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Quaternized polyethylenimines exhibit viscosity behavior very similar to that of linear flexible polyelectrolytes and thus evidently swell in dilute salt solutions. This swelling is manifested also in the rate constants for the hydrolysis of chiral or achiral nitrophenyl esters catalyzed by these polymers. Stereoselective preference is exhibited in hydrolyses catalyzed by the quaternized polymers containing covalently linked l-histidine moieties. Maximum stereoselectivity is manifested at polymer concentrations corresponding to nonswollen conformations. With added cetyltrimethylammonium bromide, the stereoselective preference of the catalyzing polymer can be reversed. A comparison of the effects of added anionic, nonionic, and cationic detergents shows decreases in rate for the first, no significant effect for the second, and substantial changes for the third, depending on the polymer and detergent concentrations. Cationic detergents of different chain lengths and structures show different effects reflecting largely their extent of binding by the polymer.

The binding of acid azo dyes having phenolic hydroxyl groups such as orange I (I), orange II (II), chrome violet (III), 4-hydroxyazobenzene-4′-sulfonate (IV), and 2,4-dihydroxyazobenzene-4′-sulfonate (V) by polyethylenimine was studied by equilibrium dialysis and spectroscopic methods. The results obtained indicate that dyes (III) and (V) with two OH groups are bound much more strongly than dyes (I), (II), and (IV) with one OH group. Also polyethylenimine is far superior to any other polymers which have been examined, including bovine serum albumin, polyvinylpyrrolidone, and poly-L-lysine, in its ability to form complexes with these dyes (III) and (V). The OH groups involved participate preferentially in complex formation with polyethylenimine. The unusual affinity of polyethylenimine for the dyes carrying OH groups is discussed.

Transformation structurelle de la structure α-cristalline de la fibre en structure β-desorientee. Immersion des fibres en solution aqueuse, a 100°C, de bromure de lithium

The effects of extension of wool fibers on the dyeing rate have been examined using C. I. Acid Orange 7 in an acidic dyebath. The apparent rate of dyeing increased with an increase of extension ratio. From the relationship between the relative dye exhaustion and the square root of dyeing time, it was found that the initial dyeing behavior which was remarkably affected by extension contributed to the increase of the apparent dyeing rate. The scanning electron micrographs of extended wool fibers showed that the cusps of the cuticle cells were curved upward and the gaps between cuticle cells were enlarged. Therefore, it seems reasonable that the increase of the initial dyeing rate is due to the rough and porous nature of the surface layer responsible to the morphological changes in the cuticle layer.

Effet du groupe alkyle du colorant (amino-1 alkylamino-4 anthraquinone sulfonate-2) sur l'importance de la liaison et les parametres thermodynamiques et comparaison avec le methyle orange et ses homologues

The effect of polyanion on the transport of sulfonated chromophore (C.I. Direct Yellow 12) from aqueous solution into cellulose membranes has been studied at 25°C. The diffusion of the chromophore into the cellulose membrane was analyzed on the basis of a parallel transport mechanism of surface and pore diffusion as developed in our previous paper, revealing that the diffusion was controlled by surface diffusion rather than by pore diffusion. Interestingly, the concentration of polyanions influenced the adsorption equilibrium of the sulfonated chromophore into the cellulose membrane but had no effect on the diffusion coefficient of the chromophore. The diffusion coefficients of the chromophore obtained in the presence of the polyelectrolyte agreed with those obtained in the presence of a simple inorganic electrolyte.

Polyester fiber has been treated in chlorinated hydrocarbon/water or water/chlorinated hydrocarbon emulsion. The chlorinated hydrocarbons used were 1, 1, 2, 2-tetrachloroethylene and 1, 1, 2, 2-tetrachloroethane. The changes in dyeing behavior, shrinkage, density, and X-ray diffraction of the fiber were studied as measures of amorphous and crystalline regions. Pretreatment in the emulsion led to greater dye uptake and rate of dye absorption. Moreover, dyeing in the presence of the emulsified tetrachloroethylene was found to increase significantly the rate of dye absorption relative to that in the absence of tetrachloroethylene or that of the fiber pretreated in the emulsion of the same composition. This appears to be due to solvent-induced structural changes of the fiber and carrier action of residual tetrachloroethylene adsorbed on the fiber.

Stereoselective hydrolyses of chiral substrates were examined in poly(ethylenimine) derivatives with optically active groups. A high stereoselective effect, kL/kD=3.6, is observed. The effect of the substrate structure influenced both the rate constant and the stereoselective ratio in the hydrolyses by poly(ethylenimine) derivatives.

A study was made of the formation of polyion complexes between a piperidinium cationic polymer and polyanions and of the binding of azo-dye anions (methyl, ethyl, propyl, and butyl orange) by these complexes. Sodium poly(acrylate), poly(styrenesulfonate), dextran sulfate, and carboxy-methylcellulose were used as polyanions. The resultant polyion complexes (insoluble in aqueous solutions) were compared for their ability to bind the small organic molecules in aqueous solutions, for example, of urea and an inorganic electrolyte (KCI), and exhibited a strong binding affinity toward these small anions. Polyion complexes that consisted of sodium poly(acrylate), dextran sulfate, and carboxymethylcellulose as polyanions cooperated in the binding, whereas the polyion complex of sodium poly(styrenesulfonate) did not. It was suggested that small organic anions interact with the polyion complexes primarily through electrostatic and hydrophobic forces.

Mesures de la fixation d'ions metalliques bivalents, Cu 2+ , Ni 2+ , Co 2+ et Zn 2+ sur le polyethyleneimine et ses derives acetyl et alkyl par la technique de la dialyse d'equilibre

Polyester fiber was pretreated with organic solvent/water solutions of various compositions. The organic solvents used in this experiment were benzyl alcohol, n-butanol, and N, N-dimethylformamide (DMF). The dyeing behaviors of the pretreated fibers with 1, 4-diaminoanthraquinone in water were studied with reference to changes in the fine structure of the fibers. Also density and X-ray diffraction of the fibers were investigated as a measure of crystallite region. The dye uptake increased in the order, fiber pretreated with water

The absorption isotherms of methanesulfonic acid, ethanedisulfonic acid, and R-acid on nylon fiber were determined in water and ethylene glycol at 80°C. The saturation values of the sulfonic acids on the nylon fiber were determined by extrapolation of a reciprocal plot of the absorption isotherms. In water, the saturation values of the three acids were near the amino group content of the fiber. In ethylene glycol, the saturation values of the dibasic acids, ethanedisulfonic acid and R-acid, were much larger than the stoichiometric quantity corresponding to the amino group content of the nylon fiber, approximately twice, though the saturation value of the monobasic acid, methanesulfonic acid, was near the amino group content. A dyeing model of nylon with polybasic dyes was proposed, in order to explain how a polybasic dye can physically saturate fixed sites.

In order to investigate the effects of glycerol on the properties of water, the proton magnetic resonance of water-glycerol mixture has been determined in the absence and presence of electrolytes.By adding glycerol into water, significant downfield shift was observed. This result suggests that glycerol would promote the intermolecular hydrogen-bonding of water.The upfield shift of water proton resonance on the addition of structure breakers, KCI, KBr and KI, of which the structure-breaking ability increases in that order, was found to be more prominent in the presence of higher glycerol content. This effect was remarkable for the electrolytes which are well known as the effective structure breakers to water. These results suggest that glycerol apparently promotes the structure breaking effects of the electrolytes.The apparent increases of the structure breaking effects of these electrolytes are explained in terms of the promotions of intermolecular hydrogen-bonding in water caused by glycerol.

Polyvinylpyrrolidones of various degrees of cross-linkage have been prepared by radical polymerization of N-vinylpyrrolidone with methylenebisacrylamide to regulate the fraction of cross-linkage. The insoluble polymers obtained were examined for their ability to bind methyl orange and its homologs, methyl orange, ethyl orange, propyl orange, and butyl orange at 5, 15, 25, and 35°C, respectively, in an aqueous solution. The first binding constants and the thermodynamic parameters that accompanied the binding were calculated. For any particular dye the extent of binding, the absolute magnitude of ΔF°, and the value of ΔS° increased as the degree of cross-linkage increased, starting with water-soluble polyvinylpyrrolidone (zero cross-linkage) and proceeding to the polymer with high cross-linking density. This behavior can be accounted for in terms of more extensive hydrophobic domains in the cross-linked polymeric matrix that enhances hydrophobic interactions in the binding process. Moreover, the cross-linked macromolecule polymerized in the presence of methyl orange and then stripped of the bound methyl orange shows substantially stronger binding for this small molecule than the polymer cross-linked in the absence of methyl orange. In contrast, the cross-linked polymer prepared similarly in the presence of the larger molecule, butyl orange, exhibits decreased affinity toward the smaller consolute, methyl orange, than either of the other polymers described. It seems, therefore, that the polymeric matrix provides favorable binding sites or pockets that can accommodate a specific small molecule. The preparative procedure, which uses a small-molecule template, molds into the polymer some structural specificity in the binding of small molecules.

Polyion complexes of sodium poly(methacrylate) and piperidinium cationic polymers [I], which are insoluble in water and have an equal number of positive and negative charges, bind organic anions (methyl orange, ethyl orange, propyl orange, butyl orange, and pentyl orange) in aqueous solution. The strength of the binding is enhanced by an increase in the hydrophobicity of the polyion complex and the small cosolute. Moreover, strong cooperative interactions appear with increased uptake of the small molecule. Urea and an inorganic electrolyte (KCl) were examined for their effect on the binding, the amount of which is strongly suppressed by these additives. The significance of hydrophobic and electrostatic interactions which accompany the binding is described.

In the previous paper, we have studied the dyeing of cellulose by Chrysophenine G (C. I. Direct Yellow 12) in aqueous sodium alginate solution and have concluded by the membrane equilibrium theory that the dye ion is concentrated into the internal solution of fiber due to the presence of sodium alginate in the bulk solution. Sodium alginate is subject to hydrolysis during the course of dyeing, which may make the interpretation somewhat dubious. In the present study we have chosen sodium polystyrene sulfonate (NaPSS) as a synthetic polyelectrolyte which is not subject to hydrolysis and have studied the dyeing of cellulose by Chrysophenine G in aqueous NaPSS solution. It is found that our model assumed in the previous paper explains the obtained results by assigning an appropriate degree of dissociation of sodium ion to NaPSS in solution.

The large enhancement in the rate of alkaline hydrolysis of p-nitrophenyl hexanoate in aqueous solutions of tetradecyltrimethylammonium bromide in the presence of bovine serum albumin was found. A maximum in the rate enhancement appeared in the vicinity of the critical micelle concentration of the surfactant. It was suggested that the rate enhancement was attributable to the formation of protein–surfactant complexes providing a new pseudo-phase for the reaction.

A large rate enhancement and a stereoselective preference are exhibited in the hydrolysis catalysed by N-decanoyl-L-histidine(2a) and a dipeptide containing L-histidyl residue (2b) in the domain of linear poly(ethylenimine) derivatives.

Bovine serum albumin exhibits remarkable acylation efficiency and stereoselectivity in the hydrolysis of optically active amino acid p-nitrophenyl esters. A stereoselective ratio, kD/kL = 66 has been observed with added Triton-x. The hydrolysis rate and stereoselectivity depend on the structure of the substrate and of added surfactants.

Catalytic hydrolysis of enantiomeric substrates by N-decanoyl-L-histidine was studied at pH 7.30, 0.02M phosphate buffer, and 25°C in the presence of quaternized polymers. The rate of reaction is remarkably accelerated in the presence of polyethylenimine derivatives, but the observed stereoselectivity depends on the structure of the substrates.

The dyeing process for a cellulose membrane–direct dye system is analyzed based on a parallel transport mechanism of surface and pore diffusion with Freundlich isotherm. Numerical solutions were obtained in order to clarify how the surface and pore diffusion resistances affect the uptake curve. The numerical solutions were also compared with an analytical solution for surface diffusion control to establish the range where the analytical solution can be considered as an acceptable approximation. The uptake curves in the cellulose membrane-chromophore (C.I. Direct Yellow 12) system in the presence of inorganic electrolyte were measured. The rate of adsorption and the maximum amount of adsorption increased with an increase in the concentration of those electrolytes. The rate of adsorption was approximately controlled by the surface diffusion rather than by pore diffusion. The surface diffusivities of the dye were little affected by either the concentration and or nature of the electrolyte.

The binding of methyl orange, ethyl orange, and propyl orange by polycations involving various apolar pendant groups such as methyl, ethyl, benzyl, or dodecylbenzyl groups has been examined quantitatively by an equilibrium dialysis method at 5, 15, 25, and 35°C. The first binding constants and the thermodynamic parameters in the course of the binding have been calculated. The favorable free energy of the binding is accompanied by an entropy gain and an exothermic enthalpy change. The shorter the alkyl chain of the dyes or the polymers, the more negative is the enthalpy change and hence the smaller is the entropy change. Furthermore, an increase in binding affinity can be created in the polycation upon introduction of hydrophobic groups. In particular, the binding ability of the polycation containing a dodecylbenzyl group for methyl orange is almost 300-fold that of bovine serum albumin. Therefore it is clear that hydrophobic interactions, as well as electrostatic ones, are involved in the binding.

Nylon 6, heat-set nylon 6 and nylon 66 have been treated with aqueous formic acid solutions of various concentrations for a predetermined time at a fixed temperature. The changes in weight loss, water absorption, shrinkage, crystallinity, crystallite size were measured in order to estimate the change in amorphous and crystalline regions of the fibers, and the structural change in fibers was related to the dyeability for C. I. Disperse Violet 1 (1, 4-diaminoanthraquinone). These parameters, except the dyeability, increased with increasing the concentration of formic acid until the fibers were dissolved completely in concentrated formic acid solutions (ca. 59% solution for nylon 6, ca. 62% solution for heat-set nylon 6, and ca. 68% solution for nylon 66). In particular, the loss in weight gradually increased when the samples were treated with formic acid solution at a concentration lower than 50%. Correspondingly, the dyeability gradually increased at a concentration lower than 50%. However, the dye uptake showed a marked decrease when the loss in weight was markedly observed. From results obtained the relationship between the dyeing behaviors and the changes in fine structure has been discussed.

The mean activity coefficients of sodium 4′-dipentylaminoazobenzene-4-sulfonate (pentyl orange, PeO) and sodium 4′-dihexylaminoazobenzene-4-sulfonate (hexyl orange, HeO) in aqueous solutions having the concentrations from 10-3 to 10-2 mol kg-1 have been determined by means of isopiestic measurements at 60°C. It has been found that the coefficient of HeO is much smaller than that of PeO, both being much smaller than unity. The coefficients are strongly influenced by the hydrophobic groups in the dye molecules. On the basis of spectrophotometric and conductometric studies, it has been concluded that PeO and HeO exist in the aggregates with their counter ions, Na+, being bound, in aqueous solution at a temperature as high as 60°C.

Dyeing of cellulose by Chrysophenine G (CI Direct Yellow 12) in aqueous sodium alginate solution at various temperatures has been studied. The effect of temperature change on dye adsorption equilibrium to cellulose in the presence of sodium alginate has been examined based on the previously described multiple equilibrium model. The affinities of the dye, which were calculated with an interpolated ionisation degree of the carboxyl group in the cellulose and by using the ionization degree of sodium alginate measured were nearly constant under the present dyeing conditions. These results confirm the previous conclusion that the dye is concentrated into the internal solution of cellulose due to the presence of sodium alginate in the bulk solution.

The differences in behavior on adsorption of direct dyes with different kinds of counterions on cellulose in the absence of an electrolyte are indicated, and an alternative role for electrolytes on adsorption of the dye on cellulose is proposed. In addition, an interesting effect of urea on the dye adsorption on cellulose at various temperatures is revealed.

The present work reports proton chemical shift of water to reveal the nature of urea in water and in tetramethylurea solutions (6_??_14mol/l) in which the regularity of water structure is decreased. The data show that addition of urea in water causes a decrease of the hydrogen bond of urea-water (high field shift) like the addition of tetramethylurea (4mol/l) in water, but causes an increase of the hydrogen bond of urea-water in the high concentration region of tetramethylurea solutions like the nature of urea in ethyleneglycol previously reported. These results suggest that urea-water hydrogen-bonded interactions exist and give some ordered arrangement of urea and water molecules because urea can build hydrogen bond to water through its four hydrogen atoms and the carbonyl oxygen. The effect of urea in water structure may be both structure breaker and structure maker.

The interaction of N-methylpyrrolidone with azobenzene in aqueous solutions containing 1 mol/l NaCl, LiCl, NaClO4 and NaSCN has been investigated by means of the solubility measurement of azobenzene. The thermodynamic parameters for the process which consists of the transfer of 1 mole azobenzene from the salt solution to the salt solution containing 6 mol/l N-methylpyrrolidone have been calculated. In the presence of the inorganic salts, the values of ΔF°u-trans were negative. However, the contributions of enthalpy and entropy changes to the free energy change of the process varied with the salt species. It was shown that in the presence of a water structure-breaking salt such as NaClO4 or NaSCN, the value of ΔH°trans was negative and ΔS°u-trans was positive, whereas in the presence of a water structure-making salt such as NaCl or LiCl, the value of Δ°trans was nearly zero and ΔS°u-trans was positive. These facts were interpreted in terms of hydrophobic interactions between the non-polar parts of azobenzene and N-methylpyrrolidone.

The binding of 4′-dibutylaminoazobenzene-4-sulfonate (butyl orange, BO) and 1-amino-4-methylaminoanthraquinone-2-sulfonate (AQ) by crosslinked polyvinylpyrrolidone and the competition between BO and AQ for binding sites of the polymer were examined. The equilibrium data showed competitive binding. Thus the intrinsic binding constants and the number of binding sites can be evaluated easily and precisely by competitive binding. The thermodynamic parameters that accompained the binding were calculated from the intrinsic binding constant and its temperature-dependence. The thermodynamic data for BO showed that the binding process is athermal and stabilized entirely by the entropy term. The binding of BO to the polymer is entropically favorable as a result of the operation of the hydrophobic effect. In contrast, with AQ a favorable free energy for a dye-polymer complex formation is associated with a large negative enthalpy and a small entropy. Therefore it is likely that the binding of AQ occurs by energetic forces and that the large aromatic ring of the dye contributes to the binding energy. On the average, BO and AQ can bind to the crosslinked polymer to the extent of 1 dye/ca 73 basemol in 0.1M tris-acetate buffer, pH 7.0.

Protonation to the fluorescent probe, 5-dimethylamino-1-naphthalenesulfonyl group, which had been conjugated to bovine serum albumin, was investigated in aqueous solutions of urea and guanidinium chloride. pK values not less than those of the free probe were present even in the positive range of net charge on the protein at high concentration of the denaturants. This was interpreted in terms of the electrostatic and nonpolar effects based on short-range interaction between the probe and its neighboring residues. These effects were substantiated by the reduction of the disulfide bonds in the protein and by the variation of the dielectric constant of the local environment surrounding the probe.

The salting-out phenomenon in water has been investigated referring to the solubility of nonelectrolytes and the proton chemical shift of ethylene glycol in inorganic electrolytes-ethylene glycol solutions. The nonelectrolytes include biphenyl, azobenzen and p-aminoazobenzene; and LiCl, NaCl, NaNO3, NaSCN, NaClO4, KCl and CsCl are used as the inorganic solutes.The solubility data have been interpreted in terms of the free energy change of transfer from pure to the salt solution (ΔFtrans.). It is found that ΔFtrans. in ethylene glycol is rather indifferent to inorganic electrolyte species as compared with that in water. On the other hand, the proton chemical shift showed that there is not any particular difference in the chemical shifts induced by the inorganic electrolytes between in ethylene glycol and in water.These results were discussed from the viewpoint of the relationship between the salting-out and the structural regularity of the solvents, and the contribution of “the structural salting-out effect” in the salting-out phenomenon in water was evaluated qualitatively.

The catalytic activities of N-decanoyl-L-histidine (Ia) and its methyl ester (Ib) toward the hydrolyses of enantiomeric substrates (II) have been investigated in the presence of cetyltrimethylammonium bromide micelles. The comparison of catalytic effects (both the rate constants and stereoselectivities) of (Ia) and (Ib) strongly suggests that carboxylate ion of (Ia) intramolecularly enhances the reactivity of the imidazole group. The presence of co-operative effects is also supported by the pH–rate profile and by the thermodynamic parameters of the reaction.

The transport of chromophore into a membrane in the presence of polyelectrolyte is enhanced much as it is in the presence of simple salt. The presence of polyelectrolyte with different kinds of counterions seem to modify this observed enhancement. The differences in enhanced transport into the cellulose membrane in the presence of polyelectrolyte may suggest a new model for reinterpretation of the transport phenomenon in a biological system.

The extent of binding of 1-amino-4-alkylaminoanthraquinone-2-sulfonates (alkylmethyl, ethyl, propyl, and butyl), which have different chemical structures from methyl orange derivatives, by polyion complexes consisting of a piperidinium cationic polymer and various polyanions such as sodium poly acrylate, poly methacrylate, poly styrenesulfonate, carboxymethylcellulose, and dextran sulfate, was measured in an aqueous solution. The effect of alkyl group of the anthraquinone dye on the binding behavior was investigated. Also, the resultant binding characteristics were compared with those previously observed with methyl orange and its homologs. These polyion complexes exhibited very strong binding affinity toward the anthraquinone dye. The polyion complex of the polycation and sodium poly styrenesulfonate bound the dye noncooperatively and the binding process was athermal. The first binding constant accompanying the binding is of the order of 105–106. In contrast, the polyion complexes composed of the polycation and the other polyanions exhibited strong cooperative binding and the binding process was exothermic. The possible mode of binding is discussed.

In the previous paper, it has been reported that heat conduction in a paper cylinder during high temperature steaming with humid air was considerably affected by the presence of urea. In the present paper, the effect of urea on the fine structure of nylon 6 fiber treated by high temperature steaming with humid air was investigated under various conditions of absolute humidity.Furthermore, nylon 6 fiber and filament were treated with various compositions of urea/water solution heated to 140°C in order to investigate in some detail the effect of urea during the steaming. Change of fine structure was observed by X-ray diffraction patterns. Further, crystallite size, lattice spacing and crystallinity were measured by means of X-ray diffractometer and density gradient tube.The following results were obtained:(1) Shrinkage of nylon 6 filament treated by the steaming increased with an increase of absolute humidity, particularly in the presence of urea. Crystal_??_size also increased.(2) Shrinkage, crystallinity and water absorption of nylon 6 fiber treated with hot solution of various compositions of urea/water increased with an increase of water content in treating medium.

Methyl orange homologs having long alkyl chains, 4′-dipentylaminoazobenzene-4-sulfonate (pentyl orange) and 4′-dihexylaminoazobenzene-4-sulfonate (hexyl orange) were synthesized. Aggregation behaviors of these dyes in aqueous solutions of various additives (urea, hexamethylenetetramine, LiCl, NaCl, KCl, and CsCl) were studied by means of spectrophotometry and conductometry in connection with the role of water in aggregation process. These dyes were found to exhibit a sharp break in the plots of optical density or conductance against molar concentration of the dye, indicating that the dyes readily form aggregates at low concentrations in the aqueous solutions. The critical dye concentration for aggregate formation was obtained from the break in the plots. The effects of the additives, in particular a water-structure breaker, a water-structure maker, and counterions, on the critical concentration were investigated. Furthermore, absorption spectra of pentyl orange in the presence of varying amounts of poly(vinylpyrrolidone) were recorded. The new absorption band at shorter wavelength, which is responsible for the aggregates of the dye bound on the polymer chain, was appeared on addition of the polymer. The pentyl orange-poly(vinylpyrrolidone) complexes showed strong resemblances to the spectra of the same dye in the presence of the electrolyte and of methyl orange-polycation complexes.

The binding of methyl orange, ethyl orange, propyl orange, and butyl orange by poly(vinylpyrrolidone) has been examined by a technique of equilibrium dialysis over a high temperature range (60–90°C). The first binding constants and the thermodynamic parameters in the course of the binding were evaluated. The results obtained at these temperatures were compared to those at lower ones (5–35°C) described previously in order to estimate the contribution of hydrophobic bonds to the binding. It was found that at the 60–90°C range complex formation between the dye and the macromolecule is associated with an exothermic enthalpy change and a positive entropy change. The enthalpy and entropy changes of the binding are of the order of −4.5 kcal/mole and 6 eu, respectively, for each dye measured. Thus the binding is mainly enthalpy-controlled. Furthermore the effect of the alkyl chain length of the dye on both the ΔH° and ΔS° values is not pronounced. Also temperature dependences of the ΔH° and ΔS° terms were not observed. All these observations in the higher temperature range can be explained as a result of the disruption of water structure in the binding environment and hence a decrease in hydrophobic bond formation between the dye and the polymer.