| Abstrakt: |
The fatigue crack propagation behaviour of rubber toughened blends of poly(2,6-dimethyl-1,4-phenylene oxide) (PXE) and polystyrene (PS) were studied. The nature of the fatigue crack tip damage zone development and the subsequent crack tip advance mechanism through this damage zone were also examined. In the control blend with no rubber particles, several long crazes preceded the crack tip and provided an easy path for crack propagation. The addition of rubber particles, however, led to massive microcrazing over a considerably enlarged zone about the crack tip. This proved to be an effective energy dissipation mechanism which resulted in reduced fatigue crack growth rates. When PS was substituted for PXE in the polymer matrix, although microcrazing still occurred over an enlarged crack tip damage zone, many of the microcrazes grew to macroscopic size, thus reducing the fatigue toughness. |
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