SYMPOSIA PAPER Published: 01 January 1997

Physical and Chemical Aging Effects in PMR-15 Neat Resin


The objective of this study was to determine whether a shifting approach can be used to account for both chemical and physical effects during long-term aging of high temperature polyimide thermoset polymers, such as the commercial material PMR-15. Stress relaxation curves measured after aging at 316°C for times up to 800 h could be shifted to form a master curve. The horizontal shift factors were found to increase with increasing aging time, consistent with a reduction in molecular mobility that occurs as a result of either physical aging or increased cross-linking. There was a correlation between the vertical shift factors and cure related chemical changes that cause Tg to increase and mass to decrease. Aging effects were partially reversed by heating the aged specimen above its glass transition temperature, indicating that a large portion of the aging is physical in nature. Specimens aged in nitrogen had a larger reversible component than specimens aged in air.

Author Information

Kamvouris, JE
NASA Lewis Research Center, Cleveland, OH
Roberts, GD
NASA Lewis Research Center, Cleveland, OH
Pereira, JM
NASA Lewis Research Center, Cleveland, OH
Rabzak, C
NYMA Inc., Cleveland, OH
Price: $25.00
Contact Sales
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Developed by Committee: D30
Pages: 243–258
DOI: 10.1520/STP11378S
ISBN-EB: 978-0-8031-5360-8
ISBN-13: 978-0-8031-1491-3