SWELLING OF POLY(GLYCIDYL METHACRYLATE) GEL PARTICLES BY ORGANIC-SOLVENTS

Fine particles of poly(glycidyl methacrylate) (PGMA) were prepared by suspension polymerization and crosslinked via the ring-opening reaction of the epoxide group with formic acid. A fraction of the spherical gel particles averaging about 70-mu-m in diameter was examined under an optical microscope with its swelling behavior in a number of solvents. Equilibrium degrees of swelling were established with accuracy to show that this polymer gel has rather unusual affinities for solvents: (i) It is swollen (and, without the crosslinks, soluble in most cases) in many types of solvents, (ii) it cannot be represented by a single value of solubility parameter, and (iii) it is not swollen at all in water nor in aliphatic alcohols, in spite of the presence of hydroxy groups in the chain.