| Abstract
| - The preparation and characterization of highly isotactic poly(vinyl alcohol)s (PVOHs) derivedfrom poly(tert-butyl vinyl ether) (PtBVE) polymerized with BF3·OEt2 were investigated. The mm sequencefraction increased with decreasing BF3·OEt2 concentration, and it reached as high as 78−79%, whichseems to be the highest value of all so-called isotactic PVOHs reported so far, but only if the catalystconcentration was reduced to below 0.5 × 10-3 mol/L. An increase in mm sequence fraction may be causedby highly isospecific propagation of a new kind of species, which is thought to be generated from ligandexchange of the BF3 complex from ether to water. We also studied the polymerization of tBVE with variousBF3 complexes, such as BF3·2CH3COOH, BF3·2CH3OH, or BF3·2CH3OH. The mm sequence fractionincreased in the following order: BF3·2CH3COOH < BF3·OEt2< BF3·2MeOH < BF3·2H2O. It increasedwith a reduction in the catalyst concentration for each type of catalyst.
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