The first cumulant T(q)/q2 can be expressed quite generally as30 where T33(fe) = (1 -µ2)/ 2 and S(k) = exp(tk-R,")/ Y.¡v2; µ = k-q. This form is not restricted to unperturbed Gaussian chains or any particular choice for the Oseen tensor, chain structure, etc. The apparent diffusion coefficient follows from it as (

Raman and ESR spectroscopy has been used to study the thermal decomposition of accelerator systems based on derivatives of dimethyldithiocarbamic acid. The combination of these two spectroscopic techniques has proved to be a very powerful method for detecting intermediate compounds that are important for the elucidation of the mechanism of accelerated sulfur vulcanization.

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The factors that determine the miscibility of two polymers, each of which hydrogen bonds (self-associates) to itself in the pure state, is discussed. Equations describing the contributions of hydrogen bonding to the free energy of mixing are presented. It is shown that mixtures of this type are much less likely to be miscible than those where only one of the components self-associates, while the other has hydrogen-bonding acceptor groups. In addition, for mixtures of two self-associating polymers, the volume fraction of the hydrogen-bonding functional group relative to the volume of the polymer repeat unit is an important factor in determining miscibility. If this quantity differs significantly in the two polymers being mixed, even if they have identical hydrogen-bonding functional groups, the mixture will phase separate.