Pusat Pengajian Kejuruteraan Bahan dan Sumber Mineral - Monograf

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Effect of corn starch and epoxidized natural rubber on the mechanical, thermal and water absorption behaviour for poly(lactic acid)halloysite nanoclay nanocomposite
(2012-06-01)
Muhammad, Nurul Athirah
PLA nanocomposite were prepared via melt mixing with halloysite nanoclay (2 wt%) and different amount of corn starch (5-15 wt%) by internal mixer followed by compression molding. The mechanical and morphological properties of PLA/HNC nanocomposites were characterized by tensile and impact test, also field emission scanning electron microscopy (FESEM). The optimum amount of corn starch which is 10 wt% is selected and used in Phase 2. In phase 2, the same procedures were repeated but at different amount of epoxidized natural rubber (ENR) (5-20%). The optimum amount of ENR which is 15 wt% is selected and used for futher test. In Phase 3, thermal properties of PLA nanocomposites were characterized by thermo-gravitational analysis (TGA) and thermo-oxidative test at 80°C. After thermo-oxidative test, the composites undergo tensile test. Water absorption test of PLA nanocomposites were performed too in 7 days. Water uptakes were recorded during water absorption test. After 7 days, tensile test and morphology properties were performed on the tensile fracture surface. It found that the addition with corn starch and epoxidized natural rubber (ENR) will influenced the tensile, thermal and water absorption behaviour. PLA/HNC/CS-10 and PLA/HNC/CS-10/ENR-15 contributes in the most water uptake during the 7 days of water absorption test.
Correlation of mineralogical characteristics with mechanical properties of meta-sedimentary rocks and granitic rocks from natm-1, Karak, Pahang and natm-4, Hulu Langat, Selangor
(2012-07-01)
Hassan, Nurfarhana
The Inter-State Raw Water Transfer (ISRWT) Project is designed to assist the process of conveying water for domestic and industrial uses from Semantan River to the Selangor and Kuala Lumpur regions. This tunnel is intended for future demand in diminish water shortage. In this study, two different locations of study areas were chosen, NATM-1 at Karak and NATM-4 at Hulu Langat in order to study the relationship between mineralogical characteristics and mechanical properties of rock. NATM-1 is represented by meta-sedimentary rocks whereas NATM-4 is represented by granitic rocks. In order to study and determine the mineralogical characteristics of the rocks, thin section on both types of rocks were prepared. Some minerals that abundance were observed in the rocks are quartz, feldspar, mica, clay-rich minerals and accessory minerals. To investigate the mechanical properties, point load test and Brazilian tensile strength test were carried out. From the experimental studies, it is noticed that grain size and type of mineral present is strongly influenced the rock strength. Weathering state also took part in affecting the rock’s strength. For granitic rocks, the finer the grain size, the higher the strength of the rock and this is an agreement in both mechanical tests carried out. However, some of samples were highly weathered hence caused to the reduction of strength value of the tested rocks. This is believed due to the abundance of high percentage of altered feldspar. In this study, it can be conclude that fine grain size minerals provides high strength to the rock considering lower percentages of feldspar contents in a fresh state of rock condition.
Ultra fine grinding of wollastonite using jet mill
(2012-07-01)
Mohamad Fithol, Mohamad Zulhairie
Wollastonite nowadays gaining it’s important to the fine particles industries application such as ceramics, plastics, cements, pharmaceuticals, metallurgical and paints. In order to fulfill the industrial demands, the fine grinding process must be took place to produce fine products of material or mineral. Fine grinding can be done using high intensity grinding mills such as jet mill. For this research, fine grinding of wollastonite is carried out using jet mill by varying the parameters of jet mill such as the feed rate, grinding pressure at different levels and the classifier rotational speed. Parameters for feed rate used are 5 kg/h and 10 kg/h, while classifier speed used for this experiment are 8000 rpm, 13000 rpm, and 18000 rpm. Grinding pressure used are 3 bar, 4 bar and 5 bar. In this grinding mill, grinding and classification took place simultaneously. The products of jet mill were characterized in terms of particle size distribution, shape and structure. Analysis has done shows that basically, coarser particle size can be obtained at a higher classifier rotational speed due to the fluctuation of inside mill condition and particle characteristics. From the particle size analysis for the products of grinding process, the smallest particle size, d50 which is 3.79 µm can be obtained at 5 kg/h feed rate, 18000 rpm classifier speed and 3 bar grinding pressure. Mineralogical analysis are includes XRF and XRD to determine the elements that present in wollastonite sample. XRF analysis shows that the percentage of SiO2 is 57.720% and CaO is 34.101%. This approved that the sample used is wollastonite because the chemical formula for wollastonite is CaSiO3.
Synthesis and characterization of copper doped zinc oxide rods
(2012-07-01)
Ong, Cheng Shian
In this project, there are two sections of synthesis process: (i) synthesis of undoped ZnO rods and (ii) synthesis of Cu doped ZnO rods. Undoped ZnO rods were successfully synthesized on Si substrates by sol-gel method using zinc nitrate tetrahydrate, Zn(NO3)2.4H2O and methenamine, (CH2)6N4 as precursors. Twin-rod structures of ZnO rods and agglomeration of ZnO rods were observed. Cu doped ZnO rods were synthesized under same condition with additional of cupric acetate monohydrate, Cu(CH3CO2)2.H2O. The effect on the morphology, crystallinity and optical property was studied. From the studied, size, aspect ratio, crystallinity and c-lattice parameter of Cu doped ZnO rods decreased with increasing of Cu dopant concentration, mainly due to the substitution of Cu2+ ions into the ZnO lattice. Besides, the optical band gap of ZnO rods became narrower, i.e. 3.3132eV for 20mol% Cu doped ZnO as compared to 3.3394eV for undoped ZnO rods. This could be attributed to the formation of CuO which has lower band gap energy (1.35eV) than ZnO when the Cu incorporated into the ZnO rods. As compared to undoped ZnO rods, additional emission peak was found at 2.97eV in the PL spectra for Cu doped ZnO rods synthesized with 10mol% Cu concentration and annealed at 650 oC for 2.0h. This emission could be related to the transition of electrons from Ec to Cu acceptor energy level radiatively. From the indications above, it could be concluded that Cu doped ZnO rods were successfully synthesized via sol-gel method using Cu(CH3CO2)2.H2O as dopant precursor.
Studies on the effect of uv exposure on the properties of poly (lactic acid) (pla)
(2012-07-01)
Yap, Hui Ping
Poly (lactic acid) (PLA) is a typical biodegradable polyester obtained by synthesis of lactic acid (or lactide), which can be produced from renewable resources such as corn or sugarcane. PLA is famous with biodegradability and good processability and expected to substitute some of the non-biodegradable plastics. However, due to its poor heat stability and brittleness, it limits the application. The purpose of this research is to study the effect of UV exposure on the properties of PLA. PLA 3051D Grades was extruded by extruder and then shaped into desired shape by using compression molding. Samples were exposed 2 to UV (0.68 mW/cm) using an accelerated weathering chamber for 0,100,200,300,400 and 500hours. Various testing was conduct to observe the effect of UV exposure on the samples. The testing consists of visual inspection, color change test tensile test, differential scanning calorimetry (DSC), gel permeation chromatography (GPC) and fourier transform infrared spectroscopy (FTIR). The results showed that the yield strength, modulus and elongation at break of PLA reduced when the UV exposure time increased. In addition, the glass transition temperature and melting temperature of PLA decreased while the degree of crystallinity of PLA increased with UV exposure time. Molecular structure of PLA was affected by UV exposure which could be seen from FTIR and GPC result.

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