GLASS WOOL-H2O2 COCL2 TEST SYSTEM FOR IN-VITRO EVALUATION OF BIODEGRADATIVE STRESS CRACKING IN POLYURETHANE ELASTOMERS/

Environmental stress cracking (ESC) in polyetherurethanes has been dem onstrated in animal models. However, duplication of this phenomenon in vitro has been a challenge. The glass wool-H2O2/CoCl2 test system was designed to provide oxidation components found in vivo, i.e., hydroxy l radical (HO .), molecular oxygen (O-2), and superoxide (O-2(radical anion)) required for auto-oxidation of polyetherurethanes. The in vitr o test is not only reliable in duplicating the characteristics of in v ivo stress cracking in polyetherurethanes at 37 degrees C, but also ac celerates ESC as much as seven times. The test results on several type s of polyurethanes showed that Tecothane 80A was as vulnerable to biod egradative stress cracking in vitro as Pellethane 2363-80A, while the new generation of polyurethanes, Corethane, demonstrated great resista nce against cracking. (C) 1995 John Wiley & Sons, Inc.