In situ preparation and resistance properties of waterborne cationic polyurethanes/polypyrrole conductive materials

A series of waterborne cationic polyurethanes dispersions(CWPU) was prepared through prepolymerization method by reacting polyethylene glycol(PEG1000) and isophorone diisocyanate(IPDI) with N-methyl diethanol amine(MDEA) as chain extender.Then FeCl3 was employed as oxidant,therefore CWPU/polypyrrole(CWPU/PPy) conductive composite was prepared by in situ chemical oxidative polymerization of pyrrole(Py) in CWPU dispersions.Fourier infrared spectra demonstrated the presence of hydrogen-bonding interactions between CWPU and PPy.The average particle size of CWPU/PPy increased from 10.61 to 30.29nm compared with pure PU,and corresponding size distribution decreased from 0.850 to 0.346.It was also found that CWPU colloidal particles were uniformly encapsulating by PPy,displaying as spherical morphology,and no aggregation among particles was detected among particles.Results also showed that the surface resistivity of CWPU/PPy composite film surface decreased to 20Ω·cm when Py concentration was 20%,reaction temperature was 40℃,reaction time was 2h and n(FeCl3)/n(Py)=2.0.