| 초록 |
Nonlinear optical (NLO) polymers are considered as a good candidate for making electro-optic (EO) devices, mainly because they offer many advantages. In the developments of NLO polymers for EO device applications, stabilization of electrically induced dipole alignment is important. Polyurethane matrix forms extensive hydrogen bond between urethane linkage and increases rigidity preventing the relaxation of induced dipoles. Physically crosslinked systems via hydrogen bonds have the advantages such as homogenity and good processability relative to the chemically crosslinked systems. In this work we prepared novel polyurethanes containing 2,5-dioxybenzylidenecyanoacetate. 2,5-Di-(2-hydroxyethoxy)benzylidenecyanoacetate (3) was prepared by hydrolysis of 2,5-di-(2-vinyloxyethoxy)benzylidenecyanoacetate (2). Diol 3 was condensed with 2,4-toluenediisocyanate and 3,3-dimethoxy-4,4-biphenylenediisocyanate to yield novel T-type polyurethanes (4-5) containing 2,5-dioxybenzylidenecyanoacetate group as a nonlinear optical (NLO) chromophore, which constitutes a part of the polymer backbone. The resulting polyurethanes 4-5 were soluble in common organic solvents such as acetone and DMF. Polymers 4-5 showed a thermal stability up to 250oC in TGA thermograms with Tg values obtained from DSC thermograms in the range of 143-145oC. Study on the SHG activities, film morphology and electro-optic properties of the polymers are in progress. |
