PHOTOPOLYMERIZATION OF BUTYL ACRYLATE MICROEMULSIONS .1. POST-POLYMERIZATION

The oil-in-water-type microemulsion polymerization of butyl acrylate i nitiated by UV light was investigated. The polymerization showed two n onstationary rate intervals with a short rise to a maximum. The rate o f polymerization was found to be proportional to the 0.7th power of th e incident light intensity. The number of radicals per particle was fo und to be much below 0.5. The initiating radicals are supposed to be f ormed by the decomposition of the excited (SDS/BA) intermediates (mic elles). Desorbed radicals were found to increase the number of new par ticles after the cessation of illumination. The number of polymer part icles increased during the whole polymerization. The micellar mechanis m was proved to apply to the present system. The dependence of the mol ecular weight, or the relative viscosity of the microemulsion versus c onversion is described by a curve with a maximum.