以2,4-二氨基苯磺酸钠为亲水扩链剂,通过预聚体法合成了水性磺酸盐型聚氨酯分散液(SW-PU).并在FeCl3氧化剂的作用下,采用原位化学氧化聚合法制备了系列不同聚吡咯(PPy)质量浓度的水性聚氨酯/聚吡咯(SWPU/PPy)分散液,并通过溶液浇铸法制得系列复合导电薄膜.随着 PPy 的引入, SWPU分子与 PPy 分子间发生反应,SWPU/PPy 的高温热稳定性亦得到提高.随着吡咯质量浓度的增加,SWPU/PPy乳胶粒的粒径增加.经适量PPy改性后,PPy可在SWPU 胶束内部和表面均匀分布,形成大小均匀的纳米复合粒子;SWPU/PPy复合膜表面粗糙度下降,SWPU与PPy间具有较好的相容性.但当PPy质量浓度高于15%时,开始呈现一定的颗粒形貌,且薄膜表面粗糙度随着 PPy 浓度的增加明显增加;当PPy质量浓度高于30%时,胶膜表面颗粒形貌明显,胶膜表面主要由 PPy 组成.复合薄膜的渗透阈值介于质量浓度为1.5%~2%之间,当Py质量浓度为30%时,电导率高达1 S/cm.
Waterborne sulfonate polyurethane dispersion (SWPU ) was prepared through prepolymerization method with 2,4-diamino-benzene sulfonic acid sodium salt (DASS)as hydrophilic chain extender.Then with the assistant of FeCl3 oxidant,SWPU/polypyrrole (SWPU/PPy)dispersions with different mass concentration of polypyrrole (PPy)were prepared by in situ chemical oxidative polymerization,and the corresponding conductive composite films were obtained by solution casting method.With the introduction of PPy,new urea bond was formed through the reaction between SWPU and PPy.The high-temperature thermal stability was also improved.With the increase of pyrrole content,the average particle size of SWPU/PPy dispersions increased.Significant aggregation was detected among SWPU colloidal particles,and the SWPU/PPy particles disperse well. With the addition of certain amount of PPy,PPy was able to distribute uniformly across SWPU colloidal particles,and homogeneous nanocomposites were therefore formed;in addition,the surface roughness decreased, and good compatibility between SWPU and PPy was detected.However,particular morphology appeared when the mass concentration of PPy was higher than 1 5%,and surface roughness increased with increasing the mass concentration of PPy.Particular morphology became apparent when the mass concentration of PPy was 30%, the surface of SWPU/PPy was mainly composed of PPy.The percolation threshold of SWPU/PPy films was in the range of 1.5%-2%,and the surface conductivity reached 1 S/cm when PPy content was 30%.