Abstract
This paper gives details of new data on neutralized Carbopol 940 dispersions. Appropriate techniques have been used to characterize the physical properties of the bulk gel and inter-phase slip at the wall. Previously published data are analysed and used wherever possible. Terminology and measurement difficulties are also addressed. The structure of Carbopol dispersions can be described in terms of polydisperse glasses made of individual swollen hydrophylic elastic sponges. They display elastoplasticity, and significant dissipation both below and above their yield stress. Hardly any creep was observed over 10 months of experiments. Scaling laws are proposed for Carbopol mechanical properties as a function of concentration. Carbopol behaviour varies with the value of concentration, and in particular when comparing percolation concentration with close-packing concentration. Constitutive equations for bulk shear stresses and for friction slip at the wall can be deduced from contact mechanics which fit rheometry data and scaling laws. Herschel–Bulkley constitutive equations may be used by ignoring elasticity, normal shear stresses and transients.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call