A NEW STRATEGY FOR THE SYNTHESIS OF CYCLIC POLYSTYRENES - PRINCIPLE AND APPLICATION

A new strategy for the synthesis of vinyl type macrocyclic polymers of controlled molecular weight and molecular weight distribution has been investigated. It involves the direct coupling of an alpha,omega-heterodifunctional linear polymer precursor previously prepared by living polymerization. The cyclization is achieved under high dilution, by appropriate activation of one of the polymer ends in order to allow its reaction with the other end function. The theoretical advantages of this approach compared to the conventional procedure involving the coupling of a living homodifunctional polymer precursor by a difunctional organic molecule are discussed. This new technique has been applied to the synthesis of cyclic polystyrenes with high yields (greater than or equal to 85-90%). The structural characterization of the polymers as well as some of their thermal properties is also reported.