Lattice crosslinks, defective

The results yielded detailed information about chemical defects which appeared in each of the cured systems. We are especially interested in the structures like defective lattice crosslinks -amine molecules with a different number of links with the entire network. 

The description of a network structure is based on such parameters as chemical crosslink density and functionality, average chain length between crosslinks and length distribution of these chains, concentration of elastically active chains and structural defects like unreacted ends and elastically inactive cycles. However, many properties of a network depend not only on the above-mentioned characteristics but also on the order of the chemical crosslink connection — the network topology. So, the complete description of a network structure should include all these parameters. It is difficult to measure many of these characteristics experimentally and we must have an appropriate theory which could describe all these structural parameters on the basis of a physical model of network formation. At present, there are only two types of theoretical approaches which can describe the growth of network structures up to late post-gel stages of cure. One is based on tree-like models as developed by Dusek7 I0-26,1 The other uses computer-simulation of network structure on a lattice this model was developed by Topolkaraev, Berlin, Oshmyan 9,3l) (a review of the theoretical models may be found in Ref.7) and in this volume by Dusek). Both approaches are statistical and correlate well with experiments 6,7 9 10 13,26,31). They differ mainly mathematically. However, each of them emphasizes some different details of a network structure. 

The crosslinks formed in less ordered regions at fold surfaces cause irregularities in the crystal lattice. Near the defect formed, a progression of further linking deeper down in the crystal on continued irradiation may be observed [58]. The result of irradiations is then a crosslinked polymer with a lower extent of crystalline r ons. 

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