STUDY OF THE HYGROTHERMAL EFFECTS ON THE COMPRESSION STRENGTH OF CARBON TAPE/EPOXY COMPOSITES

Abstract

THE WIDE RANGE OF COMPOSITE MATERIAL APPLICATIONS RESULTS IN AN ALMOST INEVITABLE CONTACT WITH LIQUIDS AND VAPORS, EITHER ORGANIC OR AQUEOUS, WHICH CAN AFFECT BOTH THE IMMEDIATE AND THE LONG-TERM PERFORMANCE OF THE MATERIAL. IN THIS STUDY, THE INFKLUENCE OF THE HYGROTHERMAL EFFECTS ON THE COMPRESSION STRENGTH OF CARBON UNIDIRECTIONAL TAPE/EPOXY 8552 COMPOSITES ([0/0]S) HAS BEEN INVESTIGATED. THE MOISTURE ABSORPTION WAS MONITORED PLACING THE SAMPLES FOR A LONG TIME (UNTIL SATURATION) IN A HUMIDITY-CONTROLLED CHAMBER (80ºC AND 95% RELATIVE HUMIDITY (RH)) AND OTHER SAMPLES IN A SALT SPRAY CHAMBER (36ºC AND 95% RH). THE COMPRESSION TESTS WERE CARRIED OUT IN TWO TEMPERATURES: THE ROOM TEMPERATURE (22ºC) AND THE HIGH TEMPERATURE (82ºC). IT WAS OBSERVED THAT THE SAMPLES TESTED AT ROOM TEMPERATURE AND SUBMITTED TO THE SALT SPRAY CHAMBER PRESENTED A DECREASE OF 8% ON THE COMPRESSION STRENGTH WHEN COMPARED WITH THE NON-CONDITIONED SPECIMENS. ON THE OTHER HAND, THE SAMPLES TESTED AT HIGH TEMPERATURE AND SUBMITTED TO THE HUMIDITY-CONTROLLED CHAMBER PRESENTED A DECREASE OF 25.7% ON THE COMPRESSION STRENGTH, WHEN COMPARED WITH NON-CONDITIONED SAMPLES. HOWEVER, THE SPECIMENS SUBMITTED TO THE SALT SPRAY CHAMBER PRESENTED A DECREASE OF 18.5% ON THE COMPRESSION STRENGTH WHEN COMPARED WITH NON-CONDITIONED SPECIMENS AT HIGH TEMPERATURE. THESE RESULTS SHOWED THAT THE COMBINED EFFECT OF THE HUMIDITY WITH THE HIGH TEMPERATURE TEST, DECREASE THE COMPRESSION STRENGTH OF THE COMPOSITE MATERIALS.