Examples of Cationic Photoinitiators

The initiation rate, V , depends on the radical yield per absorbed photon, O , and the number of photons absorbed per second in a unit volume, I. The latter quantity is a fraction of Iq, the number of photons per second per unit volume entering the process zone. 

In the chain propagation, mainly the monomer is consumed and the propagation rate depends on the monomer concentration, [M], and the concentration of polymeric radicals, [ ]. The quantity kp is the propagation rate constant. 

Chain termination occurs by combination or disproportionation of different polymer radicals. The termination rate, v is proportional to the polymer radical concentration, [ PJ, squared, with kt being the termination rate constant. Other possible chain termination processes are chain transfer and reaction of polymer radicals wifh inhibitors and radical trapping.  

The assumptions made to estimate the propagation rate, Vp, which is essentially the rate of fhe polymerization reaction, are  

The lighf used is monochromatic and is absorbed by fhe phofoinitia-for exclusively. 

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