Fractional Hansen parameter, solvents

When viscometric measurements of ECH homopolymer fractions were obtained in benzene, the nonperturbed dimensions and the steric hindrance parameter were calculated (24). Erom experimental data collected on polymer solubiUty in 39 solvents and intrinsic viscosity measurements in 19 solvents, Hansen (30) model parameters, 5 and 5 could be deterrnined (24). The notation 5 symbolizes the dispersion forces or nonpolar interactions 5 a representation of the sum of 8 (polar interactions) and 8 (hydrogen bonding interactions). The homopolymer is soluble in solvents that have solubility parameters 6 > 7.9, 6 > 5.5, and 0.2 < <5.0 (31). SolubiUty was also determined using a method (32) in which 8 represents the solubiUty parameter... 

On the simplest level. Teas charts (see Appendix 3), derived from manufacturers or conservators data, can provide a visual summary of the solubility of the polymer of great use when the properties of a number of polymers or solvents are being compared. However, they should be used with caution and only for narrowly defined comparisons. The concepts and data used in these charts are known to be incomplete and compress multidimensional properties on to a flat sheet of paper. There is much overlapping of the solvents and non-solvents on the charts. The conclusions must be checked when dealing with unfamiUar materials. The Teas fractional parameters used in this book are derived from recent Hansen solubility parameters (Hansen, 2007). 

Figure 2.2 Representation of solvents in terms of the fractional contribution to Hansen solubility parameter on a Teas plot. Dots represent different solvents and the asterisk the polymer. The circle is an idealized area on the plot where solvents within it dissolve the polymer.

This section allows the user to calculate the RED fraction from the Hansen solubility parameters for a selected polymer and a mixture of up to three solvents. If three solvents are selected the program calculates and displays the RED for each solvent, the best RED and mixture formulation for every combination of two of the three solvents, and the best RED and mixture formulation for a mixture of all three solvents. The results are displayed in a results window. 

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