Morphology and Properties of Waterborne Polyurethane/CNT Nanocomposite Adhesives with Various Carboxyl Acid Salt Groups

Three series of waterborne polyurethane (WBPU)/carbon nanotube (CNT) nanocomposites were prepared, and their morphology and properties with various 2,2-dimethylol propionic acid (DMPA) and CNT contents were investigated. The CNTs were homogeneously dispersed up to the optimum content in WBPU/CNT nanocomposite films. The degree of homogeneous CNT dispersion increased with increasing DMPA content in WBPU/CNT nanocomposite films. The optimum CNT content showed maximum tensile strength, Young's modulus and adhesive strength of WBPU/CNT nanocomposite film. The optimum CNT contents for WBPU/CNT nanocomposite samples containing 3.61, 5.16 and 5.86 wt% DMPA were about 0.50, 1.00 and 1.50 wt%, respectively. The WBPU/CNT nanocomposite adhesive showed higher adhesive strength at moderately high temperatures (40/60/80/100 degrees C) compared to conventional WBPU. The highest adhesive strength at moderately high temperatures was found with 5.86 wt% DMPA and 1.5 wt% CNT content. (C) Koninklijke Brill NV, Leiden, 2009