Molecular weight distribution crack propagation

On the basis of the foregoing discussion of the phenomenology of impact fracture it can be said that the impact resistance of a material is increased by all molecular properties or processes which assist the distribution and dissipation of the mechanical energy and permit the attainment of a large deflection before inception of rapid crack propagation. In particular the importance of the relaxation behavior [91, 93—96], of high molecular weight [106], of partial orientation [108], and of the unoccupied volume [92] have been emphasized. 

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