聚N-异丙基丙烯酰胺/聚氨酯梯度复合膜的温敏亲-疏水性及透湿性

为解决智能防水透湿膜材料温敏响应度低和温敏透湿通量不足的问题,将聚N-异丙基丙烯酰胺(PNIPAM)通过涂覆的方式复合于具有多级孔结构的聚氨酯(PU)梯度膜上,通过调控PNIPAM的涂覆量制备PNIPAM/PU梯度复合膜,并对复合膜的结构、温敏亲-疏水性和温敏湿热传递性进行研究。结果表明:PNIPAM温敏层的构筑不仅没有改变膜材料的多级孔结构,还赋予了梯度复合膜材料温敏亲-疏水转变性能,即低于转变温度(30 ℃)时表现为亲水性,高于转变温度时表现为疏水性;PNIPAM的引入提高了梯度复合膜的温敏透湿通量,50 ℃时PNIPAM质量分数为6%的梯度复合膜的透湿率为6 398.3 g/(m²·24 h),高于PU膜的透湿率(4 843.4 g/(m²·24 h)),且PNIPAM的质量分数越高,梯度复合膜的溶胀性随温度的增加下降越显著。

Thermo-sensitive hydrophilic-hydrophobic transition and moisture permeability of poly-N-isopropylacrylamide/polyurethane gradient composite membrane

To improve the temperature-sensitivity and moisture permeability of intelligent waterproof and moisture permeable membrane, poly-N-isopropylacrylamide (PNIPAM) was coated on hierarchical pore polyurethane (PU) membranes and PNIPAM/PU gradient composite membranes were prepared by adjusting the mass fraction of PNIPAM. Structure, thermo-sensitive hydrophilic-hydrophobic and thermo-sensitive moisture permeability were investigated. The results show that the construction of PNIPAM does not change the hierarchical pore structure. It has thermo-sensitive hydrophilic-hydrophobic transition properties, exhibiting hydrophilicity when temperature below the transition temperature (30 ℃), and hydrophobicity when temperature above this temperature. Meanwhile, the introduction of PNIPAM improves thermo-sensitive moisture permeability, from 4 843.4 g/(m²·24 h) of PU to 6 398.3 g/(m²·24 h) of PNIPAM/PU gradient composite membrane at 50 ℃ when mass fraction of PNIPAM is 6%. It was also found that the higher the content of PNIPAM, the more significant decrease in swelling property with the temperature increase.