Synthesis And Properties Of Polyesters Containing1,3,4-oxadiazole Or1,3,4-thiadiazole

In this paper, three kinds of new compounds which have not been reported,1,3-bis-(2-methyl acetate sulfide-1,3,4-oxadiazole)-benzene (4a),1,3-bis-(2-methyl acetate sulfide-1,3,4-thiadiazole)-benzene (4b) and2,6-bis-(2-methyl acetate sulfide-1,3,4-oxadiazole)-pyridine (4c), aresynthesized by esterifation, alkylation, cyclization, substitution with1,3-benzenedi-carboxylic acid and2,6-pyridinedicarboxylic acid as rawmaterials. Nine kinds of polyesters (P1-P9) containing1,3,4-oxadiazole or1,3,4-thiadiazole are synthesized by transesterification with three kinds ofmonomers and ethylene glycol,1,3-propylene glycol,1,6-hexylene glycol asraw materials. Coordinate polymers P8-Ni is synthesized by coordination withpolyester P8and nickel choride hexahydrate. The structure of the intermediates and polyesters (P1-P9) are confirmed by IR, UV-vis,1H NMR,13C NMR andMS. Polyesters (P1-P9) can be dissolved in DMF, DMSO and NMP, themajority polyesters can be dissolved in DMAc, indicating that polyesters (P1-P9)show well solubility. Tested by GPC, polyesters’(P1-P9) Mn are3435-5359g/mol, Mw at the5608-14951g/mol, Mz at the9564-40659g/mol, PDI in the1.63-2.79range, Mz/Mw in the1.32-3.58range. Tested by TG-DTA,Polyesters’(P1-P9)5%weight loss temperature at the255.32-269.15℃, themaximum weight loss temperature at the532.28-638.87℃, char yield in the31-40%, indicating that polyesters (P1-P9) show considerable thermalstability. Tested by fluorescence spectroscopy monomers (4a,4b,4c), polyesters(P1-P9) and P8-Ni’s fluorescent performance, the study shows that themonomers (4a,4b,4c), polyesters (P1-P9) and P8-Ni fluorescent maximumemission peaks at354-369nm wavelength range, monomers (4a,4b,4c),polyesters (P1-P9) and P8-Ni both emit violet fluorescence. Polyesters (P1-P9)containing1,3,4-oxadiazole or1,3,4-thiadiazole show well solubility, considerable thermal stability and fluorescent properties, which can be in thefield of optical functional polymer materials.