Zahurin Halim

Preliminary Review of Biocomposites Materials for Aircraft Radome Application

An aircraft radome usually refer to radar transparent, dome-shape structures which protects radar antennas on aircraft from aerodynamic loading, weather as well as impacts from bird strikes. Materials that are used for small aircraft radome usually have low dielectric constant and high toughness. Current composite material using high strength fibers such as glass fiber, carbon and aramid are commonly used in aerospace structures. However, the need for biodegradable materials has prompted the usage of natural fibers. Natural fibers have comparable mechanical properties such as low weight, low cost, renewable and biodegradable. In this preliminary work, comprehensive reviews of biocomposites materials are discussed in term of their properties for the purpose of evaluation for aircraft radome application. The present review will cover five local natural fibers namely bamboo, banana, kenaf, oil palm and pineapple leaf fiber.

Biodegradability Analysis of KBF Reinforced Poly(lactic Acid) Biocomposites

Poly(lactic acid) (PLA) and kenaf bast fiber (KBF) were melt-blended using brabender into films in the PLA/KBF ratios of 100/0, 90/10, 70/30 and 50/50 for natural soil burial test. This formulation was used to study the biodegradability of PLA and PLA/KBF biocomposites. It was found that the decompositions of the biocomposite were faster than pure PLA. The SEM morphology of the tensile fracture surface of the 30% and 50% of PLA/KBF biocomposites presented larger pores and degradation areas than smaller KBF loading (10 wt%). This result shows that the addition of larger fibre loading to the PLA matrix increased the micropore surface area of the PLA/KBF biocomposite hence accelerated the decompositions time of the biocomposites.

Cotton Reinforced Biopolymer Matrix Composite: Effect of Curing and Aging Conditions on its Mechanical Properties

The attention in natural fiber reinforced biopolymer composite materials has been rapidly growing both in terms of industrial applications and basic research. This study investigated on the effect of aging time on mechanical properties and morphological structure of thermoset protein-based composites from egg albumen reinforced by natural cotton fibres. The cotton/albumen composites (CAC) were fabricated by hands lay-up technique with 10 w/w % of fiber content. The samples were cured and aged at room temperature for different aging time from 7 to 32 days. The cotton fibres have contributed in a significant improvement in mechanical strength and toughness of the composites. Tensile strength of the composites achieved the optimum strength of 9 MPa after 21 days of aging time and constant till 32 days. As the aging time increased, impact strength of the composites also improved to some value of 20 kJ/m2. Thereby after 21 days observation, the composites show an equilibrium moisture content of 6-9 wt%, and the strength remains stable at room condition with 50-60% relative humidity (RH). Morphology studied using SEM justify that the moisture content after aging time influenced mechanical properties of the composites.

Physical properties of heat-treated rattan waste binderless particleboard

The objective of this study is to investigate the effects of heat treatment on the properties of binderless particleboard (BPB) fabricated via hot-pressing process with pressing temperature, pressing time and pressing pressure of 180°C, 5 minutes and 1 MPa, respectively. The fabricated BPB with density in the range of 0.8-0.95g cm-3 was heated in a temperature-controlled laboratory chamber at 80°C, 120°C and 160°C for period of 2 and 8 hours before underwent physical observation, mass loss measurement and thickness swelling test. The samples had remarkable color changes, mainly with samples of treatment temperature of 160˚C, where the color differences were 9.5 and 20.3. This changed the fabricated BPB samples from yellowish brown to dark brown color when treatment conditions increased. Darker color indicates greater mass loss due to severity of chemical component in the powder. Dimensional stability of fabricated BPB was improved with higher treatment temperature as more cellulose cross-linked and hemicellulose degraded that removed the hygroscopicity behavior of powder. These results revealed that heat treatment helped in improving the BPB physical properties, particularly in dimensional stability of boards.The objective of this study is to investigate the effects of heat treatment on the properties of binderless particleboard (BPB) fabricated via hot-pressing process with pressing temperature, pressing time and pressing pressure of 180°C, 5 minutes and 1 MPa, respectively. The fabricated BPB with density in the range of 0.8-0.95g cm-3 was heated in a temperature-controlled laboratory chamber at 80°C, 120°C and 160°C for period of 2 and 8 hours before underwent physical observation, mass loss measurement and thickness swelling test. The samples had remarkable color changes, mainly with samples of treatment temperature of 160˚C, where the color differences were 9.5 and 20.3. This changed the fabricated BPB samples from yellowish brown to dark brown color when treatment conditions increased. Darker color indicates greater mass loss due to severity of chemical component in the powder. Dimensional stability of fabricated BPB was improved with higher treatment temperature as more cellulose cross-linked and hemice...

Thermal analysis of kenaf sandwich panel

The introduction of the eco-core sandwich panel composite is contributing a new approach to the designer to achieve high performance and light weight. In this research project, the new kenaf eco-core sandwich panel will be developed and then laminated with galvanized steel. The final goal is to find the optimum eco-core metal matrix composite sandwich structure with maximum mechanical properties such as stiffness and buckling. Kenaf eco-core sandwich will be fabricated and study on the interaction between eco-core sandwich panel and metal faces will be performed. The characterization of the eco-core sandwich panel will be done using different analytical tools. This study would provide a way to enhance the application of this new eco-core metal matrix composite sandwich structure.The amount of sample used was approximately 12 mg. The temperature profile was from 27°C to 1000°C at a heating rate of 10°C/min. In this study, result shows that degradation of composites starts to occur at about 180°C. Increasing the kenaf percent ratio will decrease the percent residue.

Flexural Properties of Kenaf Sandwich Panel

This study concerns on effect of varying skin thickness to flexural properties of sandwich panel. The main element of the core structure is kenaf and the skin used in this study is galvanised steel sheet. Skin thickness being used in this research is 1.0 mm and 1.2 mm. In this study, comparing sandwich of skin thickness 1.0 mm and 1.2 mm, result shows that 1.0 mm skin is sufficient as mechanical properties of sandwich decreases and density of sandwich increases as skin thickens.

Thermal Analysis of Kenaf Sandwich Core Panel

The thermal stability of kenaf sandwich panel core structures are presented in this paper. Sandwich core structures tested are of varying kenaf percentage being 10, 20 and 30 wt%. The result indicated that all composite have two step degradation processes due to the presence of kenaf in epoxy. From the discussion, increasing the kenaf percent ratio will decrease the percent residue.

Cotton Reinforced Biopolymer Matrix Composite: Effect of Ultraviolet (UV) on its Mechanical Properties

Research on the production of composites from natural fibers has an enormous attention from researchers due to environmental awareness, which focusing to produce compostable bio-based composites and renewable raw materials that can be safely disposed after their use without polluting the environment. This paper reports the study on the effect of the ultraviolet (UV) to the cotton/albumen composites (CAC). The CAC were prepared by using hands lay-up technique with 10 w/w % of cotton content and cured at room temperature for 14 days. The cured samples were cut before exposing to UV light up to 20 days. The increase in tensile strength was observed up-to 10 days of exposure before it is decreasing to about 15% after 20 days of exposure to UV. The morphological study through SEM micrograph shows that fibers breakage and the biopolymer matrix loss is more with longer duration of UV exposure.

EFFECT OF FIBER LENGTH VARIATIONS ON PROPERTIES OF COIR FIBER REINFORCED CEMENT-ALBUMEN COMPOSITE (CFRCC)

This paper evaluated the effect of fiber length on the mechanical and physical performance of coir fiber reinforced cement-albumen composites (CFRCC). Albumen protein was added as a binder and the coir fibers with the lengths of 0, 2.5, 5, 10 and 20 mm was used as partial replacement of the cement mixture. Flexural and compressive strength, bulk density, moisture content and water absorption were investigated. The experimental investigations reveal that increasing in length of fiber augment the flexural strength. Incorporation of long fiber into the cement paste however, decreased the workability and thus introduced voids which results in low density. In fact, the water absorption and moisture content were also increased.