| With the improvement of living standards,the requirement of the functional clothing is getting higher and higher.Waterproof and breathable membranes have been widely used as one of functional textiles.They can not only prevent the infiltration of rain and snow in outdoor sports,but also conduct moisture to the outside in a timely manner to ensure the balance of human microenvironment,and keep the body comfortable.But with the development of science and technology,single functional protection has been unable to meet people's needs.Exploiting high-added-value textiles equipped with multiple functionalities like ultraviolet(UV)resistance,waterproofness,and thermal-moisture comfort is facing tremendous demand by more discerning consumer market.Chronically suffered from UV radiation can cause skin sunburn with typical symptoms,like reddening,swelling,burning,itching,and even skin cancer.So the development of functional textiles with effective protection against such skin damages is urgently needed.And,it is still in a hurry to create the functional materials with the multifunction of UV resistant,waterproof and moisture breathability.Herein,a new attempt of fabricating superhydrophobic electrospun polyacrylonitrile(PAN)/polyurethane(PU)/titanium dioxide(Ti O2)nanofibrous membranes has been tried,and the membranes exhibited multifunction of UV resistance,waterproofness and breathability by coating modification with 2-hydroxy-4-n-octoxybenzophenone(UV531)and fluorinated acrylic copolymer(FAC).Ti O2 nanoparticles as inorganic blocker and UV531 as organic absorber were utilized to impart the excellent double UV resistant function for the modified nanofibrous membranes.The effects of polymer concentration,PAN/PU ratio and concentration of Ti O2 on the morphology,mechanical properties and anti-ultraviolet properties of the membranes were studied.Comprehensive considering the morphology,porous structure,mechanical strength and UV resistant properties,10 wt% of polymer concentration,8/2 of PAN/PU ratio and 1 wt% of concentration of Ti O2 were chosen to conduct the following research.In order to further improve the UV resistant property,UV531 as UV absorber were introduced.The absorbent intensity enlarged with increasing UV531 concentration.When the UV531 concentration is 0.5 wt%,the UV resistance reaches the requirement.With the increase of UV531 concentration,the pore size of the membrane decreased and hydrostatic pressure increased,and the water vapor transmittance rate(WVTR)decreased with the decreased of the porosity.Comprehensive overall property,the UV531 concentration of 0.5 wt% was chosen to conduct the following research.Then FAC as hydrophobic finishing agent were introduced to create the functional membranes by blade coating.With the increase of FAC concentration,the porosity of the membrane decreased,which resulted in a decrease in WVTR.And the pore size of the membrane did not change significantly,so hydrostatic pressure is mainly affected by the surface wettability,showing a tendency to increase first and then decreased.After the regulating of FAC concentrations,the membranes modified with 2 wt% was selected.Regulating the addition amount of Ti O2 NPs,the UV531 and FAC concentration,the multiple functionalities of the modified PAN/PU/Ti O2 were systemically optimized: robust tensile strength(14.6 MPa),modest waterproofness(62 k Pa),moisture breathability(12.9 kg m-2 d-1)and good ultraviolet protection factor of 1485.The equilibrium among the multifunction of the as-prepared membranes indicated their diverse possibilities can be used in various applications,including highaltitude garments,protective clothing,covering materials,self-cleaning materials,and other medical products. |
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