预辐射接枝四氟乙烯-乙烯共聚物湿敏膜的制备及特性研究

利用2 MeV电子加速器, 在常温下采用预辐照引发接枝的方法, 在四氟乙烯-乙烯共聚物(ETFE)上接枝丙烯酸(AA)和对苯乙烯磺酸钠(SSS), 制备了一种含羧酸基团和磺酸基团的接枝膜. 傅里叶变换红外光谱(FTIR)分析结果证明了磺酸基团和羧酸基团的成功引入, 并对接枝膜的热力学和化学特性进行了研究. 结果表明, 随着接枝率的增加, 接枝膜的结晶度逐渐降低, 接触角逐渐减小, 接枝膜的亲水性逐渐增强. 利用制备的接枝膜构建了电阻型湿度传感器, 并测定了传感器的电学特性. 在相对湿度(RH)从5%变化到98%时, 传感器电阻线性变化范围接近4个数量级, 具有响应速度快(吸附<1 min, 解吸<2 min), 湿滞小(<2%RH)的特点.

Preparation and Properties of the ETFE Humidity Sensing Films by Pre-irradiation Grafting Method

Acrylic acid(AA) and sodium styrene sulfonate(SSS) were grafted onto poly(ethylene-co-tetrafluoroethylene)(ETFE) film by pre-irradiation technique using electronic beam from a 2 MeV accelerator at room temperature.A humidity sensing film with strong acid and weak acid groups was prepared.Infrared spectroscopy analysis of the grafted film confirmed the existence of sulfonate and carboxylic acid groups in the grafted film.Thermal and chemical properties of the grafted films were investigated.The crystallinity and static contact angle of the grafted films decrease,meanwhile the hydrophilicity of the grafted films increases with increasing grafting yield.A resistive-type humidity sensor was prepared using the grafted film,and its electrical response to humidity was examined.The resistive of the sensor changes linearly by 4 orders of magnitude over almost whole humidity range(5%-98%RH).Furthermore,the sensor exhibits a quick response(absorption: less than 1 min;desorption: less than 2 min) and small hysteresis(less than 2%RH).