Moisture Absorption and Desorption of Composite Materials

Expressions are presented for the moisture distribution and the mois ture content as a function of time of one dimensional homogeneous and composite materials exposed either on one side or on both sides to humid air or to water. The results apply during both moisture absorption and desorption when the moisture content and the temperature of the environ ment are constant. Test procedures are described for determining experi mentally the values of the moisture content and the diffusivity of com posite materials. A series of tests using unidirectional and π/4 Graphite T-300 Fiberite 1034 composites were performed in the temperature range 300—425 K with the material submerged both in moist air (humidity 0 to 100%) and in water. The test data support the analytical results and pro vide the moisture absorption and desorption characteristics of such com posites. Extension of the results to materials exposed to time varying envi ronmental conditions is indicated.