USE OF ACYLPHOSPHINE OXIDES AND ACYLPHOSPHONATES AS PHOTOINITIATORS

Results are presented which show that acylphosphine oxides are more efficient photoinitiators than acylphosphonates for the curing of acrylates and unsaturated polyesters, and that their efficiency is further increased by adding amines. The performance of these initiators was compared with two commercial photoinitiators 2, 2-dimethoxy-2-phenylacetophenone and benzoin methylether. From these studies, it was concluded that the acylphosphonates cannot be considered as useful photoinitiators for the production of surface coatings. The value of laser nephelometry as a method for screening photoinitiators is underscored. Some of the limitations of this method and that of bulk polymerization are assessed.