Explore And Research Of Immersion-Resistant And Moisture-Permeable Smart Fabrics

The fabric of immersion suit has to be faced with two sharply different circumstances, dry state and wet state. So it is very difficult for the existing fabrics of immersion suit to have good immersion-resistant ability meanwhile with good heat-moisture comfort (moisture permeability). Were it has both merits, the fabric's structure must be very complex and the producing technology be very hard and cost highly. In this research the hydrogel macromolecule has been introduced into textile developing and designing field and a novel 'Immersion-Resistant and Moisture-Permeable Smart Fabric' was made out. It is the layer of hydrogel come into being on the surface of fibers by grafting modification that make this kind of fabric got responsibility to the change of the circumstance between dry state and wet one. In dry environment the hydrogel macromolecules contract and the fabric has good permeability of gas and moisture as the space of pores between fibers and yarns kept open. As soon as the fabric was immersed into water the layer of hydrogel was swelling immediately with the result that all kinds of pores were closed and it got immersion-resistant effect.Firstly, the grafting method initiated by low temperature plasma (LTP) was studied. Although the hydrophilic property of polyethylene terephthalate (PET) film, polyethylene (PE) film and PET fabric was raised greatly by grafted with acrylic acid (AAc) initiated with LTP the graft ratio was too low to achieve swelling property wanted. It is the reason that the quantity of active group created on the surface of base material is very little. The fabric's water permeability rises at low graft ratio contrarily.Then the ceric ammonium nitrate (CAN) was used as initiator and cotton fabric and polyester and cotton blend fabric (T/C fabric) were grafted with AAc or acrylamide (AAm). The retention ratio of tensile strength of grafted T/C fabric can kept up 90 per cent meanwhile moisture permeability was improved. Gas permeability was depressed with growth of graft ratio firstly but batter than original fabric at high graft ratio.The grafted T/C fabric can swell at once when it reached water. Higher the graft ratio is batter the responsive intensity is and faster the responsive speed is. The responsive speed of AAm grafted fabric is faster than that grafted with AAc. The molecule weight of grafted chain is from several ten thousands to several hundred thousands. Increasing the molecule weight and frequency of grafted chain can avail to strengthen the fabric's immersion resistance. By a certain graft ratio the fabric's equilibrium rate of water permeation will reachnearly to 0 and higher graft ratio can no more prevent the minim filtration. In addition effects of concentration of NaCl, working water pressure, working water temperature and hydrolyzation of hydrogel on immersion resistant ability were also studied.In the case of fabric with closed density and yarn with same tex the plain structure is the best one for immersion resistance, twill second place and satin last. On the base of concept of hydraulic radius a model to calculate the water permeation rate at t time was built through Hagen-Poiseuille law and the factors affecting immersion resistance were analyzed theoretically. Accordingly the grafted fabric was processed with water repellent only on one surface and equational rate of water permeation was decreased further more.Finally, a double layer fabric of immersion suit was investigated primarily. The original double fabric represented a similar water-resistant phenomenon to the AAm grafted T/C fabric. And when the upper PET layer was faced to water flow the equational rate of water permeation is higher than it was backed. After the double fabric grafted with AAm the equational rate of water permeation is lower than the T/C fabric with closed graft ratio apparently.