Materials Literature
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Scientific interest in optimizing the properties of gadolinium (III) complexes as MRI contrast agents has led to many new insights into lanthanide ion coordination chemistry in the last two decades. Among these was the surprising observation that water exchange in lanthanide (III) derivatives of DOTA can be modulated…
Anodic alumina (AA) membranes are composed of highly uniform, nanometer-scale pores arranged in a hexagonal close-packed array. Depositing conformal films inside the nanopores is extremely difficult because the nanopores have an ultrahigh aspect ratio of L / d ≈ 10 3 . Atomic layer deposition (ALD) is a thin film grow…
Abstract A chelating agent, alizarin, was used to pretreat an aluminum surface before the electrochemical synthesis of polyaniline. Alizarin had two main effects on the process: (1) it suppressed the hydrogen evolution reaction and increased the current efficiency and (2) it stabilized the open‐circuit potential in a…
Abstract The free‐radical graft copolymerization of maleic anhydride (MAH) onto polypropylene (PP) with the assistance of styrene (St) in supercritical carbon dioxide (CO 2 ) was studied. The effects of the St concentration and initiator concentration on the functionality degree of the grafted PP in supercritical CO 2…
Abstract Polyamide‐12 and chlorobutyl rubber were blended by dynamic vulcanization in a high shear environment using curing systems based on sulfur, dithiocarbamate/ZnO, and 4,4‐methylenebiscyclohexylamine/MgO. As expected, all blends with curing agents show increased tensile strength and elongation at break in compar…
Abstract The influence of molecular orientation on the “memory effect” of polyamides was investigated by differential scanning calorimetry. Melt crystallization of undrawn and drawn polyamide 6 (N6) and polyamide 66 (N66) fibers showed no difference either in the rate of crystallization or crystallization temperature.…
Tungsten oxide films were successfully synthesized by electroless deposition on copper substrates from tungsten−peroxo electrolytes. The reducing electrons were provided by the copper substrate during oxidation to CuO. Mesoporous tungsten oxide was also fabricated by this method using SDS as a templating agent. This m…
Sternförmige micellare Polymere dienen als Template für die kontrollierte Umwandlung amorpher wärmehärtender organischer Silsesquioxane in geordnete nanoporöse Materialien für Halbleiterchips (siehe Bild). Die Porengröße hängt allein von der Polymergröße ab, nicht von der Konzentration oder den Herstellungsbedingungen.
The first synthesis of 1,4,9,10-tetrahydro-4,9-methanobenzo[4,5]cyclohepta[1,2-b]pyrrole (11) was achieved by the photochemical intramolecular [2 + 2] cycloaddition of N-phenoxycarbonyl- (5a) and N-ethoxycarbonyl-2-[2-(2-vinylphenyl)]pyrrole (6a), respectively, followed by basic hydrolysis of the isolated N-substitute…
High-resolution molar volume data for 4-cyano-4‘- n -octylbiphenyl (8CB) are presented as a function of temperature near the nematic to isotropic (NI) phase transition. Close to the NI transition the volume was measured at 10 mK temperature steps and at two different pressures. From the data an isobaric thermal expans…
Abstract A series of binary blends of poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), and polytetrahydrofuran (PTHF), characterized by similar average molecular weights, with selected fatty acids (capric acid, lauric acid, myristic acid, palmitic acid, and stearic acid) were prepared by melt mixing. Different…
The enhancement characteristics of a contrast agent are dependent on its pharmacokinetics within the body. In the case of macromolecular contrast agents, prolonged enhancement of the blood pool is seen after the first dose, limiting opportunities for repeated injection in the same session. If the enhancement within th…
Abstract The solubility behaviors of poly(sulfonyldiphenylene phenylphosphonate) (PSPPP), a very efficient flame retardant for poly(ethylene terephthalate) (PET), in more than 50 solvents were examined. Its solubility parameters (δ) were determined by the intrinsic viscosity and turbidic titration methods. The two met…
Abstract A thermoplastic vulcanizate (TPV) of a ethylene–propylene–diene terpolymer (EPDM) and nylon copolymer (PA) was prepared by dynamic vulcanization. Maleic anhydride (MAH)–grafted EPDM (EPDM– g –MAH), MAH‐grafted EPR (EPR– g –MAH), and chlorinated polyethylene (CPE) were used as compatibilizers. The effect of dy…
Abstract To investigate the thermally activated structural change of polyetherimide, longitudinal and transverse wave velocity, six kinds of elastic parameters (Young's, shear, and bulk moduli, Lamé parameter, Poisson's ratio, and Debye temperature), and dilational and shear internal frictions were simultaneously meas…
Oxotitanium(IV) phthalocyanine (OTiPc) has been reported to be a near-IR-active photoconductor, where crystal modifications termed phases I, II, and Y exist. In this paper, solid-state electronic absorption spectra of OTiPc have been theoretically calculated by considering three origins (i.e., exciton, charge transfer…
Abstract A series of intercalated poly(trimethylene terephthalate) (PTT)/clay nanocomposites were prepared in a twin‐screw extruder by the melt mixing of PTT with either quaternary or ternary ammonium salt‐modified clays. The morphology and structure, along with the crystallization and melting behavior, and the dynami…
Hin und her, das ist nicht schwer: Ein vollständig reversibler Ligandenaustausch unter Bindung und Dissoziation von gasförmigem Wasser und Pyrimidin induziert die wiederholte allosterische Umwandlung dreier ineinander verwobener Netzwerke zu einem einzigen, dreidimensionalen Netz. Die Umwandlung betrifft nicht die Kri…
Crystallization of pharmaceutically active compounds from saturated solutions by means of solvent evaporation typically involves a nucleation and growth process. At slow solvent evaporation rates, nuclei of the stable forms (polymorphs) will grow at the expense of any metastable forms present in the crystallizing mixt…
Fehlordnung, Ordnung und wieder Fehlordnung: Im Widerspruch zu allen früheren Untersuchungen befindet sich zwischen den zwei bekannten, fehlgeordneten Phasen (LS und HS) von [Fe(2-pic)3]Cl2⋅EtOH eine geordnete Phase (ZP) mit zwei kristallographisch verschiedenen Eisenlagen. Im Bild sind die Eisen-x-Koordinaten für all…