Viscosity development

From 1910 onward waste filament yam had been chopped into short lengths suitable for use on the machinery designed to process cotton and wool staples into spun yams. In the 1930s new plants were built specifically to supply the staple fiber markets. During World War II the production of staple matched that of filament, and by 1950, staple viscose was the most important product. The new spun-yam oudets spawned a series of viscose developments aimed at matching the characteristics of wool and cotton more closely. Viscose rayon was, after all, silk-like. Compared with wool it lacked bulk, residence, and abrasion resistance. Compared to cotton, it was weaker, tended to shrink and crease more easily, and had a rather lean, limp hand. 

Figure 5.13 Effect of tartaric acid on viscosity development (Hill Wilson, 1988b).

Starch gelatinization is the disruption of molecular orderliness within the starch granule. It results in granular swelling, crystallite melting, loss of birefringence, viscosity development, and solubilization. 

If the swelling behavior of carboxylated latexes could be characterized only by the increase in the volume fraction, i.e., in particle size, Eq. 1 would still hold but this is not the case in carboxylated latexes. The latex particles are swelled to a great extent, and the polymer segments are dissolved into the aqueous phase and interact between the particles by the hydrogen bonds and chain entanglements. Thus, Eq. 1 is not expected to hold at all and the interparticle interactions are expected to be dominant in the viscosity development of the latex. 

An elongational or extensional viscosity (%) develops as a result of a conformational transition when disperse systems are forced through constrictions, or compressed or stretched (Kulicke and Haas, 1984 Rinaudo, 1988 Barnes et al., 1989 Odell et al., 1989 Clark, 1992). The intuitive logic is that the random coils resist the initial distortion. % is believed to elicit the human sensation of stringiness (Clark, 1995). If shear viscosity is denoted iq, rheologists define a Trouton ratio as %/ti, wherein % > T) by a factor approximating 3 for uniaxial extension and 6 for biaxial extension. Alternatively stated, the Newtonian ly calculates to one-third to one-sixth % (Steffe, 1992). 

B. Transfer 100 mL of the dispersion prepared in Identification Test A into another 400-mL beaker, heat the mixture in a boiling water bath for about 10 min, and then cool to room temperature. No appreciable increase in viscosity develops. Acid-Insoluble Matter Not more than 7.0%. 

MWI [Mobil Wax Isomerization] A process for improving the quality of petroleum-based lubricating oils. The undesirable wax constituents are hydroisomerized to products of lower molecular weight, using a zeolite catalyst, and the resulting product is treated with an organic peroxide to increase its viscosity. Developed by Mobil Oil Corporation in 1990. 

Dolan, K. D., Steffe, J. E, and Morgan, R. G. 1989. Back extrusion and simulation of viscosity development during starch gelatinization. y. Food Process Eng. 11 79-101. 

The viscosity developed between the sheath of water molecules bound to the monolayer and the bulkphase (surface drag viscosity). 

Points with spokes are for oxy Hb A the others are for carbonmonoxy Hb A. Data are for samples with differing values of pH and buffer composition, as indicated in Ref. 13. Solid line is from a least-squares comparison of the data with Equation 5, the model theory for microscopic viscosity developed in the text rn/rgo = (1 — (31/R — 3ipy . 

Since, in certain applications of glyoxal-treated xanthan guin, it is desirable to delay the development of viscosity (hydration delay), a simple test was developed to monitor this behavior (Figure 8). In the hydration delay test discussed, the gum is added to the vortex (created by a magnetic stirrer) of the hydration fluid (usually synthetic tap water) and the time that is required for the vortex to dlsappeeu Isecause of viscosity development is called the hydration delay time. 

The particle size of glyoxal-treated xanthcui gum as seen in Figure 9 has little if any effect on the hydration delay time. The effect of pH of the hydration fluid on the hydration delay time (or viscosity development) is shown in Figure 10. 

Figure 4 Viscosity development of new rheology modifier technology versus pH...

The distribution of molecular weights in a polymer also influences its rheology. In general, the broader the range, the lower the shear rate at which shear thinning (decrease in viscosity) develops. Thus polymers with broad molecular-weight distribution are easier to extrude than those with narrow distribution. 

A negative result of the strong polarity of silica surfaces is the high viscosity developed during compounding. However, it may be used to measure the interaction of silica particles. We have used rheology and silane treatments to understand and control silica particle interactions. 

EVALUATION OF POLYMERS FOR OILFIELD USE VISCOSITY DEVELOPMENT, FILTERABIUTY AND DEGRADATION... 

The equations above provide a possibility to describe the viscosity changes during the reactive extrusion process in a relatively simple way. Only few parameters have to be adjusted for an accurate description of the viscosity changes on a physical basis. Figure 4.3 shows the general tendency for the viscosity development in the different types of reaction. 

In Section II.B of Chapter 3 the chemical kinetics of the gel effect was considered. However, this effect that is also known as the Trommsdorjf effect has also its implication for the development of the viscosity. Cioffy (9) studied the viscosity development during chain polymerization reactions. Three regions can be distinguished In the first region no entanglements... 

Modified white, orthophthalic, pre-accelerated, non-thixotropic resin of low viscosity, developed for RTM applications and formulated to achieve BS 476 Class 1 flame fire rating. 

Fig. 4 Viscosity development of polymer matrix at different temperatures.

A comparison was also made between the correlations for the dilute-gas viscosity developed by the same authors as mentioned above. In this case a similar behavior, both qualitatively and quantitatively, was found. 

A study into the reaction rate of these UV 2K laminating adhesives through their viscosity development along with the solvent-less systems reveals that the reaction rate of UV 2K laminating adhesives is faster than their solvent-less controls which also explain their faster bond development These systems also exhibit similar humidity and temperature resistance to the solvent-less controls. 

Figure 2.7 Transient viscosity development in carbon black natural rubber compound after various periods of rest in the viscometer...

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