Jeefferie Abd Razak

Processability of polypropylene/multiwalled carbon nanotube nanocomposites via direct melt compounding

This article presents the effect of filler loading on compounding torques as well as mechanical properties of polypropylene/multiwalled carbon nanotube (PP/MWCNTs) nanocomposites. Samples were prepared via melt compounding method using a Haake internal mixer at rotor speed of 80 r/min. The torque values in a 10-min compounding period for the incorporation of MWCNTs fillers into PP matrix were analyzed and thoroughly evaluated. The data was further confirmed by morphological analysis via transmission electron microscopy. The efficiency of direct melt-compounding method using internal mixer was evident from the homogeneity of MWCNTs dispersed within the PP matrix observed in produced nanocomposites at filler loading up to 0.75 wt%. MWCNTs showed significant compatibility with PP matrix and proved the needlessness of chemical pretreatment and complicated compounding process to produce PP/MWCNTs nanocomposites. The mechanical properties and morphological characteristics were in good correlation with the processing behavior of the nanocomposites.

NR/EPDM elastomeric rubber blend miscibility evaluation by two-level fractional factorial design of experiment

Fractional 25 two-level factorial design of experiment (DOE) was applied to systematically prepare the NR/EPDM blend using Haake internal mixer set-up. The process model of rubber blend preparation that correlates the relationships between the mixer process input parameters and the output response of blend compatibility was developed. Model analysis of variance (ANOVA) and model fitting through curve evaluation finalized the R2 of 99.60% with proposed parametric combination of A = 30/70 NR/EPDM blend ratio; B = 70°C mixing temperature; C = 70 rpm of rotor speed; D = 5 minutes of mixing period and E = 1.30 phr EPDM-g-MAH compatibilizer addition, with overall 0.966 desirability. Model validation with small deviation at +2.09% confirmed the repeatability of the mixing strategy with valid maximum tensile strength output representing the blend miscibility. Theoretical calculation of NR/EPDM blend compatibility is also included and compared. In short, this study provides a brief insight on the utilization of DOE for experimental simplification and parameter inter-correlation studies, especially when dealing with multiple variables during elastomeric rubber blend preparation.

Synthesis, characterization and application of Y3Fe5O12 nanocatalyst for green production of NH3 using magnetic induction method (MIM)

Y 3 Fe 5 O 12 (YIG) was prepared through sol-gel technique and sintered at three different temperatures (1000-1200δC). Various characterizations on the morphological and structural properties of produced YIG have been done as to understand the potential of this unique magnetic type nanomaterial to be used in the catalyst application for ammonia synthesis at ambient or green production environment. YIG catalyst exposed under magnetic induction of 0.1 T produced about 242.56μmol/h.g-cat yield of ammonia ( NH 3 ) at freezing reaction temperature of 0δC. About 95.88% improvements of NH 3 yield is produced in comparison with the absence of magnetic induction reaction condition (10μmol/h.g-cat). Synthesis at 25δC yielded reduction about 0.90% lower than the synthesis at 0δC temperature. Thus, it is proven that the temperature engaged the dominant roles in affecting the catalytic effect of YIG catalyst for NH3 production. Further parametric studies should be conducted as to explore the robustness of YIG catalyst for new route of ammonia production until the commercial scale-up could be achieved.

Effect of Filler Loading on Tracking and Erosion of Silicone Rubber Based Composites Under DC Voltage

Silicone rubber (SiR) is the most common material used nowadays for composite insulators and as a chosen candidate for outdoor high voltage applications, benefited from their excellent electrical performance. However, SiR also suffered from many drawbacks since electrical properties are becoming the major factors to the failure of insulation. Thus, by varying filler loading also is considered as an alternative way to improve the properties of SiR based composite insulator. In this paper presents the results of erosion weight and inclined plane tracking test for SiR based composite prepared by using different types of fillers. The purpose of using different fillers is to improve the properties of silicone rubber as an insulator which is necessary for good outdoor insulation applications. Calcium carbonate, silica and wollastonite were used as fillers in SiR matrix to enhance the resistance to tracking and erosion. The performances of materials also have been compared by conducting inclined plane tracking (IPT) test. Eroded mass and tracking length were examined to support the result. It is found that CaSiO3 had proved their ability as good fillers to be integrated with SiR for high voltage insulator by having the utmost number of passing sample.

Effect of Fly Ash Composition on Electrodeposited Nickel-Fly Ash Composite Coatings on Aluminium Alloy 7075 Substrate

The nickel-fly ash (Ni-FA) composite coatings were deposited on zincated aluminium alloy 7075 (AA7075) substrate by using electrodeposition technique. The electrodeposition process was carried out for 1 hour at 40°C under the current density of 3 A/dm2 in nickel-citrate bath containing various composition of fly ash (FA) particles at 10, 20, 30, 40 and 50 g/l. The produced composite coatings were characterized using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). Microhardness and wear of Ni-FA composite coatings were also investigated in this study. The co-deposition of FA particles leads to significant increase in hardness and wear resistance.

Formation of Cobalt Doped Zinc Oxide Photocatalyst for Methyl Orange Degradation

The formation of cobalt (Co) doped zinc oxide (ZnO) as photocatalyst for photodegradation of methyl orange dye was investigated. The ZnO photocatalyst was produced with different concentration of Co by using sol gel method. The hexagonal wurtzite and zincite structure were successfully formed through this method. The morphological observation of nanorod and nanodisk structure formed was done by Field Emission Scanning Electron Microscope (FESEM). While, the structural properties of Co doped ZnO were identified by X-ray Diffraction (XRD) and Raman spectroscopy. The degradation performance of methyl orange was assessed and performance of photocatalytic activity was correlated to the amount of dopant level and oxygen vacancy of photocatalyst. There is an optimum amount of Co that can be doped into ZnO nanostructure in order to provide better degradation of methyl orange.

Compressive properties of green rubber foam from reclaimed rubber glove

Nowadays, green materials are of interest due to the changes of government policies in many countries towards sustainable product development. In this study, green rubber foam from reclaimed rubber glove at various sodium bicarbonate content (4, 6, 8, 10 and 12 phr) as blowing agent was prepared via melt compounding technique and expanded via two-step heat transfer foaming process. Compression testing and water absorption were performed and the results were then supported with morphological analysis. The crosslink densities determined using Flory-Rhener equation indicated the value had slightly decreased with increasing blowing agent. The 4 phr sodium bicarbonate generated the smallest cells and the highest relative density foam of 0.9. The foam exhibited the lowest water absorption rate of 1.7 × 10 g/min as well as the highest compressive strength of 105 kPa. Increasing blowing agent evidently increased the cell size and decrease the compressive strength of the foam.

Facile Surface Modification of Graphene Nanoplatelets (GNPs) Using Covalent ATPS-Dehydration (GNPs-ATPS) and Non-Covalent Polyetherimide Adsorption (GNPs-PEI) Method

Graphene nanoplatelets (GNPs), a newly discovered nanomaterial, promise a great potential in many technological applications. However, the direct usage of GNPs was limited due to several surface property factors that require innovative modifications and treatments. In this study, the GNPs surface treatment is carried out by using a covalent and non-covalent approach. The success of the treatment was determined and evaluated through the Raman and FTIR spectroscopy analysis, FESEM, TEM and XRD morphological observation. A strong vibration of Raman peak at 2081.11 cm-1 represent a possible covalent bonding of C=C due to the ATPS-silane treatment, while the characteristic peak at 1013.82 cm-1 indicates the aromatic ring nature of polyimide that non-covalently associated with C-H and C-C, as well as C-O-C linkage from the polyether. From the IR spectroscopy, the covalent treatment on GNPs was occurred through the dehydration mechanism while hydrogen bonding in the multiple structures of –OH that associated to the carboxylic acids was obviously involved for non-covalent treatment of GNPs. TEM observation of GNPs-PEI (polyetherimide) revealed a unique phenomenon of a polymeric adsorption as represented by a nanosize gray dot morphology in between of the GNPs platelets. In overall, the facile procedure of the surface treatment that was applied in this study is reliable to yield a different type of GNPs characteristic of covalent and non-covalent surface active, which may open up broad possibilities for various cutting edges applications.

Green magnetic composite sheet from durian shell and nano magnetite particles

Biomass-derived materials such as kenaf pulp and wood chips are a perfect candidate to produce magnetic paper. Furthermore, by using biomass waste, such as paddy straw, sugarcane, bagasse and durian shell, the cost of producing magnetic paper can be further reduced while giving added value to the waste. This paper investigates the potential of producing magnetic sheet from durian shell. Initially, durian shells were dried before undergoing the pulping process. The resulted sheet was then combined with magnetic particles, the nanomagnetite using either lumen loading or in-situ co-precipitation to produce a magnetic composite sheet. After being loaded with magnetic particles, the composite sheets were tested in terms of the homogeneity of the magnetic particles in the samples, degree of loading of the magnetic particles and the magnetic properties of the samples. Results obtained show a great success in producing the magnetic sheet from durian shell waste and nanomagnetite particles. It was also found that the lumen loading method gives better magnetic properties compared to the in-situ co-precipitation method.

Synthesis and Characterization of Hematite Nanoparticles as Active Photocatalyst for Water Splitting Application

This paper highlights on the hydrogen production through photocatalytic activity by using hematite nanoparticles synthesized from self-combustion method based on different stirring period. The morphologies and microstructures of the nanostructures were determined using Field-Emission Scanning Electron Microscope (FESEM), X-Ray Diffractometer (XRD) and Particle Size Analyser (PSA). Besides that, surface area analyser was used to determine the BET surface area of the hematite samples. The hematite nanocatalyst as-synthesized are proven to be rhombohedral crystalline hematite (α-Fe2O3) with particle diameters ranging from 60-140 nm. The BET specific surface area of hematite samples increased from 5.437 to 7.6425 m2/g with increasing stirring period from 1 to 4 weeks. This caused the amount of hydrogen gas produced from photocatalytic water splitting to increase as well.