Photoinitiated cationic polymerization

The p-methoxyphenyl compounds were found to be ineffective as photoinitiators, giving very low polymer yields in the dark as well as when irradiated. This was attributed to various thermally induced reactions. In contrast, the vinyl halides were effective as photoinitiators. When irradiated, monomer/initiator mixtures gave polymer yields ranging from 1% to 22%, depending on initiator and irradiation time. Side reactions involved in the case of l-iodocyclohexene caused chain degradation and a reduction in polymer molecular weight and consequently in yield of isolated polymer.

The most effective compound investigated for use as a photoinitiator was found to be (E)-1,2-dibromo-1-(4-methoxyphenyl)- 2-phenylethene. It was also found to form films when a mixture of monofunctional and difunctional epoxides was used.