NEW SOLVENT SYSTEM FOR GEL-PERMEATION CHROMATOGRAPHY OF POLY(ETHYLENE-TEREPHTHALATE)

A new solvent system comprising a mixture of nitrobenzene and tetrachlorothane has been developed for determining the molecular size distribution of poly(ethylene terephthalate) (PET) by gel-permeation chromatography (GPC). Unlike hot m-cresol, which until now has been the standard GPC solvent for PET, the nitrobenzene-tetrachloroethane mixture can be used at room temperature and thus minimizes polymer degradation and distribution equilibration. Results with this new system reveal reproducibly discernible differences between PET samples prepared by melt and solid-state polymerization, differences not previously noted in GPC reports based on the use of m-cresol.