Study on ketalization reaction of polyvinylalcohol by ketones. V. The film properties of polyvinylketals obtained by aliphatic ketones

✍ Scribed by Naofumi Nakamura; Kimihiro Suzuki

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 620 KB
• Volume: 44
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1992.070440702

✦ Synopsis

The physical and chemical properties of polyvinylketals (PVKL) prepared from seven aliphatic ketones [acetone, methyl ethyl ketone (MEK) , methyl n-propyl ketone (nPK) , methyl i-propyl ketone (iPK), methyl n-butyl ketone (nBK), methyl i-butyl ketone (iBK), methyl t-butyl ketone (tBK) ] were studied. The moisture regain and water vapor permeability of PVKL films decrease in the following order: acetone > MEK > nPK > iPK = nBK > iBK > tBK. The contact angle measurements revealed that this order is determined by the surface free energy of films, which depends upon the kind of the original ketones. PVKL(acetone) with low ketalization degree was not soluble in neutral water and had lower moisture regain than PVA. As shown in X-ray analysis, the molecular orientation was not random, the crystalline part of PVA remaining. Thus, it becomes clear that behavior of PVKL in water is affected not only by the hydrophobicity of film surface, but also by the crystallinity of PVKL.