| The aim of current study is to use Chitosan（CS）and polyvinyl alcohol（PVA）with antibacterial and polar performances as polymer system to prepare CS/PVA blend porous membrane via non-solvent induced phase separation（NIPS）,composite with non-woven fabrics（NWFs）,deposition of halloysite nanotubes（HNTs）,and addition of polyethylene glycol（PEG）so as to inverstigate the transmission resistence-efficiency trade-off effect of polymer porous membrane in the application of air filtration and wound dressing.Simultaneously,the structural control of membrane,transmission resistence-efficiency trade-off effect,and antibacterial performance were explored to lay the foundation for its applications in air filtration and wound dressing.Firstly,the compatibility of CS/PVA blend system was studied by Schneier theory and experimental methods.Results showed that,CS/PVA casting solution was compatible when the mass ratio of CS and PVA was≤4/6 for CS with a deacetylation degree of 85.4%.The experimental results are in good consistent with those obtained from theoretical calculation.CS and PVA as polymers,adipic acid aqueous solution as solvent,and saturated sodium sulfate aqueous solution as coagulation bath were employed to prepare CS/PVA blend porous membranes via NIPS.The structural controls from casting solution thermodynamics（mass ratio）and membrane formation kinetics（coagulation bath temperature）,and the main performances of air filtration were investigated.Results showed that the average pore size and surface porosity of the CS/PVA blend porous membrane obtained at CS/PVA=3/7 and the coagulation bath temperature of 20°C were 0.495μm and 17.1%,respectively.The corresponding filtration efficiency and pressure drop were 95.6%and 633.5 Pa,respectively.Moreover,the antibacterial rates against E.coli and S.aureus were 94.8%and 91.3%,respectively.Further,HNTs@CS/PVA/NWF composite membrane was prepared by a modified immersion coating and a surface deposition of HNTs in order to reduce the pressure drop and elevate the filtration efficiency of CS/PVA blend porous membrane.The influences of polymer coating and HNTs loading on membrane structure and air filtration performance were investigated.Results showed that the average pore size of composite membrane with the polymer coating of 12.9 g m-2 and HNTs loading of 1.8g m-2 was 2.22μm.Its filtration efficiency and pressure drop were 96.8%and 144 Pa,respectively.Moreover,the antibacterial rates against E.coli and S.aureus were 99.6%and 99.1%,respectively.The composite membrane exhibited high filtration efficiency,low pressure drop,and excellent antibacterial performance,which fully meets the main performance indicators of an air filtration material.On account of the transmission resistence-efficiency trade-off effect of polymer porous membrane in the application of wound dressing,PEG as additive was added into polymer casting solution to tailor the dense skin structure of CS/PVA blend porous membrane and then improve the wound dressing performances.Results showed that the average pore size and surface porosity of the CS/PVA/PEG blend porous membrane with PEG（2 k Da and 3 wt%）were 0.109μm and 5.0%,respectively.Its water uptake and weight loss ratio were 638.2%and 13.5%,respectively.The water vapor transmission rate and oxygen permeability were 2177 g m-2 day-1 and 6.0 mg L-1,respectively.The antibacterial rates against E.coli and S.aureus were 95.9%and 92.6%,respectively.At the same time,the relative proliferation rate of mouse fibroblasts（L929）was more than 70%.In short,the blend porous membrane shows ideal performances for wound dressing. |
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