Azizah Baharum

Effect of Extrusion Rate and Fiber Loading on Mechanical Properties of Twaron Fiber-thermoplastic Natural Rubber (TPNR) Composites

Mechanical behavior of short Twaron fiber thermoplastic natural rubber (TPNR) has been studied with respect to fiber loading and extrusion rates. The composites are prepared at two different compositions of NR/LLDPE matrixes i.e., 60/40 and 40/60. Twaron fibers are varied from 0 to 25% in the composites. The temperature profile for extrusion is 140, 145, 150, and 155°C for feeding zone, melting zone, mixing zone, and die respectively with the extrusion rate of 30, 50, 80, and 100 rpm. It has been found that the tensile strength, Young’s modulus, and impact strength increases with fiber loading, but the strain at break decreases. The optimum fiber loading in the system is found to be 20% in both blends. However, there is no effect of extrusion rate on the strength of composite observed.

Mechanical properties of bio-composite natural rubber/high density polyethylene/ mengkuang fiber (NR/HDPE/MK)

The use of mengkuang fiber (MK) as a filler in NR/HDPE/MK bio-composite was investigated. The suitability of MK as reinforcing filler was studied in terms of the mechanical properties and phase morphology formed. Melt-blending was performed using an internal mixer (Haake Rheomix 600). The processing parameters identified were 135 °C temperature, 45 rpm rotor speed and 12 min processing time. The optimum MK loading in 40/60 of NR/HDPE blend was obtained at 20 wt.% with the tensile strength, tensile modulus, and impact strength of 12.4 MPa, 377 MPa and 17.2 kJ/m2, respectively. These results showed an enhancement in tensile strength of 10.7% compared to the unfilled NR/HDPE blend. The maximum impact strength obtained at 5% fiber loading was 23.5 kJ/m2, which was 7.8% higher compared to unfilled NR/HDPE blend. The FESEM micrographs showed good adhesion between MK fiber and matrix. These mechanical properties enhancements proved the suitability of mengkuang fiber as potential reinforcing filler in NR/HDPE blend.

A urethane block copolymer as binder for fire-resist palm-based fibreboard

The mechanical properties and fire resistance of medium-density fibreboard (MDF) consisting of empty fruit bunch fibre (EFB) and palm-based pre-polyurethane (pPU) as the green binder were investigated. The EFB was in the size range of 300 to 500 μm with ATH varied at 5, 10, and 15%w/w of the total mass of the resin and was added into the pPU matrix at a ratio of 65:35 of the EFB to pPU. This study discovered the significant of mixing sequence to the strength enhancement of the fibreboard. A direct proportionality was noted between the Shore D hardness and the amount of ATH with an increase up to 17% with increasing ATH content. Furthermore, this is contributed to well-disperse ATH in the pPU matrix which also increased the impact and flexural strengths. An increase in impact strength of 13, 20 and 33%, with increasing ATH loading percentage was observed. The maximum increase in flexural strength was 33%, which was associated to ATH content of 15%. On the other hand, the burning rate decreased from 6.0 to 3.2 mm·s−1 with increasing ATH content.

Mechanical properties of chemically modified Sansevieria trifasciata/natural rubber/high density polyethylene (STF/NR/HDPE) composites: Effect of silane coupling agent

The main objective of this research is to study the effects of chemical modification on the mechanical properties of treated Sansevieria trifasciata fiber/natural rubber/high density polyethylene (TSTF/NR/HDPE) composites. Processing of STF/NR/HDPE composites was done by using an internal mixer. The processing parameters used were 135°C for temperature and a mixing rotor speed of 55 rpm for 15 minutes. Filler loading was varied from 10% to 40% of STF and the fiber size used was 125 µm. The composite blends obtained then were pressed with a hot press machine to get test samples of 1 mm and 3 mm of thickness. Samples were evaluated via tensile tests, Izod impact test and scanning electron microscopy (SEM). Results showed that tensile strength and strain value decreased while tensile modulus increased when filler loading increased. Impact strength increased when filler loading increased and began to decrease after 10% of filler amount for treated composites. For untreated composites, impact strength began to...

Effect of liquid epoxidized natural rubber (LENR) on mechanical properties and morphology of natural rubber/high density polyethylene/mengkuang fiber (NR/HDPE/MK) bio-composite

The use of mengkuang fiber (MK) fibers in NR/HDPE (40/60) blend was studied via surface modification of fiber. The MK fiber was pre-washed with 5%wt/v sodium hydroxide solution prior to treatment with liquid epoxidized natural rubber (LENR). The concentration of LENR were varied from 5%-20%wt in toluene. The effects of LENR concentrations were studied in terms of mechanical properties and morphology formed. Melt-blending was performed using an internal mixer (Haake Rheomix 600). The processing parameters identified were 135°C temperature, 45 rpm rotor speed, 12 minutes processing time and at 20%wt MK fiber loading. The optimum LENR treatment concentration was obtained at 5%wt with tensile strength, tensile modulus, and impact strength of 10.3 MPa, 414.2 MPa and 14.4 kJ/m2 respectively. The tensile modulus of LENR-treated MK fiber filled NR/HDPE bio-composite has shown enhancement up to 16.7% higher than untreated MK fiber. The tensile and impact strength were decreased with increasing LENR concentration d...

Efficacy of fibre aspect ratio and prepolymerised polyurethane as binder in enhancing strength of palm-based fibreboard

Palm–based medium-density fibreboard (palm-based MDF) comprised of polyurethane prepolymer (pPU) and palm oil empty fruit bunch fibre (EFB) was prepared. The pPU was a reacting mixture in acetone consisted of palm kernel oil-based monoester polyol (PKO-p) and 4,4-diphenylmethane diisocyanate (MDI) with polyethylene glycol (Mw of 200 kDa, PEG200) as the plastisizer. EFB with size ranging from 250 μm to 500 μm (MDF S1), 500 μm to 1000 μm (MDF S2) and 1000 μm to 2000 μm (MDF S3) was investigated. The flexural strength and modulus increased with decreasing fibre size with optimum strength and modulus at 46.7 MPa and 1923 MPa respectively. Higher glass transition temperature (Tg at 77 °C) was observed in MDF S1 compared to MDF S3 (Tg at 67 °C). FTIR spectrum indicated possible formation of urethane linkage between the reactive NCO active groups in pPU with OH group from cellulose constituent in EFB fibre.

Effect of fibre aspect ratio onto the modulus of palm-based medium-density fibreboard

Polyurethane prepolymer (pPU) was used as a binder in the production of palm-based medium-density fibreboard (MDF). Untreated empty fruit bunch fibre (EFB) with three different fibre sizes was used and their effects on the mechanical and thermal properties of the MDF were studied. Palm kernel oil-based monoester polyol (PKO-p), 4,4-diphenylmethane diisocyanate (MDI) and polyethylene glycol 200 (PEG 200) were used to prepare the resin. Acetone was added into the resin as a solvent. Three different fibre sizes were used; 250 µm to 500 µm (MDF S1), 500 µm to 1000 µm (MDF S2) and 1000 µm to 2000 µm (MDF S3). Three points bending test showed that the flexural strength and modulus increased as the EFB fibres size decreased with optimum flexural strength at 46.7 MPa and optimum flexural modulus of 1923 MPa. The results were supported by the morphological study that showed better matrix encapsulation occurred in MDF S1, followed by MDF S2. The scenario was rather different in MDF S3 whereby uneven matrix distribu...