| Summary: | 碩士 === 國立成功大學 === 化學工程學系碩博士班 === 91 === In this study, three types of polyurethanes with a highly NLO active chromophore, 4-N,N-bis(2-hydroxy ethylene)amino-4’-nitroazobenzene (Disperse Red 19, DR-19), in the polymer side chain were successfully synthesized (DR-PUn’s) and characterized. The diisocyanate components of the polymers are 4,4’-methylenebis(phenyl isocyanate), tolylene-2,4-diisocyaate and 3,3’-dimethoxy-4,4’- biphenylene diisocyanate. Moreover, a trifunctionalized disperse red-type chromophore (TDR-19) was synthesized for crosslinking.
The DR-PUn’s are readily soluble in polar aprotic organic solvents, like tetrahydrofuran, N,N-dimethyl formamide, cyclohexanone, etc. Good optical quality, poled films were prepared by spin coating, followed by thermal corona poling. The glass transition temperatures (Tg) of DR-PUn’s determined by differential scanning calorimetry (DSC) decrease in the order: DR-PU2 > DR-PU1 > DR-PU3, corresponding to 142.3℃, 138.5℃ and 136.7℃, respectively. They showed no melting points in the DSC curves, suggesting an amorphous phase. The order parameters of DR-PU1, DR-PU2 and DR-PU3 were obtained to be 0.210, 0.262 and 0.178 respectively from absorption measurements before and after poling. The temporal stability of NLO properties for the three DR-PUn’s increases with Tg of the polyurethanes. The poled DR-PUn films exhibited good thermal stability of NLO properties at 90℃. The synthesis of TDR-19 is for the further study of thermally cross-linked systems. The synthesis experiences and property investigations of TDR-19 can be the extension of relative works.
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