Crack propagation epoxy matrix

Other sources of reinforcement are fibers like those of carbon and metal. Fibers can add rigidity and help prevent crack propagation. A common composite is fiberglass, which consists of small glass fibers embedded within a polymeric material that is typically an epoxy or polyester [11]. Epoxy resin is used as a structural matrix in the aerospace industry. It is also used as glue. 

In poorly bonded NT- Al O /epoxy composites, particles are clearly visible and the crack seems to have propagated aroimd their equator. Ihe fracture surface of nanocomposites consists of hemispherical holes (A), top surface of the debonded particles (B) and particles covered by epoxy matrix (C). The crack may propagate above or below the poles of the particles through the matrix. Interfacial debonding seen in the mirror zone is not seen in the hackle zone for treated alumina-epoxy nanocomposites. Another toughening mechanism noticed in the hackle zone is particle pullout, which is seen in both NT- Al O /epoxy nanocomposites and APTES-Al Oj/epoxy nanocomposites, whereas micro-cracking is noticed only in APTES-Al Oj/epoxy nanocomposites. 

Debonding between well-bonded APTFS-Al O nanoparticles and epoxy matrix depends on the crack propagation speed. It is observed only in the mirror zone. However, in the nanocomposites having poorly bonded NT- AljOj particles, particle debonding is noticed everywhere. 

Hidemitsu Hojo et al. (Hidemitsu et al., 1998) reviewed the behavior, the forms and mechanisms of corrosion of resins and glass fiber reinforced plastics under several aqueous solutions. They concluded that the concept of the corrosion rate of metals could be applied even in plastics and fiber reinforced plastics for each corrosion form. The corrosion resistance of the composites is mainly dependant on the resin s corrosion resistance properties and the corrosion crack propagation. Applications requiring corrosion resistant composite materials usually use epoxy and polyester resin as the composite matrix because these thermosets have high resistance to chemical attack. Among the various type of resins epoxies dominate the... 

ICAs cannot accommodate this large strain, the silver filler particles must move relative to one another as the epoxy matrix is strained. The most common pattern of resistance change was only increased to a point corresponding to about a 70% loss in interface contact resistance before sudden failure. This was an indication that the interface crack slightly propagated into the adhesive (74). 

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