Abstract
A cascade model for the network of coupled twoβcomponent polymer gels is presented. The network formation is assumed to be primarily due to the interaction between the functional groups of two unlike polymers. The gel modulus G versus polymer concentration C curve is constructed using the cascade formalism. The variation of G versus C curves with respect to the concentration ratio r of the two components is found to be the characteristics of mixed gels. The model parameters can be obtained by fitting G versus C curves using a nonlinear leastβsquares method (the gelβmodulus approach). The approach is applied to the experimental data for galactomannan/xanthan and glucomannan/xanthan mixed gels. Finally we discuss the gel point predicted by the cascade model. The critical concentration C~0~ for the gel point is strongly dependent on r and the functionalities for both polymers. The C~0~ versus r curve is easily obtained by experiment, and can be used to evaluate the model parameters (the gelβpoint approach). The experimental data for galactomannan/xanthan mixed gels is tested to demonstrate the validity of the gelβpoint approach. The advantages and limitations of both approaches are discussed. Β© 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006