Polyacrylic acid viscosity

Crisp, S., Lewis, B. G. Wilson, A. D. (1975). Gelation of polyacrylic acid aqueous solutions and the measurement of viscosity. Journal of Dental Research, 54, 1173-5. 

Use anionic polymers such as polyacrylic acids cross-linked with allyl ethers of pentaerythritol or sucrose as thickeners, if a gel structure and pseudoplastic (shear-thinning) properties are desirable. Consider adding colloidal alumina to further increase the viscosity at pH 13 [ 15]. 

Ting (1972) reported that the degree of drag reduction depends on the content of ionic groups in a series of hydrolyzed PAAm samples exhibiting maximum behavior . He noticed that the reduced viscosity increased sharply with increasing hydrolysis up to 40 % AAm and then decreased, in comparison to the pure polyacrylic acid. Similar investigations with polyacrylic add at different neutralization states have been made by Parker and Banijamali who obtained comparable results. 

As early as 1951, Flory and Osterheld [18] could show that partially ionized polyacrylic acid in aqueous solution of an inert salt shrinks in size if the concentration of the inert salt is increased. This shrinking process can be pushed towards the unperturbed dimensions of the NaPA chains. Known from neutral polymers as 0-state, it is reached for fully ionized NaPA [50] at T=15 °C and 1.5 M KBr. In several papers, the dependence of the intrinsic viscosity was investigated as a function of the molar mass [51]. Data were... 

Both RAMEB and SDS are called rheology modifiers, since they greatly increase and decrease viscosity. Since their discovery, CD-based rheology modifiers have been found for a great variety of associative polymers, such as a-CD for dodecylamido-polyacrylic acid [194], HP- 3-CD for hexadecyl modified hydroxyethyl-cellulose [195], and RAMEB for adamantane modified polyacrylamide [196],... 

FIG. 3 Variation of the intrinsic viscosity of long alkyl-modified polyacrylic acids as a function of the concentration of bovine serum albumin in the solvent. Solvent used for dilutions 30 mM borate buffer pH 9 and protein (top curves) or same buffer plus 0.3 M NaCl and protein (bottom curves). Black circles polymer modified with 4 mol% of C18 side groups squares polymer modified with 3 mol% of C12 groups cross-circles unmodified poly (sodium acrylate). (Reprinted with permission from Ref. 33. Copyright 1998 American Chemical Society.)... 

Semi-solid gel type preparations have also been developed for ophthalmic delivery as an alternative to traditional ointments, based on the effect of increasing the viscosity to prolong the retention of drug in the eye (for example, Pilopine HS gel, Alcon Laboratories, Inc.). Several types of gelling agents have been used, such as polyacrylic acid derivatives, carbomer and hypromellose. 

Materials. Two samples of polyacrylic acid, PAA-1 (4) and PAA-2, were obtained as gifts from S. C. Johnson Company. Their degrees of polymerization were 3090 and 4420, respectively, as calculated from the intrinsic viscosities of their sodium salts in 0.102V NaBr at 15°C using the appropriate relation of Takahashi and Nagasawa (5). The samples of the hydrolyzed copolymers of maleic anhydride witn ethylene (HEMA) and with methyl vinyl ether (HVMEMA) have been described previously (4). 

Figure 4. Effects of hound silver and hydrogen ions on the intrinsic viscosity of the TMA salt of polyacrylic acid in 0.2M TMANOs at 30°C. The abscissa 0totai denotes the sum of 0H and 0Ag. (O) silver ion bound to PAA-2 initially at a — 0.910 (D) hydrogen ion bound to PAA-2 initially...

Our group studied the release of lidocaine hydrochloride (Musial et al., 2010b) and chlorhexidine (CX) (Musial et al., 2010a) from an ionic and a non-ionic polymeric carrier, methylcellulose microgel and polyacrylic acid microgel, respectively, at standard and increased temperatures. The obtained release rates and respective amounts of lidocaine hydrochloride and CX loaded were compared with respect to viscosity, pH, and conductivity of the studied systems. This research is important for patients with differentiated skin surface temperature conditions to whom a local analgesic is to be applied. 

Hydrogenated palm kernel oil viscosity control agent, pharmaceutical topicals Isocetyl stearoyl stearate Laneth-15 Octyidodecyl stearoyl stearate PEG-150 distearate PEG-8 stearate Polyacrylic acid Tetradecyleicosanol Trihydroxystearin Triisostearyl trilinoleate Trilaneth-4 phosphate viscosity control agent, pharmaceuticals Ammonium sulfate Carboxymethyl hydroxyethyl cellulose Carboxymethyl hydroxypropyl guar Ceteareth-20 Glycol dilaurate... 

Viscosity data for the ethyl-copolymer, A, over the range a=0 to a = 1, reveal the typical electrostatic expansion behavior of a weak polyacid such as polyacrylic acid. Polymer B-II, on the other hand, exists in an abnormally compact state at low a. The curves for polymers B-I and B-III, excluded from Figure 1 for clarity, are identical in shape and differ only in relative magnitude. The five-fold increase in [f/] over the range 0.35[Pg.5]

The results are reported of a systematic study of the break up of droplets in concentrated emulsions at different viscosity ratios in simple shear flows. The system investigated consisted of silicon oil drops in an aqueons phase mixture of polyacrylic acid solution, hexylene glycol, distilled water and dobanol surfactant. The ratio between drop and matrix viscosity was varied from 0.1 to 22 and the volume fraction ranged from 0 to 70%. The results are discussed in terms of a simple mean field scaling model. 11 refs. 

---