| Summary: | 碩士 === 中國文化大學 === 應用化學研究所 === 87 === In recent years, owing to environmental protection becoming increasingly important, the organic solvent used as a diluent for the resin is gradually replaced by water, a nonpollutant solvent. For this reason, the development of water-based polyurethane (PU) resin becomes important at present.
The reaction of toluene diisocyanates with 4-hydroxycoumarin or 7-hydroxycoumarin or dicumarol and other additives to form the structure of fluorescent-dye polyurethane ionomer has been proven by FT-IR spectra. The experimental results show that the surface tensions of 4-hydroxycoumarin or 7-hydroxycoumarin solution appears to decrease with increasing the concentration of 4-hydroxycoumarin or 7-hydroxycoumarin. On the other hand, the surface tension of dicumarol solution increases with increasing dicumarol concentration, as a result of hydrophilics of dicumarol adsorbed at the surface of N,N-dimethylacetamide becoming even more order.
It also indicates that the viscosity of 4-hydroxycoumarin or 7-hydroxycoumarin solution is seen to increase with an increase in the concentration of 4-hydroxycoumarin. This is the result of increased free volumes of 4-hydroxycoumarin molecule or 7-hydroxy- coumarin molecule. It is important to note that the viscosity of dicumarol solution decreases with increasing the concentration of dicumarol, as a result of compact conformation formed or micelle-like structure formed. In addition, the number average particle sizes of fluorescent-dye polyurethane ionomer solution appears to increase with increasing the concentration of 4-hydroxycoumarin, 7-hydroxycoumarin and dicumarol, respectively. Since the interaction between hydrophilic groups of fluorescent-dye polyurethane ionomer molecules themselves becomes strong, therefore, the free volumes of these molecules are considered to be increased. This may be the reason to explain why the viscosity rises.
The tensile strength and modulus (100%) of self-cured film of fluorescent-dye polyurethane ionomer are seen to increase with increasing the concentrations of 4-hydroxycoumarin, 7-hydroxy coumarin and dicumarol, respectively. This is because increased hydrophobic groups of fluorescent-dye polyurethane ionomer will strengthen the capability of crosslinking for this ionomer film. For the elongations of fluorescent-dye polyurethane ionomer film, it appears to increase with increasing 4-hydroxycoumarin or 7-hydroxycoumarin concentration, but to decrease with increasing dicumarol concentration, as a result of the intermolecular and intramolecular interactions of this ionomer molecule.
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