By using diphenyliodonium salts with different counterions as photo acid generators (PAGs), theeffect of acidity on ring-opening polymerization of epoxy monomers and polycondensation of polyol withhexamethoxymethyl melamine (HMMM) was studied. The result shows that the rate of ring-openingpolymerization is evidently dependent on the acidity of the acid and strong photo-generated acid is required.However, there is a leveling effect in the polycondensation system; if the photo-generated acid is strongerthan protonated HMMM, the acidity does not obviously affect the polycondensation rate.
