One thing is obvious that is the absorption spectra of the initiators should be comparable to the emitted photons from a photo source. Does it mean we can choose any resin and only need to be careful about the photo-initiator? In few other studies, sensitizers are also suggested beside using photo -initiators. I am a bit confused. The initiators initiate reaction with the application of energy (absorption) and ionise which than interact with monomer resin and creats more and more ions. These ions interact chemically to each other leading to crosslinked chain of monomers which we call polymer.
It all depends on the application but I would say that the key point is to select an initiator soluble in the monomer or monomer solution (resin).
Then, depending on the opacity or the thickness of the coating (if so), the radiation source intensity and nature (UV, Electron Beam)or reaction time.The concentration of the initiator might be adapted, sometimes you'll need to use a co-initiators...
It is also important to notice the oxygen inhibition, whether you're working in inert atmosphere or if scavengers are required. (By the way we're talking about radicals, not "ions" unless you're working with cationic cure mechanisms)
Eventually, the initiator may have an influence on the final result (odor, yellowing in time, adhesion, migration, extraction and safety concerns issues...)
It must be a compromise between reactivty, post-cure stability and toxicty
Thanks ...Meriadeg Thomas... Useful discussion. what will be the case for cat ionic process. The choice of resin and initiator interns of solubility is one of the important factor. But , what about the chemistry aspects? I mean we do consider initiator work with certain wavelkength and what about resin? I mean resin absorption spectra i observed is well enough broad. So how we actually select resin , other than considering solubility.
Well I 'm not sure but for cationic processes you should be limited to epoxy groups. Especially Cycloaliphatic epoxides and maybe some 'waterborne resins'.
I would recommend the website allnex.com. I have nothing to do with this company but at first glance, you should find specific information here. Lots of downloadable content (pdf) product guides and datasheets by technology /application.Have a nice surf, I hope this helps.
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