Benzophenone/triethylamine‐photoinitiated polymerization of methyl acrylate

Abstract

Benzophenone‐sensitized photopolymerization of methyl acrylate was shown to be remarkably enhanced by the addition of small amounts of triethylamine. This was attributed to the efficient formation of an electron‐transfer complex between photoactivated benzophenone and ground‐state amine. Ketyl and amine free radicals derived from this complex were postulated to be the chain‐initiating species. Quantum yield experiments indicated that methyl acrylate itself was also a quencher of the benzophenone triplet state.

Photochemical Reaction of Polymers Having Arylketone and Tertiary Amine as Pendant Groups

“…23, No. 6,1991 and poly(DMASt) had two bands at 254nm (e= 1.2 x 10 4 ) and 310nm x 10 3 ). Figure 2 shows the UV absorption spectra of four copolymers (MtfM 2 ) in chloroform.…”

Cross‐linking photopolymerization of monoacrylate initiated by benzophenone

“…Benzophenone is one of the most well‐known photoinitiators for radical polymerization and its initiation mechanism has been studied . Benzophenone generates radicals by bimolecular reaction . Benzophenone abstracts hydrogen from H‐donors such as monomer, solvent, and co‐initiator .…”

“…By hydrogen abstraction, two types of radicals form. One is an alkyl radical generated on H‐donor, and the other is a ketyl radical . The alkyl radical can initiate polymerization.…”

“…The alkyl radical can initiate polymerization. However, the ketyl radical is unable to initiate polymerization due to its steric hindrance and electronic delocalization …”

“…[9][10][11][12][13][14][15] Benzophenone generates radicals by bimolecular reaction. 9,10,12,13,15 Benzophenone abstracts hydrogen from H-donors such as monomer, solvent, and co-initiator. [9][10][11][12][13][14][15] By hydrogen abstraction, two types of radicals form.…”