Loosely packed regions

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,... 

Changes inoi by filling control the density of the amorphous phase. The experimental data show that in the melts of oligoesters, for the whole range of interlayer thicknesses there are loosely packed regions. The dependence of the reduced specific volume, Va, on is nonlinear and characterized by the alternation of more dense and less dense regions typical for dissipative structures, formed as a result of non-reversible processes under non-equilibrimn conditions. ... 

Moreover, the mentioned dependences display two characteristic temperatures. The first is the polymer glass transition temperature, T, determining the complete decay of clusters that corresponds to polymer transition into a rubber-like state. The second, 7, corresponds to the infection on vJT) curves and is located approximately 50 K below T. Earlier, also within the frameworks of the local order concepts, it has been shown [11,12] that the temperature is associated with defreezing of the segmental mobility in the loosely packed regions of the polymer. This means that within the frameworks of the cluster model 7 can be associated with devitrification of the... 

Region 3 (0.53 0.54 < K = 1.0) is characterized by a decrease in e with K, but it is similar for both dense and loose packings and does not depend on the DIH ratio. This peculiarity is caused [ 102] by the formation of an ordered packing dependence of e (K) in this region is well interpolated by the equation... 

Figure 6.21 Photograph of a cross section from a Maddock solidification experiment at the start of the melting process. The black material shows the melt films and the regions where the melt infiltrated the loosely packed solid bed...

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