Advanced Materials Research Vol. 1133

Abstract: Fly ash is a pozzolanic material which is produced during coal combustion in thermal power plants. This paper investigates the suitability of Malaysian fly ash for geopolymer synthesis. Chemical composition analysis, particle size analysis, amorphous and crystalline phases present, bonding nature, and microstructural behavior are used to determine the suitability of fly ash for geopolymer synthesis. The results showed that fly ash contains silica, alumina, ferrous oxide, and calcium oxide in major proportions which are the main ingredients required for geopolymer synthesis. Higher portion of particles having size in the range of 1-15 µm. Fly ash contains quartz, mullite, and ferrite as the crystalline compounds while the major portion of fly ash is in amorphous form. The band due to asymmetric stretching vibration mode of Si-O-T appears at 1095 cm^-1 which is the main band used to follow geopolymer formation. Microstructure of fly ash shows that the higher portion of fly ash is in amorphous form while it contains cenospheres, magnetic spheres, carbon, and a large number of small particles. Malaysian fly ash is a suitable material for geopolymer and it can be used for geopolymer synthesis.

Abstract: The use of triacetin as an alternative plasticizer to polyvinyl chloride (PVC) was studied in term of plasticizer efficiency and tensile properties before and after ageing. The efficiency of plasticizers was evaluated based on the glass transition temperature (T_g) and the hardness value of the compounds. The T_g and hardness of all PVC/DEHP/Triacetin compounds are lower than PVC/50DEHP and PVC/50Triacetin compounds indicating synergistic plasticisation effect between both DEHP and Triacetin within the PVC compounds. The low molecular weight and chemical structure of triacetin are believed to contribute to the highest tensile strength, elongation at break and modulus of the PVC/triacetin compared with PVC/DEHP and PVC/DEHP/triacetin compounds. However, the migration ability of the triacetin plasticizer is believed to result in the biggest changes of the tensile properties of PVC compounds plasticized with triacetin before and after ageing.

Abstract: This paper describes tensile properties, and morphology analysis of different composition of RHDPE and EVA blends were studied. The main goals are to describe the effect of Caprolactam as compatibilizer used to improve the compatibility between RHDPE and EVA. The RHDPE/EVA blends were prepared at 160°C and the rotor speed of 50rpm in an internal mixer. The tensile strength for RHDPE/EVA blends increased, while adding Caprolactam by 6phr in the blend formulation significantly improved the tensile properties. The SEM micrograph show a better interfacial adhesion between RHDPE and EVA phases for RHDEP/EVA/Caprolactam blends than RHDPE/EVA blends.

Abstract: Silicone hydride copolymer was functionalized with allyl methacrylate under the platinum catalyzed hydrosilylation reaction to yield comb-like poldimethylsiloxane grafted with methacrylate. The reaction was monitored via attenuated total reflectance Fourier transform infrared spectroscopy. Silicone hydride copolymer was synthesized in advance under cationic equilibrium ring opening polymerization. From the results, silicone hydride copolymer was synthesized based on cationic equilibrium ring opening polymerization mechanism under acidic condition. The peaks obtained from attenuated total reflectance Fourier transform infrared spectrum and nuclear magnetic resonance spectra corresponded to silicone hydride copolymer structure and ascertained that the silicone hydride copolymer synthesis was completed after 72 hrs of reaction. Functionalization process of silicone hydride copolymer had proceeded according to the Chalk-Harrod mechanism. The disappearance of Si-H peak at 2157 cm^-1 had been observed in the attenuated total reflectance Fourier transform infrared spectra had indicated that the functionalization process was completed after 48 hrs of reaction.

Abstract: Natural Rubber (NR) latex cleaning compound was prepared by using three types of NR latex; HA latex, waste latex and subnormal latex. Each of these NR latex is then compounded with two different cleaning agents; monoethanolamine (MEA) and diethylene glycol (DEG) at three different phr loading; 1, 3 and 5 phr. The mechanical properties of these compounds were also investigated. Cleaning efficiency was conducted by applying the NR latex cleaning compound on the dirty surfaces. From the results, NR latex compounded with MEA exhibit better mechanical properties at loading of 3 phr MEA. The cleaning efficiency also showed the ability of NR latex compound to clean the dirty surfaces with addition of cleaning agent especially at higher loading. The waste N R latex compound compounded with MEA shows the best result in cleaning the surfaces due to the presence of filler that can adsorbed the dirt on the surfaces.

Abstract: The effect of natural weathering on tensile properties of low density polyethylene/ thermoplastic soya spent powder (TSSP) was studied. TSSP was produced by mixing the soya spent powder (SSP) with glycerol. Both blends were prepared by using internal mixer (brabender) at 150 °C with the SSP/TSSP content ranged from 0 to 25 wt%. Then, all the dumb-bell samples were exposed to Perlis environment located at Kubang Gajah, Perlis for 6 months period. The tensile properties were tested by using a universal testing machine (UTM) according to ASTM D638. LDPE/SSP blends presented lower strength and elongation at break (E_b) than LDPE/ TSSP blends meanwhile there were no Young’s Modulus values for 20 wt% onwards of both blends due to the brittle samples after 6 months of weathering.

Abstract: Infra-red spectroscopic (IR) analysis of the geopolymers provides information regarding gel chemistry, quantitative analysis, kinetics and effect of different activators on geopolymers. This review discusses the IR analysis of geopolymers and their starting materials. Different applications of IR spectroscopy, used in geopolymerization, are explored in detail. Future research questions regarding IR analysis of geopolymers are also discovered

Abstract: In tyre industries, rheological and processability properties of rubber and polymer are great of importance since there are alot extrusion processes involved in the tyre manufacturing other than calendaring and moulding processes. Uniformity and consistency in the flow behaviour and processability of rubber are essential in providing the solution to the rubber industries in order to improve productivity, products quality and energy conservation. In this works, effects of silane coupling agent on rheological behaviour and extrusion performance of silica filled ENR tread compounds were studied and compared to NR/BR tread compound. The compounds were prepared by melt mixing in tangential internal mixer, while the rheological properties of compounds were determined by Capillary Rheometer, Cure Rheometer and Mooney viscometer. The compound were further examined for its extrudability performance evaluation by extruded the rubber through 30mm cold feed extruder machine using ASTM Extrusion Die, ‘Garvey’ type. Results showed that, ENR/silica compounds exhibit higher shear viscosity curves as compared to NR/BR compound at low shear rate regime. However an opposite trend was observed towards high shear rate regime tested which ENR/silica compounds gave slightly lower shear viscosity curve compared to NR/BR compound. As for extrudability performance evaluation, NR/BR compound gave better extrusion characteristics and appearance as compared to ENR/silica compounds.

Abstract: The compressive responses and failure investigations of corrugated-core sandwich panels subjected to lateral compression are presented. The results of finite element (FE) analysis using ABAQUS/CAE are compared with experimental results from tests on sandwich panels based on corrugations of aluminum alloy, glass fibre-reinforced plastic (GFRP) and carbon fibre-reinforced plastic (CFRP). Particular focus is placed on identifying the scaling effects of number of unit cells and the thickness of the cell walls in dominating the overall deformation and local collapse of the panel. The effect of increasing the number of unit cells and cell wall thickness are investigated. The FE predictions have been shown to in reasonably agreement with the experimental measurements. The evidence suggests that corrugated composite cores offer significant potential as lightweight cores materials in sandwich construction.

Abstract: In the past years, not many works on joining sialon to martensitic stainless steel have been carried out. The effect of the cut off heat upon cooling on the joint has yet to be discussed. In this paper, this effect is studied in terms of the microstructure and hardness of the reaction layer. Diffusion bonding was utilized to join sialon and AISI 420 martensitic stainless steel. The joining processes were conducted at 1150°C and 1200°C for one hour under a uniaxial pressure of 17 MPa in a vacuum (i.e. 1.0x10^-5 Torr). The heat was cut off upon cooling and the samples were left in the furnace for about 20 hours to cool down. Thicker reaction layer was formed in 1200°C sample because interdiffusion and reaction of elements occurred more rapidly at this temperature. The cut off heat had caused the sialons to crack and it was very severe in 1150°C sample due to the formation of a very thin interface layer. This layer did not have the sufficient strength to bind sialon and steel together because one of the sialons was completely detached from the joint. Diffusion layer and parent steel were segregated due to the difference in properties between the regions and it was more noticeable in 1200°C sample. Iron silicides and aluminium oxide might be formed in the interface layer. Microstructure of the parent steel transformed from globular coarse carbide in ferrite matrix to large grain size with carbide’s precipitation along the grain boundaries. More precipitates were formed in 1200°C sample and they were concentrated near the segregation line of the diffusion layer and the parent steel. The weakest part of the joint was at the border of sialon and interface layer since their hardness were extremely different.