Prepreg gas permeation as a function of fiber orientation and aging time

A previously established simple technique was used to measure air permeability through prepreg to quantitatively describe the ability of prepreg to vent of volatiles during consolidation and curing. Both intralaminar and interlaminar permeability were measured as a function of room-temperature aging time and fiber orientation. Results of the aging study show that interlaminar permeation increases greatly with aging time, while intralaminar permeation increases only slightly. Both of these results can be explained by surface resin hardening of the prepreg samples. Furthermore, results of the fiber orientation study imply that the mechanism of intralaminar permeation is along the fiber path with no permeation occurring above a critical angle. These results demonstrate that under the same operating conditions, a prepreg laminate constructed with higher permeability aged prepreg or appropriate lamination angle should result in void-free cured laminates