Gelling polymers

A mixture of polymers that can serve as a plugging solution when taken in an equimolar ratio consists of polydimethyl-di lyl ammonium chloride, which is a strongly basic cation-active polymer, and the sodium salt of carboxymethyl-cellulose, which is an anion-active polymer. The aqueous solution contains 0.5% to 4% of each polymer. Gelling occurs because the macro ions link together from different molecules. The proposed plugging composition has high efficiency within a wide pH range [497]. 

Distinctly different approaches to avoid these problems and still achieve high viscosities were conceived and applied. The different approaches can be categorized as 1) preparation of emulsions or foams and 2) addition of crosslinkers to the polymer. Two separate processes which utilized crosslinking of polymer gelling agents were pursued. These are the use of secondary (or delayed) gelling agents and the use of metallic crosslinkers added on-site. 

Particle shape, size, and density polymer gelling-agent concentration solids concentration test temperature and fracture shear rate affect viscosity increase that results from the addition of a solid in the fracturing fluid. 

If gelation of one or both polymers precedes phase separation, the polymer gelling first will tend to be more continuous. If phase separation precedes gelation, then a rather coarse morphology may develop. Of course, both gelation and phase separation are controlled by the kinetics of polymerization and the concentration of the crosslinkers, as well as the thermodynamics of mixing. 

A different approach to overcome polymer gelling is to add inorganic salts like potassium bicarbonate. They can facilitate dehydration and precipitation of the polymers in aqueous environment which is reflected by an improved dissolution profile... 

The properties of individual polymer gels vary considerably in strength and elastidty due to differences in the number and nature of the junction zones and the degree of chain aggregation. The main polymer gelling agents and their characteristics are summarised in Table 4.1. 

Thickeners/gelling agents Forsthoff, 1991). Fatty alcohol ethoxylate, fatty acid alkylolamine, ethoxylated glucose ester and common salt are used as thickening additives in liquid washing, shower and bath preparations. Structurally viscous products retain their gel-like character by the addition of polymer gelling agents such as, polyacrylic acids, xanthan or hydroxypropyhnethylcellulose. However, the latter compound has been associated with a loss of efficacy for certain preservatives. 

In an effort to obtain a direct comparison of the solubility properties for an analogous phenylated system the bis-imide acetylene monomer was pol3nnerized with 3,3 -(1,3-phenylene)bis[2,4,5-triphenyl-cyclopentadienone]. The polymer gelled from trichlorobenzene when allowed to cool to room temperature and exhibited only partial solubility in refluxing toluene. 

Unless the reaction with bromobutyl was carried out at high dilution (0.75%) compared to chlorobutyl rubber (2.35%), it was not possible to isolate the AgBr because the polymer gelled and trapped the salt. We... 

Various methods of permeability modification have been applied. These include crosslinked polymer (gelled polymer), microbial-based, and precipitation processes. This chapter describes only the application of crosslink polymers. In-situ permeability modification is not strictly a mobility-control process in that volumetric sweep efficiency is improved through modification of rock perme-abiiity rather than through mobility adjustment of an injected fluid. The processes are related, however, because of the use of polymer systems that are similar and because the result—i.e., improved volumetric sweep—is similar. Thus, permeability modification is described in this chapter. 

The safety of cells with polymer electrolyte cells is strongly influenced by the type of polymer electrolyte. In general the trend of increasing safety will be inorganic glass or ceramic electrolytes > true sohd polymers > gelled electrolytes. 

Physically retarding acid reaction is accomphshed by thickening (viscosifying) the acid used. Viscous acids include polymer-gelled, surfactant-gelled, emulsified, and foamed acids. Combinations can also be used in addition, surfactant-retarded acid can be gelled or foamed. The intent of viscosifying acid is to slow the rate of acid diffusion outward, to the rock surfaces, and to reduce the rate of fluid loss from wormhole to unreacted matrix. Both of these effects work to increase live acid penetration distance. 

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