MICROGELS .1. SOLUTION POLYMERIZATION USING VINYL MONOMERS

Theories of gelation predict that the polymerization and copolymerization of polyfunctional monomers having an average functionality of greater than two will form a macrogel. The theories have not been found to accurately predict the degree of reaction at the gel point in the presence of solvents. This paper, the first in a series, explores a concept in which it is postulated that macrogelation in solution in many cases is not the expected outcome and that small and usually soluble internally crosslinked polymer molecules(microgels) will be the product at complete reaction. The monomers methyl methacrylate and diethyleneglycol dimethacrylate were radically copolymerized in various proportions in a range of solvents to test the hypothesis. It was found that, at essentially complete conversion in good solvents below a critical and relatively high concentration, gelation could not be obtained and a general technique for the preparation of ''microgels'' is thus revealed.