Reinforcement, degree

Polymer nanocomposites multicomponentness (multiphaseness) requires their stmctural components to be quantitative characteristics determination. In this aspect, interfacial regions play a particular role, as it has been shown earlier, that they are the same reinforcing element in elastomeric nanocomposites as nanofiller actually [ 1 ]. Therefore, the knowledge of interfacial layer dimensional characteristics is necessary for quantitative determination of one of the most important parameters of polymer composites, in general,— their reinforcement degree [2, 3]. 

The elastomeric nanocomposites reinforcement degree EJE description was derived as in what follows [3] ... 

From Eq. (6.37) it follows that nanofiller particle (aggregates of particles) surface dimension d s the parameter, controlling nanocomposites reinforcement degree [53]. This postulate corresponds to the known principle about the decisive role of numerous division surfaces in nanomateri-als as the basis of their properties change [54]. From Eqs. (6.4) to (6.6) it follows unequivocally that the value is defined by nanofiller particles... 

FIGURE 6.13 The theoretical dependences of reinforcement degree EJE on nanofiller particles size D, calculated according to Eqs. (6.4), (6.6), and (6.37), at initial nanoparticles (1) and nanoparticles aggregate (2) size using. The boundary value corresponding to true nanocomposite. Experimental data for nanocomposites NR/TC (4), BSR/TC (5), and BSR/shungite (6). 

Hence, the stated aforementioned results have shown that the elastomeric reinforcement effect is the true nanoeffect, which is defined by the initial nanofiller particle size only. The indicated particle aggregation, always taking place in real materials, changes and reduces reinforcement degree quantitatively. This effect theoretical treatment can be received within the frameworks of fractal analysis. For the considered nanocomposites the nanoparticle size upper limiting value makes up 52 nm. 

As it is known [4], Na-montmorillonite is layered silicate the plates of which have smaller thichness than their width and length. Therefore it is assumed, that the structure of nanocomposite having that filler besides actually Na -montmorillonite has crystalline regions, amorphous (rubber) phase and interfacial areas. In this case reinforcement degree EJE can be written in the following form [5]... 

In woik [3], the following equation was offered for elastomeric nanocomposites reinforcement degree E IE description ... 

As it is well known [1] that the interlacial interaction role in multiphase systems, including polymer composites, is very great. In polymer composites such interactions (interfacial adhesion) absence results in sharp reduction of their reinforcement degree [2]. For polymer nanocomposites interfacial adhesion existence in the first place means the formation of interfacial regions, which are the same reinforcing element for these materials, as nanofiller actually [3], Proceeding from the said above, it is necessary to know the conditions and mechanisms of interfacial regions formation in polymer nanocomposites for their structure control. The present paper purpose is these mechanism definition and the indicated researeh is performed on the example of three particulate-filled nanocomposites on the basis of butadiene-styrene rubber. 

The Eq. (1) allows the value estimation as a function of at fixed pjj and m, i.e. as a matter of fact a relative fraction of nanocomposite structure reinforcing element, since these materials reinforcement degree can be described by die equation [3] ... 

In Table 1, the values of elasticity modulus for the studied nanocomposites and for the initial BSR are also adduced. As one can see, if for the nanocomposite BSR/CNT-Fe the very high (with accounting of the conditionfi =03 mass%) reinforcement degree EJE =IA 5 was obtained, then for the nanocomposite BSR/CNT-Co reinforcement is practically absent (with accounting for experiment error) E>>E. Let us consider the reasons of such essential distinction. 

As it is known [4], the reinforcement degree for nanocomposites poly-mer/CNT can be calculated as follows ... 

The reinforcement degree EJE calculation results according to the Eq. (5) are adduced in Table 1. As one can see, these results are very close... 

Besides, it should be borne in mind, that experimental value a in the Eq. (1) is determined on the basis of reinforcement degree EJE, for example, on the basis of mechanical tests results. This means, that value a depends on conditions of stress transfer on interfacial boundary polymeric matrix-oiganoclay, for example, on the parameter value. Then parameter a can be determined finally as follows ... 

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