INTERACTIONS OF KEVLAR(R) FIBERS WITH SELECTED MODEL COMPOUNDS - WATER SORPTION AND DYNAMIC-MECHANICAL PROPERTIES OF FIBER MATRIX SAMPLES/

The present study deals with the sorption of water on Kevlar(R)(double dagger) fibers and on a selected range of fiber-reinforced samples, i n order to characterize the related interactions and to determine thei r influence on the dynamic properties (tan delta) of the specimens res ted. The diffusion coefficients and the water content values at equili brium show that the fibers significantly 'slow down' the diffusion wit h respect to the matrix. Water regain is proportional to the capacity of each component to sorb water. The rheological behavior of the compo sites reveals a plasticization effect associated with the water sorpti on. This phenomenon can be masked under certain experimental condition s. Among the treatments performed on the Kevlar(R) fibers to enhance t he adhesion to the matrix, an epoxy coating tends to reduce the water regain, the rate of sorption, and the plasticization effects, while th e plasma treatment did not reveal a significant effect in this study.