Association energy in strongly associative polymers

The association energy E-a, one of the most important parameters of associative polymers, is related to a ratio of two timescales: the attempt time tau(0) that controls the Rouse-type motion and the sticker lifetime tau(s) that controls the sticker dissociation. For sulfonated polystyrene slightly above the gel point, the moduli contributed from the Rouse- type motion and sticker dissociation are sufficiently but not strongly separated over the timescale, and thus, the temperature dependences of tau(0) and tau(s) can be resolved separately from analyzing the high and low frequency moduli obtained from the frequency sweep measurements. A ratio of the temperature dependences enables us to determine E-a that is consistent with E-a determined directly from the value of tau(s)/tau(0) at given T. (C) 2017 The Society of Rheology.