Hansen solubility volume

The solubility parameter has found previous use in membrane science. Casting solution components and composition have been selected using the Hansen solubility parameters (68-71). The total Hansen solubility parameter, which is equivalent to the Hildebrand parameter (.72), has been used to explain permeation and separation in reverse osmosis (23). Hansen s partial parameters have also been used to explain permeation and separation in pervaporatlon (61). The findings of these studies (61,73) plus those reported elsewhere in this volume (74) do lend credence to the use of 6, 6, and 6, for membrane material selection. 

Figure 4.1.4. Hansen s solubility volume of polytmide synthesized from 3,3 4,4 -benzophenone tetracarbo-xyhc dianhydride and 2,3,5,6-tetramethyl-p-phenylene diamine (after Lee ). [Adapted, by permission, fiorn H.-R. Lee, Y.-D. Lee, J. Appl. Polym. Sci., 40, 2087 (1990)]...

Three-component systems. Crowley et. al. proposed the three-dimensional solubility volumes (Figure 4.1.3). Better known are Hansen s three-dimensional solubility volumes (Figure 4.1.4). In Hansen s approach, the components of solubility parameters for mixed solvents are calculated from Eq. [4.1.56] ... 

Hansen developed a visual interpretation of his method. This is a three-dimensional sphere of solubility in which the centre of the sphere has coordinates corresponding to the values of the components of the polymer solubility parameter. A sphere radius can be used to characterize dissolving characteristics of polymers by different solvents. Each solvent is represented by a point on a three-dimensional space with 8, 8p, 8 as axes. The point should be inside the sphere (the solubility volume) for polymer and all non-solvents should be outside the solubility volume. 

In the original work these parameters had to be evaluated by the experimental observations of solubility. It has been assumed that if value of the each of the solubility parameter components of one liquid is respectively close to the corresponding value for another liquid then the process of their mixing should readily occur with a more negative free energy. The solubility volume has dimensions S, 8p, 28n- The factor 2 was proposed for the spherical form of solubility volumes and had no physical sense. However, sometimes a spherical solubility volume of polymer can be shown without using the factors This approach has become very popular. A variation of the Hansen method is Teas approach ... 

Hansen solubility properties are usually plotted in a three-dimensional coordinate system with the Hansen parameters as x, y, z axes. The coordinates of a solute can be determined by analyzing the solubility of a solute in a series of solvents with known Hansen parameters. By fitting a spheroid into the solubility space, the solubility volume of this solute can be identified. The solubility space of a solute is defined by the origin of a spheroid, resulting from the three coordinates, and the three radii in each dimension, with solvents inside the spheroid and nonsolvents outside. The radius of the sphere, Rq, indicates the maximum difference for solubility. Generally, good solvents are within the sphere, and bad ones are outside of it. Furthermore, the solubility distance ... 

Solvent Hansen solubility parameters. Molar volume (m mol )" Boiling point Density (gcm ) Vapor pressure at25°C (kPa) ... 

Dividing this by the molar volume, V, gives the total Hansen solubility parameter <5o (eq 7). 

A separate list of resin and polymer solubility parameters are available from another Barton publication [5] and are discussed in Chapter 5. Archer [6] discussed the use of the Hansen solubility parameter theory to reformulate a solvent-based coating. The following example demonstrates the usefulness of the Hansen method. Neither xylene nor methanol are good solvents for a D.E.N. epoxy novolac 438 resin. However, calculations suggested that a 50 50 (by volume) solvent blend should be able to dissolve the epoxy resin. Using the Hansen parameters for xylene and methanol from Table 4.1 the solubility parameters for the 50 50 blend were calculated as follows ... 

The volume is organized into two parts. Part 1 provides an extensive treatment of the major classes of organic solvents. The reader will find considerable information covering physical properties data, general use descriptions, and solubility data. The use and application of the Hansen solubility theory is... 

Where 8, 8 and 8, are the solubility parameters corresponding to the non-poiar (dispersion) contribution, polar contribution and hydrogen bond contribution respectively. Values of the Hansen solubility parameter 8 for some common solvents as well as their 8, 8 and 8j vaiues are shown in Table 4.1. In the Hansen system, solvents are represented as a single spot in the three dimensional model, while polymers are represented by a volume. Solvents that have their spot within this volume dissolve the polymer, while solvents lying outside the volume will not. For mixed solvents, a weighted average of the three partial solubility parameters can be calculated. 

Liquids, surface tension, molecular volume and Hansen Solubility Parameters... 

In Equation 3.14 the solubility parameters are given in (cal cm ), the molar volume V in cm moF, and then the surface tension is expressed in mN m . Values of the molar volumes and Hansen solubility parameters in these units are provided in Appendix 3.1 / is an adjustable parameter. 

The values of volume and (Hansen) solubility parameters are obtained from the tables provided in Appendix 3.1. 

Some attempts were made to improve the concept of the solubility volume. Jac-quel et al. found relationship between radius of this value for three approaches (Hildebrand model, Hansen model, and Beeibower model) and some conditions (temperature, ciystallinity, and molecular weight)." Hughes et al. tried to find a more deep theoretical base for the Hansen s solubility volume essentially in case of dipolar interactions." This last attempt included taking into account more reasonable partial parameters. But it was not able to overcome limitations of the initial approach. The reason can be referred to contradicted basic postulates. 

Values for the three components have been estimated by various means, most of which yield similar but uot identical numbers. Both experimental and calculation methods have been employed. When the total CED is estimated from the experimental enthalpy of vaporization, the polar and hydrogen-bonding parameters may be calculated using bond contribution methods. Values of these Hansen parameters are included in Table 2.4. In order to represent the solvent interaction with a polymer, a three-dimensional map is needed. An idealized representation is shown in Figure 2.5 for a hypothetical situation in which the solubility volume is centered at values of 8total solubility parameter is about 20.4. Also shown are the projections of the surface of the solubility volume on each of the... 

Hansen C, and Beerbower A. Solubility Parameters. In Standen A. Kirk-Othmer Encyclopedia of Chemical Technology, 2 ed. Supplement Volume. New York, NY Wiley 1971.889-910. 

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