Does the volume swell ratio relate to the weight gain when a crosslinked polymer is emersed in a solvent? Is it as simple as calculating (delta V) = (delta w)/density?
You have a polymer with Vp, Wp, and rho_p, and a solvent with Vs, Ws, and rho_s
When the polymer absorbes some solvent of mass w, the polymer mass is equal to Wp+w (since mass is conserved).
About the new polymer volume, you could say that it is equal to Vp+w/rho_s