Preparation and characterization of polyurethane /polyvinylidene fluoride waterproof permeable composite fabric

Polyurethane /polyvinylidene fluoride( PU /PVDF) nanofibrous membranes were successfully prepared by electrospinning, and the optimized preparation process of PU / PVDF membranes was explored. After that,the membrane and polyester cloth were pressed together by spraying one-component polyurethane adhesive of optimum concentration through electrospinning,and the resulting composite's waterproofness,permeability and other performances were investigated. The results showed that the optimum process parameters for electrospinning of PU / PVDF membrane were: the mass ratio of solution of PU / PVDF of 7 /3,voltage of 14 kV,traveling distance of 10 cm,mas fraction of 12% and volume ratio of component solvents of DMF / acetone of 4 /6. The distribution of adhesive appeared as micron spot or block on the surface of polyester cloth. In addition,its cohesiveness and breathability were better when the mass fraction of adhesive was about 40%. With the increase of thickness of PU membranes,the waterproof values,permeability and breaking elongation of the composite fabric were worse,while its breaking strength was better,and it had a similar moisture resistance to PU / PVDF membranes.