SYNTHESIS AND PROPERTIES OF POLYETHERURETHANE PENDANT WITH AZO-DYE BYN-SUBSTITUTION

Polyurethane elastomers pendant with ate-dye were prepared by N-substi tution by a two-step process. First, the polymer is metalated by sodiu m hydride, and then the prepared urethane polyanion is treated with om ega-bromohexyloxyphenyl-p-nitroazobenzene. The polyurethanes were char acterized by NMR, UV, FTIR, GPC, DMA, X-ray, and polarized optical mic roscopy. The reaction caused cleavage of some allophanate bond degrada tion and narrower MW distribution. As the substitution degree increase d, the hydrogen bonds in polyurethane diminished and phase mixing with ate-dye was enhanced. Photoisomerization of the pendant ate-dye was a lso observed. (C) 1996 John Wiley & Sons, Inc.