Synthesis of highly pure poly (vinylacetate) by one- step controlled radical polymerization in the presence of cobalt catalyst using cross linked suspended polyvinyl acetate particles
Subject Areas :محمد علی سمسارزاده 1 , علیرضا سبزواری 2 , سیده محبوبه رضوی 3
1 - استاد مهندسی پلیمر، گروه مهندسی پلیمر، دانشکده مهندسی شیمی، دانشگاه تربیت مدرس، تهران، ایران
2 - دانشجوی دکتری مهندسی پلیمر، گروه مهندسی پلیمر، دانشکده مهندسی شیمی، دانشگاه تربیت مدرس، تهران، ایران
3 - دانشجوی دکتری مهندسی پلیمر، گروه مهندسی پلیمر، دانشکده مهندسی شیمی، دانشگاه تربیت مدرس، تهران، ایران
Keywords: Cobalt-mediated radical polymerization, Poly )vinyl acetate(, Catalyst adsorption–desorption, Alumina column, Cross linked suspended polyvinyl acetate,
Abstract :
One of the main drawbacks in organometallic-mediated radical polymerization techniques is a high amount of catalyst residual in the polymer product, which results in deep colors in polymer mixture .In this research, cross linked suspended polyvinyl acetate )SPVAc( was used as catalyst adsorbing agent and its release in cobalt-mediated radical polymerization of vinyl acetate. For this purpose, firstly, the adsorption process of cobalt acetylacetonate on these particles and also the thermodynamics of this process were studied. SPVAc particles have the capability of the catalyst adsorption at low temperatures and adsorbed catalyst particles are gradually released by increasing temperature to polymerization reaction temperature. The kinetic studies for vinyl acetate polymerization in the presence of cobalt acetylacetonate adsorbed on the SPVAc particle is compared with cobalt acetylacetonate mediated polymerization of vinyl acetate in the absence of SPVAc particle. The results have proved positive effects of these particles on the rate and kinetic of reaction. Then, radical polymerization of vinyl acetate without the need for purification of polymer was carried out successfully through a single reaction in a column packed with alumina and a layer of adsorbed cobalt acetylacetonate catalyst on the SPVAc particles. In this method, the slow adsorption and desorption of cobalt complex by suspended polyvinyl acetate, were followed by the radical polymerization and the final separation step.