The cationic polymerization of t‐butyl vinyl ether at low temperature and the conversion into polyvinyl alcohol of poly‐t‐butyl vinyl ether

The stereospecific polymerization of t‐butyl vinyl ether (tBVE) catalyzed by BF3·O(C2H5)2 in homogeneous system is studied. The stereoregular polymer is obtained at low temperature in solvents of low dielectric constant. In homogeneous polymerization, a more highly stereoregular polymer can be obtained than in heterogeneous polymerization, but in the heterogeneous system the polymer having a higher molecular weight is formed. These results are approximately the same as in the case of isobutyl vinyl ether. As one of the characteristics of tBVE polymerization, the stereoregularity of the polymer is greatly affected by its solubility in the solvent used. Polyvinyl alcohol (PVA) and polyvinyl acetate (PVAc) can be obtained from the isotactic and atactic poly‐t‐butyl vinyl ether. The infrared spectra of isotactic PVAc are the same as those of the atactic PVAc, while there are some differences between the isotactic and atactic PVA so obtained. In the case of isotactic PVA contrary to that of atactic PVA the crystalline band near 1140 cm−1 is very week even after heating.