DYNAMIC PROPERTIES OF THE TRANSIENT NETWORK FORMED BY TELECHELIC IONOMERS STUDIED BY DYNAMIC LIGHT-SCATTERING AND DYNAMIC-MECHANICAL ANALYSIS

Solutions of alpha,omega-sodium sulfonatopolyisoprene (alpha,omega NaP IPS) in toluene are studied using static and dynamic light scattering and dynamic mechanical analysis. At concentrations above 4 g/L, which is well below the overlap concentration of the polymer chains (C), a transient network is formed characterized by a plateau modulus at high frequencies and a relatively narrow viscoelastic relaxation time dist ribution. The intensity autocorrelation function of the transient netw ork shows two relaxational modes: a relatively fast diffusional mode c lose to the co-operative diffusional mode of semidilute solutions of t he unfunctionalized polymers and a slow broader mode which becomes ind ependent of the scattering angle at a concentrations close to C. The relation between this slow mode and the viscoelastic relaxation is dis cussed. Both the slow mode and the viscoelastic relaxation processes h ave an Arrhenius temperature dependence with the same activation energ y, E(a) = 25 kJ/mol.