Rate dependent fracture behavior of highly cross-linked epoxy resin

The fracture behavior of highly cross-linked epoxy resin under plane strain conditions for crack tip rates spanning over four orders magnitude (10-4 −10-1 s−1) has been examined. toughness initially decreases with increasing rate (∊̇tip) and saturates at ∼ 0.8 MPa-m−0.5 after ∊̇tip 0.02 s−1 is attained. For all the specimens, a process zone (FPZ) forms ahead sharp pre-crack prior to catastrophic failure due intensified stresses tip. This FPZ region consists crazes that govern micro mechanism this was explicitly proved using in-situ testing in scanning electron microscope. low rates, crazing expected be dominated by chain disentanglements, craze openings more than 200 nm, whereas, chain-scission dominate higher lower 150 nm.