Rheological Behavior of Some Aqueous Gels of Carbopol with Pharmaceutical Applications

Abstract

The concentration and temperature dependence of the viscosity is observed for some aqueous dispersions of Carbopol. The experimental data are analyzed with the power model, and reveal non-Newtonian behavior (shear thinning) of the samples.

UV-Vis and XRD investigation of graphite-doped poly(acrylic) acid membranes

“…Polymeric membranes are used in the pharmaceutical industry as support for active medical drugs, and most recently in the green energy industry in the fabrication of electric fuel cells based on the oxidation of methanol or hydrogen without burning [1][2][3][4]. The use of polymers like poly(vinyl) alcohol (PVA), and most recently poly(acrylic) acid (PAA), has increased for these purposes [5,6]. Such particular applications require special features of materials that are not characteristics of pure polymers as they result from the fabrication process, but can be obtained by doping with different inorganic compounds [7,8].…”

Thermorheological properties of a Carbopol gel under shear

“…There exists a second class of previous rheological studies which observe an anomalous temperature-viscosity correlation (an increase of the viscosity with the temperature), Owen et al [31], Park and Irvine [32,33], Todica et al [44].…”

“…They did not elaborate any further on this rather unexpected result but they did note, however, that ''Perhaps this phenomenon originates from a structural change of the polymer molecules with concentration and temperature''. The most recent observation of an anomalous behavior we are aware of is due to Todica et al [44]. They have performed their measurements on a Brookfield DV II Pro viscometer, using cylindrical spindle.…”

Effect of Sodium Salicylate on the Viscoelastic Properties and Stability of Polyacrylate-Based Hydrogels for Medical Applications

“…The thickening mechanism of the neutralizer is based on alteration of coiled polymer chains into an uncoiled form through transforming acidic Carbomer into a salt through the action of a neutralizing agent, NaOH. An alternative neutralizer, such as triethanolamine, is also known to be effective [16]. When an additive in ionized form is used to modify the Carbomer system, a negative effect can occur.…”