Dzaraini Kamarun

Epoxidation of palm oil catalyzed by titanium-grafted silica catalyst

Epoxidation reaction is an important reaction in organic synthesis because the formed epoxides are intermediates that can be converted to a variety of products. Catalytic palm oil epoxidation using titanium-grafted silica, hydrogen peroxide, and peroxoformic acid was carried out at 60 °C in a fixed batch reactor. Titanium-grafted silica with different percentages of silica content was prepared through sol-gel hydrolysis and was utilized in epoxidation of palm oil. Titanium-grafted silica particles and Epoxidized palm oil were characterized by techniques such as Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscope (FESEM) and Nuclear Magnetic Resonance (NMR). The TiOSi bonds were detected at 960 cm-1 in Ti-Si 0.5 and exhibited highest yield of epoxidized palm oil (EPO) in the epoxidation process which is 84% conversion of unsaturation in palm oil to epoxy groups. New peaks observed in the range of δ 2.4 ppm to 3.6 ppm in the NMR spectrum of EPO belong to protons of the epoxy cyclic ring group, CH-O-CH confirming successful epoxidation of palm oil using the prepared catalyst.

Surface Modification of Polyvinylidenefluoride-Trifluoroethylene Film Using Argon Gas Plasma

This study investigates the surface properties of plasma surface modified spin coated PVDF-TrFE (70/30) film using Atomic Force Microscopy (AFM), Water Contact Angle (WCA) and X-ray Photoelectron Spectroscopy (XPS). The surfaces of the spin coated PVDF-TrFE film were modified using 13.56 MHz rf Argon plasma. The exposure time of the charged particle PVDF-TrFE films were varied for 1, 3 and 5mins. Prior to modification, the average surface roughness obtained was 8.615nm, but upon modification, the surface roughness was found to increase to 12.466nm. The value of the contact angle of the modified film was reduced from 90o to 43o and the XPS analysis showed dehydrofluorination of PVDF-TrFE films surfaces. The improved in surface roughness and the increased in wettability of the modified film, resulted in good biocompatibility of the modified PVDF-TrFE thin films. This phenomenon has created interest in researchers for developing functional polymer used for applications in areas such are biomedical, bio-analytical assays, textile and even food industry.

Nanopolyaniline as immobilization template for signal enhancement of surface plasmon resonance biosensor - A preliminary study

A technique for the enhancement of Surface Plasmon Resonance (SPR) signal for sensing biomolecular interactions is described. Polyaniline (PANI) of particle size in the range of 1 to 15 nm was synthesized and used as the template for the immobilization of protein molecules. Biomolecular interactions of unbound and PANI-bound proteins with antibody molecules were SPR-monitored using a model system comprising of Bovine Serum Albumin (BSA) and anti BSA. A 7-fold increased in the signal was recorded from interactions of the PANI-bound BSA with anti BSA compared to the interactions of its unbound counterpart. This preliminary observation provides new avenue in immunosensor technology for improving the detection sensitivity of SPR biosensor; and thereby increasing the lower detection limit of biomolecules.

Preparation and Characterization of Chitosan/Alginate Polyelectrolyte Complex Prepared by Using Calcium Tripolyphosphate Ionic Gelator

The formation of polyelectrolyte complexes (PECs) between chitosan and alginate has been widely investigated for many pharmaceutical and biomedical uses. Ionotropic gelation resulted from the crosslinking of polyelectrolytes (PEs) in the presence of ionic crosslinkers to form hydrogels. The most widely used ionic crosslinker for chitosan is sodium tripolyphosphate (NaTPP); and Ca2+ ions for alginates. The use of these cross-linkers to prepare PECs of chitosan and alginates resulted in hydrogels of similar moieties: chitosan-chitosan and alginate-alginate rather than the sought for hybrid chitosan-alginate PECs. Calcium tripolyphosphate (CaTPP) is a single molecule ionic gelator of chitosan and alginate that have the capability of producing the true hybrid compound of chitosan/alginate polyelectrolyte complex. This paper reported the synthesis of calcium tripolyphosphate and the preparation of a hybrid chitosan/alginate PECs using this newly identified ionic gelator. The newly-synthesized ionic gelator was characterized using ICP-OES; the PECs thereof prepared were characterized using TGA and SEM. The degradation temperature of the prepared PECs is higher than the degradation temperatures of the individual chitosan and alginates. SEM image of the prepared PECs showed rougher surfaces compared to the images of the individual chitosan and alginate compound. Both TGA and SEM revealed the possibility of the newly prepared material to be of the PECs sought for.

Silk and Silk-like Fibres: Halal Attributes from a Scientific Viewpoint

The prophet Muhammad S.A.W. has made silk unlawful for the Muslim males. The development of silk industry around the globe had made abundant the availability of textile merchandise of silk origins. Advancement of technology created textile materials of surface properties, texture and ‘feel’ which mimicked pure silks. As such, consumers and contemporary Muslims could no longer differentiate between pure silk and synthetic silk-like fabrics and are forced to face the issues of halal textiles/fabrics for wear and clothing. This paper gives an insight and review of the characteristics and properties of silk and silk-based textiles in the scientist’s viewpoint. Ways and techniques to produce synthetic and composite fabrics which resembled pure silk as reported in the literatures are revealed and discussed to identify possibilities of segregating between pure and synthetic silk-like fibres. In conclusion, it is the purpose of this paper to expose scientific background and knowledge on silk and silk-like textiles to the community so as to gain a better understanding and perspective on the issues of halal textiles.

Cure characteristic and mechanical properties of natural rubber vulcanizates with digested rice husk ash (RHA)

Rice husk (RH) is a hard shell that protects the rice grain and can be found in abundance in all rice producing countries. Burning RH as fuel to generate energy would result in a waste product, rice husk ash (RHA). RHA contains approximately 90 – 98% of silica (SiO2), after undergoing a complete combustion process, which is the highest among other agricultural wastes. Silica is one of the commonly used fillers in natural rubber (NR). A chemical treatment for the RHA was developed to collect the silica, via a simple method consisting of alkaline extraction and acid precipitation. This method can produce finer and visually whiter RHA powder. The effects of the chemical treatment on the particle size and surface area of the silica particles were measured. The precipitated silica was then incorporated into NR, using a laboratory-size two-roll mill. For comparison, commercial silica was used as a control. The cure characteristics and mechanical properties of the vulcanizates were evaluated. It was found that the chemical treatment (digestion and precipitation) on RHA has resulted in a significant decrease in its particle size and increase in its specific surface area. However, the mechanical properties of the vulcanizates produced from the treated RHA were lower than that of the commercial silica.Rice husk (RH) is a hard shell that protects the rice grain and can be found in abundance in all rice producing countries. Burning RH as fuel to generate energy would result in a waste product, rice husk ash (RHA). RHA contains approximately 90 – 98% of silica (SiO2), after undergoing a complete combustion process, which is the highest among other agricultural wastes. Silica is one of the commonly used fillers in natural rubber (NR). A chemical treatment for the RHA was developed to collect the silica, via a simple method consisting of alkaline extraction and acid precipitation. This method can produce finer and visually whiter RHA powder. The effects of the chemical treatment on the particle size and surface area of the silica particles were measured. The precipitated silica was then incorporated into NR, using a laboratory-size two-roll mill. For comparison, commercial silica was used as a control. The cure characteristics and mechanical properties of the vulcanizates were evaluated. It was found that t...

Mechanical, morphological and thermal properties of linear low density polyethylene/poly(lactic acid) blends

Melt blending of linear low density polyethylene (LLDPE) and polylactic Acid (PLA) were performed in a twin screw extruder. The blend compositions were prepared in the ratios of 0/100; 15/85; 25/75; 35/65 and 50/50 of PLA/LLDPE. The objective of this work is to study the effect of different content of the PLA on the properties of the blends. The phase morphology and mechanical properties of the thermoplastic blend samples were examined. The blend compositions were optimized by tensile and Izod impact tests. The thermal properties were examined by TGA and DSC. The tensile strength result of the blend with the addition of 50 wt.% PLA decreased by 57% as compared to the neat LLDPE. Examination of images from fracture surface of tensile specimen using scanning electron microscope (SEM) showed the presence of fibrous surface (ductile fracture) for sample with higher content of LLDPE. The TGA results for the PLA/LLDPE blends samples shows two degradation steps of mass loss during heating. DSC results for all po...

Physical and mechanical properties of compounded hydroxylated natural rubber

In this study, oil resistance properties, tensile strength and hardness properties of compounded hydroxylated Natural rubber (OONR) were evaluated. Oil and oxidation natural rubber (OONR) exhibited shorter cure time compared to the SMR-L and EPDM and recorded better crosslinks density. The performance of OONR clearly dominated the unmodified NR in terms of swelling to hydrocarbon oils and non-polar solvents. The OONR also depicted an increasing trend in hardness compared to the unmodified NR. However, the tensile strength of OONR vulcanizate was drastically decreased compared to SMR-L and EPDM compounded rubber.

Thermal properties of hydroxylated natural rubber from in-situ hydroxylation process

A thermal property of hydroxylation of natural latex has been studied in this research. The effect of the hydroxylation conversion of the double bond to hydroxyl functionality of natural rubber in one pot solution using in-situ method. It was studied at different duration; 10, 20, 30, 40 and 50 hours of reaction. A mechanism for the hydroxylation of the natural rubber was also proposed. The result shows the optimum conversions of double bond to hydroxyl functionality was recorded highest at 40 hours and remain constant although the reaction was continued until 50hrs. Fourier Transform (FT) Raman spectroscopy was used to analyze the conversion. −1HNMR was used to confirm the formation of hydroxyl to support the peak from FT Raman spectra. Differential Scanning Calorimetric analysis was used to analyze the glass transition temperature (Tg) of modified and unmodified natural rubber. The result showed lower Tg in modified natural rubber compared to the unmodified natural rubber. On the other hand, the onset o...

Tensile properties of carbon black-filled natural rubber latex films using two different approaches of film preparation

A study was structured to investigate the effects of two different approaches of black-filled NRL films preparation on tensile strengths and tensile stress at 100% strain (M100). In the “First Approach”, carbon black dispersion was added into the NRL and mixed using mechanical stirrer. Then the black-filled NRL was coagulated with acetic acid and dried to form NR black-filled masterbatch. This black-filled NR masterbatch was then masticated and mixed with other compounding ingredients on the 2-roll mill. In the “Second Approach”, carbon black dispersion was mixed with NRL plus all other compounding ingredients using a mechanical stirrer at high mechanical stirring speed (200 rpm) for 3 hrs. Tensile test-pieces from these two rubber specimens were tested according to ISO37. It was observed that the tensile strengths are affected by both methods. In the case of masticated latex masterbatch, the black-filled NRL films gave higher tensile strength (25-27 MPa) as compared to un-masticated black-filled NRL film...