The Study On Acid-Resistant And Alkaline-Resistant Properties Of The Polysulfonamide Fiber And Its Needle-Punched Nonwoven Fabric

Polysulfonamide(PSA) fiber as a research and development of China's own intellectual property rights and a high-temperature resistant fiber,its industrialization process and development of application market have caused a lot of industries' attention.Because PSA fiber has good high-temperature resistant and flame-resistant performance,high temperature filter is one of its main application markets.This thesis is a part of research and development project "Product Development and Application Research of Polysulfonamide Fiber Used to Filter" of Shanghai Tanlon Co.,Ltd.The life time of the filtration media largely depends on their chemical resistant properties because there are many acidic and alkaline substances in the smoke.This paper is based on the study of the performance of the PSA fiber needle-punched nonwoven fabric in high temperature condition.In this paper,the acid-resistant and alkaline-resistant properties of the PSA fiber and its needle-punched felt in the sulphuric acid solution and sodium hydroxide solution are studied respectively.First of all,the PSA fibers are immersed in different concentrations of sulphuric acid solution and sodium hydroxide solution respectively at certain temperature and treatment time conditions.In the second place,the treated PSA fibers are washed, dried and then treated at a standard condition of the laboratory.Thirdly,many performances such as tensile strength,elongation at breaking,fineness and crimp property are tested in order to know the acid-resistant and alkaline-resistant properties of the fiber.PSA fiber and its products are more applicable to the case of acid environment because this paper has found that the fiber's performance in the sulphuric acid solution is better than those in the sodium hydroxide solution.The four PSA fiber needle-punched nonwoven fabrics of different needle-punching density are studied.Many performances such as thickness, dimensional stability,tensile strength,elongation at breaking and aperture condition are tested in order to know the acid-resistant and alkaline-resistant properties of the nonwoven fabric.PSA fiber needle-punching nonwoven fabric is more applicable to the case of acid environment because this paper has found that the fabric's performance in the sulphuric acid solution is better than those in the sodium hydroxide solution.According to the performances of the four different needle-punched density fabrics,this paper has found that the acid-resistant and alkaline-resistant properties of the fabric are related to its original properties.In this paper,there is a unique phenomenon that the tensile strength of the PSA fiber needle-punched nonwoven fabric increases obviously after the treatment of the concentration of 10%sulfuric acid solution soaked for two hours at 85℃.Meanwhile,the tensile strength and the crimp property of the PSA fiber decrease slightly and the dimension of the nonwoven fabric keeps steady after the same treatment.For the phenomenon,this paper has made the further experiment on PSA fiber and then has found that the fineness of the fiber gets smaller and the surface friction coefficient of the fiber gets bigger after the same sulfuric acid solution treatment.Based on the analysis of the mechanics model of fiber entanglement by needle-punching,it declares:the smaller fineness of PSA fiber after the treatment is beneficial to reinforcement of the fiber entanglement under tension so that the utilization coefficient of the fiber strength is increased in the consolidation of needle-punching.The main reason for the unique phenomenon is the fineness of the fiber getting smaller after the treatment.In addition,the surface friction coefficient of the fiber getting bigger also plays a helpful role in the reinforcement of the PSA nonwovens.