Aqueous solutions of polymers

Polymeric Calcium Phosphate Cements. Aqueous solutions of polymers such as poly(acryHc acid), poly(vinyl alcohol), gelatin, etc, and/or autopolymerizable monomer systems, eg, 2-hydroxyethyl methacrylate, glycerol dimethacrylate, calcium dimethacrylate, etc, have been used as Hquid vehicles (41,42,76) for the self-setting calcium phosphate cement derived from tetracalcium phosphate and dicalcium phosphate [7757-93-9J. 

Other uses of thickening agents include pharmaceutical preparations, paper production, and oil well drilling fluids. This latter use is necessary because oil is obtained from rock that is porous. In order to remove the oil without altering the mechanical properties of the porous rock, viscous liquids ( drilling fluids ) are pumped into the rock to replace the oil. Among the substances that can be used for this purpose are thickened aqueous solutions of polymers such as poly(acrylic acid) or poly(acrylonitrile). 

UV irradiation either of the aqueous solutions of polymers mixtures in the presence of photoinitiators and curing agents, or of the PVA hydrogels swelled with acrylic acid ... 

So, the PVA/poly(sodium styrene sulphonate) [PSSNa] blend was obtained by casting aqueous solution of polymers mixture (PVA with Mw= 124,000-186,000 and HD=99% and PSSNa with Mw= 70,000). The resulted films were crosslinked with 1,2-dibromethane in gaseous phase. A semi-interpenetrating network (SIPN) in which polyelectrolyte (PSSNa) chains are trapped inside a based PVA network was obtained [44], A totally miscible blend with a very good film clarity and high mechanical resistance [44] resulted. 

To that, we have to add the concentration of salts of the resulting aqueous solution of polymer. These salts come from the residual polymerisation auxiliaries and the neutralising agents. 

Fig. 42 Monomer to excimer ratio as a function of pH aqueous solution of polymer and adsorbed polymer on alumina...

Major damage results from the radiolytic products of water experiments with aqueous solutions of polymer reveal such effects but could hardly increase the damage by much more than a factor of about 10. 

This chapter concentrates on the results of DS study of the structure, dynamics, and macroscopic behavior of complex materials. First, we present an introduction to the basic concepts of dielectric polarization in static and time-dependent fields, before the dielectric spectroscopy technique itself is reviewed for both frequency and time domains. This part has three sections, namely, broadband dielectric spectroscopy, time-domain dielectric spectroscopy, and a section where different aspects of data treatment and fitting routines are discussed in detail. Then, some examples of dielectric responses observed in various disordered materials are presented. Finally, we will consider the experimental evidence of non-Debye dielectric responses in several complex disordered systems such as microemulsions, porous glasses, porous silicon, H-bonding liquids, aqueous solutions of polymers, and composite materials. 

In other techniques of oil production, the microlatices can be usefully employed for ground consolidation, manufacture of drilling muds and as completion or fracturation fluids. Another use concerns the prevention of water inflows into production wells. The method consists injecting from the production well into the part in the field to be treated, an aqueous solution of polymer prepared by inverse microlatex dissolution in water. The polymer is adsorbed on the walls of the formation surrounding the well. When the latter is brought in production, the oil and/or the gas selectively traverse the treated zone whereas the passage of water is inhibited. 

SURFACE ACTIVITY. The surface tension results for aqueous solutions of Polymer JR and Oxiatrlsof t are given In Figure 1. The hydrophobe modified polymers clearly show more surface activity than the unmodified polymer. The surface activity of the modified polymers as measured hy the surface tension criterion Is only moderate compared to conventional surfactants which exhibit ultimate surface tension values In the range of 20-40 mN/m. The effect of the molecular changes resulting In this moderate surface activity can, however, be considerable on other properties of the polymer, as will- be shown In subsequent sections. 

Fig. 15 Fluorescence spectra of ANS in differently concentrated aqueous solution of polymers at RT (P8 contains 5 wt% of the macromonomer)...

Fig. 32 Rapid complexation of P22 by Me-P-CD. Transmittance as a function of temperature for an aqueous solution of polymer/Me-P-CD complex P22a at a heating/cooling rate of 1°C min-1. [P22a] = lOOg L 1 (13.75g L 1 polymer, 86.25g L-1 Me-P-CD)...

Figure 33.11 (a) An illustration of molecular diffusion in an aqueous solution of polymer materials containing random meshwork structures, (b) General behavior of anomalous diffusion in inhomogeneous solution with simple mesh structure. 

Protonation of Polymer I. The sodium cation associated with Polymer I was replaced with the hydrogen ion by acidifying an aqueous solution of Polymer I with IN hydrochloric acid. The protonated polymer was insoluble in water but soluble in organic solvents, especially chlorinated solvents. The bond strength of the protonated polymer was very poor (Figure 5). 

Many Investigations have been devoted to exploration of the structure of water In aqueous solutions of polymers as well as In water-adsorbed or water-swollen polymeric substances. Although there Is some controversy among researchers regarding the actual structure. It Is generally accepted that water molecules in the vicinity of the polymer segments behave somewhat differently from the normal "bulk" water because of their Interaction with the polymer (l. ) This anomalous water Is often called "bound", "non-freezing", "hydrated", "ordered", and so on. Moreover, some workers have pointed out that there may be present another type of water which is neither identical to the bulk nor to the bound water The amount of these anomalous waters Is apparently... 

Figure 108. Spin-lattice relaxation time of water in aqueous solutions of polymer excipients. , Polyvinylpyrrolidone , gelatin , polyethylene glycol (PEG) 20,000 , PEG400 A, sucrose o, glucose. 7) °, Spin-lattice relaxation time of pure water. (Reproduced from Ref. 460 with permission.)...

The solid substrates were introduced into the laccase-LD complex solutions placed in a 50 mL round bottom flasks and the mixtures were magnetically stirred at room temperature. After the end of the process the reaction products were separated and purified by the following procedure initially the mixtures were centrifuged at 2800 G force for 60 min, the clear aqueous solution of polymer-enzyme complex was filtered through 0.45 pm Whatman cellulose filter and kept at 4 C for fiirther oxidations. The yellow to brown precipitate was collected, washed twice with DI water and dried at room temperatiu e under vacuum. It was analyzed by SEC in THE. The separation of the oxidation product(s) was achieved by preparative fractionation on the same SEC system. The THE solvent in each fraction was evaporated and the dry contents were analyzed spectroscopically. The general sequence of procedures is depicted on the flow chart in Scheme 1. 

The aqueous solutions of polymer samples were prepared by adding the required quantity of the polymers slowly to distilled water to avoid lumping, and with continuous stirring by a magnetic stirrer at a temperature of 60 °C for 4 hours. For CMS and CMS-g-PAM (M), 0.5 wt% solutions were prepared. The rheological characteristics are shown in Figure 5.9a and Figure 5.9b. 

Poly(vinyl alcohol), or PVAL, is the polymer that was used for this purpose. It is a neutral, partially water-soluble polymer (43,44) that is generally considered to be biocompatible and nontoxic (45-47). Its structure is shown in Figure 3B. PVAL has been used as a matrix for entrapment of several enzymes in gels formed by gamma irradiation of aqueous solutions of polymer/enzyme mixtures (45,48-50). In some of our experiments, allyl methacrylate (AM) was added to the polymer to facilitate cross-linking at lower doses. 

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