This study was conducted to evaluate the discomfort level of students from the Polytechnic Kuching Sarawak while they were sitting on chairs. Polytechnic Kuching students (n=500) completed a set of questionnaires utilizing a survey form which showed the body chart discomfort using Borg’s CR-10 Scale. The students was asked to identify body areas experiencing discomfort and to rate this discomfort using score rating groups (0 to 5) where score 0-1.99 = No discomfort (1), score2.00-3.99 =Discomfort (2) and score 4.00-5.00 = Very uncomfortable (3).The evaluation of seating discomfort levels showed acceptable levels for the students and possible outstanding problems. Students were asked to rank over an order 10 statements about comfort and choose three responses which gave the most consistent equal interval scale. The results showed that the main response of discomfort indicated the students felt cramped, stiff, numb, sore and tender muscle, unbearable pain, barely comfortable and uncomfortable. This project was identified to evaluate the comfort level for classrooms chairs of polytechnic students. Overall, there was a significant discomfort level for the students whilst sitting on chairs and a possible solution put forward is to design a new type of classroom chair made of natural fibre reinforced composite.
Vinyl esters combine the best of polyesters and epoxies in terms of properties and processing. Without
complicating presence of reinforcing fibres, this study investigated the effects of catalyst amount, preheating time, molding temperature, and pressure on flexural and water absorption properties of cast vinyl ester (VE) using a factorial experiment. Longer preheating time enhanced the stiffness of VE, while higher molding pressure reduced the flexural modulus. All the four factors did not affect the flexural strength and elongation at the break of molded VE significantly. Using a high molding pressure also caused molded VE to have higher water absorption for a long water exposure period. Meanwhile, greater water absorption at bigger amount of catalyst and higher preheating temperature indicate possible interactions between these factors. The results suggest possible negative effects of high molding pressure through the increase in the network of micro-cracks, and thus lowering the integrity of cast VE sheets. Judicious selection of the process parameters was required in order to obtain good quality molded VE sheets and by extension fibre-reinforced VE composites. Molded VE-unsaturated polyester (UP) blend is a significantly different material which is 1.49 times stronger, 2.38 times more flexible, but it is 0.69 less stiff than neat VE and with significantly higher water absorption. The results obtained warrant for a further investigation in process optimization of VE molding and the use of VE-UP blend as a matrix for natural fibre-reinforced composites.
The use of natural fibres obtained from plants and trees as reinforcing materials has attracted many researchers to widen their applications. Natural fibres are low cost, low density, have high specific properties, biodegradable and non-abrasive. Oil palm fibre (OPF) can be obtained directly from natural resource, it is cheap and also has advantages due to its renewable nature, low cost, and easy availability. In this study, the mechanical performances of single oil palm fibre are measured and evaluated. The diameter of OPF was in the range from 250 to 610 μm while moisture content was between 2.2 to 9.5%. The average tensile properties obtained were tensile strength, 71 MPa, Young’s modulus, 1703 MPa and elongation at break, 11%.
The aim of this paper was to describe the effects of treated sugar palm yarn fibre loading on the mechanical properties
of reinforced unsaturated polyester composites. Composites with varying fibre loads (10, 20, 30, 40 and 50 wt. %) were
prepared using a hand-layup process. The composites were tested for tensile, flexural and impact strength according to
ASTM D3930, ASTM D790 and ASTM D256 standards, respectively. The results showed that an increase in fibre loading
of up to 30 wt. % increased tensile strength (31.27 MPa), tensile modulus (4.83 GPa), flexural strength (58.14 MPa)
and modulus (4.48 GPa). Maximum loading can be attained at 40 wt. % of fibre loading for impact strength (38 kJ/
m2). The effectiveness of stress transfer mechanism through the fibre-matrix interaction, coupled with the optimization
of fibre loading in resisting fracture and failure, boosts the overall mechanical performance of sugar palm composite.
Introduction: Innovative ways of balancing indoor relative humidity without compensate for the optimal working environment is crucial as excessive dampness is a risk factor for health symptoms among people and deteriorate building performance. This study examines the potential of fabricating humidity controlling material by sintering a mixture of diatomite, waste glass and cockle shell powder. Moisture sorption isotherms, moisture buffer values, pore structure, surface morphology and flexural strength of the final products were determined. Methods: Mixture of diatomite, powdered waste glass and cockle shell powder is mixed at different ratio, pressed and sintered at 1100°C for 20 minutes. The final products were examined using nitrogen gas adsorption-desorption and scanning electron microscopy for mesoporous and morphology properties. The moisture adsorption-desorption performances of the samples were tested using desiccator method while the flexural strength is tested using universal testing machine. Results: The sintered products have specific surface area from 5.744 m2/g to 14.765 m2/g and have pore size from 39.5-67.7 nm. The best product, manufactured by mixing 60% diatomite, 30% waste glass and 10% cockle shell powder, showed a good moisture buffer value (MBV: 1.3 g/m2 %RH) and flexural strength of 8.23 ± 1.8 MPa satisfy the standard of those commercial porous ceramics. Conclusion: Usage of waste glass and cockle shell powder in development of humidity control material helped in the waste reduction. The humidity control material produced can regulate indoor humidity without additional energy consumption. The superior products show excellent charac- teristics and highly promising for various construction applications.
Fibre reinforced composites have gained use in a variety of applications. The performances of these composites may suffer when the material is exposed to adverse environments for a long period of time. Kenaf fibre reinforced unsaturated polyester composites were subjected to water immersion tests in order to study the effects of water absorption on the mechanical properties. Composites specimens containing (10%, 20%, and 30%) weight percentages of fibre were prepared. Water absorption tests were conducted by immersing these specimens in a distilled water bath at 25oC for four months. The tensile properties of the specimens immersed in water were evaluated and compared with the dry composite specimens. A decrease in the tensile properties of the composites was demonstrated, indicating a great loss in the mechanical properties of the water-saturated samples compared to the dry samples. The percentage of moisture uptake was also increased as the percentage of the fibre weight increased due to the high cellulose content. The water absorption pattern of these composites was found to follow the Fickian behaviour.
This paper studied the thermal behaviour of pineapple leaf fibre (PALF) reinforced high impact polystyrene (HIPS) composite. Thermogravimetric analysis (TGA) and differential scanning calorimetric (DSC) analysis were used to measure the thermal characteristic of HIPS/PALF composites. In particular, the TGA analysis was utilized to measure the degradation and decomposition of materials in neat polystyrene, pineapple fibre, and the composites. The measurements were carried out in the temperature of 25°C – 800°C, at a heating rate of 20°C min-1 and the nitrogen gas flow was 50 mL min-1. The temperature of the DSC analysis was programmed to be between 25°C – 300°C. The results from TGA analysis show that the addition of pineapple fibre has improved the thermal stability of the composites as compared to neat HIPS. In addition, the effects of compatibilising agent and surface modification of PALF with alkali treated were also determined and compared.
This paper presents the study of mechanical properties of short random oil palm fibre reinforced epoxy (OPF/epoxy) composites. Empty fruit bunch (EFB) was selected as the fibre and epoxy as the matrix. Composite plate with four different volume fractions of oil palm fibre was fabricated, (5 vol%, 10 vol%, 15 vol% and 20 vol%). The fabrication was made by hand-lay up techniques. The tensile and flexural properties showed a decreasing trend as the fibre loading was increased. The highest tensile properties was obtained for the composite with fibre loading of 5 vol% and there were no significant effect for addition of more than 5 vol% to the flexural properties. Interaction between fibre and matrix was observed from the scanning electron microscope (SEM) micrograph.
The physical properties by natural fibre have a great importance, specifically in the structural of natural fibre which reinforces matrix. Response surface methodology with Box-Behnken (BB) design of experiment was utilized to study water absorption and melt flow index (MFI) of abaca fibre reinforced high impact polystyrene (HIPS) composites. The design utilizes fraction of weight abaca fibre, maleic anhydride (MAH), and impact modifier to develop models for characteristic behaviours of water absorption and MFI of composites. Abaca fibre reinforced high impact polystyrene (HIPS) composites were produced with different fibre loadings (30, 40, and 50 wt%), different compositions of coupling agent, maleic anhydried (MAH) (1, 2, and 3 wt%) and different compositions of impact modifier (4, 5, 6 wt%). The individual optimum of water absorption was found when loading abaca fibre close to 34.61 wt%, maleic anhydride 1 wt%, and impact modifier 4.01 wt%. The individual optimum of melt flow index dealt with loading abaca fibre 36.71 wt%, maleic anhydride 3 wt% and impact modifier 4.02 wt%. Meanwhile, the optimum condition for water absorption of abaca fibre reinforced HIPS composites was followed by a decreasing trend of the value of melt flow index.
Currently, there is a growing interest of using woven material in composite production for many applications such as
structural applications, non-structural applications, household utilities, parts for automobile, aerospace components,
flooring and ballistic laminate composites. The structure and properties of the woven fabric is very important as it dictate
the woven composite properties. The properties of yarn like linear density, twist factor and strength can influence most
of the woven fabric properties. Strength of woven fabric is one of the most important properties which make it superior
in final composite applications. In this study, the effects of linear density i.e. 500, 1000, 1500 and 2000 tex on physical
and mechanical properties of kenaf yarn were evaluated. The assessment on twist type, twist angle, yarn diameter, yarn
structure, fibre density, moisture content, water absorption and mechanical properties were carried out on kenaf yarns.
The yarn mechanical properties were tested on the tensile strength, Young’s Modulus and elongation. It was found that,
different linear density of yarn exhibited different behavior of yarn properties. Higher linear density yarn produced
wider yarn diameter compared to lower linear density yarn, resulting to higher fibre and moisture content yarn. Yarn
tensile strength has increased by 46% when linear density was changed from 500 to 2000 tex due to higher amount of
individual fibres. However, for Young’s Modulus, the values reduced as the yarn linear density increased due to several
factors including number of fibres and moisture content of yarn.