Polyurethane encapsulated carbon black particles and enhanced properties of water polyurethane composite films

Polyurethane-encapsulated carbon black (ECB) particles were synthesized successfully through a facile method by encapsulating carbon black (CB) particles in the presence of an amphiphilic isocyanate-terminated polyurethane pre-polymer. Fourier transform infrared spectroscopy demonstrated the existence, of a polyurethane layer on the surface of encapsulated CB, and thermo-gravimetric analysis indicated the encapsulation percentage reached 15.77 wt.%. The results of dynamic light scattering, transmission electron microscopy, and UV-vis spectroscopy analyses revealed that the ECBs exhibited better dispersibility and stability in water in comparison with the dispersant-dispersed carbon black (DCB) prepared by simply dispersing CB particles using a polymer super-dispersant. In particular, scanning electron microscope observation of PUB/ECB composite films obtained by blending ECB particles with a waterborne polyurethane binder (PUB), showed enhanced dispersibility and compatibility of the ECBs in the PUB matrix. Therefore, as test results demonstrated, PUB/ECB composite films showed better mechanical, water resistance, and color properties compared with those of PUB/DCB composite film. It is expected that this effective encapsulation method for preparing functional CB dispersions will be used to make waterborne coatings in the leather and textile finishing fields. (C) 2016 Elsevier B.V. All rights reserved.