Hydrolysis kinetics of condensation polymers under humidity aging conditions

The hydrolytic stability of polycarbonate (PC), poly(ethylene terephthalate) (PET), and resorcinol polyarylate (RPA) films was studied at 65-95 degrees C and 23-95% relative humidity (RH) by measuring the time to embrittlement as measured by a bending test on films. The data show that the hydrolysis of these polymers is second order in RH with overall kinetics 1/t(fail) = A exp(-E-a/RT) [RH](2) where t(fail) is the embrittlement time in days, R is the gas constant, T is the temperature in kelvins, and RH is the fractional relative humidity. The activation energy, E-a, in kJ/mol and In(A), respectively, for the polymers were PC: 92, 24.9; PET: 129, 39.3; RPA: 102, 30.0. (C) 2013 Elsevier Ltd. All rights reserved.