Soluble resins solution concentration

Suspension- and emulsion-polymerized PVDF exhibit dissimilar behavior in solutions. The suspension resin type is readily soluble in many solvents even in good solvents, solutions of the emulsion resin type contain fractions of microgel, which contain more head-to-head chain defects than the soluble fraction of the resin (116). Concentrated solutions (15 wt %) and melt rheology of various PVDF types also display different behavior (132). The Mark-Houwink relation (rj = KM°-) for PVDF in A/-methylpyrrohdinone (NMP) containing 0.1 molar LiBr at 85°C, for the suspension (115) and emulsion... 

Water-soluble resin in powder form, screen printing adhesive for all types of machinery, can be washed off easily, compatible with all dyestuffs very effective in low concentrated solutions (1 14 for light weight cotton fabrics). 

Urea (NH2CONH2) reacts with formaldehyde similarly to phenol to produce methylol derivatives that then condense further to yield a cross-linked network (Scheme 1). Actually, at a mole ratio of 1.5-2 mol of formaldehyde to urea and a pH of 7.5, a mixture of the monomethylol, dimethylol, trimethylol, and tetramethylol ureas are formed. For further extensive condensation to take place, the pH of the system must be made acidic. Thus, it is possible to concentrate the initial resin solution or spray-dry it to a soluble powder that can be dissolved and mixed with an acid catalyst at the time of application to induce the curing reaction. The ratio of formaldehyde to urea used in commercial resins varies with the manufacturer, but is always less than 2 1. 

For unknown resins, use several solvents and/or blends which appear at varying points on the chart (see Figure 1). Determine by observation which solvents will dissolve the resin. The non-volatile content should be kept low at the outset so that solubility is not masked by an overload of solute. By increasing the level of solute, the capacity of the solvent for the resin is observable. The viscosity at any solute concentration can be measured, and a cost calculation of the solvents can be made. Using... 

The discontinuous curves show the solubility extension at lower solubility parameters using certain solvents mixed with alcohol. For example, the maximum solute concentration with isopropyl alcohol (11.5 8) is 58%. By substituting increasing amounts of heptane until the mixed solvent contains only 10% alcohol, resin solubility extends to 7.9 8. The extension into lower delta values corresponds to a reduction in solids content. Solubility at lower than 11.5 8 is not successful above 58% resin concentration. 

Diluents or organic liquids with low solvent power for the vinyl resin are frequently used to lower cost, alter evaporation rate, change rheological properties of the solution, or to achieve special characteristics such as flow out, odor, flammability, resistance to blushing, etc. A more soluble resin and a high concentration of good solvent in the system permits wider latitude in using the diluent. 

Dilution ratio, DR, is used to express the tolerance of solvents to diluents, most frequently, toluene. DR is the volume of a solvent added to a given solution that causes precipitation of the dissolved resin. This ratio can characterize the compatibility of a diluent with a resin solution in primary solvent. When compatibility is high, more diluent can be added. Only a multi-parameter approach provides a satisfactory correlation with solubility parameters. DR depends on the polymer concentration. With polymer concentration increasing, DR increases as well. T emperature influences DR in a similar manner. Determination of DR must be performed at standard conditions. DR can be related to the solubility parameters but such correlation depends on concentration. 

Expressesd as % wt resin content. The figures represent the lowest solids content solution which is possible to prepare. Where complete solubility at all concentrations is obtained this is denoted by CS. 45% is the limit of solubility. At 23°C. Note Although alcohols and aromatic hydrocarbons are not by themselves true solvents for EPIKOTE resins, mixtures of them frequently are, especially for the lower molecular weight members. They may be used to improve the flow and film properties by providing a better solvents balance at lower raw material cost. In view of the occurrence in certain cases of limited tolerance, it is recommended that concentrated solution be first prepared and that this solution be subsequently diluted to the desired solids content. 

Ymyl chloride-aaylic acid copolymer and epoxy resin latices and a phenol formaldehyde resin solution were used to modify sand-cement mortars at room tanperature. The compression strength increased with an increase in the latex/resin concentration and with the addition of calcium chloride or calcium carbonate and a superplasticiser. Tensile and flexural strengths also increased with polymer incorporation. The porosity of the modified mortars decreased with the addition of resin. The percentage of water absorption and acid solubility decreased for the latex/resin modified samples. 21 refs. INDIA... 

Higher solution viscosity results from higher resin soUds, whereas an inerease in solvent volume reduces viscosity. Soluble resins (polymers) produce more pronounced viscosity changes than do insoluble pigments or plastic particles. A plastisol suspension (plastic particles in a liquid plasticizer) may have a medium viscosity at 80% solids, whereas a coating may be highly viscous with a 50% solid concentration. The specific solvent will also have an effect on the viscosity, depending whether they are true solvents, latent solvents, or nonsolvents. Refer to Refs. 1 and 2 for more detail. 

The film forming process is very different from a solvent soluble resin and is much more difficult to control. From polymer solutions, the polymer chains are already present in a fully interpenetrated network with the molecules of solvent fully solvating the polymer species. On drying, the solvent merely evaporates, leaving the fully interpenetrated network of polymer chain as a concentrated uniform layer. 

Chemical Properties and Reactivity. LLDPE is a saturated branched hydrocarbon. The most reactive parts of LLDPE molecules are the tertiary CH bonds in branches and the double bonds at chain ends. Although LLDPE is nonreactive with both inorganic and organic acids, it can form sulfo-compounds in concentrated solutions of H2SO4 (>70%) at elevated temperatures and can also be nitrated with concentrated HNO. LLDPE is also stable in alkaline and salt solutions. At room temperature, LLDPE resins are not soluble in any known solvent (except for those fractions with the highest branching contents) at temperatures above 80—100°C, however, the resins can be dissolved in various aromatic, aUphatic, and halogenated hydrocarbons such as xylenes, tetralin, decalin, and chlorobenzenes. 

Surface Applied Surfactants. Antistat agents can be appHed direcdy to the surface of a plastic part. Usually the antistat is diluted in water or in a solvent. The antistat solution is appHed by spraying, dipping, or wiping on the surface. The water or solvent dries leaving a thin film that attracts moisture. Since it is appHed to the surface, migration through the resin is not a factor. In practice, the quaternary ammonium compounds find the most use. They are soluble in water and effective at low concentrations. 

The viscous oil resin Is slurried twice with 250 cc portions of methanol to remove any unreacted primary amines. The oil residue after being washed with methanol is dissolved in ethyl alcohol and 75 cc of concentrated hydrochloric acid is added dropwise to the warm alcohol solution of the base. The dihydrochloride salts of the several hydroabietyl ethylenediamines precipitates immediately from solution. The salt is then separated by filtering and is washed twice with 100 cc portions of cooled ethyl alcohol. The dihydrochloride salts of the dehy-droabietyl, dihydroabietyl and tetrahydroabietyl ethylenediamine mixture have a melting point of about 292°C to 295°C. On subjecting the mixture to solubility analyses it Is found that the dehydroabietyl ethylenediamine is present in substantially the same proportion as is the dehydroabietylamine in the original "Rosin Amine D."... 

Co-administration of ofloxacin and chitosan in eyedrops increased the bioavailabUity of the antibiotic [290]. Trimethyl chitosan was more effective because of its solubility (plain chitosan precipitates at the pH of the tear fluid). On the other hand, N-carboxymethyl chitosan did not enhance the corneal permeability nevertheless it mediated zero-order ofloxacin absorption, leading to a time-constant effective antibiotic concentration [291]. Also W,0-carboxymethyl chitosan is suitable as an excipient in ophthalmic formulations to improve the retention and the bioavailability of drugs such as pilocarpine, timolol maleate, neomycin sulfate, and ephedrine. Most of the drugs are sensitive to pH, and the composition should have an acidic pH, to enhance stability of the drug. The delivery should be made through an anion exchange resin that adjusts the pH at around 7 [292]. Chitosan solutions do not lend themselves to thermal sterilization. A chitosan suspension, however. 

Orange shades are realized with lipophilic natural colorants like paprika oleo-resin, P-carotene, and canthaxanthin after previous emulsification to yield water-dispersible forms. Yellow shades can be achieved using turmeric as a water-soluble solution, but the solution is light sensitive. To maintain constant color, 3 to 6 ppm of P-carotene may be added. Stable brown coloration is obtained from caramel a concentrated syrup is easily incorporated, well flavored and stable in creams. ... 

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