Photoinitiator

Basics

• Chemicals that are light sensitive
• Upon Exposure to light (Usually of a certain frequency, such as UV Light) they emit various reactive species (such as free radicals, cations or anions)

Photoinnitiators of Intrest

Pyridinium salts

• From Wikipedia:

"Generally pyridinium photoinitiators are N-substituted pyridine derivatives, with a positive charge placed on the nitrogen. The counter ion is in most cases a non-nucleophilic anion. Upon radiation, homolytic bond cleavage takes place generating a pyridinium cationic radical and a neutral free radical. In most cases, a hydrogen atom is abstracted from the oligomer by the pyridinium radical. The free radical generated from the hydrogen abstraction is then terminated by the free radical in solution. This results in a strong pyridinium acid that can initiate polymerization.[11]"

Pyridinium Chloride?

• Pyridinium Chloride can be produced by passing Hydrogen Chloride in Pyridine dissolved in Diethyl Ether. The chemical formula are as follows:

{\displaystyle {\ce {C5H5N + HCl -> C5H6N+Cl- v}}} {\displaystyle {\ce {C5H5N + HCl -> C5H6N+Cl- v}}}

See Also

• Photopolymer

Useful Links

• The Wikipedia Page on Photoinitiators
• The Wikipedia Page on Pyridinium Chloride