Surface preparation Terms Links

The weakest link in an FRP composite material strengthening application is the FRP s resin matrix/interfacial adhesive this, indisputably, is the most vulnerable component in terms of adaptability and endurance to extreme environmental exposures. This fact has long been established and confirmed by a number of experimental and theoretical investigations (Chiew et a/., 2011 Hahn, 1976 Karbhari and Shulley, 1995 Kasen, 1981 Lord and Dutta, 1988 Weiss, 1982). If optimized surface preparation of the adherend is assumed,... 

Supports used for obtaining Ziegler-Natta catalysts can differ essentially from one another. Some of the supports may contain reactive surface groups (such as hydroxyl groups present in specially prepared metal oxides) while others do not contain such reactive functional groups (such as pure anhydrous metal chlorides). Therefore, the term supported catalyst is used in a very wide sense. Supported catalysts comprise not only systems in which the transition metal compound is linked to the support by means of a chemical covalent bond but also systems in which the transition metal atom may occupy a position in a lattice structure, or where complexation, absorption or even occlusion may take place [28]. The transition metal may also be anchored to the support via a Lewis base in such a case the metal complexes the base, which is coordinatively fixed on the support surface [53,54]. 

A number of asymmetric reductions have been reported using asymmetric hydrogenation catalysts. Akabori et al. (1956) reduced (XII) on a palladium on silk catalyst and obtained, after hydrolysis, optically active phenylalanine. Hartung (Beamer et al., 1960) has discussed such asymmetric reductions in terms of asymmetric active sites on the catalyst surface. An ordinary catalyst is envisaged as having equal numbers of enantiomorphic sites, some of which, however, may be linked so that only one at a time may function. To prepare a catalyst having a disparity... 

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