CB-g-WPU/WPU复合材料的制备与气敏响应性能

Preparation and Vapor Sensing of CB-g-WPU/WPU Composite

通过对导电填料炭黑(CB)进行官能化,在CB表面引入羧基官能团,利用CB表面的羧基等活性官能团与端异氰酸酯基聚氨酯预聚物反应得炭黑接枝水性聚氨酯(CB-g-WPU),采用乳液共混法制备得CB-g-WPU/WPU气敏导电复合材料,并对CB-g-WPU/WPU复合材料的气敏响应行为进行了研究。X射线光电能谱(XPS)、傅立叶变换红外光谱(FTIR)、热重分析(TGA)等分析结果表明聚氨酯接枝到了炭黑表面;SEM分析表明,炭黑经过接枝改性后均匀分散在基体WPU中。该法制备的CB-g-WPU/WPU复合材料逾渗值低、气敏响应度大、响应范围广,是一种综合性能优异的气敏导电复合材料。

Carboxyl groups were introduced onto the carbon black （CB） surface by 4, 4, -azobis （4- cyanopentaoic acid） （ACPA）, then PU prepolymer was grafted onto the surface of CB by direct condensation polymerization between the terminal NCO of PU prepolymer and carboxyl groups on CB surface. The composite of waterborne PU （WPU） filled with CB having high dispersibility and stability was successfully obtained by the use of WPU-g-CB. The vaPor sensing of the prepared CB-g-WPU/WPU was studied. The results of FT IR and TGA showed that PU prepolymer was successfully grafted onto the surface of CB, and the result of SEM analysis showed CB dispersed well in WPU after the graft modification. Besides the low percolation threshold, the composites were quite sensitive to organic solvent vapors regardless of their polarities as characterized by the drastic changes in conductivity. It was seemed that CB-g-WPU/WPU composite could be used as a promising gas sensing material.