Rosli Mohd Yunus

Oil palm bio-fiber-reinforced polypropylene composites: effects of alkali fiber treatment and coupling agents

The major challenge for natural fiber composites is their inherent poor adhesion between fiber and the matrix, high moisture absorption, and UV degradation. Lignin and hemicelluloses are the major composites of natural fiber which are responsible for UV degradation and moisture absorption, respectively. In this study, the lignocelluloses (oil palm empty fruit bunch) were treated with alkaline peroxide to separate lignin and hemicelluloses. Composites were produced with treated and untreated fibers using up to 45% fiber with polypropylene matrix using twin-screw extruder followed by injection molding. To improve the interfacial bonding, maleic anhydride grafted polypropylene (MAPP) was used as a coupling agent in the formulation. Properties of composites were evaluated using tensile testing, flexural testing, impact testing, SEM, and FTIR. The tensile, flexural, and impact properties were found to be improved with alkaline peroxide-treated fiber composites compared to untreated fiber composites. Addition of coupling agent (MAPP) also found to provide improved properties of composites.

Facile synthesis of copper nanoparticles in glycerol at room temperature: formation mechanism

A copper sol is usually synthesized by the reduction of a copper precursor with a suitable reducing agent in the presence of a stabilizer. There are few reports regarding the preparation of copper nanoparticles in glycerol without using a stabilizing agent, but at elevated temperatures. The formation of reduced copper (Cu0) is usually verified by a UV-vis spectrophotometer where a ‘red copper sol’ was formed. In the present paper we synthesized the copper sol at room temperature in a glycerol medium using hydrazine as a reducing agent. The chemical states of copper in the sol and their composition were analyzed by X-ray absorption near edge structure spectroscopy (XANES) with the linear composition fitting method. A series-parallel mechanism of the reaction was proposed. An average particle size of 5 ± 1 nm was visualized via transmission electron microscopy (TEM).

Synthesis of Copper Nanoparticles at Room Temperature Using Hydrazine in Glycerol

Copper nanoparticles (CuNPs) have been prepared by the reduction of copper chloride in glycerol using hydrazine at ambient conditions. The reduction process takes place under vigorous stirring for 8 h. The formation of CuNPs and size were confirmed by UV/Vis analysis and TEM imaging respectively. The experiment result showed that, 7.062 mM of hydrazine solution and 0.0147 mM of Cu2+ solution were needed to synthesize narrow size monodisperseCuNPs.The presence of nanoparticle was found after an induction period of 4 h and further reaction time, complete Cu0 state nanoparticle was obtained as deep red wine colour was observed. Stability study of CuNPs showed that the nanoparticles were stable up to 4 days. The particle size of the nanoparticles have been analysed by transmission electron microscopy (TEM) and the average size of CuNPs was in the range 2 to 10 nm.

Oil palm fiber reinforced polypropylene composites: effects of fiber loading and coupling agents on mechanical, thermal, and interfacial properties:

This study investigates the effects of fiber type, fiber loading, and coupling agent on the performance of oil palm biomass (OPB) fiber composites. Fiber composition and fiber morphology were evaluated by scanning electron microscope (SEM) and Energy-dispersive X-ray spectroscopy (EDAX). Grinded fiber was compounded into polypropylene by means of a twin-screw compounder. Maleated polypropylene (MAPP) was used as a coupling agent during compounding. The incorporated fiber contents for OPB composites were up to 40% (by weight). The compounded samples were prepared into test specimens by injection moulder. The composites were characterized by tensile testing, flexural testing, impact testing, melt flow index, SEM, thermogravimetric analysis (TGA), and differential scanning calorimeter (DSC). The most significant effect on strength and modulus were found by the addition of coupling agent. This was attributed to the thermodynamic segregation of the MAPP toward the interface, resulting in the formation of covalent bonding to the –OH groups of the fiber surface. Composites with MAPP also provided better thermal stability.

A CFD study of heat transfer through spacer channels of membrane distillation modules

Abstract The computational fluid dynamics modeling in this paper examines transient flow and temperature patterns in spacer-filled membrane distillation channels. The instantaneous velocity profiles at various time steps show that at higher Reynolds number the vortices emerge behind spacer filaments, move along with the flow and then finally diminish. This unsteady behavior causes variation in local temperatures and heat transfer coefficients with time. The temperature polarization is usually low near the locations where high velocity region hits the top or attaches to the bottom surface. The region near the filament at the bottom is a stagnant zone and an area of higher temperature polarization at all times. The effect of filament spacing is also investigated. At low Reynolds number and a small filament spacing of 2 mm, maximum values for average shear stress and heat transfer coefficient are obtained. When Reynolds number is high, this spacer becomes unsuitable due to smaller magnitudes of these paramet...

Effects of different coupling agents on the mechanical and interfacial properties of oil palm fiber reinforced polypropylene composites

This study investigates the effects of fiber loading and coupling agent on the performance of EFB fiber composites of oil palm biomass. The dried EFBs were ground in random sizes for composite production. Fiber composition and fiber morphology were evaluated by SEM and EDAX. Ground fiber was compounded with PP by means of a twin-screw compounder for the preparation of EFB/PP composites. Two types of MAPP were used as a coupling agent during compounding. The incorporated fiber contents for EFB composites were 10—40% (by weight). The test specimens were prepared by injection molding. The composites were characterized by melt flow index and mechanical testing such as TS, TM, FS, FM, and IS. Surface morphology was studied by SEM.

Tailoring base catalyzed synthesis of palm oil based alkyd resin through CuO nanoparticles

Palm oil based alkyd resin was synthesized by an alcoholysis–polyesterification process over a base catalyst tailored by copper oxide (CuO) nanoparticles. In the present paper we synthesized CuO sol in glycerol and subsequently used it in alkyd resin synthesis. The formation of the alkyd resin was confirmed by FTIR, Raman, 1H-NMR and 13C-NMR methods and its molecular weight was determined by gel permeation chromatography (GPC). The antimicrobial activity of the pseudo-homogeneous additive was determined via the Kirby–Bauer method and the stability of the CuO was determined by X-ray absorption near edge structure spectroscopy (XANES). The addition of CuO nano-sol to the conventional homogeneous base catalyzed system explored a new catalytic route for the preparation of bioresin from vegetable oil, reducing the reaction time as well as adding antimicrobial properties to the resin.

Review on the Fundamental Aspects of Petroleum Oil Emulsions and Techniques of Demulsification

This review is aimed to introduce a comprehensive survey on the most prominent and sustainable techniques and methods that could abate the environmental worries as well as financial insecurities in treating petroleum emulsions, since the existence of water is not desired because of the paramount troubles it may cause on the processing streamlines, as well as financial cost associated with transporting water mixed with petroleum. Currently, the most commonly used method for treating petroleum emulsion is the application of chemical additives, known as demulsifiers. Althogh, there are many other methods that are claimed to be more favorable from economic and environmental perspectives, yet, have not being fully put into real life practice, because of the drawbacks and disadvantages. In this review, several techniques have been surveyed including, chemical, electrical, membrane, centrifuge, bacteria, air floatation, ultrasonic, and microwave. Based on this Theoretical survey, silcone based demulsifiers were reported to be very effective and environmental friendly, but expensive. Also microwave and ultrasonics were reported to be very effective in treating petroleum emulsion and could be recommended as future ulternatives for treating petroleum emulsions.

Effects of fiber loading, fiber type, its mesh sizes, and coupling agent on the properties of oil palm biomass/polypropylene composites

This study investigates the effects of fiber type, mesh size, fiber loading, and coupling agent on the performance of oil palm biomass (OPB) fiber composites. The dried OPB fibers were ground and screened into 63, 150, 250, 450, and 500 µm meshes for composite production. Fiber composition and fiber morphology were evaluated by scanning electron microscope (SEM) and energy disperse analysis of X-Ray. Ground fiber was compounded into polypropylene (PP) by means of a twin-screw compounder. Maleated polypropylene (MAPP) was used as a coupling agent during compounding. The incorporated fiber contents for OPB composites were 10%, 20%, 30%, and 40% (by weight). The compounded samples were prepared into test specimens by injection molder. The composites were characterized by tensile testing, flexural testing, impact testing, melt flow index, and SEM. The analysis of variance of the effects of fiber types, fiber mesh sizes, and fiber contents and their interactions on the OPB–PP composite properties were studied and found to affect on composite properties significantly. The most significant effect on strength and modulus was found by the addition of coupling agent which was suggested to be due to the thermodynamic segregation of the MAPP toward the interface resulting in covalent bonding to the −OH groups on the fiber surface.

Effects of coupling agent on oil palm clinker and flour-filled polypropylene composites

This study gives the comparative analysis of polypropylene (PP)/oil palm flour (OPF) and PP/oil palm clinker (OPC) composites using maleated polypropylene (MAPP) as a coupling agent. Ground flour and crashed OPC were compounded separately into polypropylene with and without MAPP using a twin-screw compounder. The incorporated OPF and OPC in the composites were up to 40 wt%. The compounded samples were prepared into test specimens by injection molder. The composites were characterized by tensile strength, tensile modulus, flexural strength, flexural modulus, impact strength, and melt flow index. The surface morphology of composites was evaluated by scanning electron microscope. Incorporation of coupling agent showed better result than that of without coupling agent. Various properties of composites incorporated with OPC represented considerably close to the composites with OPF.