Development of a quantitative analysis method for polypropylene additives using on-line SFE/SFC

A procedure is described for the quantitative analysis of (Irganox 1076, Ir ganox 1010 and Tinuvin 327) in polypropylene matrices using on-line SFE/SFC . The effects of pressure, extraction time, type of matrix (particle or fil m) and matrix parameters (particle size, film thickness, sample weight) are studied in order to optimize supercritical fluid extractions. The collecti on efficiency is determined from the recovery of known concentrations of co mpounds. About 30% of extracts are lost during collection. Calibration curv es for polymer samples are established from ground polymer (particle size 1 00 mu m < d < 160 mu m) and polymer film (30 mu m thickness) under the opti mum supercritical fluid extraction conditions. The three additives are inco rporated together into polymer at concentrations ranging from 0.04% to 0.6% . Very poor recoveries are obtained from ground samples, but we observed ve ry good recoveries from films (45-70% depending on the additive) and calibr ation curves were established for the different antioxidants. (C) 1999 Soci ety of Chemical Industry.