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Polymer as well as polymer composites are inclined to premature due to effect on mechanical and physical properties during service time. In this paper, the effect of thermal cycling (−30 to 80 °C) on the physical and tensile properties of Polypropylene (PP), Kenaf/PP, Kenaf/PP/CNTs and Kenaf/CNTs/MAPP/PP hybrid composites for the injection moulded car battery tray was investigated. Although this study had found no physical changes on the samples in terms of colour or cracking, the samples, however, had experienced warpage and dimensional changes. The dimension of samples containing CNT had increased by 20%, while the PP and PP/Kenaf samples had decreased by 3.5% and 87%, respectively. Although the process of thermal cycling was found to have rapidly decreased the hardness of Pure PP and Kenaf/PP composites, it had, however, gradually increased the hardness of composites with CNT fillers. The tensile strength, Young's modulus and elongation of the composites had also been examined in this research. Furthermore, according to the fractographic investigations using scanning electron microscope, it is perceived that the fracture morphology of the samples is strongly influensed by thermal cycling.

The use of kenaf fiber as a reinforcement material for polymer composites is gaining popularity, especially in the production of automotive components. The main objective of this current work is to relate the effect of alkali treatment on the single fiber itself and the composite material simultaneously. The effect of temperature condition during mechanical testing is also investigated. Composite materials with discontinuous natural kenaf fibers and epoxy resin were fabricated using a compression moulding process. The epoxy composites were reinforced with 50 wt% untreated and treated kenaf fibers. The kenaf fiber was treated with NaOH solution (6% by weight) for 24 h at room temperature. Kenaf fiber treated with NaOH treatment had a clean surface and no impurities. For the first time we can see that alkali treatment had a damaging effect on the mechanical properties of kenaf fibers itself and the treated kenaf/epoxy composites. The composite reinforced with untreated kenaf fiber and treated kenaf fiber showed increased tensile strength (72.85% and 12.97%, respectively) compared to the neat epoxy. Reinforcement of the composite with treated kenaf fiber decreased the tensile strength due to the fiber pull out and the formation of voids which weakens the adhesion between the fibers and matrix. The temperature conditions also play an important role in composites with a significant impact on the deterioration of composite materials. Treated kenaf fiber has thermal stability and is not sensitive to temperature and as a result reinforcement with treated kenaf gives a lower loss value of 76%.

Hot isostatic pressing technique is one of the alternative fabrication processes that have been used to enhance the densification rate in ceramic processing. The aim of this paper is to observe the microstructure and determine the physical and mechanical characterization of alumina ceramic pellets sintered via conventional technique compared to hot isostatic pressing. The semidry alumina ceramic pellets obtained from uniaxially pressing were dried in an oven earlier before sintering via two different techniques. The microstructure of alumina ceramic pellets analyzed by scanning electron microscopy that showed the pellet with particle size (25 μm) and sintered via hot isostatic pressing had larger uniform grain shape and size (16.25 μm), lowest porosity (20.76%), highest bulk density (3.60 g cm−3), low top (2.87%) and bottom (2.68%) shrinkage, and highest hardness (871.56 Hv). The optimum particle size of alumina and sintering technique (HIP) improved the microstructure and physical characterization of ceramic pellets.

Composite materials have increasingly become crucial in manufacturing engineering products and producing commodity materials in the major industries including; automotive, aerospace, marine, construction, agriculture and health science. However, several improvements regarding the strength, dimensional stability and the cost of production are required. In this study, composite of Kenaf, multi-wall carbon nanotube (MWCNT) and polypropylene (PP) with maleic anhydride-grafted polypropylene (MAPP) are examined. The results highlight that increasing MAPP loading, in turn, increases the value of the mechanical properties. The composites are produced by blending kenaf/MWCNT/PP using a Sigma blade mixer and injection moulding. Injection moulding is a significant operation used to produce plastic products. In the study, Kenaf core fibre was mixed with MWCNT and polypropylene, in addition to MAPP. The MAPP is added by applying different percentage (1, 2, 3 and 4 wt. %) during the blending process. The main objective of the study was to analyse the effects of MAPP concentrations on the mechanical properties of the Kenaf/MWCNT/PP composite. The results of the study established that MAPP 3 wt. % concentration with MWCNT 3 wt. % loading and Kenaf 30 wt. % filler provide optimum results for the composites. There was approximately, a 21% enhance in tensile strength of Kenaf 30 wt. %/MWCNT, 3 wt. %/MAPP, 3 wt. %/PP observed compared to the (without) MAPP composite. The composites with coupling agent stimulate better filler dispersion between Kenaf, MWCNT and PP observed using a scanning electron microscope (SEM) and field-emission scanning electron microscope (FESEM).

To date, the mechanical performance of kenaf composites is still unsatisfied in term of its mechanical performance. Therefore, research focuses on kenaf composites fabrication through the selection of polymer resin, including epoxy, polypropylene, and polylactic acid. The incorporated kenaf fibre at 10 wt % to 40 wt % loadings was conducted using injection and a compression moulding process. The compressed materials indicated high tensile strength at 240 MPa compared to inject materials (60 MPa). Significant improvement on impact strength (9 kJ/m2) was due to the unpulled-out fibre that dispersed homogenously and hence minimize the microcrack acquire. Meanwhile, high flexural strength (180 MPa) obtained by kenaf/epoxy composites due to the fibre orientate perpendicular to the loading directions, which improve its mechanical properties. The findings indicate that the kenaf fibre reinforced thermoset materials exhibit better mechanical properties as a function to the battery tray applications.

The development of bio-composites as biodegradable and renewable materials for sustainable technology are advantageous in creating a green and healthy environment. However, the application of natural fiber as a bio-composite material have been found to be restricted especially as it has lower thermal resistance in comparison to synthetic fiber. Therefore, the objective of this study is to investigate the influence of fiber orientations on the tensile properties at various tensile temperatures for unidirectional kenaf polypropylene (PP) composite. Samples were prepared by hot pressing process. In this study, kenaf long fibers that are produced from water retting process is use as a reinforcement agent while PP as a polymer in the composite fabrication. A tensile test was carried out at different temperatures (30°C, 60°C, 90°C, 120°C) for various orientations (0°, 45° and 90°). It was found that an increase of temperature will reduce the modulus and tensile strength where the highest reduction occurred between 60°C to 120°C and most significantly on the orientation of 45° and 90°, which is lower than pure PP. This concludes that the application of kenaf PP composite is optimum between room temperature with a cut-off temperature at 60°C.

The interest of using kenaf fibers in composite fabrication has grown due to renewable, sustainable and environmental issues. The applications of kenaf composite have been broadly exploited especially in automotive industry. In this research, unidirectional kenaf polypropylene (PP) composites were prepared using the hot pressing method. The processing parameter need to be optimized to ensure that the fabrication process will enhance the mechanical properties of the composite. Thus, a research on the optimization process on the processing parameter (temperature, pressure, pressing time and kenaf percentage) on the tensile properties was conducted by using a two-level full factorial design. The effect of the individual factors and their interaction were observed. From statistical analysis, the main effect of tensile strength and young modulus is the percentage of kenaf fibers with 21.67% contribution. The interaction between kenaf percentage and pressing time also contribute an effect on the tensile properties with 13.29% contribution. Finally, the result showed that at 190°C, pressure 5 MPa, 5 minutes pressing time and 50% fiber content will give the optimum tensile strength and young modulus which is 163.12 MPa and 11.17 GPa respectively with improvement of 486% tensile strength compared to pure PP.

Processing conditions are one of the factors that significantly influences the properties and characteristics of the polymer matrix composites products. Therefore, the suitable processing parameters must be selected in order to yield the optimum properties of the composite products. In this work, Box-Behnken Design (BBD) was selected as experimental design approach. Biodegradable composites from unidirectional long kenaf fibre reinforced polylactic-acid were fabricated by hot pressing method. Response surface methodology (RSM) and analysis of variance (ANOVA) were used to optimize as well as determine the significance of the factors affecting the tensile strength. Three factors studied were pressure, temperature and heating time at three different levels. The experimental results showed that all three factors are the significant processing parameters affecting the strength of composite. The combination of hot pressing parameters for optimum tensile strength was 200 o C temperature, 3MPa pressure, and heating time at 8 minutes. Confirmation runs test yield error less than 7% verified the validity of the model.

Due to current trend and increasing interest towards natural based fiber products, Kenaf (Hibiscus cannabinus) fibers have been used for the developments of many products. Therefore, Kenaf fiber-reinforced composites have been widely used in engineering and industrial applications. The present work deals with the fabricating and characterization of untreated and treated kenaf/polypropylene (PP)-reinforced composites. Composites of PP reinforced with treated and untreated kenaf fibers were fabricated using the injection molding technique. Different fiber loadings of 10, 20, 30, 40, 50 wt% treated and untreated kenaf composites were also prepared. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and thermo gravimetric analysis (TGA) were performed on the treated, untreated kenaf fibers and kenaf/PP composites. Moreover, the alkaline-treated kenaf composites exhibit better physical, morphological, and mechanical properties because of the compatibility of kenaf with PP. However, variations in tensile and flexural properties depend on treatment and kenaf fiber contents. The percentage increase in the mechanical properties of the treated kenaf/PP composites relative to that of PP was also measured. In addition, 40 wt% kenaf fiber loading resulted in higher mechanical properties. By contrast, kenaf/PP composite with 50% fiber loading was not successfully prepared because of improper mixing and the burning of kenaf fibers in the PP matrix. To conclude, 40% kenaf/PP composites with superior physical and mechanical properties may be used in variety of applications such as automotive, sports, construction, animal bedding, and mass production industries.

Given the environmental issues faced by the industry, the development of engineering products from natural resources has increased worldwide. The increasing demand for cost and weight reduction can be attained by sustainable manufacturing techniques. Kenaf plants are natural resources, which show high performance compared with other natural fibers. Kenaf fibers can be modified by physical and chemical methods. Kenaf polymer composites are fabricated via processing technologies based on thermoforming, thermoplastics, and thermosets. Thermoplastic processes, such as compression molding, pultrusion, extrusion, and solution blending, have been adapted but are limited to two-dimensional structures based on polymer composites. However, the thermoset processes include sheet molding and resin transfer molding techniques, which were also employed for the fabrication of kenaf polymer composites. Most of the recent work discussed Kenaf-Reinforced Composites (KRCs) prepared by compression molding. However, resin transfer molding has received attention because of its versatility. This chapter aimed to highlight and explore advance research related to the fabrication of kenaf polymer composites by various routes, as well as their physical and mechanical properties. A brief description of KRCs with different additives, fiber loadings, treatment, and polymers is also discussed. Furthermore, these KRCs with versatile mechanical properties may be used for construction, building materials, animal beds, corrosion resistance, marine, electrical, transportation, and automotive applications.

Over the last decade, awareness of environmental issues and the shortage of petroleum resources contribute to the important factors that encourage researchers to explore the potential use of natural fibers such as kenaf as reinforcement in fiber reinforced composites. The objective of this study was to investigate the effect of different processing condition (temperature, pressure and pressing time) on the tensile properties of unidirectional kenaf fiber polypropylene composite. Samples of composites were prepared by a hot pressing method. In this work, kenaf continuous long fibers from water retting process at 40%wt were aligned in parallel. Polypropylene (PP) in the form of pellets and powder had been used as a matrix. The results showed that, samples produced at temperature 2100C and pressure 5 MPa for 6 minutes hot pressing gives excellent tensile properties which 262% of improvement as compared to pure PP. This indicates that, kenaf fiber is suitable as reinforcement in polymer composite.

In this work, the consolidation of different alumina particles via sintering process was conducted to the compacted alumina pellets. This consolidation was also assisted with the sintering aid, MgO to densify the final ceramic structure. Comparison between the influence of additive to the different particles size of compacted alumina by observing the microstructure and physical properties was conducted. The value physical properties and microstructure clearly show that for both particle size of alumina, MgO additive can increase the density value and improve microstructure properties.

This research focused on the simulation analysis of wood polymer composites (WPCs) based on polypropylene (PP) for the injection moulding of automotive parts, namely car battery trays (CBTs). A plastic CBT, which is commonly used to support the battery in a car engine, is manufactured completely through the injection moulding process. The conventional design method is clearly unable to satisfy production requirements; however, with the application of the Moldflow software rational production process parameters, the filling time, injection pressure, clamping force, and others, can be formulated. A moulded CBT was designed using a computer-aided design tool, namely CatiaV5R20, before being imported to the finite element analysis tool, Moldflow. The use of the Moldflow software enabled a full analysis to be conducted of the material flow inside the mould cavity for the moulded CBT. Two types of gates, namely, the sprue and pinpoint gates, were used, through which the analyses were carried out by the Moldflow software to check the filling time, injection pressure, clamping force and warpage, by simulation in the sequential trials. The data on the wood fibre/PP composite, where 40 wt% of wood fibre loading was used. Finally, the use of the Moldflow simulation software was presented.