New insights into Hansen's solubility parameters

Correlations among the three components, δ d 2 (dispersion), δ h 2 (hydrogen‐bonding), and δ p 2 (polar) that make up the Hansen solubility parameter equation, δ o 2 = δ d 2 + δ h 2 + δ p 2 , have been analyzed for a large number of organic solvents. A relationship is found that enables δ h and δ p to be estimated if δ o and δ d are known. This relationship is applied to a variety of common polymers and remarkably good agreement is obtained with tabulated values for δ h and δ p . Additional correlations are found that can be expressed in approximate functional form. The analysis also reveals relationships, expressed as inequalities, among the parameters that limit their range of possible values.