Further studies on the postpolymerization of methyl methacrylate

A search has been made for electroinitiators of postpolymerization. A number of hydroxycarboxylic acids and some of their sodium salts have been found to be quite efficient. Factors controlling the rate of polymerization and yield have been described. Surprisingly, citric acid, though not an electroinitiator of polymerization, is a good initiator of postpolymerization. Other active species that deserve mention are tartaric acid and its salts. A free radical mechanism involving formation of oligomeric initiator fragments, growth by attachment of imbibed monomer, and termination by chain transfer has been proposed to explain the observed facts.