E.S. Zainudin

Thermo-mechanical behaviors of thermoplastic starch derived from sugar palm tree (Arenga pinnata).

In recent years, increasing environmental concerns focused greater attention on the development of biodegradable materials. A thermoplastic starch derived from bioresources, sugar palm tree was successfully developed in the presence of biodegradable glycerol as a plasticizer. Sugar palm starch (SPS) was added with 15-40 w/w% of glycerol to prepare workable bioplastics and coded as SPS/G15, SPS/G20, SPS/G30 and SPS/G40. The samples were characterized for thermal properties, mechanical properties and moisture absorption on exposure to humidity were evaluated. Morphological studies through scanning electron microscopy (SEM) were used to explain the observed mechanical properties. Generally, the addition of glycerol decrease the transition temperature of plasticized SPS. The mechanical properties of plasticized SPS increase with the increasing of glycerol but up to 30 w/w%. Meanwhile, the water absorption of plasticized SPS decrease with increasing of glycerol.

Studying the effect of fiber size and fiber loading on the mechanical properties of hybridized kenaf/PALF-reinforced HDPE composite

Hybridization, especially where only variant natural lignocelluloses are combined, is fast receiving encouraging attention because it offers a range of properties that may be difficult to obtain with a single kind of reinforcement. In this study, tensile, flexural, and impact properties of hybridized kenaf/PALF-reinforced HDPE composite were studied. Sheets from which tensile, flexural, and impact specimens were cut out were produced from the compression molding of composite pellets and subsequently conditioned in an oven for 21 h at 103°C. The tensile and flexural specimens were tested according to ASTM D638 and ASTM D790 using a 5-kN INSTRON bluehill universal testing machine accordingly. While a notched Izoid impact test was conducted using a 1-J universal pendulum according to ASTM D256. All specimens were prepared at a fiber ratio of 1:1 kenaf:PALF and fiber lengths of 0.25, 0.5, 0.75, and 2 mm; fiber loadings of between 10% and 70% were utilized for the study. About 0.25 mm fiber showed the best tensile and flexural properties with a linear increase in properties up to 60% fiber loading while impact strength showed better property with 0.75 and 2 mm fiber lengths. At 0.25 mm fiber length, tensile strength of 32.24 MPa, flexural strength and modulus of 34.01 MPa and 4114.11 MPa, respectively, were observed at 60% fiber loading. Moduli results of all the composites formulated generally obeyed the ROM. SEM was used to examine the surface of composites produced. Tensile and impact strengths result showed inverse proportionality while flexural strength of the composite generally adhered to the ROM. However, a positive effect was observed in the case of composite’s impact strength in respect of increasing fiber length. Thus, reduction in some mechanical properties of the composite with respect to increasing fiber length is attributed more to fiber entanglement rather than attrition.

Mechanical properties and water absorption behavior of hybridized kenaf/pineapple leaf fibre-reinforced high-density polyethylene composite

This work provides variation in mechanical properties such as tensile, flexural and impact strength of hybridized kenaf and pineapple leaf fibre-reinforced high-density polyethylene composite. Two or more natural fibres are hybridized to provide an effective means of designing materials for various service requirements. The composite of kenaf/pineapple leaf fibre high-density polyethylene-based hybrid composite with different weight proportion of fibres were prepared. Total overall fibre loading in the composite was kept at 40%. The hybrid composites prepared were subjected to water immersion for 14 days to see how this concept can affect water uptake. At equal percentage ratio of the fibres, hybridization effect was optimized for tensile and flexural test; however, K6P4 gave the optimum impact strength while K3P7 resulted in the least overall water uptake. Strength and modulus values increased with increase in percentage of pineapple leaf fibre in the composite and the higher aspect ratio of kenaf helped in the dispersion of matrix in the composite. Favorable balance between the inherent advantages and disadvantages of these two fibres complemented each other. While pineapple leaf fibre helped the composite in tensile and flexural properties, kenaf provided impact strength and in reduction of water uptake. Dependence of modulus on the percentage of cellulose in natural fibres was clear. Kenaf and pineapple leaf fibre offered tremendous potential for hybridization. SEM was used to describe this interesting phenomenon.

The tensile properties of single sugar palm (Arenga pinnata) fibre

This paper presents a brief description and characterization of the sugar palm fibres, still rare in the scientific community, compared to other natural fibres employed in polymeric composites. Sugar palm fibres are cellulose-based fibres extracted from the Arenga pinnata plant. The characterization consists of tensile test and the morphological examination. The average tensile properties results of fibres such as Youngs modulus is equal to 3.69 GPa, tensile strength is equal to 190.29 MPa, and strain at failure is equal to 19.6%.

Mechanical performance of woven kenaf-Kevlar hybrid composites

Hybrid composites offer a combination of advantages of constituent components to produce a material with determined properties. In the present work, woven hybrid composite was prepared by hand lay-up method in laminate configuration. Kevlar/kenaf hybrid composites were fabricated with total fibre content of 30% and the ratio of Kevlar/kenaf varies in weight fraction of 78/22, 60/40, 50/50, 26/74, and 32/68, respectively. The Kevlar/epoxy and kenaf/epoxy were also prepared for comparison. The mechanical properties of hybrid, kenaf/epoxy, and Kevlar/epoxy composites were tested. Morphological properties of tensile fracture surface of hybrid composites were studied by scanning electron microscopy. Results have established that the mechanical properties of kenaf-Kevlar hybrid composites are a function of fibre content. The hybrid composites with Kevlar/kenaf (78/22) ratio exhibited better mechanical properties compared to other hybrid composites. This result indicates the potential of Kevlar-kenaf hybrid composite for impact applications.

Sugar palm tree: a versatile plant and novel source for biofibres, biomatrices, and biocomposites

The use of green materials is a vital component in tackling problems of environmental protection. At the same time, these materials help solve problems arising from the shortage and undegradable nature of petroleum-based materials. Among the numerous green material sources in Malaysia, the sugar palm tree is a versatile plant that can produce biofibres, biomatrices, and biocomposites for a wide range of applications. This paper focuses mainly on the significance of the unutilised part of sugar fibres, as they are highly durable and easy to process. Besides discussing recent advances in research into sugar palm fibres and their biocomposites, this paper also addresses recent advances in research into the development of new biodegradable polymers derived from sugar palm starch. Fibre surface treatment, product development, and efforts to enhance the properties of sugar palm fibre composites are also considered.

Compatibilization of HDPE/agar biocomposites with eutectic-based ionic liquid containing surfactant:

In this research, eutectic-based ionic liquid specifically choline chloride/glycerol was prepared at a 1:2 mole ratio. The choline chloride/glycerol was added with the different content of surfactant (hexadecyltrimethylammonium bromide). The choline chloride/glycerol-hexadecyltrimethylammonium bromide was introduced into high-density polyethylene/agar biocomposites through melt mixing. The mechanical testing results indicated that the impact strength and tensile extension of the biocomposites increased with the introduction of the choline chloride/glycerol-hexadecyltrimethylammonium bromide. The scanning electron microscope, differential scanning calorimetry and thermal gravimetric analysis results exhibited that significant decrease in the number of agar fillers pull-out, melting point and thermal decomposition temperatures of the biocomposites are also due to the choline chloride/glycerol-hexadecyltrimethylammonium bromide. The Fourier transform infrared spectra and X-ray diffractometer patterns of the biocomposites introduced with the choline chloride/glycerol-hexadecyltrimethylammonium bromide demonstrate the presence of physical interactions, which contributes to the increase of compatibility between both high-density polyethylene and agar. In conclusion, high-density polyethylene/agar biocomposites could be compatibilized with eutectic-based ionic liquid containing surfactant, choline chloride/glycerol-hexadecyltrimethylammonium bromide.

Investigating ballistic impact properties of woven kenaf-aramid hybrid composites

In this study, the ballistic impact performance of woven kenaf-Kevlar hybrid and non-hybrid composites against fragment simulating projectiles (FSPs) was investigated. All the composites were prepared using the hand lay-up technique, method, followed by static load compression. The hybrid composites consist of Kevlar fabric and woven kenaf layers. The results obtained indicate that the energy absorption, ballistic limit velocity (V50) and failure behaviour of the composites during the impact event were affected by the woven kenaf hybridisation. The additional kenaf layers in hybrid composites resulted in the increase in composites thickness and areal density, thus increased the energy absorption (14.46 % to 41.30 %) and V50 (5.5 % to 8.44 %). It was observed that the hybrid composites failed through a combination of fibre shear, delamination and fibre fracture in the impacted surface, woven kenaf-Kevlar interface and rear surface respectively. Although the specific energy absorption was lower for the hybrid composites, further investigations need to be carried out to utilise the great potential natural fibres.

Effect of Fiber Loading on the Mechanical Properties of Kenaf Fiber Reinforced Thermoplastic Polyurethane Composite

Removed at Authors Request

Optimizing Processing Parameters and Fiber Size for Kenaf Fiber Reinforced Thermoplastic Polyurethane Composite

In this study, composite of Themoplastic polyurethane (TPU) reinforced with short fiber (Hibiscus Cannabinus) kenaf (KF) were prepared via melt blending method using Haake Polydrive R600 internal mixer. Effect of various processing temperatures, times and speeds on tensile strength was studied, together with effect of various fiber sizes on tensile, flexural properties and impact strength. Optimum blending parameters were 190°C, 11 min, and 40 rpm for temperature, time and speed, respectively. Using the optimum processing parameters TPU-KF composites with different fiber sizes were prepared. Composite sheets were prepared by hot press machine at 190 °C for 10 min. Five samples were cut from the composite sheet. Mean value was taken for each composite according to ASTM standards. Tensile and flexural strength were best for fibers between 125-300 micron. Impact strength showed an increasing trend with increasing fiber size.