Darstellung und [η]-??-Beziehung von Mikrogelen aus polyvinylalkohol

✍ Scribed by Arbogast, Wolfgang ;Horvath, Andreas ;Vollmert, Bruno

• Publisher: Wiley (John Wiley & Sons)
• Year: 1980
• Weight: 563 KB
• Volume: 181
• Category: Article
• ISSN: 0025-116X
• DOI: 10.1002/macp.1980.021810714

✦ Synopsis

Abstract

Microgels were prepared by crosslinking of poly(vinylalcohol)s with different molecular weights (saponification degree: 88 mole‐%) with glutaraldehyde in aqueous solutions. The degree of crosslinking was varied between 0 and 10% (i.e. 10 crosslinks per 100 structural units). Viscosity measurements showed that the viscosity number [η] of the microgels decreases considerably with increasing degree of crosslinking — as to be expected with increasing mean density of the random coils: The mean coil volume in aqueous solution shrinks by introducing 10 crosslinks per 100 structural units to 1/10 of the primary volume. A comparison of the logarithmic [η]‐M̄‐plots of our microgels showed a linear decrease of the exponent a, from a = 0,73 (uncrosslinked) to a = 0,16, with increasing degree of crosslinking. By extrapolation, with a degree of crosslinking of 13% (i.e. 13 cross‐links per 100 structural units of polymer chain), it was found that [η] becomes independent of the molecular weight of the primary PVAl‐samples.