Reactivity of Radicals Derived from Dimethylanilines in Acrylic Photopolymerization

Abstract

Relative reactivities of radicals derived from several p-dimethylanilines toward the polymerization of butyl acrylate have been calculated. It was observed that the reactivity of the radicals increases as the electron-withdrawing character of the groups attached in the para position increases. The experimental efficiency factor if) has been found to be proportional to the value defined in the Hammett equation. The dependence of the reactivities on the nature of the radicals has also been explained through their frontier orbital characteristics. The high similarity of the behavior of /versus and/versus £somo led us to conclude that the simple perturbative molecular orbital calculations can be used to predict the relative reactivity of initiating radicals with similar structure toward the polymerization of acrylic monomers.

New Fluorescent Probes for Monitoring the Photoinduced Polymerization of Acrylic and Methacrylic Monomers

“…The procedure for photo-DSC analysis has been described previously. [11] After the given conversion was reached, the sample pan was placed into the fluorimeter sample holder and the fluorescence spectrum was acquired. No appreciable dark reaction was observed -the fluorescence spectra remained invariable if recorded immediately after irradiation or 2 h later.…”

Kinetic study of free-radical polymerization photoinitiated by cyanine-borate salts. II.

“…The first method usually yields free radicals with different reactivities, 5,9 and this might have an impact on the final rate of photoinitiated polymerization. 10 The use of the cyanine borates represents the second method and, as one can expect, creates a unique opportunity to change the driving force of the electron-transfer process without a change in the type of the yielding free alkyl radicals. Translating this into a practical application of the Marcus equation to the photoinitiation process, one can anticipate that under certain conditions (identical or very similar free radicals are formed), the rules regulating the primary processes can be also applied to the secondary processes.…”

A reappraisal of the photopolymerization kinetics of triethyleneglycol dimethacrylate initiated by camphorquinone-N,N-dimethyl-p-toluidine for dental purposes

“…It is used with coinitiators such as amines, which accelerate the rate of polymerization [3 -6, 13]. The kinetics of the photocuring process by a CQ/amine couple have been studied mainly in a nitrogen atmosphere [14,15], but not in an oxygen atmosphere (air).…”