Polymers viscosity retention

Gel permeation chromatography (GPC) is the established method for the determination of molar mass averages and the molar mass distributions of polymers. GPC retention is based on the separation of macromolecules in solution by molecular sizes and, therefore, requires a molar mass calibration to transform elution time or elution volume into molar mass information. This kind of calibration is typically performed with narrow molecular mass distribution polymer standards, universal, or broad calibration methods or molar-mass-sensitive detectors like light-scattering or viscosity detectors. 

Ryles (1988) observed that the HPAM solution viscosity remained stable at >100% retention until the polyacrylamide was hydrolyzed to about 60 mol%, when the concentration was below 200 ppm. Between 60 and 80 mol%, polymer solutions lost almost one half of their original viscosity. Thus, when hydrolysis is limited to less than about 60 mol%, excellent long-term stability can be achieved. This observation is supported by data from Han et al. (2006a). Increasing the concentration to 500 ppm had a more pronounced effect on viscosity retention, even though the polyacrylamide remained soluble. Mg " had similar but less effect than Ca +. At 50°C, the rate of hydrolysis was so slow that viscosity was retained essentially intact after 21 months of aging. Note that the tests were under anaerobic condition. 

Polymer Wt. of Acid Viscosity Number Viscosity Retention ... 

Polymer Injectivity/Retention. Due to the increased viscosity, the rate of injection of a polymer solution into a porous matrix is less... 

The base additive packages required for the stabilization of polyolefins usually comprise combinations of phenolic antioxidants (primary antioxidants, radical scavengers), phosphites or phosphonites (secondary antioxidants) and acid scavengers. The co-operative performance of such an additive combination is certainly influenced by the proper choice and concentration of all individual components. Even acid scavengers can play an important role in melt viscosity retention during processing as well as in the long term stability of the final polymer article. 

Figure 4.2. Seawater viscosification and viscosity retention of a number of polymer types at 90°C (from Davison and Mentzer, 1980).

Polymer front breakdown by fingering Polymer adsorption/ retention in porous media. Polymer degradation Thief zones Loss of mobiiity control and flood front Natural synthetic tracers. Polymer concentration in production water. Oil/water rates Multi-place measurement of viscosity and polymer concentration. Backflow tests. O2, Feand bacteria measurements On-site polymer viscosity tests before and after. Use of tracer and better defined geology. Wells inteqritv... 

Eactors that could potentiaHy affect microbial retention include filter type, eg, stmcture, base polymer, surface modification chemistry, pore size distribution, and thickness fluid components, eg, formulation, surfactants, and additives sterilization conditions, eg, temperature, pressure, and time fluid properties, eg, pH, viscosity, osmolarity, and ionic strength and process conditions, eg, temperature, pressure differential, flow rate, and time. 

Other. A large variety of additives are used in paper-coatiag colors primarily to modify the physical properties of the colors (102). At high soHds concentrations in water, mineral pigment particles tend to associate and form viscous pastes. Dispersants (qv) are used to prevent this and to provide low viscosity slurries. Common dispersants include polyphosphates and sodium polyacrylate [9003-04-7]. Various water-soluble polymers are added to coatiag colors and act as water-retention agents and as rheology modifiers. 

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