Entanglements nodes

FIGURE 2.4 The schematic dependences mechanical losses angle tangent tgd (1) and fractal dimension of chain part between entanglements nodes (2,3) on temperature T for... 

The greatest molecular draw ratio is reached at complete orientation of chain between entanglements nodes and, hence, it corresponds to the conditions =1.0 and k = 1.0, as it has been noted above. In Fig. 7.2, the shaded region indicates literary values Q range for polyethylenes from Q = 5.4 [24] up to Q = 7.0 [25]. As one can see, exactly in this range of values max... 

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... 

Figure 1.25 Theoretical (1) and experimental (2, 3) dependences of the molecular weight MJ of chain part between entanglements nodes on the temperature T) for initial (2) and annealed at 393 K (3) PC [91]...

Prior to the estimation of the correctness of one or another value, one should understand the physical significance of the front-factor A in Equations 1.24 and 1.56. One variant [112] provides that the A value can be changed within the range of 0.5-1.0, where A = 0.5 corresponds to the case of the so-called phantom network, which displays full freedom of fluctuations of macromolecular entanglements nodes around their middle positions, and A = 1.0 corresponds to the affine network, in which such freedom is completely suppressed. An alternative [113] provides a quantitative relation between value A and functionality F of macromolecular entanglement network nodes ... 

One of the examples of the scaling representation of macromolecules is the reptation model [48], according to which the tube diameter O, in which the macromolecule is confined (equal to the distance between entanglements nodes), can be estimated according to the relationship [49] ... 

The main distinction between physical entanglements ( sweeps ) nodes and chemical crosslinking nodes is chains sliding in the former. The density of both can be determined according to the high-elasticity theory and for calculation of chains sliding in entanglements nodes the coefficient 0.8 is added [49]. 

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