Polymer Solution Preparation

Important disadvantages of this geometry are evaporation and free boundary effects for polymer solutions prepared with volatile solvents. Moreover, measurements are restricted to relatively low shear rates because polymer melts and other fluids will not stay in the gap at high rotational speeds. The cone-plate geometry is not recommended for measuring the viscosity of multiphase systems because in some cases domain sizes may be of the same order of magnitude as the gap size. 

Cordova et al. explored the CE behavior of protein charge ladders obtained by acetylation of lysozyme and carbonic anhydrase II using noncovalent polycationic coated capillaries. Two of them, polyethylenimine and Polybrene, were very effective in preventing the adsorption of positively charged proteins. Conditions used were fused-silica capillary (50 p.m i.d. x 38 cm) coated with the polymer by flushing the capillary with a 7.5% (w/v) polymer solution, prepared in 25 mM Tris-192 mM Gly buffer (pH 8.3), for 15 min. The running buffer was 25 mM Tris-192 mM Gly buffer (pH 8.3) in the absence of polymer. Separations were obtained within 5 min. 

The mobile phase used in most high-temperature SEC is toxic, and handling operations must be carried out with considerable care. Polymer solution preparation and solvent distillation have to be carried out in a fume cupboard, and under a blanket of nitrogen. Addition of anti-oxidants is important to reduce oxidative degradation, and typically 200 ppm of Santanox-R is added to polymer solutions. 

The materials used were PCL with a weight average molecular weight of 80 000, glacial acetic acid (purity >99.7%) as the solvent for PCL, and pyridine (purity >99.0%), as the additive for increasing conductivity. The polymer solutions prepared had five concentrations (10,12.5,15,17.5 and 20% w/v) and seven levels of conductivities obtained with different levels of salt (0,0.1,0.2,0.5,1,2 and 5% v/v). 

Briefly summarized, the observations of Breitenbach and Kauffmann [2] are these. In a polymerization system, such as that of acrylic acid, which is characterized by the formation of a polymer that is insoluble in its pure monomer, if the monomer cannot penetrate the polymer coil, no proliferating polymerization is possible. If, however, a solvent for the polymer, e.g, water, is present, there are concentration ranges in which the monomer can penetrate the polymer coil, and popcorn polymers form. Under the experimental conditions [polymerization of acrylic acid containing 35 X 10" moles of 2,2 -azobis(isobutyronitrile) per mole of acrylic acid at 40°C along with some water], compositions containing 96.6wt. o or more of acrylic acid exhibit no tendency to popcorn polymer formation. Systems containing between approximately 86 /o and 96<7o of acrylic acid proliferate only after polymerization times of 15-50 hr. At concentrations of 50-80% of acrylic acid, popcorn polymers form very rapidly (1.5-4 hr). At about 35% of acrylic acid the appearance of popcorn polymers occurs only after approximately 17 hr of polymerization. Unfortunately the behavior of 25-30% solutions of acrylic acid in water was not reported upon. This happens to be the concentration range usually recommended for practical polymer solution preparation. 

Table 3.3 Summary of suggested polymer solution preparation procedures and requirements for different types of experiment.

In this section, the relevant laboratory tests that should be carried out on polymers in support of a proposed polymer pilot will be described. Virtually all of the actual technical points concerning polymer properties—such as compatibility/stability, filterability and formation plugging, polymer solution preparation, adsorption in porous media, in-situ rheology—have been discussed in detail elsewhere in this book. However, earlier the objective was to present an explanation and a view on the science of the various phenomena involved in polymer physics and chemistry both in bulk solution and in flow through porous media. Here, the intention is to abstract the much more limited subset of experiments that should be carried out in support of a practical polymer flood application in the field. In all of the discussion below, it is assumed that a range of commercially available off-the-shelf polymers... 

Figure 1. Inherent viscosities of BTDA-3,3 -DABP polymer solutions prepared in diglyme (0.5% concentration at 35 C).

Besides pyrolysis, the polymer solution preparation, spirming process, solvent exchange process and others are important steps to ensiue the production of excellent carbon membranes. 

Reliability of the polymer solution preparation plant (continuous delivery with 60> 44 cP Fe < 1 ppm)... 

Intrinsic viscosities have been measured for the injected and produced solutions. For the injected product, the intrinsic viscosity is comparable to the intrinsic viscosity of the polymer solution prepared in the laboratory, indicating that the equipments used for preparing the polymer solution in the fieid are satisfoctory (fig. 11). The viscosity of a polymer sample from well CY55 (March 1990) is also reported. It is lower than the intrinsic viscosity of the injected soiution, this correlates well with a lower molecular mass or with a complexation of polymer molecules with divalent cations (see next paragraphs). 

Architecture studies selected the concept of a polymer solution prepared from powder, rmder a continuorrs process which is described below. 

The operability of deep offshore polymer injection usingdesulfated sea water demonstrated successfully. Uptime was averaging 80%, and polymer solution prepared on board the FPSO was of good quality. Since the beginning of polymer injection (December 2008), filterability has been good (FR<1.1) and the insoluble content is low (<0.5%). The oxygen content of the diluted polymer solution at the riser departure is also very low (<10ppb). 

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