Preparation and properties of waterborne polyurethane/polyaniline codoped with dodecyl benzene sulfonic acid and hydrochloric acid blends

A conductive poly(aniline codoped with dodecyl benzene sulfonic acid and hydrochloric acid) [PANI-D/H, yield: 32.2%, intrinsic viscosity ([eta]): 1.39 dL/g, electrical conductivity: 7.3 S/cm] was synthesized by chemical oxidative polymerization from aniline-dodecylbenzene sulfonic acid salt (A-DS)/aniline-hydrochloric acid salt (A-HS) (6/4M ratio) in an aqueous system. Waterborne polyurethane (WBPU) dispersion obtained from isophorone diisocyanate/poly(tetramethylene oxide)glycol/dimethylol propionic acid/ethylene diamine/triethylene amine/water was used as a matrix polymer. The blend films of WBPU/PANI-D/H with various weight ratios (99.9/0.1-25/75) were prepared by solution blending/casting. Effect of PANI-D/H content on the mechanical property, dynamic mechanical property, hardness, electrical conductivity, and antistaticity of WBPU/PANI-D/H blend films was investigated. The dynamic storage modulus and initial tensile modulus increased with increasing PANI-D/H content up to 1 wt %, and then it was significantly decreased about the content. With increasing PANI-D/H content, the glass transition temperature of soft segment (T-gs) and hard segment (T-gh) of WBPU/PANI-D/H blend films were shifted a bit to lower the temperature. The tensile strength and hardness of WBPU/PANI-D/H blend films increased a little with increasing PANI-D/H content up to 0.5 wt %, and then it was dramatically decreased over the content. The elongation at break of WBPU/PANI-D/H decreased with an increase in PANI-D/H content. From these results, it was concluded that 0.5-1 wt % of PANI-D/H was the critical concentration to reinforce those various properties of WBPU/PANI-D/H blend films prepared in this study. The electrical conductivity of WBPU/ultrasonic treated PANI-D/H (particle size: 0.7 mum) blend films prepared here increased from 4.0 X 10(-7) to 0.33 S/cm with increasing PANI-D/H content from 0.1 to 75 wt %. The antistatic half-life time (tau(1/2)) of pure WBPU film was about 110 s. However, those of WBPU/ultrasonic treated PANI-D/H blend films (tau(1/2): 8.2-0.1 s, and almost 0 s) were found to decrease exponentially with increasing PANI-D/H content (0.1-9 wt %, and above 9 wt %). (C) 2004 Wiley Periodicals, Inc.