Papers by Author: Tao Yu Wan

Abstract: This study examined the effect of the coating speed, coating solution, cure temperature, knife gap and fabric matrixes on surface properties, water vapor permeability and hydrostatic head test. The optimum conditions for surface high water vapour permeability that enables the user to “dial in” the right balance of properties based on the findings of the experimental. This sample showed high excellent resistance to +7m in hydrostatic head tests for a single-layer coated fabric and. Surface morphology showed that the coating was continuous without cracks or pin holes and appeared to be well adhered to the substrate even after a harsh wash.

Abstract: In this work, polyurethane coating on the fabrics is studied in the Basecoater 200. The structure and morphology of coated fabrics were investigated using SEM and soaking test in the cured coated samples. Coating thicknesses, surface friction coefficient and surface roughness variation of the samples were measured using the surface tester of the KESF. Results showed that uniform and cross linking degree of the surface layer of coated samples have close relevant with coat processing. The performance quality of end products can be achieved by optimization of process variables, including coating speed, coating solution, and cure temperature and fabric matrixes during fabric coating processing.

Abstract: Aqueous solutions of polyvinyl alcohol (PVA) with FeCl3 were homogenously mixed and subsequently electrospun; and its characteristics were studied as a function of voltage, tip-target distance and solution flow rate. Fiber mats of (PVA)/FeCl3 composite, in the diameter of 700–1100 nm were prepared by electrospinning. Lower concentrations of solution tended to facilitate the formation of fibres with beads. With increasing concentration, the morphology was improved with smooth and uniform fibres and the increased fibre diameters in the nano range. Spinning voltage also had an important influence on the diameters of the nano fibres, while the collection distance affected fibre diameters. Nano fibres of smaller diameter were formed when lower voltages are applied. The morphology of the electrospun from PVA/FeCl3 nano fibres and their magnetic power was observed and analyzed by scanning electron microscopy (SEM).The fibres produced in this way could potentially be applied to manufacture magnetic sensors, flexible magnets.

Abstract: This paper reports a novel method of developing SMART nanocomposite membranes and coatings by in situ synthesis of iron oxide particles in a Poly(vinyl alcohol) (PVA)matrix, using co-precipitation of different amounts of Fe(II) and Fe(III) taken in an alkaline medium. Poly(vinyl alcohol) was used to encapsulate iron oxide nanoparticles, as scaffold for particle nucleation and its influence on particle size and on magnetic properties were studied. The ferrogels were prepared by a freeze/thawing process of the solutions containing magnetite nanoparticles. Magnetite particles with an average diameter of 20-40 nm were obtained homogeneously within the matrix because of the tridimensional structure and chelating capacities of PVA. Calcium-alginate PVA gel was used to encapsulate the iron oxide/PVA nanocomposite. The mechanical properties and the saturation magnetization of the system were measured. The combination of magnetic properties of iron nanoparticles with the biocompatibility of calcium-alginate suggests that these materials have great potential for use as controlled delivery systems activated externally by magnetic stimuli.