Swelling, polymer formulations

Hydrocolloids and hydrogels are complex polymer formulations used in wound management. They swell in the presence of moisture absorbed from the skin. 

Kimber, J.A., Kazarian, S.G., and Stepanek, F. (2013) Formulation design space analysis for drug release from swelling polymer tablets. Powder Tech-nol, 236, 179-187. 

Cyanoacrylate adhesives cure by anionic polymerization. This reaction is catalyzed by weak bases (such as water), so the adhesives are generally stabilized by the inclusion of a weak acid in the formulation. While adhesion of cyanoacrylates to bare metals and many polymers is excellent, bonding to polyolefins requires a surface modifying primer. Solutions of chlorinated polyolefin oligomers, fran-sition metal complexes, and organic bases such as tertiary amines can greatly enhance cyanoacrylate adhesion to these surfaces [72]. The solvent is a critical component of these primers, as solvent swelling of the surface facilitates inter-... 

In the case of cellulose acetate (CA) casting dopes the solution structurization is mainly due to hydrogen bonding between polymer molecules and additives (swelling agents) in the solution. Therefore, a choice of a proper additive is an important step in the casting dope formulation. 

Viscoelastic Measurement. A number of methods measure the various quantities that describe viscoelastic behavior. Some require expensive commercial rheometers, others depend on custom-made research instruments, and a few require only simple devices. Even qualitative observations can be useful in the case of polymer melts, paints, and resins, where elasticity may indicate an inferior batch or unusable formulation. For example, the extrusion swell of a material from a syringe can be observed with a microscope. The Weissenberg effect is seen in the separation of a cone and plate during viscosity measurements or the climbing of a resin up the stirrer shaft during polymerization or mixing. 

Baloglu, E., et al. 2003. An in vitro investigation for vaginal bioadhesive formulations Bioadhesive properties and swelling states of polymer mixtures. Farmaco 58 391. 

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