To insoluble gels

The support medium provides the matrix in which protein separation takes place. Various types of support media are used in electrophoresis and range from pure buffer solutions in a capfilary to insoluble gels (e.g., sheets, slabs, or columns of starch, agarose, or polyacrylamide), or membranes of cellulose acetate. Gels are cast in a solution of the same buffer to be used in the procedure and may be used in a horizontal or vertical direction. In either case, maximum resolution is achieved if the sample is applied in a very fine starting zone. Separation is based on differences in charge-to-mass ratio of the proteins and, depending on the pore size of the medium, possibly molecular size. 

From the present study, it is clear that methylsilane can be easily polymerized to poly(methylsilane), using either DMT or DMZ as catalyst. By proper choice of conditions, a polymer completely soluble in common organic solvents can be obtained, but prolonged reaction eventually leads to insoluble gel. As will be described elsewhere, this cross-linking reaction is of some advantage when the polymers are used as precursors for synthesis of silicon carbide. 

A typical example is total monomers. 100 sodium stearate, 5 potassium persulfate, 0.3 lauryl mercaptan, 0.4 to 0.7 and water, 200 parts. In this formula, 75 parts of 1,3-butadiene and 25 parts of 4-methyl-2-vinylthiazole give 86% conversion to a tacky rubber-like copolymer in 15 hr at 45°C. The polymer contains 62% benzene-insoluble gel. Sulfur analysis indicates that the polymer contains 21 parts of combined 4-methyl-2-vinylthiazole (312). Butadiene alone in the above reaction normally requires 25 hr to achieve the same conversion, thus illustrating the acceleration due to the presence of 4-methyl-2-vinylthiazole. 

Polymers in Solution. Polyacrylamide is soluble in water at all concentrations, temperatures, and pH values. An extrapolated theta temperature in water is approximately —40° C (17). Insoluble gel fractions are sometimes obtained owing to cross-link formation between chains or to the formation of imide groups along the polymer chains (18). In very dilute solution, polyacrylamide exists as unassociated coils which can have an eUipsoidal or beanlike stmcture (19). Large aggregates of polymer chains have been observed in hydrolyzed polyacrylamides (20) and in copolymers containing a small amount of hydrophobic groups (21). 

Superabsorbents. Water-sweUable polymers are used extensively in consumer articles and for industrial appUcations. Most of these polymers are cross-linked acryUc copolymers of metal salts of acryUc acid and acrylamide or other monomers such as 2-acrylamido-2-methylpropanesulfonic acid. These hydrogel forming systems can have high gel strength as measured by the shear modulus (134). Sometimes inorganic water-insoluble powder is blended with the polymer to increase gel strength (135). Patents describe processes for making cross-linked polyurethane foams which contain superabsorbent polymers (136,137). 

Inorganic Esters. Boric acid and borax form cycHc esters with poly(vinyl alcohol) (85—100). The reaction is markedly sensitive to pH, boric acid concentration, and the cation-to-boron ratio. An insoluble gel is formed at pH above 4.5—5.0 ... 

Poly(acryhc acid), poly(methacryhc acid), and maleic anhydride containing polymers reacts with poly(vinyl alcohol) to form insoluble gels (119—122), which are usehil as absorbents for water, blood, urine, etc. 

Hazer [20,25] reported on the reaction of a po]y(eth-ylene g]ycol)-based azoester with methacryloyl chloride in the presence of (CH3CH2)3N. In this reaction double bonds were attached to the chain ends of the poly(ester) thus obtaining a macroinimer. Being used for the thermal polymerization of styrene, the material formed an insoluble gel [20]. Probably, both the C=C double bonds and the azo bonds reacted in the course of the thermal treatment. The macroninimer in a later work [25] was used for thermally polymerizing poly(butadiene) thus leading to poly(ethylene glycol-/ -butadiene) block copolymers. 

The intermolecular interactions stabilise the helices and greatly influence the properties of exopolysaccharides in solution, ie solubility, viscosity and gel-formation. A strong interaction or good-fit between molecules will lead to insolubility, whereas poor interaction will lead to solubility of exopolysaccharides. The interactions between molecules is influenced by the presence of side-chains. For example, cellulose is insoluble but introduction of a three monosaccharide side-chain into the cellulose chain gives the soluble xanthan. Small changes in the structure of the side-chains can alter the molecular interactions and thus properties of the exopolysaccharide. 

As the poly(alkenoic acid) ionizes, polymer chains unwind as the negative charge on them increases, and the viscosity of the cement paste increases. The concentration of cations increases until they condense on the polyadd chain. Desolvation occurs and insoluble salts precipitate, first as a sol which then converts to a gel. This represents the initial set. 

The presence of 0.25-0.5 wt-% DCP at 180°C resulted in the formation of about 20% of a cyclohexane-insoluble fraction. The presence of 5 wt-% MAH (based on EPR) increased the amount of cyclohexane—insoluble gel, whose concentration decreased from 65% to 27% as the DCP content increased from 0.25 to 1.0 wt-% (based on EPR), respectively. The cyclohexane-soluble polymer contained about 1 wt-%... 

Polysilanes bearing triflate groups are very reactive and form an insoluble gel with a trace of moisture. The triflate group is hydrolized to silanol which rapidly condenses with the remaining triflate groups to a siloxane unit, linking intra or intermolecularly silicon atoms ... 

Figure 3. Influence of temperature on the rate of cross-linking of three methacrylate polymers plotted in terms of time relative to the gel dose R. Insolubility at R/R = 10 used as a measure of fl/a, the ratio of chain breaks to cross-links formed. For composition of polymer 59, see Table I.

SOLUBLE/INSOLUBLE (GEL) FRACTION. If crosslinking predominates over scission (when G(crosslink) > 4 G(scission)), the decrease in soluble fraction above the gel dose, may be used to derive G values for both processes. An equation was derived by Charlesby and Pinner for the most probable molecular weight distribution and similar equations have been derived for other distributions. 

For cases in which the NPs are not soluble in the supporting electrolyte in which they will be examined, it is possible to solvent-cast a thin film of the NPs on the electrode surface followed by evaporation [44] or to directly apply an insoluble gel containing the NPs [45]. In a related approach, films of anionic Prussian Blue NPs that had been synthesized in a solution containing chitosan (a cationic glucosamine polymer) were drop-cast onto glassy carbon surfaces, giving very stable... 

For an un-cross-linked material that undergoes predominantly cross-linking when exposed to ionizing radiation, solvent extraction experiments reveal that at certain absorbed dose (the critical dose), a percentage of the material, is converted into insoluble gel. Beyond that point, the percentage of gel increases as a function of irradiation dose. In general, both the degrees of... 

Transfer reactions to polymer are easily observed. Indeed, for the very high yields of the acrolein polymerization, Insoluble gels are obtained. With IT - as counter Ion, the polymerization being very fast, this phenomenon cannot be avoided. On the other hand, with Li+ and Na, no gel Is obtained if the yields remain lower than 70%. 

To enhance the shelf life of finished paper product, the step 1 product was applied below its critical micelle concentration (CMC). Materials additized above the CMC formed insoluble gels when aged for 8 days at 73°C. The CMC ranges was determined using glyoxalated poly(vinylamide-co-diallyldimethyl-ammonium chloride) containing 90 wt% vinylamide and are provided in Table 1. 

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