Materials Literature
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Abstract To evaluate the compatibilization effects of an isocyanate group on poly(ethylene terephthalate)/polypropylene (PET/PP) blends through a reactive blend, PP grafted with 2‐hydroxyethyl methacrylate‐isophorone diisocyanate (PP‐ g ‐HI) was prepared and blended with PET. In view of the blend morphology, the prese…
The rational design of catalysts with a high efficiency for the destruction of NO x compounds (DeNO x process) is a major problem in environmental chemistry. The adsorption of NO, NO 2, and N 2 O on MgO(100), Zn 0.06 Mg 0.94 O(100), Cr 0.06 Mg 0.94 O(100), and Cr 2 O 3 (0001) was studied using high-resolution photoemi…
A new class of noncoordinating anions are the carbosilane dendrimers with perfluoroarylborate end groups (see picture). They activate and stabilize metallocenes to give catalytic systems that polymerize olefins, such as ethene, propene, and 1-hexene, with high activity.
BaTiO 3 thin films were epitaxially grown on SrTiO 3 (001) and LaNiO 3 /SrTiO 3 substrates by pulsed laser deposition under different oxygen pressures. The oxygen content in the BaTiO 3 films was determined using modified Rutherford backscattering. The structural characteristics of the films were analysed by x-ray dif…
A di-walled molecular umbrella (1a) has been synthesized by acylation of the terminal amino groups of spermidine with cholic acid, followed by condensation with bis(3-O-[N-1,2,3-benzotriazin-4(3H)-one]yl)-5,5'-dithiobis-2-nitrobenzoate (BDTNB), and displacement with glutathione (gamma-Glu-Cys-Gly, GSH). Replacement of…
Four oxamato-bridged heterotrinuclear Ni(II)Cu(II)Ni(II) complexes of formula ([Ni(bispictn)](2)Cu(pba))(ClO(4))(2).2.5H(2)O (1), ([Ni(bispictn)](2)Cu(pbaOH))(ClO(4))(2).H(2)O (2), ([Ni(cth)](2)Cu(pba))(ClO(4))(2) (3), and ([Ni(cth)](2)Cu(opba))(ClO(4))(2).H(2)O (4) and a binuclear Ni(II)Cu(II) complex of formula [Cu(…
The structure and ion-exchange properties of tetraalkylammonium (TAA; alkyl = methyl, ethyl, propyl) manganese oxide gels produced from colloidal manganese oxide solutions are presented. TAA manganese oxide xerogels are analyzed by X-ray powder diffraction (XRD) and extended X-ray absorption fine spectra (EXAFS) and c…
The proligand citric acid has been used to assemble two new anionic NiII clusters, [Ni7(cit)6(H2O)2]10− and [Ni21(cit)12(OH)10(H2O)10]16− (see picture; Ni=black spheres), from basic aqueous solution. The former possesses a high-spin S=7 ground state, while the latter shows predominantly antiferromagnetic exchange.
New perylene chromophores, phenyl-substituted diindeno[1,2,3-cd:1',2',3'-lm]perylenes 5a,b and 4,4',7,7'-tetraphenyldiacenaphtho[1,2-k:1',2',k']diindeno[1,2,3-cd:1',2',3'-me]perylenes 22a,b, have been synthesized from substituted fluoranthene derivatives 3a,b and 4a,b by means of a surprisingly simple oxidative cyclod…
Recent constant composition dissolution studies of sparingly soluble calcium phosphates have revealed an interesting and unusual behavior in that the rates decreased, eventually resulting in effective suppression, even though the solutions remained undersaturated. Contrary to traditional theories of dissolution, these…
Dendrimere sind wohldefinierte hochverzweigte Makromoleküle, die bei hinreichender Größe charakteristische globuläre Strukturen aufweisen. Sie haben viele Chemiker zur Entwicklung von neuen Materialien angeregt, und eine Reihe von Anwendungen, auch in der Katalyse, wurde bereits untersucht. Die jüngsten Fortschritte b…
The highly symmetric structure of a cagelike host enables the inclusion geometry of guest molecules in the host to be predicted in a dynamic fashion by analyzing not the guest but the host framework. For example, an S4 orientation of two 1,2-diketone guests in the clathrate complex was predicted by NMR spectroscopy an…
Abstract Poly(vinyl alcohol) (PVA) can be dissolved in a nonaqueous medium in the presence of catalytic concentration of ethyl nitrate dimethyl sulfoxide, C 2 H 5 ONO 2 · DMSO (EN · DMSO). From the PVA solution, poly(vinyl butyral) (PVBu) was prepared by acid‐catalyzed homogeneous acetalization of PVA with butyraldehy…
Abstract Polyhydrazides and poly(amide‐hydrazide)s were prepared from two ether‐sulfone‐dicarboxylic acids, 4,4′‐[sulfonylbis(1,4‐phenylene)dioxy]dibenzoic acid and 4,4′‐[sulfonylbis(2,6‐dimethyl‐1,4‐phenylene)dioxy]dibenzoic acid, or their diacyl chlorides with terephthalic dihydrazide, isophthalic dihydrazide, and p…
Three lengths for the dynamic glass transition will be compared: a kinematic length from computer simulation, a heterogeneity length from multidimensional nuclear magnetic resonance, and a characteristic length from calorimetry. A qualitatively consistent picture is obtained after discussion of their different origins…
Hydrolytic removal of the core unit and cross-linking of their wedges enables dendrimers to be “cored” (see schematic representation). By internalizing the alkenes, the ring-closing metathesis reaction will “stitch” the dendritic wedges together intramolecularly, even at dendrimer concentrations of 10−3 M. In contrast…
Abstract Prior to curing, we evaluated thermal stability of poly(butylene succinate) (PBS). Above 170°C, PBS was severely degraded and the degradation could not be successfully stabilized by an antioxidant. PBS was crosslinked effectively by DCP at 150°C, and the gel fraction was increased as DCP content increased. Th…
As a result of advances in experimental and theoretical physics, many interesting problems have arisen in condensed-matter physics, typically as a result of the quantum-mechanical nature of a system. Areas of interest include Anderson localization, universal conductance fluctuations, normal electron persistent current…
A system of identical particles interacting through an isotropic potential that allows for two preferred interparticle distances is numerically studied. When the parameters of the interaction potential are adequately chosen, the system exhibits coexistence between two different liquid phases (in addition to the usual…
Abstract After curing, phenol‐formaldehyde resins were postcured at 230°C in air for 32 h and then carbonized and graphitized from 300 to 2400°C. Thermal fragmentation and condensation of the polymer structure occurred above 300°C. The crystal size of the cured phenolic resins decreased with the temperature increase.…