Preparation of Stereoregular Poly (Vinyl Alcohols) by the Use of Vinyl Trimethylsilyl Ether as a Monomer

• Published in: Kobunshi Kagaku Vol. 23; no. 255; pp. 550 - 558
• Main Authors: Murahashi, Shunsuke, Nozakura, Shun-ichi, Sumi, Masao, Fuji, Saburo, Matsumura, Keiji
• Format: Journal Article
• Language: Japanese
• Published: The Society of Polymer Science, Japan 1966
• ISSN: 0023-2556; 1884-8079
• DOI: 10.1295/koron1944.23.550

The vinyl trimethylsilyl ether (VOSi) was polymerized with cationic catalysts. Poly (VOSi) was easily converted into poly (vinyl alcohol)(PVA) by solvolysis after the polymerization. Based upon the study of the IR spectra of PVA, the PVAs obtained by the polymerization in less polar solvents were found to be rich in isotactic and those obtained with polar solvents were found to be rich in syndiotactic. Effect of polymerization conditions on the stereoregularity of the polymer was studied to find out the optimum condition for the stereoregulation. The highest syndiotacticity was effected by the polymerization at -78°C, using a system VOSi-EtNO2-SnCl4 and a monomer concentration of 5-10vol%. The highest isotacticity was produced by the polymerization at -95°C using a system VOSi-Toluene-EtAlCl2 and a monomer concentration of 5vol%. Hence, it was found that the stereoregularity of the PVA could widely be regulated by using VOSi and by selecting the suitable catalyst and the solvent. From the comparison of IR spectra of the differently stereoregular PVAs, it was found that the optical density ratio, D1450/D2930, was more suitable as a qualitative measure of the stereoregularity than D916/D849 in the highly isotactic region.