Preparation And Characterization Of Waterproof And Breathable Composite Nanofiber Materials

Waterproof and breathable membrane is a kind of functional membrane material with waterproof performance and moisture permeability.It can be combined with fabric to prepare functional clothing and applied in some severe rain and snow or hot and humid environment,which can not only ensure the protection performance of human body,but also provide comfort for the wearer.Electrospinning is one of the most commonly used technologies for the preparation of nanofiber membrane,and the prepared fiber membrane has the advantages of small diameter,small pore diameter and high porosity,which can be used for the design and development of functional waterproof and breathable materials.In this paper,an electrospinning technology suitable for polyurethane material was proposed.Based on the relationship between the structure of polyurethane fiber membrane and the moisture permeability,hydrophobic modified silica?F-Si O₂?and polyacrylonitrile?PAN?were introduced.Combined with the electrospinning technology,the composite fibrous membrane material with moisture permeability was optimized.The research content of this topic was summarized as follows:Using polycarbonate diols?PCDL?as soft segments,isoflurone diisocyanate?IPDI?as hard segment,isophorone diamine?IPDA?as chain extender,and polyurethane?PU?was synthesized.The average molecular weight?Mn?of PU was 63482,the weight average molecular weight?Mw?was 102182,and the PU with large molecular weight had excellent spinnability.Then,the electrospinning of PU was carried out,and the nanofibers prepared by PU at 13 wt%were tested and analyzed.The nanofibers were easy to be prepared,and the hydrophobic angle and moisture permeability of PU fiber membrane and homogeneous membrane were compared.The results showed that the moisture permeability of PU homogeneous membrane was 1.0976 kg/m²,the hydrophobic angle was 90.3°,and the moisture permeability of fiber membrane was 8.12 kg/m^-2,the hydrophobic angle was 118°,which was more advantageous in the preparation of waterproof and breathable functional materials.F-Si O₂was prepared by hydrophobic modification of silicon?Si O₂?dioxide with 1H,1H,2H,2H-perfluoroedecyl triethoxysilane,and then it was added into PU spinning solution to mix evenly.F-Si O₂has excellent dispersible stability,and PU/F-Si O₂composite fibrous membrane was prepared by electrostatic spinning technology.The addition of hydrophobic F-Si O₂increased the surface roughness and hydrophobic angle of PU/F-Si O₂composite fibrous membrane.When the addition of F-Si O₂was 3 wt%,the maximum moisture permeability of the fiber membrane reached 10.1 kg/m²,and the addition of F-Si O₂was 5 wt%,the hydrophobic angle of the composite fibrous membrane reached130°,and the hydrophobic angle of the surface of the fiber membrane changes little during the process of external force stretching,which was basically not affected by the external mechanical force.The fiber membrane maintained excellent and stable hydrophobic performance.On the basis study of PU/F-Si O₂composite fibrous membrane,PAN material was introduced,PU/F-Si O₂and PAN composite fibrous membrane was prepared by the electrospinning process of two parallel nozzles.The moisture permeability of the composite fibrous membrane was improved by the addition of PAN.When the feeding speed ratio of?PU/F-Si O₂?/PAN=1.2,the moisture permeability of the composite fibrous membrane was improved to 10.3 kg.m^-2.d^-1.The waterproof and moisture permeability of?PU/F-Si O₂?/PAN composite fibrous membrane were excellent.Based on the research of composite fibrous membrane material with water and moisture permeability,the double-layer fiber membrane material with unidirectional moisture conductivity was further researched and developed.PAN fiber membrane was selected as the hydrophilic layer structure,and polyethylene pyrrolidone?PVP?with better hydrophilic performance was added for mixed spinning to further improve the hydrophilicity and wettability of PAN fiber membrane.The addition amount of PVP was 2wt%,the wicking height of PAN/PVP fiber membrane could reach 9.8 cm,and wetting the entire fiber membrane surface within 1 s,then select PU fiber membrane as hydrophobic layer,and use dopamine solution to improve the wettability of the surface,using electrostatic spinning process to composite PAN/PVP fiber membrane and dopamine treated PU fiber membrane to prepare a double-layer structure composite fibrous membrane,and investigating the effect of unidirectional wet performance on the thickness ratio of PAN/PVP fiber membrane and PU fiber membrane,the liquid moisture management tester?MMT?test showed that when?PAN/PVP?/PU thickness ratio was 2:1,The wet coefficient?AOTI?reaches 967%,and water can be transferred from the PU fiber membrane interface to the PAN/PVP layer,achieving a unidirectional wet effect.