PROPYLENE OLIGOMERS - EXTRACTION METHODS AND CHARACTERIZATION BY FTIR, HPLC, AND SEC

Propylene oligomers were isolated from polymer matrix by dissolution p recipitation and Soxhlet methods and characterized by Fourier transfor m infrared spectrometry, ultraviolet, high-performance liquid chromato graphy, and gel permeation chromatography. Both extracts showed that t hese hydrocarbon chemicals have a maximal absorption at 210 nm and are eluted from a C8 column with a strong mobile phase (tetrahydrofuran). However, their average molecular weights are different depending upon the quality of extraction: the fraction obtained by the dissolution-p recipitation method is homogeneous in molecular weight, whereas the on e obtained by Soxhlet extraction has a higher polydispersity index (<( M-n)over bar>n/<(M-w)over bar>). The specific migration test of propyl ene oligomers in a food simulant (isooctane) shows total diffusion wit hin min. (C) 1999 John Wiley & Sons, Inc.