Normal phase gradient polymer elution chromatography of polyester resins

Polymers can be characterized by gradient elution techniques in order to ob tain information on their chemical composition and molar mass. In this pape r, features and applications of Normal Phase Gradient Polymer Elution Chrom atography (NP-GPEC) for the characterization of (co)polyesters are investig ated. Two polyesters were characterized, using various stationary and mobil e phases. Separation was shown to be dominated by end groups in most cases, and to a lesser extent by molar mass. A distinct influence of both column type and mobile phase type was observed. A polymer based polyamine (PA) col umn provided the best results, although no complete separation between the mono- and di-acid fractions could be obtained. In all cases, separation was governed by sorption rather than by precipitation/redissolution. NP-GPEC w as shown to be a potentially interesting technique for the characterization of copolyesters according to the chemical composition of the backbone, ind ependent of end groups.