Macromolecular entanglements cluster network density

Macromolecular entanglements cluster network density v j can be estimated as follows [8] ... 

FIGURE 2.5 The dependences of elasticity modulus E (1) and equilibrium modulus (2) on macromolecular entanglements cluster network density n, for PC [47],... 

The plotted according to the experimental data dependencies of elasticity modulus E on macromolecular entanglements cluster network density (Figs. 2.5 and 2.6) break down into two linear parts, the boundary of which serves loosely packed matrix glass transition temperature which is lower on about 50K of polymer glass transition temperature [50]. Below the value E is defined by the total contribution of both clusters and loosely packed matrix and above - only by clusters contribution. It becomes clear, if to taken into consideration, that above the elasticity modulus value of devitrificated loosely packed matrix has the order of 1 MPa [51], that is, negligible small. It is an extremely interesting the observation, that loosely packed matrix in the value E, determined by the plot E (v, ) extrapolation to = 0, is independent on temperature. Such situation is not occasional and deserves individual consideration. 

The dependence of impact toughness on macromolecular entanglements cluster network density was considered briefly by the authors of Ref [15]. In Fig. 10.6, the dependence of impact toughness of PASF aged... 

In the stated above treatment not only nanostructure integral characteristics (macromolecular entanglements cluster network density v, or nanocluster relative fraction cp j), but also separate nanoeluster parameters are important (see Section 15.1). In this case of particulate-filled polymer nanocomposites (artificial nanocomposites) it is well-known, that their elasticity modulus sharply increases at nanofiller particles size decrease [17]. The similar effect was noted above for REP, subjected to different kinds of processing (see Fig. 15.28). Therefore, the authors of Ref. [73] carried out the study of the dependence of elasticity modulus E on nanoclusters size for REP. 

Figure 1.1 The dependences of the macromolecular entanglements cluster network density on the testing temperature T for (1) PC and (2) PAr [7]...

Figure 1.15 The dependence of the macromolecular entanglement cluster network density on Lyapunov s index Xj for amorphous glassy and semi-crystalline...

In the treatment stated above it is not only the integral characteristics of the nanostructure (macromolecular entanglements cluster network density or relative fraction

particulate-filled polymer nanocomposites (artificial... 

As it is known [5], in amorphous phase two types of macromolecular entanglements are present traditional macromolecular binary hooking and entanglements, formed by nano clusters, networks density of which is equal to and v, respectively. value is determined within the framework of mbber high-elasticity conception [2] ... 

In Figure 5.13 the dependences of network density of the macromolecular entanglements cluster on the integral molecular parameter received for... 

The estimation /(oo) for the number of polymers using literary data [11] shows that the value of /() is approximately constant at [7]. This fact allows a conclnsion to be made that at some critical value of /(°°)(t / ) freezing of the formation of local order domains (clusters), i.e., the physical macromolecular entanglements clnster network, is impossible because of the high thermal mobility of macromolecules (the indicated network density at is equal to zero [8]). As a result. Equation 1.37 can be rewritten as follows [7] ... 

Thus, the density of chemical crosslinking points cannot serve as an index for the cormectivity of the macromolecular skeleton of network polymers. This makes it impossible to use to characterise the structure of network polymers in a computer simulation, which follows from the results presented previously. The d value, which provides determination of elastic properties, may serve as a suitable parameter. However, to estimate other properties, one more parameter is required, which would characterise the degree of thermodynamic nonequilibrium of the structures of vitreous polymers. This role can be played by dfOr the density of the cluster network of physical entanglements [48], or by the proportion of clusters (p [140] For instance, the necessity to take into account d, V i or [Pg.334]

FIGURE 58 The dependence of cluster entanglements network density vcl on macromolecular coil fractal dimension for hnear polyaiylates. 

---