Thixotropy of different concentrations of microcrystalline cellulose:sodium carboxymethyl cellulose gels.

An extensive study is made of the rheologic behavior of microcrystalline cellulose:sodium carboxymethyl cellulose gels at six different concentrations (between 1 and 2.5% by weight). The thixotropy of these gels was analyzed in terms of agitation time, the duration of storage, concentration, and temperature; a semiempirical function was thus obtained providing thixotropic area as a function of these variables. The instantaneous variation rate in thixotropic area was defined, providing a better understanding of the rate of structural breakdown. Also, it is shown that after 5 min of agitation, the variation rate becomes negligible (approximately 0.7% of the initial value); this result is practically independent of the remaining variables.