Materials Science Forum Vol. 846

Abstract: Poly(lactic acid) (PLA)-based nanocomposites filled with graphene nanoplatelets (xGnP) and containing epoxidized palm oil (EPO) as plasticizer were prepared by melt blending method. PLA was first plasticized by EPO to improve its flexibility and thereby overcome its problem of brittleness. Then, xGnP was incoporated into plasticized PLA to enhance its mechanical properteis. Plasticized and naonofilled PLA nanocomposites (PLA/EPO/xGnP) showed improvement in the elongation at break by 61% compared with plasticized PLA (PLA/EPO). The use of EPO and xGnP increases the mobility of the polymeric chains, thereby improving the flexibility and plastic deformation of PLA. The nanocomposites also resulted in an increase of up to 26.5% in the tensile strength compared with PLA/EPO blend. PLA/EPO reinforced with xGnP shows that increasing the xGnP content triggers a substantial increase in thermal stability. The TEM image of PLA/EPO/xGnP shows that the xGnP was uniformly dispersed in the PLA matrix and no obvious aggregation is observed.

Abstract: Cellulose Micro/Nano fibers (CMNF) from various plants which is Resak (Vatica spp.) waste, Merbau (Intsia bijuga) waste, banana (Musa acuminata) pseudo-stem and pineapple (Ananas comosus) leaf fibers have been isolated and characterized. Isolation of microfibril cellulose from raw fibers was achieved using alkaline treatment and bleaching. The treated and untreated samples were characterized using x-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Characterizations of treated and untreated samples were compared. The comparison between those treated and untreated samples giving different crystallite size, crystallinity, arrangement of CMNF and surface morphology from different plants. Hence, with these information different nanocomposite from CMNF can be constructed and manipulated for various application.

Abstract: The intercalation of herbicide, 3,4-dicholorophenoxyacetic acid (3,4D), into zinc-aluminium-layered double hydroxide (LDH) for the formation of a new nanocomposite ZADX, was accomplished via anion exchange method. Due to the intercalation of 3,4D with LDH interlayer domain, basal spacing expanded from 8.9Å in the ZAL to 17.7-19.0 Å in the ZADX. The percentage loading of 3,4D in the ZADX is 51.4 % (w/w). The FTIR spectra of the nanocomposite shows resemblance peaks of the 3,4D and Zn-Al-layered double hydroxide indicating the inclusion of 3,4D into the layered double hydroxide. Surface area of the resulting nanocomposite increased from 1.3 to 7.14 m²g^-1 with the nitrogen adsorption-desorption of type IV.

Abstract: Banana pseudostems waste is abundantly available as agro-waste and has been used in different applications. In this work, the isolation of CMNF from the pseudostems of banana plant were explored. The dried stems from the species Musa acuminata were first cleaned by soxhlet extraction, alkali treatment and bleaching. Segal method will be employed to analyze data from XRD to determine crystallinity of the CMNF. Morphology of the CMNF will be determined using FESEM. Characterizations of treated and untreated samples were compared. The comparison between those treated and untreated samples giving the information about crystallite size, crystallinity and surface morphology for each treatment.

Abstract: Mg doped Zinc oxide nanorods films were successfully deposited on glass substrate prepared by aqueous solution-immersion method. The influence of annealing temperature on the nanorod films were studied at different annealing temperatures 0°C, 250°C and 500°C respectively. FESEM showed the morphology of the films with hexagonal nanorods growth. XRD results indicated the crystalline structure of ZnO doped Mg nanorods films where the peak intensity of ZnO was decreased as annealing temperature increases. Photoluminescence (PL) measurement at room temperature showed the increasing of intensity peak for visible spectra with increasing of annealing temperature.

Abstract: This work describes the growth of 1-D Al-doped ZnO nanorods via low temperature hydrothermal reaction on seeded substrates. The amount of Al doped ZnO nanorods were tuned by using different concentration of aluminum nitrate from 1-20 mM. The optimum 5 mM Al doping produced an arrays of sharp-tip nanorods with average length of ~1.16 μm and average diameter of ~118 nm. I-V characteristic of the Al-doped ZnO nanorods fabricated onto Al electrodes were observed under UV illumination and dark condition. The change in photoconductivity of Al-doped ZnO nanorods under UV light was found two orders of times higher compared to ZnO nanorods. Different concentrations of aluminium doped ZnO nanorods UV sensing showed response to UV light but with different sensing value. 5 mM Al-doped ZnO showed high responsivity of fabricated UV sensing at 3V with 23.56 A/W which was higher compared to other concentrations. This suggested that the responsivity of Al-doped ZnO NRs UV sensing could be controlled to some extent by controlling the percentage of Al-doped.

Abstract: Polyaniline (PAni) Nanocomposites Containinganiline (Ani) Monomer and Hexanoic Acid (HA) Dopant were Successfullysynthesized by Using Chemical Oxidation Method. Titanium Dioxide (TiO₂)and Different Dimension of Multiwall Carbon Nanotubes (MWNT) Have been Added Inorder to Improve the Dielectric Permeability and Magnetic Permittivityproperties of the Pani Nanocomposites. Fourier Transform Infrared (FTIR) Andultraviolet-Visible (UV-Vis) Spectra Confirmed the Chemical Structure of Paninanocomposites. Conductivity and Magnetization Behavior were Investigated Byresistivity Meter and Vibrating Sample Magnetometer (VSM). Microwave Absorptionstudies were Carried out by Microwave Vector Network Analyzer (MVNA) from 0.5to 18 Ghz. among all the Pani Nanocomposites, Pani Nanocomposites with MWNT (D = 10-2- Nm, l = 5-15 μm) Shows Agood Reflection Loss (RL = -58 Db) at 7 Ghz with a Sharp and Narrow Peak due Tohigher Values of Magnetization (0.074 Emu/g) Andmoderate Electrical Conductivity (1.11 x 10^-2 S/cm)

Abstract: In the present work, it was attempted to electrodeposit Cu-Al₂O₃ and Ni-Al₂O₃ metal matrix composite (MMC) coatings onto a copper substrate using a modified Watts bath containing dispersed nanosized Al₂O₃ with an average particle size of 50 nm. The prepared nanocomposite coatings were subjected to different tests to characterize their surface morphology, crystalline structure and mechanical properties. The microstructure and composition of the composite films were studied with Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) techniques. The use of nanoparticles could change the microstructure and morphology of the electrodeposits, depending on the metal matrix composites. The hardness and wear resistance tests were carried out on nanocomposite coating samples to investigate the mechanical properties. The co-deposited Al₂O₃ nanoparticles in the deposit increased the hardness and wear resistance, which were closely related with Al₂O₃ content in the nanocomposites. The hardness of the Ni-Al₂O₃ coating increased by about 26.3 % compared to pure copper plate due to the dispersion hardening effect. The hardness of the Cu-Al₂O₃ coating decreased by about 25.2 % as compared to pure copper plate due to the minimization of surface energy and the surface porosity of the coating. The wear resistance of the Ni-Al₂O₃ coating on the copper substrate was higher than that of Cu-Al2O3 as deduced from the lower mass loss of the former. The novelty of this project is the creation of very hard coating using a relatively low cost method.

Abstract: A study on the synthesis of multiwalled carbon nanotubes (MWCNT) and zinc oxide (ZnO) hybrid materials using the mecahnochemical technique has been conducted. MWCNT was dispersed in sodium dodecyl sulfate (SDS) solution. ZnO was formed at milling time between 2 and 5 hours, where at 10 hours the XRD results showed only small peaks of ZnO. This suggests that at longer milling time, the ZnO crystals were either become amorphous or have reduced in sized so as not to be detected using XRD. ZnO has also been doped with Manganese (Mn) which have affected the crystal structure and surface morphology of the sample.Keywords:Doping, Manganese nitrate, Mechanochemical technique, Multiwalled carbon nanotubes (MWCNT), Surfactant method , Zinc Oxide (ZnO)

Abstract: Sleep disorder study by means of polysomnography (PSG) is the most well adopted and reliable procedure in medical practice. The present-day sleep monitoring devices for the PSG procedure is equipped with relatively expensive apparatus and technically complex modus operandi. Thus the PSG procedure must be conducted by well trained personnel. This study is about development of an ultra-sensitive breath sensor for medical procedures. The miniature size breath sensor design gives an added advantage on the final design of the sleep monitoring device for sleep disorder study or personal therapy. This solid state breath sensor is structured with micro tungsten inter-digitated electrode (IDE) platform that covered with multi-walled carbon nanotubes (MWCNT) as sensing material. The MWCNT is grown on a thin oxide layer on top of the tungsten IDE using plasma enhance chemical vapor deposition (PECVD) technique. These MWCNT structures are capable of sensing and capturing breathing behavior thus a quick response capacitive sensor is developed. Typical photolithography and sputtering processes are involved in the sensor structure fabrication. A customized test jig imitating a human like breathing pulse was fabricated to test the sensor’s performance in relation to sensitivity and response time. Human subjects are used as well to further confirm the breath sensor performance. The research study shows this newly developed breath sensor device is highly sensitive and shows remarkably fast response; within sub-second.