Rheological behavior of water-creosote and creosote-water emulsions

✍ Scribed by C. Tiu; A. K. Podolsak; T. N. Fang; J. B. Watkins

• Book ID: 104767320
• Publisher: Springer-Verlag
• Year: 1992
• Tongue: English
• Weight: 731 KB
• Volume: 31
• Category: Article
• ISSN: 0035-4511
• DOI: 10.1007/bf00418336

✦ Synopsis

The effect of temperature on the steady-shear viscosity of two base emulsions (water-in-cresosote (w/o) and creosote-in-water (o/w)) and a pigment emulsified creosote (PEC) was investigated. The PEC is a water-in-creosote emulsion which contains also a solid, micronised pigment, and is used industrially as a wood preservative. All three emulsions exhibited shear thinning characteristics at different temperatures. The viscosity-shear rate relationships follow a modified Quemada model. A temperature-superposition method using the reduced variables t//r/= and tc~ was applied to yield a master plot for each of these emulsions at different temperatures. The effect of creosote concentration on the viscosity of four other o/w emulsions at different temperatures was also studied. The same reduced variables were able to produce a temperature-concentration superposition plot for all of the o/w emulsion results.

The effective (average) radius of the globules (dispersed phase) was found to increase with increasing temperature for the base w/o and the PEC emulsion. The collision theory could be used to explain the increase in the droplet size. However, while little overall variation in globule size was observed for the o/w emulsions, microscopic observation indicated an increase in the proportion of large diameter droplets with temperature at the highest creosote concentration (60%). A "creaming" effect (phase concentration) was observed with these emulsions at higher temperatures, precluding an accurate estimate of droplet size based on collision theory.