Untersuchungen über Poly(arylenvinylen)e. XVIII [1]. Synthese von Poly(1,4-phenylen- 1 -phenylvinylen) durch Dehydrochlorierung

Investigations on Poly(arylenevinylene)s. XVIII. Synthesis of Poly(1,4-phenylene-1-phenylvinylene) by Dehydrochlorination Reaction Dehydrochlorination reaction has been applied successfully to the polycondensation of 4-chloromethylbenzhydryl chloride 2 with potassium tert-butoxide in hexamethylphosphoric triamide, whereby soluble poly(1,4-phenylene-1-phenylvinylene) 1 was obtained. Some properties of 1 are described.     

High Strength 3D Non‐Vacuum Electron Beam Weld Joints ‐ Setting of Gradient Material Properties and Testing of Weld Quality

Highly loaded structures made of modern metallic materials are increasingly being placed under stringent standards with regard to the mechanical strength and deformation properties of their individual parts as well as with regard to the loading capacity of their joints. In order to create strain profiles in individual structural components, such components are heated with an electron beam at defined locations in order to bring in local microstructure changes and consequently the targeted local changes in the strength and deformation properties of the material with respect to a delayed crack growth. Additionally, components with specifically set tensile strength are welded to high quality structures. For this purpose the young but efficient non‐vacuum electron beam welding (NV‐EBW) method is used and further developed. Weld quality is examined especially in regard to an improved beam positioning, process control and weld joint defect detection.     

The Relationship between Structural and Electrical Characteristics in Perylenecarboxydiimide‐Based Nanoarchitectures

The controlled assembly of the prototypical n‐type organic semiconductor N,N′‐1H,1H‐perfluorobutyl dicyanoperylenecarboxydiimide (PDIF‐CN₂) into ordered nanoarchitectures and the multiscale analysis of the correlation between their structural and their electrical properties is reported. By making use of the Langmuir–Blodgett (LB) technique, monolayers of PDIF‐CN₂ arranged in upright standing molecular packing on different substrates are formed. Postdeposition thermal treatment makes it possible to trigger a reorganization into layered ultrathin crystalline nanostructures, exhibiting structural and photophysical properties similar to those of microscopic crystals obtained by solvent‐induced precipitation. The controlled engineering of these molecular architectures on surfaces enables us to identify both a dependence of the monolayer resistance on the molecular tilt angle in vertical junctions and a pronounced charge‐transport anisotropy with enhanced transport along the π–π stacking direction of the PDI core. While a charge carrier mobility for electrons as high as 10^–2 cm² V^–1 s^–1 is determined in monolayer field‐effect transistors for the in‐plane direction, being the highest yet reported value for a n‐type LB monolayer, the out‐of‐plane mobility measured by conductive atomic force microscopy in multilayered structures is found to be one order of magnitude lower.     

New energetic materials from triazoles and tetrazines

Abstract

Nitrotriazoles and tetrazines - among them compounds without nitro groups - are multi-purpose energetic materials. We found examples for all classes of explosives: primary explosives, IHE, and gas generators. By reaction with methazonic acid 3-amino-5-nitro-1,2,4-triazole (ANTA) could be converted into a new explosive with theoretically improved performance, a bitriazolyl compound. Starting with 3, 6-diamino-1,2,4,5-tetrazine three compounds of differing explosive behaviour were prepared. Physical data and small scale explosive properties of the new substances are published.