THERMAL FIELD-FLOW FRACTIONATION OF POLYTETRAHYDROFURAN

The possibility to fractionate polytetrahydrofuran (PTHF) samples effe ctively with Thermal Field Flow Fractionation has been investigated. R etention measurements of four standards of different molecular mass we re performed in eight organic solvents. When methylethylketone or diox ane were used no retention was found. Highest retention for a given mo lecular mass was obtained with the solvents toluene and ethylbenzene. However, in ethyl acetate the highest separation speed was observed. P late height measurements showed that both the thermal and molecular di ffusion coefficients of the PTHF standards are very high in ethyl acet ate. According to theory, this combination should result in a high sep aration speed. A baseline separation of two PTHF standards with molecu lar masses of 67 000 and 282 300 could be obtained in 8 minutes when e thyl acetate was used as the solvent.