Effect of rubber particle size on deformation mechanisms in glassy epoxy

摘要: When tested in tension, a cross-linked epoxy resin can be made to exhibit shear yielding. A modified von Mises criterion, τ = τ0 − μP describes the yielding behavior of same under biaxial stress system, indicating that flow material is pressure sensitive. Butadien-acrylonitrile elastomer particles suspended matrix induce large local deformations when composite stressed. Particles few hundred Angstroms diameter cause glassy banding, and macroscopic failure envelope such system follows criterion similar resin. It was found coefficient internal friction, τ, activation energy for are approximately two cases. With larger (5-15,000 diam) mode changes as shown by yield associated energy. Electron micrographs fracture surfaces show microcavitation, crazing around each particle; deformed polymer particle retracts upon heating above its Tg. The surface work value unmodified 1.75 × 105 ergs/cm2. 10 pph small particles, increases 3.32 with 15.48