Network structure formation during crosslinking of organic coating systems

Crosslinking is a very important process in coating film formation and the structure of the formed network determines the application properties of th e coating film. In this review, general features of crosslinking and evalua tion of network structure are described. Network formation theories and the ir applicability to special chemical systems are analyzed. The kinetics of network formation is usually controlled by chemical reactivity of functiona l groups. A transition to the regime controlled by segmental mobility is ty pical for film formation especially for ambient temperature drying. Formati on of inhomogeneities in multicomponent systems determined by composition a nd group reactivities and/or by thermodynamic segregation may also play an important role. In the last section, special features of formation of cross linked structured from designed precursors - polyfunctional molecules with designed backbone architectures, such as telechelic polymers, stars, combs, microgels, dendrimers, or hyperbranched polymers are reviewed. Introductio n of precursors of special architecture allows us not only to modify the pr ocessing and material properties of the film, but also brings about new pro blems in explaining and modeling the formation and properties of coating fi lms. (C) 2000 Elsevier Science Ltd. All rights reserved.