A New Single Fiber/Resin Interface Test for Highly Cross-Linked Resin Systems

A new single fiber/resin interface test technique has been developed to test fibers in highly cross-linked resins that were difficult to characterize before. The new approach was based on the fracture mechanics considerations to allow brittle thin resin film with embedded single fiber to undergo large strain elongation. This was achieved by sandwiching the resin between high elongation epoxy doublers. Several systems with graphite fibers in highly cross-linked epoxy and bismaleimide resins were successfully characterized for strains up to 6%. Because of the thin resin film used, even matrix materials with limited transparency in bulk form could easily be tested. At sufficiently high strains, the fiber/resin systems showed interface-related behavior consistent with their edge delamination performance previously studied.