Continuous polymer fractionation of poly(methyl vinyl ether) and a new Kuhn‐Mark‐Houwink relation

Continuous polymer fractionation (CPF) — a new large‐scale method — was applied to the technical poly(methyl vinyl ether) (PVME) using toluence as solvent and petroleum ether as non‐solvent. Two different devices served as fractionation apparatus, namely a column packed with glass beads and a set of mixer‐settler extractors. Advantages and draw‐backs of these devices are discussed. The experiments yielded numerous PVME fractions, varying in molar mass from 22 to 87 kg/mol and in molecular non‐uniformity U = ( M¯ w / M̄ n ) – 1 from 0,25 to 0,41 according to gel‐permeation chromatography as compared with ca. U = 1,30 for the starting material. The following Kuhn‐Mark‐Houwink relation was established for PVME in ethyl methyl ketone at 30°C: [η]/(mL/g) = 2,6 . 10 −3 M̄ 0,86 .