Abstract: Natural fibers are potentially used as composite reinforcement in polymeric materials, but lacking of research exploration such as kenaf fibers has limited implementation in Malaysia. The advantages of natural fibers are renewable, less hazardous during fabrication and handling process and relatively cheaper as compared to synthetic fibers. The objectives of current project are to determine the fracture energy of woven fabric kenaf composite (KFRP) plates with various fiber orientations. The experiment framework includes a variation of fiber orientations as designated in testing series by using single-edge notch (SEN) testing technique. The experimental results demonstrated that testing coupons with woven fabric with 90o fiber orientation has largest fracture toughness Gc value compared to other fiber orientations understudied. Good correlations and findings were found in other parametric studied.
Abstract: This paper presents an empirical force model quantifying the effect of fibre volume fraction and fibre orientation on the cutting forces during orthogonal cutting of unidirectional composites. Glass fibre plates and high speed steel cutting tools are used to perform orthogonal cutting on shaping machine whereas cutting forces are measured using platform force dynamometer. The analysis of forces shows almost linear dependency of cutting forces on the fibre content for both cutting and thrust forces. High dependency of cutting forces is also observed on fibre orientation with high percentage contribution ratio (up to 95.31%). Lowest forces corresponded to 30o and highest to 90o fibre orientation. Multivariate regression technique is used to construct the empirical model.
Abstract: The depletion crude oil has urged many researchers to find a suitable material to replace the current synthetic polymer products. Furthermore the shortage of landfill and ingestion of plastic by animals has to be taken in consideration in finding a material that can be easily biodegraded by enzyme or bacteria. In this study both fibre and matrix are from plant fibre, which makes the product highly compostable after the intended life usage. The fibre surface is modified with various alkaline concentrations before mixing with matrix through extrusion technique. The product of the extrusion is pelletized and hot compressed into specimen size according to ASTM. The specimen was tested for mechanical properties and the result shows the alkaline concentration affects the strength of the composite.
Abstract: This paper presents a research study conducted on the usage of vegetable oil for the production of eco-friendly Vege roofing tiles. Conventional roofing tiles which constitute of concrete and clay are considered as environmentally unfriendly because of the significant amount of greenhouse gas emission during their production. An entirely novel methodology of utilizing catalyzed vegetable oil is proposed which can totally replace the use of traditional binders like cement and clay. Limited trails conducted on prototypes samples revealed that when catalyzed vegetable oil mixed with aggregates, properly compacted and heat cured at 190oC for 24 hours, have shown flexural strength up to 9.5 MPa. The superior strength gain of these prototype samples was considered due to the use of the catalyst with vegetable oil, which resulted in the initiation of catalytic oxy-polymerization set of reactions during heat curing, converting vegetable oil to solid, hard polymer which is considered responsible for strength achievement factor for these novel Vege roofing tiles. All prototypes samples were tested for performance indicators like water absorption, permeability, and flexural strength according to ASTM standards. Moreover, the susceptibility of oil leachate from the tiles oil, when tested using electrical conductivity method showed a negligible amount of the electrical conductivity. Moreover, the estimated embodied energy requirements for these tiles were found quite less when compared to conventional tiles.
Abstract: The utilization of fly ashes produced by circulated fluidized bed combustion (CFBC) has been limited in construction application due to their inherent high sulfate and carbon contents although CFBC fly ash exhibits very good binding properties without requiring any supplementary activator. This study reports alkali silica reaction (ASR) behavior of CFBC fly ash geopolymer mortars in terms of activation energy using a modified ASTM C 1260/C 1567. Two different strengths of NaOH solution were used to test reactive and potentially reactive aggregates in the presence of CFBC fly ash. The other variables included a longer test period of 3 months and three different temperatures, namely 60°C, 70°C, and 80°C. It was observed that there was no significant expansion in CFBC fly ash based geopolymer mortar regardless of variation of temperature and alkalinity of test solution. Activation energy of CFBC fly ash geopolymer for ASR was higher than that of plain cement mortar irrespective of strength of NaOH solution.
Abstract: Experimental work has been carried out on the crushing behaviour of jute, glass, and hybrid jute-glass/epoxy foam filled bi-tubes under lateral loading. Inner and outer tubes diameters of 50 mm and 100 mm respectively were fabricated by hand lay-up method. Tube length of 150 mm is maintained for all the fabricated specimens. Polyurethane foam filler was used to fill the gap between the inner and outer tubes. Lateral loading was applied on the foam filled bi-tubes as well as the inner and outer tubes individually. Lateral load-displacement relations were drawn and the energy absorption was calculated. Effect of material used and foam filler on the load-displacement relations, maximum and mean loads, and failure mode was investigated. Crush force efficiency and stroke efficiency were determined and discussed. Results show that the glass/ epoxy foam filled bi-tubes supported load higher 22.45%, 28.94% and 36.80% than the glass-jute, jute-glass and jute/ epoxy bi-tubes respectively. It has been found that the glass/epoxy foam filled bi-tubes supported load higher 18.08% than that obtained from the combination of the maximum loads of the inner and outer empty tubes. The performance of the foam filled bi-tubes under lateral loading is improved by using the polyurethane foam filler and influenced by the stacking sequence of the material used. The specific energy absorption of the foam filled glass/ epoxy bi-tubes is found higher 5.47%, 12.86 % and 20.68% than the glass-jute, jute-glass and jute/ epoxy foam filled bi-tubes. Failure mechanism of the fractured specimens was discussed.
Abstract: The effect of alkali treatment and nanoclay addition on the mechanical properties and water absorption behavior of rice husk particle (RHP) reinforced unsaturated polyester (UP) composites was investigated. Thermogravimetric analysis (TGA) indicated that the alkali treatment removed most of the hemicellulose and impurities from the RHP with the tensile strength, tensile modulus, flexural strength and flexural modulus of the resulting composites being improved by alkali treatment. The results indicated that the 5% sodium hydroxide concentration had the optimum performance on mechanical strength and water absorption resistance. Furthermore, the influence of nanoclay addition (1, 3 and 5 wt%) on the properties of optimum alkali treated RHP-UP composites was investigated with the lowest content (1 wt%) of nanoclay showing the highest mechanical performance. However, further addition of nanoclay improved the moisture absorption resistance of the composites. Good interface bonding between the filler and matrix was observed from scanning electron micrographs for the optimum RHP alkali treated and nanoclay dispersed RHP-UP composites.
Abstract: The usage of multi-wall carbon nanotubes (MWCNTs) as reinforcement has been limited due to difficulties associated with dispersion of MWCNTs during the processing and poor adhesion between MWCNTs and matrix. In this paper, the effect of chemical functionalization with strong acid on the dispersion of MWCNTs were studied. The functionalization of MWCNTs were performed in chemical solution of sulphuric acid (H2SO4) and nitric acid (HNO3) with ratio of 3:1 and prepared at 80°C for 4 hours. The pristine MWCNTs (PMWCNTs) and acid treated MWCNTs (AMWCNTs) were analyzed using TEM, XRD, FTIR and Pycnometer density. The effect of dispersion of PMWCNTs and AMWCNTs was studied in three different matrices which are in aqueous media (distilled water), metal matrix and polymer matrix. The XRD results determined that the impurities in pristine MWCNTs such as NiZn3 have been removed after the purification process. The presence of carboxylic acid (-COOH) and hydroxyl (-OH) functional groups were determined using FT-IR. Based on the dispersion analysis in aqueous media, PMWCNTs were poor in suspension stability. While, the TEM images showed less agglomeration of the AMWCNTs compared to PMWCNTs and obtained a uniform dispersion in metal matrix (Cu) and polymer (epoxy) matrix composites.
Abstract: Liquefaction is known to be an effective method for converting biomass into a biopolyol. The biomass liquefaction of oil palm fruit waste (OPFW) in the presence of liquefaction solvent/polyhydric alcohol (PA): Ethylene glycol (EG), polyethylene glycol 400 (PEG400) and glycerol using sulfuric acid as catalyst was studied. For all experiments, the liquefaction was conducted at 150°C and atmospheric pressure. The mass ratio of OPFW to liquefaction solvents used in all the experiments was 1/2, 1/3 and 1/4. The results revealed that almost 50% of the oil palm fruit waste converted into liquid product within 2 hours at 150°C with OPFW/PA ratio of 1/4. Biopolyol produced under different condition showed viscosities from 210 to 650 Pa.s. The result in this study may provide fundamental information on integrated utilization of oil palm fruit waste via biomass liquefaction process.
Abstract: Oil palm fruit waste (OPFW) was conducted using polyhydric alcohol (PA) as liquefaction solvent with H2SO4 in three different OPFW/PA ratio (1/2, 1/3 and 1/4). During the liquefaction, cellulose, semi-cellulose and lignin are decomposed, which results in changes of acid value and hydroxyl value. The liquefied OPFW were characterized by Fourier Transform infrared (FT-IR) spectroscopy. The hydroxyl and acid values of the liquefied oil palm fruit waste (OPFW) varied with the liquefied conditions. It was observed that with an increase in the liquefaction solvent (PA) amount in the mixture resulted in a high acid value and hydroxyl value for the OPFW. FT-IR spectroscopy analysis showed that the resulting biopolyol was suitable monomer for polyurethane (PU) synthesis for the production of PU foams.