Permittivity, dielectric loss tangent, radial coupling coefficient, and radial frequency constant have been measured as a function of composition for pressure-sintered Li,rNa,-,NbO, in the range 0.015~xS0.15. An anomaly in each of these properties when plotted as a function of composition is associated with a structural transition between 2 ferroelectric phases; this transition lies near room temperature for compositions where x ~0 . 1 2 . Compositions near this phase boundary exhibit room-temperature properties which are of interest for highfrequency filter applications.

The economical use of expensive enzymes in chemical synthesis can be improved by the immobilization of the catalyst on a suitable support material. Textile fabrics made of polyester, polyamide, or cotton represent comparatively inexpensive alternative carrier materials in contrast to conventional supports. Textile‐inherent advantages like its flexible and lightweight construction allow the use in reactors of arbitrary geometry, a quick separation from the reaction liquor, and the generation of residue‐free product. A low preparative and economical expense is needed to prepare fabrics with high enzyme loads (20–70 mg enzyme/g textile carrier), high relative activity (up to 20%) and excellent permanence against enzyme desorption as well. In this study, we present different strategies for the covalent fixation of enzymes on fiber forming polymers such as photochemical grafting, the use of bifunctional anchor molecules, monomeric, and polymeric cross‐linking agents or specific enzyme modification for direct immobilization. In addition, we compare the strategies in terms of load, catalytic activity, and reusability. All presented immobilization methods yield products, which exhibit a considerable activity even after twenty recycling steps. In conclusion, we have successfully identified textiles as alternative, new and promising low cost carrier materials for enzymes.

Polyvinylamine-coated polyester fibers as a carrier matrix for the immobilization of peroxidasesBiocatalytic transformations that employ immobilized enzymes become increasingly important for industrial applications. Synthetic or natural textile fiber materials such as polyester, polyamide or viscose are support materials that are comparatively inexpensive. Contrary to traditional support materials, their flexibility enables their use in reactors of any geometry and a fast and residue-free removal from batch reactors. In this study a permanently immobilized peroxidase (Baylase R ) has been investigated on polyester felt as a solid support as a new heterogeneous catalyst system. The polyester felt was functionalized by coating with polyvinylamine and subsequent activation with glutaraldehyde as a crosslinking agent. The enzyme load on the textile surface, the activity of the immobilized protein after repeated use as well as the storage stability was evaluated. Scanning electron micrographs and UV Vis spectroscopy made it possible to verify the enzyme immobilization on the textile surface. Furthermore, the load of immobilized peroxidase was determined by ICP OE spectrometry to be 9-12 mg per gram of textile. The activity of immobilized Baylase R remained high over 35 reaction cycles and a storage period of 8 weeks.

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