solubility parameter (δ) provides a numerical estimate of the degree of interaction between materials, and can be a good indication of solubility, particularly for nonpolar materials such as many polymers
The definition of solubility parameters is defined as the square root of heat of vaporization divided by the molar volume of the substance. Hansen solubility parameters can also be estimated. Please see the book of Hansen: Hansen Solubility Parameters: A user's handbook, Second Edition. Boca Raton, Fla: CRC Press.