Radical polymerization initiated from a solid substrate. 3. Grafting from the surface of an ultrafine powder

摘要

Kinetics of grafting radical polymerization of styrene and methyl methacrylate from the surface of titanium dioxide powder has been studied. Polymerization was initiated by hydroperoxide macroinitiator attached to the surface of the TiO2 particles. The rate of grafting is linearly proportional to the rate of the initiation reaction from the surface. The fraction of the grafted polymer in the total polymer yield depends on the chain transfer reaction and on the mechanism of chain termination (combination or disproportionation). A mathematical model of the process has been used to explain the kinetics. The Trommsdorff effect has been found for the case of methyl methacrylate graft polymerization when the grafting amount approached high values. The regime of the multilayer coating formation has been studied in model experiments in the presence of macroinhibitor with the powder before coating by PMMA.