Knowledge base

INTRODUCTIONIn the process of UV-curing, the characteristics of the light source have longbeen a neglected factor. Adaptations of the formulation' (in particular, thephotoinitiator) have been the.action of choice whenever cure problems wereapparent, whereas the light source has remained relatively unaffected.In recent years, pigmented UV-fromulatio

IntroductionToday modern composite resisns consisting of monomers, fillers andadditives are widely used in denistry (2 , 5 - 9). This new catego—ry of materials allows it to restore by carious destroyed hard toothtissues with very satisfactory esthetic results.The modern composite materials for tooth fillings have become veryimportant for restorati

IntroductionThere are two distinct cross-sectional regions toconsider when irradiating an acrylate functional coating withUV. energy: the thin layer;of coating at the'air-coatinginterface, commonly called the surface; and all the remainingdepth of the coating. In order to obtain a commerciallyacceptable level of overall cure, both the surface and b

1. IntroductionTriarylsulfonium salts have found prominence in the electronics industry for photoinitiatedacid catalyzed reactions of polymers and oligomers. There have also been uses forsulfonium salts in polymer films for photo-doping and photo-optical applications. Thiswide range of uses for triarylsulfonium salts has prompted interest into mech

IntroductionInvestigations of intermediate paramagnetic products ofphotochemical reactions helps one to understand mechanism ofsuch reactions. These intermediate species, are as a rulesufficiently stable at low temperatures and it is easy to detectthem by EPR spectroscopy. Information concerning the structure ofthe radicals can be obtained using th

INTRODUCTION(a) PolvmensationEmulsion polymerisation is one of the fundamental methods whereby homo and copolymerscan be prepared. [1]. Its particular value is that the polymers are produced as small particleshaving a narrow molecular weight range. By way of contrast suspension polymerisatiónproduces particles usually of large size with the molecul

1. IntroductionRecently there has been a growing interest in radiation curing of coatingsMost'progress has been made in the-field of radical polymerization and network'formation of acrylic systems by UV-light Since Crivello and 1 reported thepossibility of cationic polymerization by UV-light in 1977, cationicallycurablesystems have developed:th'éin

IntroductionPolymerization mechanism of epoxy resins photoinitiated by ironarenecationic-initiators has been proposed by Meier and Zweifel(ref.l).Photolysis of the iron arene-salts in the presenceof monodentate ligands, leads to new complexes of the type3 (ref.2),whereas in pure aprotic solvents, ferrocene and iron salts are' formed (ref.3 and