Synthesis and characterization of yellow water-borne polyurethane using a diol colorant as extender

A novel and facile method toward a series of yellow water-borne polyurethane was developed by using an intrinsically colored diol in this paper. The yellow aqueous dispersion PCLD-HENA-PU was synthesized based on isophorone diisocyanate (IPDI), polycaprolactonediol (PCLD) and 2,2-dimethylol propionic acid (DMPA) using a yellow diol N,N-bis(2-hydroxyethyl)-4-nitroaniline (HENA) as a chain extender. Due to the complete reaction of OH group in colorant HENA with NCO group in diisocyanate, a series of stable yellow polyurethanes could be obtained conveniently and easily. The structure of PCLD-HENA-PUs was confirmed by means of Fourier transform infrared spectroscopy. The UV-visible absorption analysis showed a blue shift effect of about 7 nm when HENA was blocked into polyurethane chain. The absorption intensity of PCLD-HENA-PUs increased with increasing HENA content. It was found that the tensile strength enhanced from 8.6 to 19.6 MPa with HENA content increased from 0 to 18.0%, while the extensibility decreased from 449 to 300%. The thermal gravimetric analysis presented that the initial decompose temperature began from about 250 degrees C, and had a little increase with increasing the HENA content. (C) 2009 Xing Yuan Zhang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.