The Development Of Carbon Nanotube/Carbon Nanofibre From Polyacrylonitrile Electrospun Nanofibre Precursor For Electronic Applications

Carbon nanofibre (CNF) have attracted much attention among researchers due to their excellent properties such as high mechanical strength, thermal and electrical conductivity. CNF have been proposed for various applications such as filtration, smart material, tissue engineering, fuel cell, capacitors and sensors. Recently, electrospinning technique followed by pyrolysis process of the precursor material has been proposed as a simple and economic alternative for fabricating CNF. In this study, the best parameters on fabrication process of CNF with and without the inclusion of multi-walled carbon nanotubes (MWCNT) fillers were determined and their properties were characterised. MWCNT was selected due to its superior electrical properties. Previously, considerable amount of effort have been made on studying the physical, chemical, and mechanical properties of electrospun CNF. However, there are limited studies dedicated to investigating the electrical properties of the CNF especially in terms of conductivity, complex permittivity (dielectric constant and loss factor)and loss tangent. Therefore, the scope of this research is to investigate the relationship of electrical properties with physical and chemical properties of the fibres. Polyacrylonitrile (PAN) precursor nanofibre were prepared using electrospinning technique. The best parameters for electrospinning were investigated by preparing the samples at electrospinning distances of 5 cm to 30 cm and applied voltage of 5 kV to 20 kV. Furthermore, the best pyrolysis process was determined by varying the carbonisation temperature of 800 ºC, 1000 ºC and 1200 ºC with heating rate of 3 ºC/min and 5 ºC/min in a nitrogen filled furnace. As the optimum parameters were achieved, nanofibre samples with and without MWCNT were prepared. The characterization of the electrospun CNF was carried out using scanning electron microscopy (SEM), transmission electron microscope (TEM), ImageJ software, Fourier transform infrared spectroscopy (FTIR), four-point probe methods and dielectric probe. Based on fibre diameter, morphology, and deposition amount; the optimum electrospinning distance was found to be between 10 cm to 20 cm with an applied voltage between 15 kV to 20 kV. The results also suggest that increase in carbonisation and heating rate during pyrolysis process would increase the rate of elimination of non-carbon elements. This is evidenced by flatter FTIR spectrum and higher electrical conductivity of the samples which were carbonised at 1200 ºC and heating rate of 5 ºC/min. The electrical conductivity of CNF was significantly increased with the inclusion of MWCNT. The highest electrical conductivity was showed by CNF with 0.1 wt% of CNT with value 155.90 S/cm. However, samples with higher amount of MWCNT (> 0.1 wt%) showed reduced electrical conductivity to 21.56 S/cm. This could be explained by the formation of broken fibre network and agglomeration of MWCNT as observed using SEM and TEM. Finally, complex permittivity values of pure CNF and MWCNT-filled CNF were highest with dielectric constant value of 338.38 and loss factor value 488.72 at 1 GHz frequency. The knowledge gained from this study would extend the use of electrospun nanofibre in electronic applications such as sensors and other nano-sensing applications

Cleaner Production Implementation At Chicken Slaughtering Plant

Moving towards developed and high income nation by 2020, the pace of industrialisation in Malaysia has been increasing rapidly. On the other side of the spectrum, industrialisation process that is not considering the sustainable development would significantly increase the risk to safety, health and environment. Therefore, Cleaner Production (CP) provides an assessment of production process that aim to reduce the impact to safety, health and environment as well as increase the productivity of the company. This paper aims to investigate the carbon dioxides emission from the chicken slaughtering industry by focusing into five entities namely fuel consumption, electricity consumption, water consumption, wastewater generation and solid waste generation. The methodology used to achieve the objective are direct observation, reviewing relevant documents and on site measurement. It is found that among the five entities, the highest contribution of carbon dioxide emission is from the electricity consumption. CP options were suggested to the company to reduce the electricity consumption and subjected to the feasibility study in the future

Nylon Electrospun Nanofibre Water Filtration Media For Wastewater Treatment

Uncontrolled discharge of wastewater effluent has been a major concern due to the negative impact to human health and the environment. Increasingly stringent regulation has caused filter manufacturers to explore new materials to improve their products. Water filtration media using ultrafine fibres could be one of the potential solutions due to their promising characteristics. In this study, nanofibre incorporated water filtration media were produced, investigated, and characterized. A thin nylon electrospun nanofibre layer were deposited onto standard glass fibre filters and samples were collected at different electrospinning times. Suspended solid retention test was conducted using a vacuum filtration system based on BS EN 872:2005 standard. The absorbance of the feed and filtrate in terms of suspended solid and chemical oxygen demand of the water samples were also measured using a colorimeter based on Hach Method 8006 and 8000 respectively. The morphology of the filters was studied using scanning electron microscopy whilst porosity of the filtration media was inspected using mercury porosimetry. The results showed that the suspended solid and chemical oxygen demand removal capabilities of the filtration media improved significantly with the inclusion of nanofibre layer. A positive correlation was found between the performance of the filter and the amount of deposited nanofibre. It was also found that the inclusion of thin nanofibre layer had minimal effect to the overall porosity of the standard filters. Findings from this study provide a useful insight into the use of nanofibres in water filtration applications

Preparation, characterization, and electrical conductivity investigation of multi-walled carbon nanotube-filled composite nanofibres

There is a growing interest in carbon nanofibre materials especially for applications that require high surface area, excellent chemical inertness, and good electrical conductivity. However, in certain applications a much higher electric conductivity is required before one can take the full advantage of the nanofibre network. Therefore, incorporating superconductive materials such carbon nanotubes is thought to be a feasible approach to enhance the electrical properties of the carbon nanofibres. The objectives of this study were to prepare and characterize multi-walled carbon nanotube-filled composite nanofibres. Carbon nanofibres were produced via electrospinning technique using precursor solutions of polyacrylonitrile in dimethylformamide loaded with different amount of multi-walled carbon nanotubes (MWCNT). The electrospun fibre samples were then pyrolyzed in a nitrogen-filled laboratory tube furnace. Characterization process was performed using scanning electron microscope (SEM), transmission electron microscope (TEM), and four-point probe method. It was found that the incorporation of MWCNT into the carbon nanofibre structures could significantly increase the electric properties of the nanofibres. The composite nanofibres with 0.1 wt.% of MWCNT loading has the highest electrical conductivity of 155.90 S/cm compared to just 10.71 S/cm of the pure carbon nanofibres. However, the electrical conductivity of the composite fibres reduced drastically when higher weight percentages of MWCNT were used. This was caused by agglomeration of MWCNT causing premature percolation, and broken fibre network as evidenced by SEM and TEM examinations. The results obtained from this study may facilitate improvements in the development of superconductive high surface area materials for electronic applications

Determination of optimal electrospinning distance and applied voltage for polyacrylonitrile electrospun fibre production

Electrospinning process is highly dictated by electric field strength. Thus, two key parameters i.e., electrospinning distance and applied voltage, determine the quality of electrospun fibres. Incorrect selection of these parameters will result in poor fibre qualities. There ought to be an optimal combination of electrospinning distance and applied voltage to produce best quality fibres from a given material. In this study, the optimal combination of electrospinning distance and applied voltage was assessed based on consistency of electrospinning process, amount of fibre, fibre morphology, and average fibre diameter. Polyacrylonitrile (PAN) electrospun fibre samples were prepared at different combinations of electrospinning distance and applied voltage. Scanning electron microscopy and image analysis were conducted to assess the quality and average diameter of the fibres. The results indicate that for electrospinning of PAN, the distance should be between 10 and 20 cm with a 15 to 20 kV of applied voltages. Findings from this study is crucial for producing optimal fibre quality in PAN electrospun nanofibre synthesis