Inclusion polymerization of Isoprene in the channels of sepiolite

We have tried an inclusion polymerization in the channels of sepiolite, and studied the structure of polymer formed inside and outside the channels. Isoprene was polymerized not only on the outer surface but also in the channels of the sepiolite at 25 °C. Strong Brønsted acid sites in the outer and inner surfaces of the sepiolite intitiate a polymerization of isoprene and styrene. Double bonds of polyisoprene formed in the channels were protonated by the strong Brønsted acid sites of the sepiolite. The interaction between the protonated double bonds and the acid sites changed the color to violet. The outer surface of the folded sepiolite whose channels were collapsed formed a usual polyisoprene which caused no color change.