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 gives two products, namely the expected branched macromolecules and some propylene oxide homopolymer, resulting mostly from transfer reactions. The separation of these two products was attempted using potentially selective solvents such as diethyl ether, tetrachloromethane and hexane. FTIR, 1H NMR, DCS and SEC techniques showed that the latter solvent, used under reflux, was the most suitable liquid in terms of selectivity. Both fractions were thoroughly characterised and useful information was thus gathered about the actual composition of the reaction products as well as their structure, molecular weight, Tg and viscosity.