Thermal stability and degradation of sound absorbing PUR based materials

Abstract

Polyurethane (PUR) based open cell foams (Gumotex, Breclav, Czech Republic) and PUR based nonwoven nano-fabric (SPUR, Zlin, Czech Republic) produced by means of Nanospider technology (ELMARCO, Liberec, Czech Republic) thermal stabilities (DTA, TG analysis) in the temperature range of + 40 to + 500 °C were studied with respect to their application in automotive and aeronautic industry as sound damping materials. Correlation between PUR chemical structure, dimensions of the foam individual cells, nano-fabric air flow resistivity, mechanical, acoustic properties and thermal stability were evaluated. For thermal degradation data evaluation the formal kinetic model proposed by Ozawa, Flynn and Wall was applied ("T. Ozawa: Bull. Chem. Soc. Japan, 1965, 38, 1881"). It was found, that the thermal degradation consists of two steps: 1. step in the temperature range 200 - 310 °C, weight loss of 23 - 58 % (activation energy 97 kJ/mol), 2. step in the temperature range 310 - 450 °C, weight loss 33 - 71 % (activation energy 132 kJ/mol). At the temperature of 265 °C an endothermal peak was found from DTA data.