Macromolecules segments

Therefore, the interaction energy is reasonably expressed by Eq. (3.15) not only for low-molecular-weight substances but also for macromolecules, if the substance X is a macromolecule segment. 

Thus, in dependence on the way of macromolecule conformation change, ratio of life times of salt bonds and correlation time of macromolecule segment rotation, change of local macromolecule units density, under formation of complex polyelectrolyte-SAS segment mobility of macromolecule may be increased, decreased or remains constant. 

However, crosslinked pol5Utrethanes are not considered a good model for investigation of molecular mobihty and its dependence on the amoimt of filler because at high temperatures there is no clear tan maximum for dipole-segmental relaxation processes. For hnear polyurethanes, the clearly expressed dipole-group relaxation process at 168-179 K and dielectric losses connected with macromolecule segments relaxation at 238-248 K are typical (Fig. 6.5). As seen from the... 

Condensation reaction is one where two monomers or short functional macromolecule segments combine together to form a long segment, usually with the elimination of a small molecule such as water or alcohol. For this to take place, each reacting segment must have chemically reactive end groups. The reaction of a pair of snch... 

In Ref. [25], the asymmetrical periodic function is adduced, showing the dependence of shear stress x on shear strain (Fig. 4.2). As it has been shown before [19], asymmetry of this function and corresponding decrease of the energetic barrier height overcome by macromolecules segments in the elementary yielding act are due to the formation of fluctuation free volume voids during deformation (that is the specific feature of polymers [26]). The data in Fig. 4.2 indicate that in the initial part of periodic curve from zero up to the maximum dependence of x on displacement x can be simulated by a... 

It is obvious that the fraction c of macromolecules segments able to form clusters should reduce during the formation of clusters and, accounting for the condition = const, for each epoxy polymer, the value of should also decrease. This explains the availability of unstable clusters, which have smaller values of [5, 6, 91], in the amorphous state structure of polymers. This also explains the self-similarity of the structure of a cluster within the scales range of its existence. Let us note one more important circumstance - the system of Equations 5.12 and 5.13 is applicable to all studied epoxy polymers and the system of Equations 5.14 and 5.15 is applicable to each separately [89]. 

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