Dye sensitized polymerization of vinyl monomers synthesis analysis and charcterisation

Abstract

Cyclic oligosaccharides, formed from 1,4- glucopyranose units known as newlinecyclodextrin, exhibits a torus- shaped structure with a hydrophobic cavity and a newlinehydrophilic exterior. They consist of 6(a), 7(p), 8(y) or more units of 1,4-linked newlineglucose.These molecules are able to encapsulate hydrophobic monomers as guest into newlinetheir cavities to form host-guest complexes in aqueous solution. This research work is newlinefocused on photo polymerization of few vinyl monomers in homogeneous aqueous newlinemedium by complexation with (3 - cyclodextrin. A comparative kinetic study of newlinepolymerization reactions initiated with both complexed and uncomplexed monomers newlinerevealed a higher polymerization rate and better polymerization yield in the presence newlineof p - cyclodextrin / monomer complex. Obviously, this complexation opens a new newlineway for using water insoluble monomer more effectively in aqueous polymerization newlinesystem. This is also a facile method for producing high quality polymers with low newlinepolydispersity arid having high thermal stability. Due to water mediation of newlinepolymerization, the process is also ecofriendly. newlineThe present investigation involves the photosensitized polymerization of three newlinevinyl monomers like Methyl methacrylate, Butyl acrylate and styrene using four dyes newlinelike acryflavine, fluorescein sodium, erythrosine and pyronin-Y as initiator., in newlinepresence of ascorbic acid as reducing agent in buffer medium. Polymerization done in newlineabsence of P~CD using ethanol as solvent is compared with that of presence of P-CD newlinein aqueous medium by different parameters such as percentage conversion, rate of newlinepolymerization, molecular weight determination and TGA analysis. The presence of newlineCD showed obviously effects on the polymerization, so as to increase the rate newlineof polymerization and percentage conversion of monomer. Kinetic equation of newlinethe photo polymerization process is derived. It is justified from the experimental newlinevalues by graphical methods. Effect of P- cyclodextrin on polymerization of vinyl newlinemonomers is investigated. Structural aspects of cyclodextr