SYNTHESIS OF POLYESTERS CARRYING NORBORNADIENE (NBD) MOIETIES BY THE RING-OPENING COPOLYMERIZATION OF GLYCIDYL ESTERS CONTAINING NBD MOIETIES WITH CARBOXYLIC ANHYDRIDES AND THEIR PHOTOCHEMICAL-REACTIONS

Various epoxy monomers containing norbornadiene (NBD) moieties were pr epared by reactions of potassium salts of NBD derivatives with excess epichlorohydrin using tetrabutylammonium bromide (TBAB) as a phase tra nsfer catalyst; The copolymerization of glycidyl 13-phenyl-2,5-norborn adien-2-yl)carboxylate (GPNC) with phthalic anhydride (PAn) proceeded smoothly using TBAB as a catalyst in sulfolane at 100 degrees C for 24 h to give polyester P-1 containing pendant NBD moieties. Copolymeriza tions of various epoxy monomers containing certain NBD moieties with c arboxylic anhydrides gave the corresponding NBD polyesters in good yie lds. The photochemical valence isomerizations of the NBD moieties in t he polymers were carried out in the film state or in the solution. Rat es of the isomerizations of some NBD moieties in the polymers were str ongly enhanced by the addition of photosensitizers such as 4-(N,N-dime thylamino)benzophenone (DABP). The T(g)s of the polyesters having NBD residues and stored thermal energy in the corresponding quadricyclane (QC) groups in the polymers were measured by DSC analysis. The T(g)s o f the NBD polymers were 45-93 degrees C. Polyesters having QC groups a fter photoirradiation released their stored thermal energies (about 90 kJ/mol) at temperatures above the T(g)s of the corresponding NBD poly mers.