No abstract

Crystalline polymers of 1,3‐pentadiene, which are composed of trans‐1,4 units and show an isotactic configuration of the tertiary carbon atoms, have been obtained with the use of the heterogeneous Al(C2H5)3VCl3 catalytic system. The cis or trans isomer of pentadiene yields polymers that are more stereoregular than those obtained from mixtures of the two isomers. Isotactic trans‐1,4‐poIypentadiene may exist in two modifications: crystalline and paracrystalline (unidimensionally regular). The two modifications are characterized by different x‐ray spectra and different densities. trans‐1,4 Isotactic polypentadienes contain tertiary carbon atoms which are actually asymmetric. This permitted obtaining optically active polypentadienes by using polymerization catalysts prepared from optically active aluminum trialkyls.

No abstract