The synthesis and photoinitiated cationic polymerization of cyclic ketene acetals

A new, high yield synthesis of novel cyclic and acyclic ketene acetals has been developed which makes these compounds readily available. The ketene acetal monomers were fully characterized by IR,NMR and by elemental analysis. A study of the photoinduced cationic polymerization of a series of cyclic and acyclic ketene acetal monomers was carried out using various onium salt photoinitiators. It was observed that the cyclic monomers underwent facile cationic polymerization to give high molecular weight polymers while the acyclic ketene acetals did not. The position and type of substitutents in the cyclic ketene acetals were the major factors in determining the proportion of vinyl to ring-opening polymerization which took place.