Materials Literature
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The crystalline morphology of a relatively high molecular weight isotactic polypropylene (i-PP) ( M w = 18000 g/mol) with well-defined regio- and stereoirregularities is studied by means of atomic force microscopy (AFM), wide-angle X-ray scattering (WAXS), small-angle X-ray scattering (SAXS), and light microscopy. Thi…
J. Rebek, Chem. Soc. Rev., 1996, 25, 255 DOI: 10.1039/CS9962500255
Doxorubicin is a potent antineoplastic agent with activity against numerous human cancers. Encapsulation of doxorubicin inside a liposome alters bioavailability, biodistribution and thus its biological activity significantly. The physical properties of the liposome (size, lipid components and lipid dose) play a major…
Fluorescence decay dynamics and structure of a meso -tetrakis( p- sulfonatophenyl)porphyrin, referred to herein as either H 2 TSPP 4- or TSPP, which aggregates in highly acidic homogeneous solution, are discussed. The fluorescence lifetime of the aggregate is found to depend on whether electronic excitation is to the…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTA Versatile and Highly Efficient Catalyst System for the Preparation of Polyesters Based on Lanthanide Tris(2,6-di-tert-butylphenolate)s and Various AlcoholsWillem M. Stevels, Marc J. K. Ankoné, Pieter J. Dijkstra, and Jan FeijenVie…
Pentadentate ligands (salpr) anchored to the surface of MCM-41 type silica through covalently linked organic moieties are further converted into MnIII(salpr) complexes by ligand exchange without loss of the regular porous structure of the support.
In this last paper of a series devoted to uncatalyzed and catalyzed reduction of NO by carbon, we discuss some mechanistic aspects of this reaction, which is thought to be a viable alternative to selective catalytic reduction by ammonia or hydrocarbons. We present a summary of the results of isothermal and temperature…
Four valence tautomeric complexes with the general composition [Co(3,5-DTBSQ) 2 (N⌒N)] have been investigated, where 3,5-DTBSQ - is the semiquinonate form of 3,5-di- tert -butyl- o -quinone. The diiminium ligand N⌒N is one of the following ligands: phen (1,10-phenanthroline, complex 1 ); bpy (2,2‘-bipyridine, complex…
Abstract An extrusion process for manufacturing microcellular plastics is presented. In the past, microcellular structures have been produced in batch processes by using a thermodynamic instability of a polymer/gas system. In order to utilize such a thermodynamic instability in a continuous extrusion process, a large…
A new concept for the synthesis of hyperbranched macromolecules involving the use of AB x macromonomers containing linear oligomeric units is introduced. This methodology is used for the preparation of a series of novel hyperbranched poly(ethylene glycol) derivatives containing linear poly(ethylene glycol) units of va…
A series of symmetric derivatives of 4-(dicyanomethylene)-2-methyl-6-( p -(dimethylamino)styryl)-4 H -pyran (DCM laser dye) has been synthesized, and the nonlinear optical properties and thermal decomposition temperatures of each of the chromophores has been measured. The symmetric chromophores all have larger hyperpo…
The synthesis and characterization of the tapered building blocks 3,4,5-tris(1 H,1 H,2 H,2 H,3 H,3 H,4 H,4 H,5 H,5 H,6 H,6 H,7 H,7 H,8 H,8 H -perfluorododecan-1-yloxy)benzoic acid ( 11-8/4 ), 3,4,5-tris(1 H,1 H,2 H,2 H,3 H,3 H,4 H,4 H,5 H,5 H,6 H,6 H -perfluorododecan-1-yloxy)benzoic acid ( 11-6/6 ), 3,4,5-tris(1 H,1…
Different oxidation levels, regarded as polaron, bipolaron, and metallic states, are usually found in conjugated heterocyclic polymers. We found that poly(3,4-ethylenedioxythiophene) (PEDOT) also has these different oxidation levels, using in situ UV−VIS−NIR spectroscopy. The transitions between the different oxidatio…
A simple method to prepare porphyrin “wheels” on a micrometer scale is described. It is possible to arrange several types of porphyrin derivatives, including Protoporphyrin IX and Chlorophyll- a, in the form of rings using this method. A mechanism for the formation of these types of assemblies is proposed that is base…
Micromechanical methods developed to describe the thermomechanical behavior of solids are applied to phase transition related problem. Results obtained are compared with those obtained using a macroscopic phenomenological approach. This micromechanical analysis is based on a kinematical description of the physical str…
This paper takes the structure example of the AlPdMn quasicrystal, as determined from diffraction data, to derive useful self-similarity rules in consistency with composition and atomic valence constraints. These rules are then accounted for to explain inelastic-neutron-scattering data and thermal conductivity behavio…
Abstract The possibility of phase transformation toughening is demonstrated by the example of the β‐modification of isotactic polypropylene (β‐iPP), which undergoes βα‐transformation (i.e., from hexagonal to monoclinic) during mechanical loading. The resulting α‐iPP exhibits a higher crystalline density than the initi…
A titanium-containing mesoporous material with a cubic structure, Ti-MCM-48, is synthesized by a two-stage hydrolysis method using tetraethylorthosilicate and tetrabutylorthotitanate and found to be more active than Ti-MCM-41 in the epoxidation of bulky alkenes using H2O2.
We have determined the phase behavior of a series of model poly(ethylene)−poly(ethylethylene) (PE−PEE) diblock copolymers with poly(ethylene) block volume fractions ( f PE ) ranging from 0.25 to 0.46. Four ordered microstructures make contact with the ODT: spheres arranged on a body-centered cubic lattice ( Im 3̄ m sp…
Poly(acrylic acid), poly(vinylsulfonate) and poly(styrenesulfonate) have been incorporated between the positively charged sheets of layered double hydroxides (LDHs)M1–xAlx(OH)2+(M = Mg, Ca, Co) and Zn1–xM′x(OH)2+(M′= Al, Cr) to form layered nanocomposites. The resulting nanocomposites contained the LDH sheet structure…