Synthesis of Poly(ester−amide)s Containing Norbornadiene (NBD) Residues by the Polyaddition of NBD Dicarboxylic Acid Derivatives with Bis(epoxide)s and Their Photochemical Properties

Abstract

N,N‘-Bis[(3-carboxynorbornadien-2-yl)carbonyl]methylenedianiline (BNMA) was synthesized in 87 % yield by the reaction of 2,5-norbornadiene-2,3-dicarboxylic acid anhydride with 4,4‘-methylenedianiline. Other dicarboxylic acid derivatives containing norbornadiene (NBD) residues were also prepared by the reaction of 2,5-NBD-2,3-dicarboxylic acid anhydride with certain diamines. When the polyaddition of BNMA with bisphenol A diglycidyl ether (BPGE) was carried out using tetrabutylammonium bromide as a catalyst in NMP at 100 °C for 24 h, a polymer with a number average molecular weight of 18 000 was obtained in 91% yield. Polyadditions of other NBD dicarboxylic acid derivatives with BPGE were also performed under the same conditions. The reaction proceeded very smoothly to give the corresponding NBD poly(ester−amide)s in good yields. Furthermore, the photochemical reactions of the NBD poly(ester−amide)s were evaluated in the film state or in solution. The photochemical valence isomerization of NBD residues in the polymer films proceeded smoothly to form the corresponding quadricyclane (QC) groups upon irradiation with sunlight. The photochemical reversion of the resulting QC groups in the polymer films proceeded efficiently by irradiation of 272 nm light. The stored energy in the QC groups of the polymers was evaluated to be about 84 kJ/mol by DSC measurement of the irradiated polymer films.