The proton resonance spectra of poly‐α‐methylstyrenes

The proton resonance spectra of a number of poly‐α‐methylstyrenes have been measured, and from them it is possible to measure the relative amounts of the isotactic, syndiotactic, and heterotactic forms. Polymers prepared by means of cationic catalysts are found to be the most stereoregular, whereas catalysts which with other monomers give stereoregularity do not do so with α‐methylstyrene. In all the polymers the syndiotactic placement seems to be favoured over the isotactic. The irregular behaviour is thought to be associated with the considerable steric strain in the polymer.