Table 2.

The equations used for the estimation of the solubility parameter and its components in Hoy’s (1985) group contribution system [79].

Equations Used in the Calculation	Low Molecular Weight Substances	Amorphous Polymers
Additive molar functions	$Ft={\displaystyle \sum N_i{F}_{t,i}}$
	$Fp={\displaystyle \sum N_i{F}_{p,i}}$
	$V={\displaystyle \sum N_i{V}_i}$
	${\Delta }_T={\displaystyle \sum N_i{\Delta }_{T,i}}$	${\Delta }_T{}^{(P)}={{\displaystyle \sum N_i{\Delta }_{T,i}}}^{(P)}$
Auxiliary equations	$Log\alpha =3.39\log (T_b/T_{cr})-0.1585-\log V$	$\alpha (P)=777{\Delta }_T{}^{(P)}/V$
	$T_b/T_{cr}=0.567+\Delta T-{\left(\Delta T\right)}^2$	$n=0.5/{\Delta }_T{}^{(P)}$
Calculation of total and partial solubility parameters	${\delta }_t=(F_i+B)/V$	${\delta }_t=(F_i+B/n)/V$
	${\delta }_p={\delta }_t{\left(\frac{1}{\alpha }\frac{F_p}{F_t+B}\right)}^{1/2}$	${\delta }_p={\delta }_t{\left(\frac{1}{{\alpha }^{(P)}}\frac{F_p}{F_t+B/n}\right)}^{1/2}$
	${\delta }_h={\delta }_t{\left[(\alpha -1)/\alpha \right]}^{1/2}$	${\delta }_h={\delta }_t{\left[({\alpha }^{(P)}-1)/{\alpha }^{(P)}\right]}^{1/2}$
	${\delta }_d={({\delta }_t{}^2-{\delta }_p{}^2-{\delta }_h{}^2)}^{1/2}$

F_t—total molar attraction constant for each group; F_p—polar molar attraction constant; F_i—sum of molar attraction constants of constituent groups; V—molar volume of the molecule or repeated unit in the polymer; Δ_T—Lydersen correction for non-ideality (values for low molecular substances have been provided by Lydersen [96], while values for polymers Δ_T^(P) have been derived by Hoy; T_b—boiling point; T_cr—critical temperature; B—base value (B = 277).