Waterproof moisture-permeable films with excellent water resistance and breathability are employed in functional clothing to improve the comfort of wearers. Although polytetrafluoroethylene microporous membranes exhibit outstanding water resistance and moisture permeability, their application is limited because of the environmental impact of fluorinated compounds. For this reason, herein, we aimed to improve the hydrophobicity of thermoplastic polyurethane (TPU) microporous membranes while maintaining their moisture permeability. We employed silane coupling agents to modify nanosilica particles, which were then coated on TPU microporous membranes to enhance their waterproof performance. The optimized parameters for the modification process of silica nanoparticles are γ-aminopropyltriethoxysilane and hexadecyltrimethoxysilane (silane coupling agents) concentrations of 8% relative to the mass of silica, a modification time of 2 h, and a temperature of 70°C. The water contact angle of the particles modified under these conditions reached 138.58°. The modified SiO2 particles were used to treat the TPU film, with an optimal mass fraction of the modified silica of 3% and a modification time of 4 h. The water vapor transmission of the modified TPU film was 5661.92 g/(m2·24 h), with enhanced hydrophobicity, and its water absorption rate was 12.41%, which is 16.49% lower than before modification. Additionally, under simulated heavy rain conditions, the water absorption rate of the composite fabric with modified TPU film was lower by 14.7% than that of the composite fabric with unmodified film.
Gaoshuo Jiang,Liqiang Luo,Lu Tan,Jinliang Wang,Shenxiang Zhang,Feng Zhang,Jian Jin
Superhydrophobic membranes with extreme liquid water repellency property are good candidates for waterproof and breathable application. Different from the mostly used strategies through either mixing or postmodifying base membranes with perfluorinated compounds, we report in this work a facile methodology to fabricate superhydrophobic microporous membranes made up of pure poly(vinylidene fluoride) (PVDF) via a high-humidity induced electrospinning process. The superhydrophobic property of the PVDF microporous membrane is contributed by its special microsphere-fiber interpenetrated rough structure. The effective pore size and porosity of the PVDF membranes could be well tuned by simply adjusting the PVDF concentrations in polymer solutions. The membrane with optimized superhydrophobicity and porous structure exhibits improved waterproof and breathable performance with hydrostatic pressure up to 62 kPa, water vapor transmission rate (WVT rate) of 10.6 kg m–2 d–1, and simultaneously outstanding windproof performance with air permeability up to 1.3 mm s–1. Our work represents a rather simple and perfluorinated-free strategy for fabricating superhydrophobic microporous membranes, which matches well with the environmentally friendly requirement from the viewpoint of practical application.
危险品化学品经营许可证（带存储）