Radiation‐induced liquid‐ and solid‐phase polymerization of acetylene

Radiation‐induced polymerization of acetylene was investigated in the liquid and solid states of the monomer. It was concluded from these experimental results that the liquid phase polymerization proceeds by a cationic mechanism and the solid phase polymerization proceeds by a cationic mechanism and the solid phase polymerization not by a radical or ionic mechanism, in an ordinary sense. The structure of the polymer obtained in the liquid and the solid state polymerization is quite different, that is, the former is mainly cis ‐form polyacetylene and the latter mainly trans‐form one. These facts confirm that a stereospecific polymerization is possible in solid state polymerization, using ionizing radiation, as was previously pointed out by the authors. Radiation‐induced polymerization mechanism in the vapor, liquid and solid phases of acetylene were proposed.