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Bulk gel

Although the total intensity of the SFG spectra decreased as the pressure on the PVA gel was increased, the intensity ratio between the peaks corresponding to icelike water and liquid-like water was almost constant. Since the OTS-modified quartz surface was hydrophobic, the water squeezed from the bulk gel was ice-like at the PVA gel/OTS-modified quartz interface. [Pg.92]

Fourier transform infra-red techniques were performed on a block of hydrated gel, similar in form to that shown in Figure 2. The resulting spectra are shown in Figure 9. Spectrum B is after the water background had been subtracted. A comparison of this spectrum with that of A in Figure 8 indicates no real structural difference between the bulk gel and a dried gel film. [Pg.395]

The spontaneous shrinking of a colloidal dispersion due to the release and exudation of some liquid frequently occurs in gels and foams but also occurs in flocculated suspensions. Mechanical syneresis refers to enhancing syneresis by the application of mechanical forces. Micro-syneresis is a special case of syneresis in which the polymer molecules cluster together while retaining some of the original bulk gel structure. This process creates regions of free liquid within the gel network. [Pg.397]

Drying stresses result from the pressure gradient in the pores of the bulk gel. How they are related to microstructural features and to the drying rate is discussed. [Pg.271]

Crosslinked polymer-like bulk gel used in water shut-off has very poor flowability the viscosity is very high (>10,000 mPa s). Uncrosslinked polymer is used to increase water viscosity. A movable gel is used in between it has the intermediate viscosity, and more importantly, it can flow under some pressure gradient. Colloidal dispersion gel (CDG) is a typical gel used in these situations. The mechanisms of a movable gel are (1) it has high viscosity to improve mobility ratio like an uncrosslinked polymer solution (2) it has a high resistance factor and high residual permeability reduction factor and (3) it has viscoelasticity so that the remaining oil in the rocks can be further reduced. [Pg.119]

Fielding Jr., R.C., Gibbons, D.H., Legrand, F.R, 1994. In-depth drive fluid diversion using an evolution of colloidal dispersion gels and new bulk gels An operational case history of North Rainbow Ranch Unit. Paper SPE 27773 presented at the SPE/DOE Improved Oil Recovery Symposium, Tulsa, 17-20 April. [Pg.576]

FIG. 4 Potentiometric titration curves with 0.1 M NaOH in the absence (a) and the presence (b) of 0.1 M NaCl for the copolymer (closed circles), the bulk gel (open triangles), and the microgel (open circles) at 25°C. (From Ref. 33.)... [Pg.611]

FIG 26 Changes in apparent dissociation constant (pKa) with the degree of dissociation ( d) f°r the copolymer (closed circles), the bulk gel (open triangles), and the microgel (open circles) in the absence (a) and the presence (b) of 0.1 M NaCl at 25°C. A very slight initial fall in pKa was observed in the salt-free system with the copolymer. This was reproducible and not an experimental error thus it seems that in the case of the copolymer the interaction (being discussed in the text) appears not only at 35°C but also at 25°C. (From Ref. 33.)... [Pg.652]

Suzuki H, Kokufuta E. Inhomogeneous binding of ionic surfactants to bulk gels and microgels consisting of poly (A- i sopropy 1 aery I am idc). Colloids Surfaces 1999 A 147 233-240. [Pg.660]

The thin-film-forming process differs from the processes of gelation, aging, and drying described earlier for bulk gels (see Figure 1) in several fundamental ways (118) ... [Pg.379]

This paper will focus on the effect of pH on network formation by soy glycinin systems in bulk and at interfaces. The properties of bulk gels formed at pH 3.8 and 7.6 will be compared. The same will be done for the interfacial properties and the suitability for foam formation at pH 3 and 6.7. Similarities between bulk and interfacial properties and the relation with molecular structure and foam properties will be discussed. [Pg.242]

Submicrometer-sized gel particles Since the rate of response is inversely proportional to the square of the size of the gel (Shibayama and Tanaka 1993), small hydrogel particles respond to the external stimuli more quickly than bulk gels (Oh et al. 1998). [Pg.11]

The manufacturing of topical transdermal products (patches) has many problems in scale-up and validation. Problems analogous to production of topical creams or ointments include uniformity of the drug substance and particle size in the bulk gel or ointment. Uniformity and particle size are particularly significant when the drug substance is suspended or partially suspended in the vehicle. Viscosity also needs control because it can affect the absorption of the drug the dissolution test is important in this regard. Other areas that need special inspectional... [Pg.90]

To this, 0.22 itiL of hydrochloric acid dissolved in 5 mL of nltrapure water was slowly added, and the mixture was agitated (200 rpm) for 90 min at 35 °C. Then, 10 mL of lipase solution (18.29 mg mL ), PEG solution (5 mg mL , 8 mL added), and 1 mL of ammonium hydroxide dissolved in 6 mL of ethanol were added (hydrolysis solution), and the mixture was kept under static conditions for 4 h to obtain the chemical condensation. The bulk gel was washed with heptane and acetone and dried under vacuum at room temperature for 24 h [6]. [Pg.328]

The observed I-V characteristics for the developed gels are shown in Figure 12.24. The linear nature was found for HjPO gel complex. The other two gel complexes exhibit nonlinear I-V characteristics, which are probably due to the formation of ion channels by the d-band metallic ligands of submicron dimensions. The observed characteristics may be due to formation of ion channels within the bulk gel. The same characteristic has been observed for natural gels [43]. [Pg.349]


See other pages where Bulk gel is mentioned: [Pg.150]    [Pg.162]    [Pg.347]    [Pg.170]    [Pg.163]    [Pg.146]    [Pg.236]    [Pg.174]    [Pg.113]    [Pg.115]    [Pg.120]    [Pg.123]    [Pg.418]    [Pg.243]    [Pg.271]    [Pg.271]    [Pg.296]    [Pg.120]    [Pg.128]    [Pg.612]    [Pg.650]    [Pg.651]    [Pg.350]    [Pg.379]    [Pg.381]    [Pg.382]    [Pg.250]    [Pg.251]    [Pg.29]    [Pg.31]    [Pg.515]   
See also in sourсe #XX -- [ Pg.170 , Pg.171 ]

See also in sourсe #XX -- [ Pg.174 ]




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