Rigid-chain polymer interactions, macromolecular

Let us note one more important aspect. The Eqs. (54) and (55) comparison allows to give one more definition of flexible- and rigid-chain polymers. The indicated equations suppose, that the greatest values of macromolecular coil fiactal dimension are equal to 2.0 (i.e., a coil in ideal 0-solvent [10]) for flexible-chain polymers and 1.667 (i.e., a coil in good solvent [10])—for rigid-chain ones. Hence, such polymers, chain rigidity of which (intramolecular interactions) allows to compensate it by... 

It follows that for polymer interaction with the filler surface as a result of adsorption and orientation effects, caused by interphase boundaries, redistribution of the segments and small portions of macromolecular chains caused by conformation changes occurs in the polymer siuface layers. At the same time, a boundary layer is formed, which might conditionally be termed rigidly elastic. Formation of this layer determines the maximum strength of the filled polymer-solid substrate adhesive bond. 

As it has been shown above, a macromolecular coil in solution fractal dimension is defined by two groups of factors polymer-solvent interactions and macromolecular coil elements between themselves. As an approximation, the first from the indicated factors can be characterized by the difference of polymer 6 and solvent 6 solubility parameters A8= 6 6j [16]. As to the second group of factors, then a parameters number exists, influencing on value in some way chain rigidity, bulk side groups availability, hydrogen bond and so on. Since at present the strict theory of polymer regular solutions has not still developed, then analytical relationships... 

The problem is more difficult when polymers are considered. If they are supposed to be rigid rods, without "soft" interactions,the Flory lattice theory provides a model in agreement with experiments. If the macromolecular chain is semi-flexible, the situation is less clear. Several theories are currently developed their main features are described in this volume. They also describe the transition as first order, but with a strong second order component. 

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