To solve the following problems of a solvent of cationic polymerization using the solvent simultaneously materializing height of polarity of the solvent advantageous to the cationic polymerization and stabilization of a cationic catalyst: because a generated polymer is easy to be precipitated in a low-polarity solvent, synthesis of a polymer having a high molecular weight is difficult; a halogen-based solvent exerts a bad influence on the environment; and an ether-based solvent such as diethyl ether that is a middle polar solvent is a special ignitable substance and has a problem in safety.
This cationic polymerization method uses tetrahydropyran as the solvent of cationic polymerization reaction of monomers (a vinyl ether compound, an N-vinyl compound, a styrene compound), and uses a protic acid or a Lewis acid as the catalyst.
MAEDA YOSHIHIKO
Atsushi Hayashi