EPR STUDIES ON SINGLET OXYGEN PRODUCTION BY PORPHYRINS

Abstract— EPR studies of the porphyrin-sensitized photooxidation of 2, 2, 6,6-tetramethyl-piperidine to the nitroxide demonstrate that all the porphyrins examined are able to generate ¹O₂, although the efficiency of the photoprocess is dependent on the nature of the side chains. Incorporation of metal ions into the porphyrin molecule depresses or even inhibits the formation of ¹O₂. Comparison of these results with previously obtained kinetic data points out that the efficiency of porphyrins as photosensitizes is controlled by the lifetime of their lowest triplet state.     

Preparation of coatings via cationic photopolymerisation: influence of alcoholic additives

Coatings obtained through photopolymerisation of vinylethers, propenyl ethers and epoxy resins are described. The influence of alcohols and of comonomers bearing OH groups on the cationic mechanism of the curing process is discussed. The final properties of the coatings are evaluated and correlated to the structures of the additives.     

New Vistas in Frontal Polymerization

Frontal Polymerization is a technique for the synthesis of polymers that, by exploiting the heat liberated by the self-same reaction, generates a hot front that can sustain and propagate itself from one end of the reactor to the other converting monomer into polymer. After the activation and following formation of the front, it is not necessary to provide any other form of energy in order to carry out polymerization. In this article we will summarize some of the recent results we have obtained in the application of Frontal Polymerization to the preparation of polyurethanes, unsaturated polyester resins, and polyacrylates.     

ChemInform Abstract: Derivation of Force Field Parameters,and Force Field and Quantum Mechanical Studies of Layered α- and γ-Zirconium Phosphates.

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