Advanced Materials Research Vol. 701

Abstract: High volume fraction Aluminum/alumina-fused silica hybrid metal matrix composites containing alumina with 0, 10, 30 and 50 wt% fused silica were produced by melt squeezing casting method. Microstructure of hybrid composite was investigated by optical microscope and scanning electron microscopy (SEM). The SEM images showed uniform distribution of fused silica particles in composite microstructure. Also compressive strength of the composites changed (310-110 MPa) with amount of fused silica.

Abstract: The effect of fibre modification via vacuum resin impregnation on tensile properties of sugar palm fibre reinforced thermosetting composites was studied. The fibres were impregnated with unsaturated polyester, vinylester and epoxy at the pressure of 600mmHg (79.99kPa) for 30 mins. After curing time, it was observed that tensile strength of impregnated fibre was significantly increased with epoxy (EPX) was the best with 188.06 MPa. It was followed by unsaturated polyester (UP) and vinylester (VE) with 107.12 MPa and 158.31 MPa. However, tensile modulus for sugar palm fibre impregnated with EPX increased up to 21% compared to un-impregnated sugar palm fibre followed by UP (12.7%) and VE (8.4%). It was observed that different impregnation agents gave different values of strength of sugar palm fibre composites.

Abstract: This paper describes the experimental investigation to develop the concrete mix design Nomograph for concrete containing PET as fine aggregate. The physical and mechanical properties were determined by using mix proportion containing 25%, 50% and 75% of PET with water cement ratio (w/c) 0.45, 0.55 and 0.65. The data obtained showed that the inclusion of PET aggregate reduce the strength performances of concrete. All the data obtained were combined into one single graph to develop a preliminary mix design nomograph for PET concrete. The nomograph consist of ; relationship between compressive strength and water cement ratio; relationship between splitting tensile strength water cement ratio; relationship between splitting tensile strength and PET percentage and relationship between compressive strength and PET percentage. The mix design nomograph can be used to assists in selecting the proper mix proportion parameters based on the criteria required.

Abstract: The aim of this work is to study controllability of cell structure of foam by a Polypropylene (PP)/Polystyrene (PS)/ Polymethyl methacrylate (PMMA) ternary polymer blend. The effects of different polymer matrix, its blend morphology, and rheology on the cell structure of the ternary blend foam were investigated. The batch pressure quenched foaming of the ternary blend with supercritical carbon dioxide (CO₂) was conducted in the temperature range from 60 to 160°C for PP matrix and 60 to 140°C for PS and PMMA matrices to observe the controllability of bubble location and size. The experimental results showed that interfacial tension, foaming temperature, and viscoelasticity are the important factors to control the cellular structure in ternary blend system.

Abstract: Sugar palm frond fibre has a potential to be as reinforcement in natural fibres reinforced polyester composites. This paper investigates the tensile properties of sugar palm frond fibre reinforced polyester composites. The sugar palm frond fibres were mixed with polyester composites at the 5 % fibre volume fraction with three different vacuum pressure of 5, 10 and 15 psi. The composites panels were fabricated using a vacuum bagging techniques. The tensile test was carried out in accordance to ASTM D638 respectively. The results showed that the vacuum pressure at 15 psi gave maximum value for tensile strength and tensile modulus. The results indicate that by increasing the vacuum pressure, it created a better bonding between fibre and the matrix. Minitab software was used to perform the one-way ANOVA analysis to measure the significant. From the analysis, there is a significant effect of vacuum pressure on the tensile properties.

Abstract: This paper pertains to the reduction process of local low grade iron ore using palm kernel shell (PKS). It is well known that low grade iron ores contain high amount of gangue minerals and combined water. Biomass waste (aka agro-residues) from the palm oil industry is an attractive alternative fuel to replace coal as the source of energy in mineral processing, including for the treatment and processing of low grade iron ores. Both iron ore and PKS were mixed with minute addition of distilled water and then fabricated with average spherical diameter of 10-12mm. The green composite pellets were subjected to reduction test using an electric tube furnace. The rate of reduction increased as temperature increases up to 900 °C. The Fe content in the original ore increased almost 12% when 40 mass% of PKS was used. The reduction of 60:40 mass ratios of iron ore to PKS composite pellet produced almost 11.97 mass% of solid carbon which was dispersed uniformly on the surface of iron oxide. The aim of this work is to study carbon deposition of PKS in iron ore through reduction process. Utilization of carbon deposited in low grade iron ore is an interesting method for iron making process as this solid carbon can act as energy source in the reduction process.

Abstract: Ultra high performance fiber concrete (UHPFC) is an advanced formula concrete that is proven to be more superior than conventional concrete because it embrace the qualities of steel and concrete. Therefore UHPFC properties which include high durability and strength are fully exploited in the research of rehabilitation and strengthening in concrete and even non-concrete structures. This article presents the findings of an experimental study carried out to examine the bonding strength behaviour between normal concrete (NC) substrate and UHPFC as a repair material, under flexural strength test by using third-point loading beam test method. Three types of NC substrate surface preparation were used: as-cast (without surface preparation) as a reference, wire-brushed, and sand-blasted. The flexural test results clearly indicated that all failures occurred through the NC substrate and no de-bonding was observed in the interface between NC substrate and UHPFC. The results of the flexural strength confirmed that adhesion bond strength between NC substrate and UHPFC was stronger than the substrate regardless, the substrate roughness. This proves that UHPFC is able to link and bond strongly with the substrate.

Abstract: This paper is focusing on mechanical properties of rubber toughened polyester filled carbon black (RPCB) for automotive parts and integrated circuits (IC) encapsulations applications. The samples were fabricated via hand lay-up and open molding technique in which 3 % of LNR was added as toughening agent in this composite and percentages of carbon black (CB) used vary from 0, 2, 4, 6, 8 and 10%. The mechanical properties were evaluated by impact and flexural testing. The result for each test was discussed to determine the most optimum loading of carbon black used to produce the composite. It was found that the addition of carbon black increased impact strength by 87%, flexural modulus by 33%, and flexural strength by 3%, at 4% of filler loading. The microstructures of the composites fracture surface were examined using a scanning electron microscope (SEM) to correlate and further explain the mechanical properties of the composites with morphology observation .

Abstract: This research is to identify the difference in melt flow and mechanical properties in hybrid composites between kenaf and rice husk that each of the filler was compounded with composite material of calcium carbonate (CaCO3) and high density polyethylene (HDPE) in different loading amount. Different filler loading up to 30 parts of kenaf fibers and rice husk particulate were mixed with the fixed 30% amount of CaCO3. Compounded hybrid composite were prepared and tested for melt flow index, tensile and impact strength. Addition of both fillers had decreased melt flow index (MFI). MFI of rice husk/CaCO3 was higher than kenaf/CaCO3 in HDPE composites. Tensile strength, elongation at break and impact properties of both hybrid composites had decreased with increasing filler content. Tensile strength of kenaf/CaCO3 was higher than rice husk/CaCO3 due to intrinsic fiber structure of kenaf which has some reinforcing effect compared to rice husk. While, impact strength of rice husk/CaCO3 was improved with addition of filler but drastically decrease as the rice husk content were increased up to 30% due to high silica content in rice husk. The Youngs Modulus was increased with addition of natural fibers in CaCO3/HDPE composite.