addition of treatment with an amplitude of 60% which produces a micro structure with the most fine grain. For 1-step sintering process, the highest hardness of 134.51 VHN obtained at 40 % amplitude. The hardness of the alloy depends on the size of the grain boundary associated with the difficulty of the dislocation movement
BIOREDUCTION AND CHARACTERIZATION OF SILVER NANOPARTICLES FROM OIL PALM EMPTY FRUIT BUNCH
Get PDFBIOREDUCTION AND CHARACTERIZATION OF SILVER NANOPARTICLES FROM OIL PALM EMPTY FRUIT BUNCH (OPEFB). The synthesis of silver nanoparticles was successfully carried out by extracting oil palm empty fruit bunch. The precursor used was silver nitrate (AgNO3) with a concentration of 9x10-4 M and 5 wt% of the oil palm empty fruit bunch extract. OPEFB acted as a capping agent in the synthesis of silver nanoparticles. The bioreduction method Ag+ to Ag0 produced a silver nanoparticle colloid in brown color. The results of the UV-Vis spectrophotometer showed the silver nanoparticles colloids spectrum at a wavelength of 420 nm with an absorbance value of 0.5. FTIR shows the reduction and shift of absorption peak in the hydroxyl functional group (-OH) at wavenumbers of 3323 cm-1 and the presence of absorption peaks at 560 cm-1. While, XRD pattern showed the specific crystallinity peaks of silver nanoparticles at 2θ: 33.24°; 39.98°; 61.23°; dan 79.13° respectively with the face-centered cubic crystal structure (FCC) and crystallite size of 15 nm. PSA analysis showed two specific peaks with an average size distribution silver nanoparticles of 43.5 nm and a PDI value of 0.4. Analysis of TEM shows the average particle size of 20 nm with a spherical particle shape
CHARACTERIZATION OF COMPOSITE CONTAINING LDPE (LOW DENSITY POLY ETHYLENE) AND MODIFIED PINEAPPLE LEAF FIBER
Get PDFCHARACTERIZATION OF COMPOSITE CONTAINING LDPE ( LOW DENSITY POLY ETHYLENE) AND MODIFIED PINEAPPLE LEAF FIBER. Pineapple leaf fiber could be used as a reinforcing material in natural fiber composites production with a synthetic polymer matrix. The typical problem in this process was the weak bond between the fiber component and the matrix. This study aimed to improve the bonds strength between pineapple leaf fibers and the polymer matrix of LDPE (Low Density Poly Ethylene) by modifying pineapple leaf fibers. The modification of pineapple leaf fibers was carried out through an enzymatic process using the xylanase enzyme. A modified fiber was then used as a fiber component in the composite using a commercial LDPE plastic matrix. Composites were made by the sandwich method using a hotpress machine at a temperature of 130 °C for 10 minutes. The evaluation of the composites were carried out by testing the tensile strength properties using the Tensolab tool and thermal properties using the TGA (Thermal Gravimetry Analysis) instrument. The results of the mechanical properties test of the composite showed the modified pineapple leaf fiber-based composite had a better tensile strength (34.3 MPa) than the untreated pineapple leaf fiber-based composite (30.2 MPa). The results of the thermal properties test showed the decreasing of the mass occurred at temperature of 300-350 °C due to degradation of the fiber,and it completely degraded at temperature of 450 °C
EFFECTS OF CHITOSAN COATING ON THE PHYSICAL, MECHANICAL AND ANTIMICROBIAL PROPERTIES OF FOOD PACKAGING PAPER
Get PDFEFFECTS OF CHITOSAN COATING ON THE PHYSICAL, MECHANICAL AND ANTIMICROBIAL PROPERTIES OF FOOD PACKAGING PAPER. The coating process on food packaging paper is carried out to improve the food safety and health aspect from dangerous substance migration from food packaging into food. Chitosan has attracted interest in packaging, especially in food packaging as edible films and coatings. A paper from oil palm empty fruit bunches (OPEFB) pulp was coated with chitosan using different pulp weight (1, 1.5, 2 g) and chitosan content (0.25, 0.50, 0.75, 1 g) as parameters. The effect of chitosan as coating material on physical, mechanical, and antimicrobial properties was studied. The results showed that the density and grammage values of the paper increased after coating due to the increasing of chitosan content. The mechanical properties of the coated paper, such as tensile strength, tensile modulus and elongation, improved in line with the increase of chitosan content and pulp weight. The addition of chitosan on paper imparts antimicrobial properties against Gram-positive bacteria (Staphylococcus aureus) and Gram- negative bacteria (Escherichia coli)