Chemical cross-links in the

The two-network theory for a composite network of Gaussian chains was originally developed by Berry, Scanlan, and Watson (18) and then further developed by Flory ( 9). The composite network is made by introducing chemical cross-links in the isotropic and subsequently in a strained state. The Helmholtz elastic free energy of a composite network of Gaussian chains with affine motion of the junction points is given by the following expression ... 

A5. Chain disentangling prior to and after introduction of chemical cross-links in the strained state is negligible. 

Re A5. The experiment shows that no chain disentangling takes place after introduction of chemical cross-links in the strained state. Chain disentangling may take place prior to cross-linking if the relaxation period is long enough. 

It was registered above 200°C the effective formation of intermolecular chemical cross-links in the PE-MMT nanocomposite, as a result of recombination reactions of the products of radical decomposition of hydroperoxides, caused by deficiency of oxygen in a polymeric matrix due to the lowered oxygen permeability. 

The appearance of several new types of rubbers called thermoplastic elastomers was apparently a most exciting development in recent years. These materials have properties of conventional rubbers such as high strength, and they are readily fabricated by various melt-processible techniques, which are characteristic of thermoplastic materials because they do not have any chemical cross-links in the... 

Stoehler et al. [44] studied the thermal properties of polyethylene-montmorillonite nanocomposites and found evidence for accelerated formation and decomposition of hydroperoxides during the thermooxidative degradation of the nanocomposites in the range of 170°C to 200°C, as compared to unfilled polyethylene, as weU as the formation of intermolecular chemical cross-links in the nanocomposites above 200°C due to recombination reactions involving the radical products of hydroperoxide decomposition. 

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