Hugenberg, N., Loske, S., Müller, A.H.E., Schärtl, W., Schmidt, M., Simon, P. F.W., Strack, A.and Wolf, B. A

"Synthesis and large scale fractionation of non-linear polymers: Brushes and hyperbranced polymers"

Journal of non-crystalline solids 2002, 307, 765-771.

Abstract: Polymer brushes with poly(methyl methacrylate) (PMMA) backbone and polystyrene side chains were synthesized by radical polymerization of w-methacryloyl-polystyrene macro-monomers. Hyperbranched PMMA was obtained by means of self-condensing group transfer copolymerization of methyl methacrylate with an initiator-monomer containing a polymeri-zable methacryloyl moiety and an initiating silylketeneacetal function. Both nonlinear prod-ucts were fractionated using the method of Continuous Polymer Fractionation, consisting in a particular type of continuous countercurrent extraction. The combination of methyl ethyl ke-tone (solvent) with acetone (precipitant) turned out to suitable for the fractionation of the polymer brushes; in case of the hyperbranched material acetone served as the solvent compo-nent and methanol as the precipitant. The achieved fractionation was checked by means of GPC measurements and in case of the polymer brushes also by AFM, where the differences in the size of the macromolecules became clearly visible.

preprint number: 225