Local plasticity level

The strain energy release critical rate Gj, characterizing polymer local plasticity level (see the Eq. (5.13)), is coupled with material structure. The higher entanglements cluster network density v, is the more intensively shear local deformation mechanism is realized [13], and the larger Gj is. This means, that growth should result to Gj reduction. Actually, for PASF considered samples such correlation was obtained and it can be approximated by the following relationship [1] ... 

In the craze-initiation model, the above mechanistic considerations are combined in an approximate manner (Argon 2011). Thus, at craze initiation at the local plastic enclaves of the surface grooves, the local mean normal stress must reach such a level as to satisfy... 

There are many other examples of miscible polymer blends arising from specific submolecular interactions of the components. The miscible polymer pair of polystyrene and poly(phenylene oxide), for example, was recently studied by the 2D FT-IR technique in an effort to understand the molecular origin of the miscibility of this system [55]. Specific interactions between polymers and various small molecules, such as additives and plasticizers, were also studied by 2D IR. The importance of localized submolecular level interactions among functional groups of mixture components was demonstrated. 

Thus, the direct usage of fractal dimension of failure surface, formed by instable crack, for pol miers limiting properties characterization is deprived of sense. The multifractal treatment application [46] in the given case does not change the situation. Nevertheless, if fractal dimension reflects local plastic deformation level, then similar correlations has, at any rate, applied significance [47]. 

As it has been noted above, the main feature of polymers is that they consist of long chain macromolecules. Therefore, it is to be expected that polymer chains structure and their characteristics will be influenced essentially on bulk polymers properties. One of such polymer chain structural factors is availability in it of bulk side groups, which results to bulk polymers brittleness enhancement [40], A side groups effect on plasticity level for heterochain polymers was considered in Ref. [41], where brittleness increase was explained by side groups nonparticipation in local or macroscopic plasticity processes. 

Among the newer probes now being developed, spectroscopic observations of crystals in the elastic-plastic regime hold promise for limited development of atomic level physical descriptions of local defects [91S02]. It is yet to be determined how generally this probe can be applied to solids. The electrochemical probe appears to have considerable potential to describe shock-compressed matter from a radically different perspective. 

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