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Photoactivated cationic ring-opening frontal polymerizations of oxetanes

2005; Taylor & Francis; Volume: 8; Issue: 6 Linguagem: Inglês

10.1163/156855505774597803

1568-5551

J. V. Crivello, Umut Bulut,

Photochromic and Fluorescence Chemistry

Abstract The photoinitiated cationic ring-opening polymerizations of 3,3-disubstituted oxetanes display a characteristic induction period followed by very rapid thermally accelerated polymerization. When a thin-film sample of such a monomer is irradiated for a time within the induction period and then allowed to stand at room temperature, no appreciable further conversion of monomer to polymer takes place. However, when heat is applied to a small portion of the films rapid polymerization takes place as a front, which propagates rapidly throughout the entire reaction mass. To characterize these frontal polymerizations, a new monitoring technique, employing optical pyrometry has been instituted. This method provides a simple, rapid means of following these polymerizations and quantitatively determining their frontal velocities. Keywords: PHOTOPOLYMERIZATIONCATIONIC POLYMERIZATIONFRONTAL POLYMERIZATIONOXETANE MONOMERSEPOXIDE MONOMERS