Solubility parameters surface tension

Critical surface tensions of functional polymers were experimentally determined. This set of data and the data on elastomers obtained previously were used to elucidate the proposed solubility parameter-surface tension relationship and the proposed parachor-surface tension relationship. The results show that the former has a higher correlation coefficient than the latter. The correlation coefficients, including three highly hydrogen-bonded polymers, are 0.731 for the former and 0.299 for the latter. Otherwise, they are 0.762 for the former and 0.178 for the latter. For the size of samples examined, we can conclude that the proposed solubility parameter-relationship is more effective than the proposed parachor-relationship in calculating critical surface tension of a polymer. 

Solvent logA , Solubility parameter Surface tension Dielectric constant... 

Figure 2.3.22. Hildebrand solubility parameter surface tension for four groups of solvents.

The solubility and surface tension results itemized in Table XVII confirm that there is a larger interaction between ethanol and the TAA salts as the size of the cation or organic portion increases. The data show that in spite of the R4NBr salts becoming more soluble in water as the cation size increases, their solubility increases much more rapidly in ethanol, in fact by a factor of 10 greater in ethanol than in water as the salt series of the present investigation is ascended. As a result, the two highest members of the series, the tetrapropyl and tetrabutyl salts, are actually more soluble in ethanol than in water, while the reverse is true for the lower three. Consequently, on the basis of relative solubilities of the salts studied in both ethanol and water, trends in the salt effect parameters similar to those of this work, based on the vapor-equilibrium studies listed in Table XVIII would be observed. 

The use of the ADR method may not always provide accurate vehicle compositions for a given solute since intermolecular forces are dependent on structural characteristics of the solvent and solute that are not expressed by It is possible, and perhaps desirable, to substitute other measures of cosolvent polarity, such as solubility parameter, surface or interfacial tension, etc., for e when blending solvents, although inaccuracies in vehicle predictions will generally continue to exist. 

The solubility parameter defined by eqn (5.39) is not identical to that conventionally measured by swelling, solubility or surface tension data, since in the first case the solute is at infinite dilution in the polymer, while in the other cases its concentration is high. Because it is possible that at high dilutions the behaviour as a regular solution, inherent to the development of the Hildebrand-Scatchard theory, is more rigorously obeyed, 8" may be more meaningful than 8j. 

In a fundamental sense, the miscibility, adhesion, interfacial energies, and morphology developed are all thermodynamically interrelated in a complex way to the interaction forces between the polymers. Miscibility of a polymer blend containing two polymers depends on the mutual solubility of the polymeric components. The blend is termed compatible when the solubility parameter of the two components are close to each other and show a single-phase transition temperature. However, most polymer pairs tend to be immiscible due to differences in their viscoelastic properties, surface-tensions, and intermolecular interactions. According to the terminology, the polymer pairs are incompatible and show separate glass transitions. For many purposes, miscibility in polymer blends is neither required nor de-... 

The efficiency of extraction is mainly dependent on temperature as it influences physical properties of the sample and its interaction with the liquid phase. The extraction is influenced by the surface tension of the solvent and its penetration into the sample (i.e. its viscosity) and by the diffusion rate and solubility of the analytes all parameters that are normally improved by a temperature increase. High temperature increases the rate of extraction. Lou et al. [122] studied the kinetics of mass transfer in PFE of polymeric samples considering that the extraction process in PFE consists of three steps ... 

The above set of equations can be solved numerically given input parameters, including initial bubble radius Uo, temperature, ambient pressure Pf, surface tension a, solubility relation, D and p as a function of total H2O content and temperature, and initial total H2O content in the melt. 

In several previous papers, the possible existence of thermal anomalies was suggested on the basis of such properties as the density of water, specific heat, viscosity, dielectric constant, transverse proton spin relaxation time, index of refraction, infrared absorption, and others. Furthermore, based on other published data, we have suggested the existence of kinks in the properties of many aqueous solutions of both electrolytes and nonelectrolytes. Thus, solubility anomalies have been demonstrated repeatedly as have anomalies in such diverse properties as partial molal volumes of the alkali halides, in specific optical rotation for a number of reducing sugars, and in some kinetic data. Anomalies have also been demonstrated in a surface and interfacial properties of aqueous systems ranging from the surface tension of pure water to interfacial tensions (such as between n-hexane or n-decane and water) and in the surface tension and surface potentials of aqueous solutions. Further, anomalies have been observed in solid-water interface properties, such as the zeta potential and other interfacial parameters. 

U/V, equalling the square of the solubility parameters reported in Table 3.1. The work that must be done against this stiffness in order to create cavities that are able to accommodate a solute of given size in a series of solvents is proportional to this quantity. This work is also given by the product of surface tension a of the solvent (Table 3.9) and the surface area of this cavity. (This holds strictly for macroscopic cavities, but is apparently extendable also to molecular sized ones.) For non-associated solvents another measure of their stiffness is the internal pressure, Pl (see Table 4.2), that equals... 

Furthermore, Hildebrand and Scott [32] found a relationship between the solubility parameter, 5, and surface tension, as, for polar and non-polar liquids. Their relationship can be written as [66]... 

At this point, it is important to present a disclaimer. Many notable engineers could claim the author is loco to think he can resolve all database needs with only the eight physical properties given or otherwise derived in this book. Let me quickly state that many other extended database resources are indeed referenced in this book for the user to pursue. Only in such retrieval of these and many other database resources, such as surface tension and solubility parameters, can PPE be applied. An example is that surface tension and solubility parameters must both be determined before the liquid/liquid software program given herein can be applied. This liquid-liquid extraction program (Chemcalc 16 [1]) is included as part of the PPE presentation. (See Chap. 7.) It is therefore important to keep in mind that many database references are so pointed to in this book—Perry s, Maxwell s, and the American Petroleum Institute (API) data book, to name a few. 

Another interesting empirical relationship, viz. between surface tension and solubility parameter, was found by Hildebrand and Scott (1950) ... 

The Rao function has the same form as the Sugden function or Molar Parachor (Ps = My1/4/p), derived by Sugden in 1924, which correlates the surface tension with the chemical structure. Also the Small function or Molar Attraction Function, which correlates the cohesion energy density, ecoh, and the solubility parameter, 8, with the chemical structure, has this form ... 

Wettability of Elastomers and Copolymers. The wettability of elastomers (37, 38) in terms of critical surface tension was reported previously. The elastomers commonly used for the reinforcement of brittle polymers are polybutadiene, styrene-butadiene random and block copolymers, and butadiene-acrylonitrile rubber. Critical surface tensions for several typical elastomers are 31 dyne/cm. for "Diene rubber, 33 dyne/cm. for both GR-S1006 rubber and styrene-butadiene block copolymer (25 75) and 37 dyne/cm. for butadiene-acrylonitrile rubber, ( Paracril BJLT nitrile rubber). The copolymerization of butadiene with a relatively polar monomer—e.g., styrene or acrylonitrile—generally results in an increase in critical surface tension. The increase in polarity is also reflected in the increase in the solubility parameter (34,39, 40) and in the increase of glass temperature (40). We also noted a similar increase in critical surface tensions of styrene-acrylonitrile copolymers with the... 

Compatibility of polymers implies a semi-quantitative measure can be used to predict whether two or more polymers are compatible. The use of one of the semi-quantitative approaches, solubility parameter, was demonstrated by Hughes and Britt (22). It was concluded (8) that one parameter was insufficient to predict the compatibility. In this paper, we now introduce critical surface tension which is determined from the surface properties of a polymer. Though both of these parameters have been related by Gardon (15), we are inclined to use the latter because we can further describe the wettability between two polymers. For instance, by the use of yc, we can predict equally well that compatibility between polystyrene and polybutadiene can be improved if butadiene is... 

Critical surface tensions (yc) of a series of functional polymers were determined. These results are compared with those calculated on the basis of solubility parameter (8) according to the following equation ... 

The purpose of this paper is to use data already aquired on critical surface tension for a correlation with solubility parameters and parachors of polymers. The theoretical background of these parameters is briefly mentioned. The evaluation of the calculated values is then discussed. Because of the complexity of the polymer conformation on the surface, we do not imply that a straight-forward relationship between the surface and the bulk properties is available, even in the case of a liquid-like amorphous polymer. Another purpose of this paper is, therefore, to point out the complicating factors and the difficulties in predicting the surface wettability on the basis of bulk properties. 

Solubility Parameter and Surface Tension. Cohesive energy density (CED) (9) is the energy, in calories per cubic centimeter, necessary for an infinite separation of the molecule in 1 cubic centimeter of liquid versus the action of intermolecular attraction ... 

An empirical relationship between the solubility parameter and the liquid surface tension of a nonpolar liquid was obtained by Hildebrand and Scott (9)... 

Despite the approximation, Zisman s critical surface tension (39, 40) still provides the most convenient means of expressing the surface tension of a solid. Later Gardon (6) suggested a possible linear relationship between the critical surface tension yc and the solubility parameter for liquid-like polymers. He also proposed the following relation between solid surface tension and critical surface tension ... 

In Table III, critical surface tensions of thirty-nine polymers are reported, calculated on the basis of Equation 5 by assuming < = 1. In other words, these calculated results are equivalent to the calculated solid surface tensions (y8). Solubility parameters of several polymers listed in the table were calculated on the basis of Small s constants (35), and all molar volumes were calculated on the basis of the molecular weight of the repeat unit and the density of the polymer. The results in Table III were used to prepare a graph (Figure 2) for the comparison between the calculated and the observed critical surface tensions of these polymers. The data are rather scattered, and the calculated values are generally lower than those observed directly. The following factors may be contributing to the deviations ... 

Density Solubility Parameter Critical Surface Tension... 

Thus, by considering the apparent solubilities of water with various types of inorganic salts, and the surface tensions of these solutions, we were able to make determinations concerning the apparent associated Cohesive Energy Density parameters. 

For true compatability of solute and solvent, matching of all these partial solubility parameters (i.e., 8, Bp, 8 ) is necessary. The total solubility parameter can be easily calculated [1, p. 307] finm the material s enthalpy of vaporization, vapor pressure as a function of temperature, surface tension, thermal expansion coefficient, critical pressure, and second virial coefficient of its vapor, as well as by calculating its value for the chemical structure of the material. For the calculation of the Hildebrand solubility parameter fi om chemical structure, we use Small s [58] equation ... 

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