Molecular mobility intensification

Let us consider the reasons of the adduced in Table 7.1 values k < 1 for nonoriented polymers. As it has been shown in chapter two, the value characterizes molecular mobility (deformability) level of the indicated chain part [17]. At = 1.0 this mobihty is suppressed completely and at =2.0 it reaches the greatest possible level, typical for rubber-like state. Molecular mobility intensification results to corresponding stress relaxation intensification, applied to chain part between entanglements and, as consequence, to its reduction lower than macroscopic sample fracture stress [18], Such treatment assumes availability of the correlation between parameters K and This assumption is confirmed by the plot of Fig. 7.1, where the dependence for 10 polymers, pointed out in table 7.1, is adduced... 

It is known [13], that molecular mobility intensification results to energy dissipation increase and enhancement of polymer toughness at failure. In chapter two, it has been shown that the molecular mobility level can be characterized by the value of fiactal dimension of chain part between mac-romolecular entanglements nodes DJ < < 2 [14]). Fractional part change (i.e., 1) from 0 up to 1 gives all possible spectrum of molecular... 

As it IS known [13], the value increases at molecular mobility intensification and the latter is associated with chains mobility in polymer structure loosely packed regions [71]. Within the fi ameworks of model [7] loosely packed matrix, surrounding clusters is such region. Its relative fraction cpj can be determined according to the Eq. (2.4). In Fig. 10.20, the dependence Ap((p,j ) is shown, which has the expected character. In conformity with the data of Ref. [13] linear growth at increase is observed and the condition Ap = 0 is realized not at (Pj = 0, what was to be expected, but at cpj 0.352. This value (p, according to the Eq. (2.4) corresponds to cp j 0.648,... 

A decrease in the coefficient a with an increase in temperature as a result of the intensification of the molecular mobility in the polymer matrix with the increase in temperature. The increase in temperature decreases the energetic barrier Eor. In the amorphous-crystalline polymers all these processes occur in the amorphous phase of the polymer where reactants are dissolved. 

In Figure 17.2, the dependence of deformation energy release critical rate, calculated according to the Eq. (17.5), on the parameter e value is adduced for the considered blends PET/PBT, which demonstrates linear Gi, growth at e increasing. Such look of the dependence G (e) was expected, since repulsion interactions intensification enhances molecular mobility, that always results in polymers plasticity enhancement. The correlation (e) can be described analytically by the following empirical equation ... 

As earlier [6, 22, 67], the linear dependence of p.j, on is obtained, showing the order parameter index of a thermal cluster, by which the structure of epoxy polymers is simulated, at the intensification of the molecular mobility, characterised by dimension (or the intensification of the thermal interactions). In the same fignre the dependence p.j,(D ) for polyhydroxyester-graphite (PHE-Gr) particulate-filled composites is shown by a dotted line [22, 67]. The dependences Pj.(D ) for the... 

A possibly substantial intensification of the microflotation process follows from the findings. If we provide a maximum intensive microflotation process, it simultaneously intensifies the purification of the system from molecular impurities. This leads to an increase of the residual mobility and, correspondingly, to an increase of the collision efficiency. Unfortunately this way of intensification is restricted by the existence of an optimal volume fraction of bubbles (Derjaguin Dukhin, 1986). 

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