Papers by Author: Noor Azilah Mohd Kasim

Abstract: The functionalization of multi-walled carbon nanotubes (CNT) with amide group is reported as an alternative to enhance response time, recovery time and sensitivity of detecting acetone gas. We have fabricated an interdigitated transducer (IDT) deposited with amide-functionalized CNT. The elemental compositional analysis was characterized using Energy Dispersion X-ray spectroscopy and CHNOS elemental analyzer. The detection of acetone gas was performed in room temperature and digital multimeter was employed to record the changes of resistivity of IDT upon exposure of acetone. Results showed that amide functional group increases sensitivity, shortens the response time as well as recovery time of the sensor.

Abstract: A simple, low cost and rapid analytical method for determination of HCl concentration after being treated with cellulose and cellulose nanofibers (CNF) is developed. This method is based on color intensity after the HCl solution is doped with sodium iodide (NaI). The color of HCl solution changes from colorless to yellow. The intensity of the color is measured by UV – Visible spectroscopy. The UV-Visible spectra of 0.15 M HCl treated with cellulose and cellulose nanofibers is reduced from its initial concentration. The CNF absorption capacity is higher as compared to cellulose. FT-IR analysis showed that there is interaction between C-H group from the CNF backboned and chloride ion from HCl solution.

Abstract: Current world events have made several countries as a target for terrorism. Chemical weapon such as nuclear weapon is commonly referred as a weapon of mass destruction. Organophosphorus (OP) compounds have long been used as pesticides and developed into warfare nerve agents such as tabun, soman, sarin, and VX. They are highly toxic and considered to be the most dangerous chemical weapons. Development on the protection material against OP compounds has gained interest among researcher. Nanocellulose has shown a great potential for high-performance filtration material due to its interesting characteristics such as high adsorption capacity, large surface area, high strength, renewable, chemical inertness, and versatile surface chemistry. Therefore, the evaluation of the chemical interaction between nanocellulose and organophosphorus is important. The analyses of fourier-transform infrared spectroscopy (FT-IR), ultraviolet-visible (UV-Vis), and elemental analysis were carried out in this study. It was found that the nanocellulose is capable to adsorb OP compound by forming the hydrogen bonding. The adsorption rate was increased as the nanocellulose concentration increased. This is the initial step to discover the potential of nanocellulose to be used in military protection mask.

Abstract: We report the synthesis of two dipolar thiazole derivatives functionalized with nitro group as electron acceptor and amino group as electron donor, in order to study their optical properties in the UV-vis range. Their structures were verified by ¹H NMR, ¹³C NMR, HRMS and FT-IR. The resulted thiazole derivatives have good thermal stability with decomposition temperature, T_d of 320.20 °C and 284 °C for compounds 1 and 2 respectively. The absorbance bands of compound 2 in the UV-vis range are more red-shifted than that of compound 1 which made compound 2 could have high potential as a great organic NLO material.

Abstract: Oxidation by acid treatment is one of the chemical methods used to introduce surface oxygen functional group (SOFG) and defects on the surface of carbon nanofibers (CNFs). Therefore, many researchers used this method to improve the dispersion ability of CNFs in aqueous media. However, only few researchers used combination of chemical and mechanical method for oxidation of CNFs. In this work, as-received CNFs were treated using chemical method with an addition of mechanical method. On the first experiment (Method A) concentrated sulphuric acid and nitric acid were used and followed by combinations of mechanical method using ultrasonication water bath under reflux. The addition mechanical method through reflux was eliminated and different times of ultrasonication were used in method B and method C. Outer diameter of each CNFs samples were determined from FESEM images and were found to be in range of 50 nm–190 nm. Whereas, Raman spectroscopy was used to analyse any structural defects of CNFs samples during each treatment methods. From the findings, acid treatment of CNFs with addition of mechanical method using ultrasonication showed remarkably effect on the CNFs morphology.

Abstract: Functionalization of multiwalled carbon nanotubes (MWCNT) is one of several methods used to improve the compatibility of CNT. Even though acid functionalised method is effective, the strong acids such as H₂SO₄/HNO₃ were normally employed and long hours of sonication is used to disperse the CNTs in the solution frequently can damage the nanotube, thus limiting their great performance as mechanical and electrical reinforcements. Here we are reporting comparison between three methods used in acid functionalized treatments of MWCNT. The first method, MWCNT was functionalized using ultra sonication water bath and followed by reflux (Method A). The second method, MWCNT was functionalized using ultrasonication water bath only for 2 hours (Method B). Finally, the third method MWCNT was functionalized using ultrasonication water bath only for 6 hours (Method C). Raman spectroscopy measurements were used to examine the general relationship between the chemical treatment and the amount of non-graphitic carbon. Electron microscopy analysis revealed that MWCNT functionalized using Method C suffered the highest degree degradation such as, nanotube shortening and additional defect generation in the graphitic network. Method B proved to be the most effective for this aim.

Abstract: Modification of multi-walled carbon nanotube (MWCNT) plays an important role to produce MWCNT crossbreeds that may be useful for exploration of new materials. In this report, characterization of dimethyl dioctadecylammonium bromide (DDOAB) modified multi-walled carbon nanotube (Mo-MWCNT) using Fourier Transform Infrared (FTIR) spectroscopy and Thermogravimetric analysis (TGA) and X-ray diffraction (XRD) is described. FTIR shows the presence of both aliphatic (CH stretching and CH bending) and ammonium (CN stretching) groups from DDOAB and the existence of C=C aromatic functional group from the structure of MWCNT in Mo-MWCNT spectra. This result was supported by TGA result which suggests that there are weight losses due to the degradation of DDOAB (between 250 °C to 500 °C) in the product. In addition, XRD pattern remain after modification suggesting attachment of MWCNT and DDOAB occurs at the surface of MWCNT.

Abstract: Reaction 3-thiocyanatoacetylacetone with leucine (C6H13O2N1) was found to give 3-(5-acetyl-2-aminothiazol-4-ylthio)-4-hydroxypentan-2-one (I). Compound I crystallized in the orthorhombic system with space group Pbca a= 8.143 Å, b=13.831Å, c=21.878Å. V= 2463.7Å3, Z=8.

Abstract: Multi walled carbon nanotubes (MWCNTs) were synthesized using floating catalyst-chemical vapor deposition (FC-CVD) with ferrocene and benzene as catalyst and carbon source, respectively. Argon was used as a purging gas while hydrogen was used as a carrier gas. Hydrogen flow rate, reaction time and reactor temperature were varied to obtain high yield and purity of MWCNTs. The morphology and microstructures of MWCNTs produced were studied using Scanning Electron Microscopy (SEM). It was found that the maximum yield and purity of MWCNTs were produced at hydrogen flow rate of 300 ml/min with reactor temperature of 900°C and reaction time 45 minutes. It was observed that the MWCNTs are film-like, randomly oriented and in some cases entangled with uniform diameter.