Jalaluddin Harun

Chemical and Morphological Characteristics of Malaysian Cultivated Kenaf (Hibiscus cannabinus) Fiber

In this study, an attempt is made to understand the chemical and morphological characteristics of Malaysian cultivated kenaf fractions (bast, core, and whole stem). Results based on morphologyand chemical analysis indicate that bast and core fiber fractions in the kenaf are significantly different, although the chemical composition of kenaf is quite similar to the woody mass. In the case of whole stem fibers, it is concluded that the effective length of fibers from the whole stem is reasonably good for the purpose of making printing papers.

Effect of chitosan addition on the surface properties of kenaf (Hibiscus cannabinus) paper

The present paper studies the effect of chitosan, cationic starch and polyvinyl alcohol (PVA) as sizing agents to enhance surface properties of kenaf paper. The polymers were incorporated into the sheets by spray application. The results clearly showed that the addition of chitosan to a sheet formed from beaten fibers had excellent improvement in surface properties, compared to the effect of other additives. Sizing quality of cationic starch fairly matched with the sizing quality of chitosan, however, it was able to reduce the water absorption potential of paper more than chitosan at a same concentration. In most other properties, particularly the most important property for printing papers, surface smoothness, chitosan-sized papers are superior to the paper sized with cationic starch or PVA.

Enhancing Dry-Strength Properties of Kenaf (Hibiscus cannabinus) Paper Through Chitosan

The present study was focused on the effect of chitosan, a linear amino-polysaccharide, on the properties of handsheets made from bleached kenaf kraft pulp. Chitosan was incorporated into the sheets by three distinct techniques, equilibrium adsorption (pH 5), precipitation (pH 10), and spray application. The chitosan dosages tested were 0.5%, 1%, 1.5%, and 2% based on oven dry pulp. Chitosan was found to increase the dry-strength properties of paper such as tear, burst, and tensile index, but its effectiveness was strongly dependent on the method of addition. Spray application gives superior strength properties, followed by equilibrium adsorption. Chitosan is less effective under alkaline conditions. The results showed that chitosan addition improved the mechanical properties of sheets, but the rate of increase in strength properties was higher from 0% to 0.5% compared to 1% to 1.5% regardless of the treatment techniques.

Rheological Behaviour of Injection Moulded Oil Palm Empty Fruit Bunch Fibre – Polypropylene Composites: Effects of Electron Beam Processing Versus Maleated Polypropylene

In this study, oil palm empty fruit bunch fibres (EFB) reinforced polypropylene (PP) composites were prepared by two different methods i.e. physical treatment of the composites using electron beam irradiation and chemical treatment by adding coupling agent such as maleated PP. The composites pellets were then subjected to injection moulding for preparation of test pieces for physical, mechanical and rheology properties study. Haake Rheometer RS 150 was used to study the changes in viscosities of the composites at different shear rates. The melt flows of the composites were also measured to complement and confirm the rheology behaviour of the composites. Upon irradiation, the viscosity of PP decreased due to chain scission and the sudden drop of viscosity at high shear rate was not significant. The presence of EFB fibre in the PP matrix was obviously interrupted the flow ability of PP that cause viscosity to increase. Upon irradiation of EFB/PP, the viscosity of the composites decreases. This indicate that no crosslinking occur between EFB and PP during melt mixing although PP and EFB active radicals were present in the composites. On the other hand, the additional malaeted PP increases interfacial adhesion that result in enhance resistance to flow, thus significantly increased in the viscosity of the composite. The addition of 6% maleated PP exhibited significant drop in viscosity of the composites. These results were further confirmed by the melt flow measurement of irradiated EFB/PP with reactive additives and maleated PP. The rheological behaviour of the composite is important parameters in plastic processing particularly in relation to the shear rates for injection moulding and extrusion processes.

Feasibility of Manufacturing a Medium Density Fibreboard Made of 4-Year Old Rubber Tree RRIM 2020 Clone

This research was conducted to study the feasibility of producing medium density fibreboard (MDF) from 4-year old rubberwood clone RRIM 2020. The 4-year old rubberwood is obtained from different planting densities, which is 500, 1000, 1500 and 2000 trees/ha and were processed to produce MDF. The MDF is analyzed in term of its mechanical properties (static bending and densities to comply with JIS A 5905-2006 Standard (Type 30, MOR > 30.0 MPa and MOE > 2500 MPa and Type 25, MOR > 25.0 - 30.0 MPa and MOE > 2000 - 2500 MPa). MDF made from 25 year trees clone, PB260 which come from the same clone was used as a control. The results showed that the PB260 and the 4-year old rubberwood clone with planting densities of 500 trees/ha satisfied the requirement of Type 30, and the remaining passed at Type 25. It shows that it is feasible to produce an MDF using the 4-year old rubberwood clone.

Effect of Totally Chlorine Free and Elemental Chlorine Free Sequences on Whole Stem Kenaf (Hibiscus cannabinus) Pulp Characteristics

ABSTRACT Totally chlorine free (TCF) and elemental chlorine free (ECF) single and multistage sequences were used to bleach whole stem kenaf pulp. The results indicated that in contrast to unbleached kraft wood pulps, kraft kenaf pulps can be easily bleached to a brightness of 91.4% using a four-stage TCF [Q1(PO)Q2P] bleaching sequence. The ECF bleaching pulps had slightly higher selectivity and yield than those of the TCF bleached pulps. The strength properties of the TCF [Q1(PO)Q2P] and ECF (D1ED2EP) bleached pulps were comparable, with the exception of tear index and tensile index, which were slightly higher and lower for TCF pulps, respectively.

Effect of Accelerated Aging on Properties of Kenaf(Hibiscus cannabinus) Paper Sized with Various Polymers

ABSTRACT The effect of aging on the properties of paper sized with chitosan, cationic starch, and PVA was investigated under accelerating conditions (90°C and 50% RH). The observations from this study demonstrate that the brightness and pH of papers decrease with an increase in aging time. At each aging time, paper sized with chitosan shows the highest reduction in brightness, whereas decreases in brightness in papers sized with PVA and cationic starch do not show much difference. The results demonstrate that paper sized with any of the polymers gave higher levels of tear index, tensile index, and folding endurance than the control sheet. Statistical analysis indicated that the polymers used in this experiment have a statistically significant effect on the folding endurance of sized paper that was highest in the cases of PVA and chitosan.

Effect of resin content and pressure on the performance properties of rubberwood-kenaf composite Board Panel

The possibility of manufacturing rubberwood and kenaf (Hibiscus cannabinus L.) stem medium density fibreboard (MDF) panels at different pressure and resin content were investigated. The effect of mechanisms of interacted independent variables (resin content and pressure) on MDF properties was analyzed. The board performance was evaluated by measuring internal bond (IB) strength, modulus of rupture (MOR), modulus of elasticity (MOE), water absorption (WA) and thickness swell (TS). The test results were statistically analyzed by using response surface method (RSM) to determine the significant independent variables that influenced MDF properties. A mathematical simulation or response surface models were developed to predict the MDF properties (MOR, MOE, IB, WA and TS). The obtained results showed that MDF density and all interactions between the experimental variables were significant factors that influenced the mechanical properties of MDF. At 8 bar and 14 % resin content, the MDF recorded WA of 83.12 % and TS of 20.2 %. It can be inferred that two parameters (resin content and pressure) had positive effect on physical and mechanical properties of MDF. We concluded that resin content show more significant effects on MDF manufacturing as compared to pressure parameters.