SYMPOSIA PAPER Published: 01 January 1985

Hygrothermal Degradation of Sheet Molding Compounds


Environmental variables such as moisture and temperature degrade fiber-reinforced polymer composites to various levels. This paper characterizes the hygrothermal degradation of a sheet molding compound (SMC) containing 65% by weight of E-glass fibers. Six different environments were chosen for the study: room temperature (RT)/65% relative humidity (RH), RT/98% RH, RT/water, 75°C/65% RH, 75°C/65% RH, 75°C/98% RH, and 75°C/water. The extent of degradation was evaluated using visual, microscopic, and chemical analysis techniques. From this study, distinct color changes and blistering on the specimen surfaces were evident. Degradation was manifested in the ultrasonic attenuation and in the reduction of short beam strength and stiffness.

Author Information

Hosangadi, AB
Washington University, St. Louis, MO
Hahn, HT
Washington University, St. Louis, MO
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Developed by Committee: D30
Pages: 103–118
DOI: 10.1520/STP34018S
ISBN-EB: 978-0-8031-4938-0
ISBN-13: 978-0-8031-0415-0