Photoinitiators for Polymerization at 532 nm and 1064 nm by Two-Photon Absorption; Evaluation of Their Initiation Efficiency Using Microlasers
Irene Wang, Patrice Baldek, Cecile Martineau, Gilles Lemercier, Jean-Cristophe Mulatier and Chantal Andraud
We report on the characterization of efficient photoinitiators for radical polymerization induced by two-photon absorption (TPA), using an inexpensive Nd:YAG microlaser. A symmetrically substituted fluorene is used to initiate TPA polymerization of acrylates in the visible range at 532 nm. New conjugated ketones, with a molecular structure similar to that of the Michler ketone, are presented for the IR photoinitiation at 1064 nm. The efficiency of these initiators is evaluated by the determination of the absorbed energy density threshold for polymerization.