Structure of polymers formed in 4-vinylpyridine-tris(pi-allyl)chromium systems

The products of the thermal degradation of polymers formed in 4-vinylpyridi ne-tris(pi-allyl)chromium systems were studied by mass spectrometric therma l analysis. Some features of the polymerization mechanism distinguish the b ehavior of this monomer from that of 2-vinylpyridine under the same conditi ons. The composition and ratio of the products formed by the thermal degrad ation of 4-vinylpyridine polymers suggest that of the interaction of the gr owing chains with pyridine rings of monomeric units in the course of polyme rization plays an important role. This feature, resulting from a higher spa tial accessibility of nitrogen atoms in the pyridine rings of 4-vinylpyridi ne, compared to 2-vinylpyridine, favors the formation of cyclic and cross; linked structures in the products of 4-vinylpyridine polymerization.