M. Haberer and B. A. Wolf
"Continuous Polymer Fractionation of Poly(acrylic acid)"
Angewandte Makromolekulare Chemie 1995, 228, 179-184.
Abstract: 45 g of poly(acrylic acid) (PAA 500) with a trimodal molar mass distribution ((M) over bar(w) = 500 kg/mol, ((M) over bar(w)/(M) over bar(n)) - 1 = 2.33) were fractionated by means of CPF (continuous polymer fractionation) in two steps using 1,4-dioxane as solvent. The counter-current extraction was performed in a glass column (length: 190 cm, diameter: 1.5 cm) filled with a network of wires, introducing the feed 75 cm from its upper end. The distribution of the highest molar mass fraction ((M) over bar(w) = 760 kg/mol) is unimodal and comparatively narrow ((M) over bar(w)/(M) over bar(n)) - 1 = 0.66). Indications exist that fractionation is not only taking place with respect to molar mass but also with respect to tacticity.

preprint number: 157