Hagenaars, A.C., Bailly, C., Schneider, A. and Wolf, B. A.

"Preparative fractionation and characterization of polycarbonate / eugenol-siloxane copolymers"

Abstract: Bisphenol-A polycarbonate eugenol-siloxane copolymers were fractionated at the preparative scale by the Continuous Polymer Fractionation (CPF) technique. It is the first example of copolymer fractionation by CPF. The distribution of siloxane-species across the fractions was assessed for copolymers differing in initial siloxane concentration and block length. On-line and off-line combinations of size exclusion chromatography and infrared spectroscopy were used to analyse chemical composition of the un-fractionated samples across the molecular weight distribution enabling comparison with the fractions. A PC-siloxane copolymer containing 10 weight percent of very short siloxane blocks (dp=2) was fractionated solely according to molecular weight. By contrast, a copolymer containing 5 weight percent siloxane blocks with a larger degree of polymerisation (dp=23) was fractionated according to molecular weight as well as to chemical composition. This "chemical drift" effect for the larger siloxane block length can be ascribed to large solubility differences of low molecular weight chains, which drastically vary in composition according to the (small) number of siloxane blocks they contain.

Polymer 2002, 9, 43, 2663-2669.

preprint number: 223