The search for reactive peroxides and hydroquinones in an acrylic copolymer blend via supercritical fluid extraction-chromatography

Summary

The objective of this work was to extract, identify, and quantify dibenzoyl peroxide (DBPO), N,N-dimethyl-p-toluidine (DMPT), hydroquinone (HQ), and the methylether of hydroquinone (MEHQ) in an ethyl and methyl methacrylate copolymer blend cured at 35°C for two different time periods. The reactivity of BPO, HQ, and MEHQ made working with supercritical fluids most advantageous. Exactly 0.85 gram of cured polymer was placed in a 5 mL extraction vessel. In order to obtain efficient collection of the analyte after supercritical fluid extraction, a solid phase trap (C₁₈) was used. Various polymer samples were cured at different times and then extracted and analyzed. The level of DMPT decreased by 50% (0.22% to 0.12%) as the cure time increased from 30 minutes to 24 hours. The BPO level did not vary with increasing cure time (0.44% vs 0.43%). The MEHQ level could not be ascertained since it was below our detection limit for MEHQ.