Polymeric additivess have a great influence on the processing parameters in the produciton of high‐performance ceramics. The various types of additives are described and the interactions between the organic additives and the inorganic ceramic powders, some examples of which are shown in the figure, are examined with emphasis on one of the most important ceramic forming processes.

The apparent thermorheological simplicity of disordered diblocks is reconciled with the failure of time−temperature superposition of corresponding miscible blends by examining the relaxation of the constituent blocks using rheo-optical techniques. Diblocks of 1,4-polyisoprene (PIP) and polyvinylethylene (PVE) are examined over a range of temperatures for two compositions (φPIP = 0.25 and 0.75). Unlike blends of PIP and PVE, the block copolymers appear to obey time−temperature superposition on the basis of their viscoelastic properties. However, departure from thermorheological simplicity is exposed in their stress−optical behavior. In particular, the copolymer rich in the high T g component (φPIP = 0.25) shows distinct temperature dependencies for the individual blocks, in accord with the behavior of PIP/PVE blends. The block copolymer rich in the low T g component (φPIP = 0.75) is thermorheologically simple because both blocks have similar monomeric friction coefficients ζo, PVE ≈ ζo,PIP, again in accord with prior results on PIP/PVE blends. The failure of time−temperature superposition in these diblocks was not previously observed because the change in ζo,PVE/ζo,PIP with temperature produces subtle changes in the overall relaxation spectrum relative to a linear chain of uniform friction.

We have performed a dielectric investigation of the ionic charge transport and the relaxation dynamics in plastic-crystalline 1cyano-adamantane (CNA) and in two mixtures of CNA with the related plastic crystals adamantane or 2-adamantanon. Ionic charge carriers were provided by adding 1% of Li salt. The molecules of these compounds have nearly globular shape and, thus, the so-called revolving-door mechanism assumed to promote ionic charge transport via molecular reorientations in other PC electrolytes, should not be active here. Indeed, a comparison of the dc resistivity and the reorientational -relaxation times in the investigated PCs, reveals complete decoupling of both dynamics. Similar to other PCs, we find a significant mixinginduced enhancement of the ionic conductivity. Finally, these solid-state electrolytes reveal a second relaxation process, slower than the -relaxation, which is related to ionic hopping. Due to the mentioned decoupling, it can be unequivocally detected and is not superimposed by the reorientational contributions as found for most other ionic conductors.