Homopolymerization of dicyclopentadiene induced by Ziegler‐Natta catalysts and by other transition metal systems

The homopolymerization of dicyclopentadiene induced by catalysts, containing transition metals of the groups IV, V, VI, and VIII of the periodic table of elements, yields polymers having different monomeric units depending on the transition metal and on the acid base character of the catalytic system. Seven different monomeric units, some of which not observed up to now, could be assigned on the basis of infrared spectroscopic measurements. All monomeric units derive from the ring cleavage or from the addition to the double bonds of both unsaturated five‐membered rings, whereas the saturated five‐membered ring of the monomer is always retained in the polymer. In the presence of some particular catalysts the polymerization leads to products having uniform chemical structure.