Impression creep of PMR‐15 resin at elevated temperatures

Abstract

AbstractThe polyimides formed from the polymerization of monomeric‐reactants (PMR) approach have been increasingly used as matrix materials in fiber‐reinforced composites on aerospace and space structures for high temperature applications. The performance of PMR‐based structures depends on the mechanical durability of PMR resins at elevated temperatures, including creep and stress relaxation. In this work, the creep behavior of PMR‐15 resin was studied using the impression technique in the temperature range of 563–613 K and the punching stress range of 76–381 MPa. It was found that there existed a steady state creep for the creep tests performed at temperatures of 563 K and higher, from which a constant impression velocity was calculated. The steady state impression velocity increased with temperature and punching stress with the stress exponent in the range of 1.5–2.2. The average of the apparent activation energy of the PMR‐15 was calculated as 122.7 ± 6.1 kJ/mol. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers