丙烯酸水溶液聚合法制备PTFE/PAA/Nafion膜及其性能

采用廉价的多孔聚四氟乙烯(PTFE)膜作为基底, 用少量的Nafion与PTFE膜复合可制备低成本的质子膜. 但疏水性的PTFE膜与亲水性的Nafion膜结合性不佳. 基于此, 本文对疏水性的PTFE膜材料表面进行设计, 先采用丙烯酸对疏水性的PTFE膜表面进行亲水性改性, 再喷涂亲水性Nafion膜, 完成低成本PTFE/PAA/Nafion膜的制备. 实验结果表明， 改性前的PTFE膜材料水接触角为150°, 改性后的膜接触角变为55.6°, 亲水性大幅上升, 膜的机械强度和尺寸稳定性(断裂强度为25.2 MPa, 80 ℃下的溶胀率为11.9%)均优于Nafion117膜, 而 Nafion用量则节省了60%. PTFE/PAA/Nafion膜具有高质子导通率(80 ℃下达到131.9 mS/cm), 接近于Nafion117膜, 最大功率密度可以达到404.2 mW/cm².

Preparation of PTFE/PAA/Nafion Composite Membrane by Aqueous Polymerization of Acrylic Acid and Its Properties

Low cost proton membrane can be prepared by using cheap polytetrafluoroethylene as substrate and a small amount of Nafion film and polytetrafluoroethylene（PTFE） film. But hydrophobic PTFE film and hydrophilic Nafion do not combine well. In this paper， the surface of hydrophobic PTFE material was designed. Firstly， the hydrophobic PTFE film surface was modified with acrylic acid， and then sprayed with hydrophilic Nafion film to complete the preparation of low-cost PTFE/PAA/Nafion film. The results showed that the water contact angle of PTFE material before modification was 150°， and that of composite film after modification was 55.6°. The mechanical strength and size stability（fracture strength of 25.2 MPa， swelling rate of 11.9% at 80 ℃） of the composite film were better than those of Nafion117 film， while the amount of Nafion was reduced by 60%. The composite membrane has high proton conductivity（up to 131.9 mS/cm at 80 ℃）， which is close to that of Nafion117 film， and the maximum power density can reach 404.2 mW/cm².