Fabrication Of Antibacterial Polyurethane Nanofibrous Membranes With Waterproof-breathable Performance

Waterproof and breathable membranes as the core functional layer of waterproof-breathable fabric,which has outstanding waterproofness,moisture permeable properties,windproofness and warmth retention properties,this membranes can prevent the penetration of sleet while allowing moisture vapor transforming from wearers that can provide effective comfort for human beings.Besides the secretion of sweat and sebaceous glands breeds a lot of microorganisms,causing harm to the human body,the functional membranes for antibacterial treatment is of great significance.Sympatex film on the market has outstanding waterproofness but smaller moisture flux because of its closed channel.Gore-tex's PTFE film has excellent waterproofness and moisture permeability,but has complicated manufacturing processes,high cost and degradation is difficult after discarding.Therefore,the development of microporous membrane with high water resistance,high moisture flux,simple manufacturing process,low cost,environmentally friendly and multifunction(such as antibacterial,antistatic,far-infrared etc.)is an important trend of waterproof-breathable membranes materials.Electrospun membranes have the advantages of high porosity and small pore size,simple formation process,wide adaptability of raw materials,therefore,electrospinning is a common method to prepare waterproof-breathable nanofibrous membranes.Choosing polyurethane(PU)as raw material,fluorinated polyurethane(FPU)and lithium chloride(LiCl)as additives,N,Ndimethylacetamide(DMAc)as solvent,and organic antibacterial agent(SCJ)as antibacterial finishing agent,antibacterial and waterproof-breathable nanofibrous membranes was fabricated through electrospinning followed by antibacterial treatment.Then,studying their morphology,antibacterial properties,mechanical properties and waterproof-moisture permeability.The goal is to obtain waterproof-breathable membranes with excellent comprehensive performance.Among the spinning raw materials,polyurethane(PU)as an environmentally friendly raw materials,which has excellent abrasion resistance,elasticity,thermal stability and other characteristics that can increase the material's mechanical properties.In PU elastomer raw materials,fibrous membrane prepared by PU-4394(denoted by PU-A)with low hydrostatic pressure but high water vapor transmittion(WVT)due to its less bonding structure.While PU-9370AU(denoted by PU-B)fibrous membrane has opposite characteristics.Therefore,this paper selects two kinds of PU blends to prepare fibrous membranes with high water resistance pressure and moisture permeability.FPU was added to the solution to improve the hydrophobicity of fibrous membranes.LiCl adjusts the structure of the fibrous membranes.SCJ imparts the fibrous membranes excellent antibacterial properties,protecting the body from bacterial infection.In this study,in order to adjust the morphology of fibrous membranes,we changed the concentrations of PU-A(12wt%,14wt%,16wt%,18wt%)solution,FPU(0wt%,1wt%,2wt%,3wt%)and LiCl(0wt%,0.0015wt%,0.003wt%,0.0045wt%).When the concentration of PU-A is 16wt%,beads all disappeared and fibers evenly distributed.When the concentration of FPU is 2wt%,fibrous membranes has optimum hydrophobicity.Finally,when the concentration of LiCl is 0.003wt%,fiber diameter is fine and spinning without spraying.Similarly,the concentration of PUB,FPU and LiCl were 12wt%,2wt% and 0.003wt%,respectively.In order to study the effect of two kinds PU solutions on the structure and properties of the fibrous membranes,the nozzle ratio of PU-A to PU-B was adjusted to 5/0,3/2,2/3,0/5.With the increasing of PU-B content,the fibers become more adhered,fiber diameter,pore size and porosity were all reduced,the tensile strength of the fibrous membrane increased,the hydrostatic pressure increased but water vapor transmission decreased.The results showed that the optimal ratio of PUA to PU-B is 3/2.Further to optimize the structure and properties of fibrous membrane by changing the thicknesses(10?m,25?m,40?m,55?m)of membranes.The experimental results showed that hydrostatic pressure increased and water vapor transmission decreased,thickness of 40?m is the best choice.Finally,studying the concentrations of SCJ(0wt%,1wt%,3wt%,5wt%,7wt%)whther has effect on the antibacterial rate,structure and properties of fibrous membrane,the results showed concentration of 3wt% is more better than others.In summary,the fibrous membrane fabricated in this experiment was endowed with high antibacterial rate of 99.3%,outstanding hydrostatic pressure of 75.9 kPa and water vapor transmittion rate of 11.2 kg·m-2·d-1,modest air permeability of 6.5 mm·s-1,robust tensile stress of 11.3 MPa and good breaking elongation of 389.9%.Therefore,these properties suggest the fibrous membrane as a promising candidate for a variety of potential applications,such as protective clothing,filter and surgical clothing.