KINETICS OF PEEK SULFONATION IN CONCENTRATED SULFURIC-ACID

The sulfonation kinetics of poly(oxy-1,4-phenyleneoxy-1,4-phenylenecarbonyl-1,4-phenylene) (PEEK) was studied in 96.3% sulfuric acid. The reaction rate was found to be first order and inversely first order with respect to the PEEK and the sulfonated PEEK chain repeat unit, respectively. The latter results from desulfonation taking place in this system, rather than an inhibition caused by the water produced. The reaction progress at three PEEK concentrations, 0.02, 5.0, and 20 g of PEEK/sulfuric acid, is in agreement, indicating an absence of the effect of the initial PEEK concentration. The reaction follows the Arrhenius equation over the temperature range of study, 25-75-degrees-C with a calculated activation energy of 20.4 kcal/mol of repeat unit, within the range of related reports.