A study of fluorescent-dye polyurethane ionomer

The reaction of toluene diisocyanate with 4-hydroxycoumarin or 7-hydroxycou rmarin or dicumarol and other additives to form the structure of fluorescen t-dye polyurethane ionomer, which has been successfully synthesized at our laboratary, is demonstrated by Fourier transform infrared spectra. The fluo rescence study of coumarins present in N,N-dimethyl acetamide indicates tha t these coumarins form aggregations and exhibit fluorescence at around 304n m. The experimental results show that the surface tension of 4-hydroxycouma rin or 7-hydroxycoumarin in N,N-dimethylacetamide appears to decrease with increasing concentration of 4-hydroxycoumarin or 7-hydroxycourmarin. On the other hand, the surface tension of dicumarol in N,N-dimethylacetamide incr eases with increasing hydrophilic groups of dicumarol adsorbed at the surfa ce of N,N-dimethylacetamide become even more ordered. For fluorescent-dye p olyurethan ionomer in aqueous solution, the number average particle sizes a re seen to increase with an increase of coumarin concentration. Since the i ntermolecular interaction between hydrophilic groups of fluorescent-dye pol yurethane ionomer molecules are considered to be increased significantly. T his may be why the number average particle size becomes large. For self-cur ed films made by fluorescent dye polyurethane ionomer, the tensile strength is seen to increase with increasing concentration of coumarin, as a result of increased crosslinking resulting from increased hydrophilic groups of c oumarins attached to the backbone of the ionomer molecules. The elongation of self-cured film made by dicumarol-based polyurethane ionomer, on the oth er hand, decreases with increasing concentration of dicumarol. Copyright (C ) 2000 John Wiley & Sons, Ltd.