Synthesis and photochemical properties of poly(ester-amide)s containing norbornadiene (NBD) residues

Abstract

N,N′-Bis[(3-carboxynorbornadien-2-yl)carbonyl]-N,N′-diphenylethylenediamine (BNPE) was synthesized in 70% yield by the reaction of 2,5-norbornadiene-2,3-dicarboxylic acid anhydride with N,N′-diphenylethylenediamine. Other dicarboxylic acid derivatives containing norbornadiene (NBD) residues having N,N′-disubstituted amide groups were also prepared by the reaction of 2,5-NBD-2,3-dicarboxylic acid anhydride with certain secondary diamines. When the polyaddition of BNPE with bisphenol A diglycidyl ether (BPGE) was carried out using tetrabutylammonium bromide as a catalyst in N-methyl-2-pyrrolidone at 100°C for 12 h, a polymer with number average molecular weight of 69,800 was obtained in 98% yield. Polyadditions of other NBD dicarboxylic acid derivatives containing N,N′-disubstituted amide groups 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. Photochemical reactions of the obtained polymers with N,N′-disubstituted amide groups on the NBD residue were examined, and it was found that these polymers were effectively sensitized by adding appropriate photosensitizers such as 4-(N,N-dimethylamino)benzophenone and 4,4′-bis(N,N-diethylamino)benzophenone in the film state. The stored energies in the quadricyclane groups of the polymers were also evaluated to be about 94 kJ/mol by DSC measurement of the irradiated polymer films. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 917–926, 1999