Cyclodextrin in polymer chemistry. Kinetic studies on the free-radical polymerization of cyclodextrin-complexed styrene from homogeneous aqueous solution

Styrene was encapsulated by an equimolar amount of randomly methylated beta-cyclodextrin (CD) in water resulting in a water-soluble CD complex. Polymerization of this complex was carried out at 50 degrees C using different amounts of the water-soluble azo-initiator 2,2'-azobis[N,N'-dimethyleneisobutyramidine] dihydrochloride. Unthreading of CD during polymerization led to water-insoluble polystyrene. Analysis of the polymers obtained showed that the polymerization from homogenous aqueous solution can be described by an equation similar to the classical polymerization in solution (number-average degree of polymerization vs. initiator concentration: P-n(-1) similar to [I](0.5)).