炭黑/水性聚氨酯复合材料的制备与气敏性能

Preparation and vapor sensitivity of carbon black/waterborne polyurethane composites

以环境友好的水性聚氨酯(WPU)为基体,以炭黑(CB)为导电填料,采用乳液共混法制备了低逾渗值的炭黑/水性聚氨酯(CB/WPU)导电复合材料,研究其在不同有机蒸汽环境中的气敏响应性能.研究发现,CB/WPU复合材料对有机溶剂蒸汽的气敏响应速率快,当复合材料置于饱和有机溶剂蒸汽环境时,电阻迅速增大,60s左右电阻即可达到最大值,然后趋于稳定值;当复合材料转移到干燥空气中时,电阻急剧下降,直到回复初始电阻值.另外,CB/WPU复合材料具有广谱的气敏响应特征,表现为对极性和非极性有机溶剂蒸汽均呈现较大的气敏响应度.从而表明,CB/WPU复合材料是一种气敏响应度大、响应速度快、具有广谱气敏响应性能等综合性能优异的气敏导电复合材料.

The carbon black/waterborne polyurethane （CB/WPU） composites with low percolation threshold were prepared by adding carbon black to waterborne polyurethane latex and the vapor sensing response of the electric resistance of the composites against saturated solvent vapors was investigated. It was found that the CB/WPU composites were sensitive to organic solvent vapors regardless of their polarities as characterized by the drastic changes in conductivity. The resistance of the CB/WPU composites drastically increased to 103-106 times of the initial resistance （about 60 s） when the composite was transferred from dry air to saturated vapor. It also returned quickly to their initial value when they were transferred to dry air. It seems that CB/WPU composite can be used as a promising gas sensing material with high electrical responsibility, stability and reproducibility.