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 diisocyanate with polyester, metal-complex dye and other additives forms weather-resistant metal-complex dye polyurethane ionomers, and their structures have been proven by FT-IR spectra. Experimental results show that the viscosity for weather-resistant polyurethane ionomer with metal-complex dye in aqueous solution increases with increasing the concentration of metal-complex dye, as a result of increased free volume of polyurethane ionomer molecule. For weather-resistant polyurethane monomer containing metal-complex dye present in aqueous solution, the average particle size of weather-resistant polyurethane ionomer molecule appears to increase with an increase in the concentration of Tinuvin328 and metal dye, respectively. This is because the intermolecular interaction resulting from increased hydrophilic groups attached to polyurethane ionomer molecule makes the free volume of weather-resistant polyurethane ionomer molecule become large. Thus, the average particle size of ionomer molecule increases.
The experimental results indicate that for the film of self-cured polyurethane ionomer the tensile strength and modulus become weak under the UV for a period of time or become weak as the concentration of Tinuvin328 increases. Owing to the intramolecular interaction, the capability of crosslinking for weather-resistant polyurethane ionomer becomes weaker. Thus, the tensile strength and modulus decrease. On the other hand, it is interesting to note that weather-resistant polyurethane ionomer increase under the UV, as a result of strong intermolecular interaction. For the film of weather-resistant polyurethane ionomer containing metal-complex dye, the elongation appears to increase with increasing the concentration of Tinuvin328 or to increase under the UV. This is the result of the formation of expanded conformation resulting from the strong intermolecular interaction. Contrarily, the elongation for weather-resistant polyurethane ionomer is seen to decrease with increasing the concentration of metal-complex dye or to decrease under the UV for a period of time, as a result of compact conformation formed.
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