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The evolution of the α‐relaxation during an isothermal crystallization process of a series of flexible copolyesters of hydroxybutyrate (HB) and hydroxyvalerate (HV) has been followed in real‐time by wide‐angle X‐ray scattering and dielectric complex permittivity measurements. The change of the dielectric parameters with crystallization time can be phenomenologically described in terms of the Havriliak‐Negami equation. The dielectric strength follows a sigmoidal‐shaped pattern similar to that shown by the crystallinity. A reduction of the overall mobility with crystallization time of the polymeric chains in the amorphous phase has been observed. This slowing down effect depends on the HV molar content. The influence of the chain flexibility on the crystalline‐induced restriction has been discussed in the light of similar studies carried out with more rigid polymers. Dielectric experiments suggest that the progressive immobilization of polymer segments as crystallization proceeds cannot be exclusively associated with the amount of crystalline material. Differences in microstructure, depending on the HV molar content, seem to be responsible for the observed behavior. The progressive broadening and symmetrization of the α‐relaxation with increasing crystallization time has been explained as due to a restriction of the large‐scale motions of the polymeric chains, as the material is being filled in with crystals. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 37–49, 1999

New polyamides, containing a benzimidazole side group and ethylene oxide moieties in the structural repeat unit, were synthesized by low‐temperature polycondensation. The aim of this design was to obtain polyamides that were more soluble in common organic solvents and hence had better processability than benzimidazole polyamides while maintaining the water sorption properties characteristic of the latter. The results showed that the number of ether linkages of the repeat unit played an important role in the glass‐transition temperature and in the water sorption properties, the polyamides with one or two ethylene oxide units being more hydrophilic than benzimidazole polyamides. However, the length of the ethylene oxide chain played a minor role in the solubility because the second member of the series, with two ether linkages (i.e., one ethylene oxide unit), reached the same level of solubility as those polyamides with more ethylene oxide moieties. No crystallinity was observed by X‐ray and calorimetric measurements for the new polymers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 112–121, 2005

A sensory polymeric material for the colorimetric sensing of cyanide in water has been developed based on the reactivity of this anion with the pyrylium cation.

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