Study On Phase Change Material Of Vest

Many workers have to work in the high temperature. Therefore, there is an important significance to research the phase change material of cooling vest. It can reduces human body temperature own to it absorbs heat of the skin surface, then its phase changed along with the process of cooling surrounding, consequently it is beneficial to prolonging working time under the high temperature condition.Firstly, the water gel materials were selected as the phase change material according the cooling effect and comfort requirements to be investigated. The water gel materials were composed of host materials and cross-linking agent. The host materials are poval, polyethylene glycol and polyacrylamide respectively, meanwhile cross-linking agent are borax, glutaraldehyde and citric acid. The water gel was prepared by the mixing the aqueous solution of host materials with the cross linking agent, and the results shows that the combination of poval and borax has the best gel effect, the lowest rate of water loss and the quickest gel speed. Secondly, single factor experiment was carried out. The dosage of poval, borax, cooling agent and the variety of cooling agent are determined. The dosage of poval,10%borax solution and the amount of isopropyl alcohol were optimized based on response surface analysis, respectively, and furthermore the best mass ratio of poval, 10%borax, isopropyl alcohol, tap water is 5:18:2:100 respectively. Under this condition, the initial melt temperature of prepared cool storage material is-2~-3℃,dissolving potential heat is 260~280 J/g, and the cooling time in 35℃ no wind environment can be up to 5 hours. Finally, PVA water gel phase change material characteristic was measured by SEM, XRD, FT-IR and TG. According to the results of the water loss rate and repeated utilization of latent heat after 200 and 500 times, it found that PVA hydrogel has better stability, furthermore the first gel and second gel have approximate phase change point through secondary utilization test. It is proved that it can improve utilization rate of raw material which is beneficial to environment protection. These results should be valuable for designing a new type of phase change cool storage materials with large potential heat, long cooling time and secondary utilization。...