Papers by Author: Xun Gai Wang

Abstract: Randomly orientated electrospun poly(vinylidene fluoride) nanofiber membranes were directly used as active layers to make mechanical-to-electrical energy conversion devices. Without any extra poling treatment, the device can generate high electrical outputs upon receiving a mechanical impact. The device also showed long-term working stability and ability to drive electronic devices. Such a nanofiber membrane device may serve as a simple but efficient energy source for self-powered electronics.

Abstract: Wet textile colouration has the highest environmental impact of all textile processing steps. It consumes water, chemicals and energy and produces liquid, heat and gas waste streams. Liquid effluent streams are often quite toxic to the environment. There are a number of different dyeing processes, normally fibre type specific, and each has a different impact on the environment. This research investigated the energy, chemical and water requirements for the exhaust colouration of cotton, wool, polyester and nylon. The research investigated the liquid waste biological oxygen demand, total organic carbon dissolved solids, suspended solids, pH and colour along with the energy required for drying after colouration. Polyester fibres had the lowest impact on the environment with low water and energy consumption in dyeing, good dye bath exhaustion, the lowest dissolved solids levels in waste water, relatively neutral pH effluent and low energy in drying. The wool and nylon had similar dyebath requirements and outputs however the nylon could be dyed at far lower liquor ratios and hence provided better energy and water use figures. Cotton performed badly in all of the measured parameters.

Abstract: Sorption potential of hemp powders as sorbents converted from wasted hemp fibers for Zn2+ ions from diluted aqueous solution was explored. Spectrophotometric method was selected to determine the concentration of Zn2+ ions in the solutions. The influence of different factors on the sorption, such as pH, amount of hemp powder applied as well as initial concentration, were studied, respectively. The obtained results show that the sorption capacity for Zn2+ was the maximum when the pH was 5.85. Increasing the initial concentration of the solutions resulted in increased sorption capacity. Depressed uptake capacity was obtained while amount of hemp powders was increased.

Abstract: Electrospraying or electrohydrodynamic spraying is a technique of liquid atomisation by utilising electrical forces. In the electrospraying technique, the liquid at the outlet of a nozzle is subjected to an electrical shear stress by maintaining the nozzle at high electric potential. This produces a fine mist of extremely small and in some cases down to nanometer size droplets. The charge and size of the droplets can be controlled by adjusting the flow rate and voltage applied to the nozzle. Extending the scope of electrospraying, textile substrates can be coated with suitable polymer solution to enhance the surface functionalisation. This paper highlights the deposition of chitosan on wool subtrates using elctrospraying and its potential application in medical textiles.

Abstract: Compared to other spinning system, the ring spinning process has been used to produce higher quality yarns, but with a much lower spinning efficiency, resulted from the relatively high spinning tension that leads to increased yarn breakage rates and makes high power consumption. Thus, depressing yarn tension is essential to change the status. In this paper, we design a movable balloon controller system to reduce yarn tension. The system is automatic, composed of powder switch, touch screen, PLC (Programmable Logic Controller), pulling-thread displacement sensor, controller of step motor, step motor and linear module. PLC, the core of the system, controls the position of the balloon controller by a series of programs. Then yarn tension was tested while spinning with movable balloon control ring, fixed balloon control ring and no balloon control ring, respectively. The result shows that the yarn tension can be depressed indeed by equipping this movable balloon controller system to some extent. Additionally, we find that the number of hairiness of ring spun yarns with this system can be reduced to some extent, while yarn tensile properties are not as sensitive to be worse. It is significant to cut down ends-down rate, improve the quality of ring spun yarns, the spinning efficiency as well as the energy efficiency of ring spinning.

Abstract: In this study, cellulose nanofibers were obtained from wood pulp using a chemo-mechanical method and thin films were made of these cellulose nanofibers. The morphology of the films was studied by scanning electron microscopy (SEM). SEM image analysis revealed that the films were composed of cellulose nanofibers with an average diameter of around 32 nm. Other properties were also characterized, including the degree of crystallinity by X-ray diffraction, chemical bonding by infrared attenuated total reflectance analysis, and thermal properties by differential scanning calorimetry. The foldable, strong, and optically translucent cellulose nanofiber films thus obtained have many potential applications as micro/nano electronic devices, biosensors and filtration media, etc.

Abstract: In our previous work, we have produced a photochromic wool fabric by applying a thin layer of hybrid silica-photochromic dye onto the wool surface. The coating showed a very fast optical response, but had little influence on the fabric handle, however durability was low. In this context, we reported that durability of the hybrid layer can be improved by introducing epoxy groups into the silica matrix via co-hydrolysis and co-condensation of an alkyl trialkoxysilane (ATAS) and 3-glycidoxypropyltrimethoxysilane (GPTMS). The presence of epoxy groups in the silica enhanced both washing and abrasion durabilities. Also, the optical response speed was slightly increased as well. Effects of the type of alkyl silane and the GPTMS:alkyl silane ratio on the coating durability, fabric handle and optical response were examined.