Oxypropylation of sugar beet pulp. 2. Separation of the grafted pulp from the propylene oxide homopolymer

It is well known that the oxypropylation of polymeric substrates always giv es two products, namely the expected branched macromolecules and some propy lene oxide homopolymer, resulting mostly from transfer reactions. The separ ation of these two products was attempted using potentially selective solve nts such as diethyl ether, tetrachloromethane and hexane. FTIR, H-1 NMR, DC S and SEC techniques showed that the latter solvent, used under reflux, was the most suitable liquid in terms of selectivity. Both fractions were thor oughly characterised and useful information was thus gathered about the act ual composition of the reaction products as well as their structure, molecu lar weight, T-g and viscosity. (C) 2000 Elsevier Science Ltd. All rights re served.