Crosslinked Epoxy Polymers as Natural Nanocomposites

At present it is obvious that polymeric systems by virtue of the special features of their structure are always nanostructural systems [1]. However, treatment of such a structure can be different. The authors [2-4] used for this purpose the cluster model of the amorphous state structure of polymers [5-7], which supposes that the indicated structure consists of local order domains (clusters), immersed into a loosely packed matrix. In this case the latter is considered as a natural nanocomposite matrix and the clusters as a nanofiller. A cluster presents itself as a set of several densely packed collinear segments of various macromolecules with sizes up to several nanometres [5-7]. It has been shown that such clusters are true nanoparticles - the nanoworld objects (nanoclusters) [2], 

In the present chapter the formation of the structure of these materials and the properties defined by it will be studied within the frameworks of such a representation of the structure of crosslinked epoxy polymers using fractal analysis methods. 

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In connection with the treatment of crosslinked epoxy polymers as natural nanocomposites the question arises about the applied stress concentration in a loosely packed matrix. The stress concentration factor defines to a considerable extent the strength of composites [36] and depends on their structure change [37]. The last aspect was the most important in paper [38], the authors of which fulfilled the study of the structural factors defining the stress concentration factor value and, hence, characterising a change in the structure of crosslinked epoxy polymers. 

Hence, proceeding from that stated above and considering crosslinked epoxy polymers as natural nanocomposites, their reinforcement degree can be defined as the ratio " / E. Three basic cases of the dependence of the reinforcement degree EJE on the... 

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