Estimation and characterization of polyester oligomers

Oligomers were obtained from polyester samples by solvent extraction and dissolution methods. Dioxane, chloroform, and chlorobenzene were used for the extraction method, whereas dimethyl formamide and phenol : tetrachloroethane (1 : 1 mixture) were used for the dissolution method. The oligomers were separated and analyzed by a thin-layer chromatographic technique. It was observed that extraction with chloroform and dissolution with phenol : tetrachloroethane gave higher oligomer contents. Also, the values were higher for as-spun fibers. Thin-layer chromatographic analysis showed that in all the cases lower oligomers were obtained with a maximum of the cyclic trimer, whereas the efficiencies of solvents varied for removal of higher oligomers. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1987–1991, 1999