The stereospecific polymerization of alkyl acrylates by organometallic compounds

<jats:title>Abstract</jats:title><jats:p>Stereoregular polymerizations of <jats:italic>n</jats:italic>‐butyl, isobutyl, <jats:italic>sec</jats:italic>‐butyl, <jats:italic>tert</jats:italic>‐butyl and methyl acrylates were studied with a radical initiator, as well as homogeneous and heterogeneous anionic catalysts.</jats:p><jats:p>Polyisobutyl, ‐<jats:italic>sec</jats:italic>‐butyl and ‐<jats:italic>tert</jats:italic>‐butyl acrylates were obtained in a crystalline form by use of a heterogeneous organometallic compound, such as strontium‐zink tetraethyl as catalyst at low temperature.</jats:p><jats:p>Poly‐<jats:italic>n</jats:italic>‐butyl acrylate prepared by strontium‐zinc tetraethyl complex was shown to be amorphous, but markedly different in its infrared spectrum from the authentic amorphous, poly‐<jats:italic>n</jats:italic>‐butyl acrylate, prepared with azo‐bis‐isobutyronitrile (AIBN). polyacrylic acid obtained from the strontium‐zinc tetraethyl catalyzed poly‐<jats:italic>n</jats:italic>‐butyl acrylate gave a crystalline X‐ray photograph.</jats:p><jats:p>Amorphous polymethyl acrylate prepared by the above heterogeneous anionic catalyst was hydrolyzed to give rise to a crystalline polyacrylic acid.</jats:p><jats:p>It can generally be said that heterogenous organometallic compound systems were often favorable for the stereoregular polymerizations of acrylates.</jats:p>