Extender structure effect loss factor

During the course of these and related studies, notably those concerned with the temperature dependence of the mechanical anisotropy and the identification of relaxation processes in structural terms, it became apparent that the aggregate model was successful in low density polyethylene because it described effectively the influence of the very anisotropic x-relaxation process on the mechanical behaviour. Stachurski and Ward were even able to extend the aggregate model to deal with the anisotropy of dynamic loss factor. (See Chapter 9 for further discussion.) It was, however, more in the spirit of the original conception of the aggregate model that it would deal with mechanical anisotropy in glassy polymers, where morphology was of secondary importance. 

The equilibrium between globular and extended macromolecules is obviously controlled by electrostatic repulsions and entropic effects involving hydrophobic interactions and solvent structuration. However, the main factor is the ability of hydrophilic protonated tertiary amine to deprotonate easily to hydrophobic tertiary amine. Therefore, the difference between N-protonation and N-methylation in their ability to impart water-solubility to P(TDAE) chains is because the non-methylated chains can expel all their electric charges by deprotonation and thus macroscopically precipitate when hydrophobic interactions become greater than electrostatic repulsive forces. In the case of N-methylated molecules, stable tetralkyl ammonium groups prevent the loss of all the electric charges and thus stabilize the deprotonated macromolecules in their dispersed globular form. 

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