Synthesis and Characterization of Poly(1,1′-Bi-2-naphthylidene-toluene-2,4-disulfonate)

Abstract

Poly(1,1′-bi-2-naphthylidene toluene-2,4-disulfonate) (PBNTDS) was synthesized by the interfacial polycondensation of 1,1′-bi-2-naphthol and toluene-2,4-disulfonyl chloride using water:1,2-dichloroethane as an interphase, alkali as an acid acceptor, and cetyl trimethyl ammonium bromide as an emulsifier. PBNTDS is highly soluble in common solvents. The structure of PBNTDS is supported by elemental and spectral (FTIR and FTNMR) data. Weight average molecular weight w (17877), number average molecular weight n (6918), and polydispersity w/ n (2.58) confirms formation of moderate molecular weight of PBNTDS. The intrinsic viscosity of PBNTDS was determined in chloroform at 30°C, and the observed value is 0.24 dlg−1 further supports formation of moderate molecular weight of PBNTDS. The density was determined by specific volume method. The observed values (1.1507–1.7182 gcm−3) differ considerably from calculated value (1.4084 gcm−3). DSC thermogram (10°C/min in nitrogen atmosphere) showed Tg to be 171.6°C. The observed endothermic transition at 335.2°C is due to decomposition reaction. PBNTDS is thermally stable up to about 285°C in an inert atmosphere and then undergoes a single step decomposition reaction (285–400°C). The temperature of maximum weight loss is 319.8°C with 30.4% weight loss and producing about 36% residue at 500°C. The least squares kinetic parameters of thermal degradation: E, A, n, and ΔS* are found to be, respectively, 399.8 kJ mol−1, 3.33 1033 s−1, 4.26, and 391.1 J K−1.