Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
We describe a numerical implementation of self-consistent mean field theory for block copolymers that requires no assumption of the mesophase symmetry. The method is amenable to massively parallel screening of self-assembly in complex block copolymer systems, characterized by high-dimensional parameter spaces. We illu…
Epitaxial thin films of an oxide-diluted magnetic semiconductor, Mn-doped ZnO, were fabricated by pulsed-laser deposition technique. Solubility of Mn into ZnO exceeds thermal equilibrium limit as a result of nonequilibrium film growth process. As Mn content is increased, the lattice constants of both a and c axes of w…
We demonstrate the detection of molecular vibrations in single hemoglobin (Hb) protein molecules attached to isolated and immobilized silver nanoparticles by surface enhanced Raman scattering (SERS). A comparison between calculation and experiment indicates that electromagnetic field effects dominate the surface enhan…
Polypropylene/polyamide 6 blends were prepared by melt mixing, without or with the addition of a suitable commercial product, a polypropylene grafted with 1% maleic anhydride, used as an interfacial modifier. The oxygen permeation through their films was studied as a function of temperature and the effect of the prese…
Ethylene-propylene-diene monomer (EPDM) terpolymers were prepared using either vanadium (VOCl3/Al2Et3Cl3) or zirconocene (Et(Ind)2ZrCl2/MAO) catalyst systems. Residual metal contents in EPDM films were determined by Rutherford backscattering spectrometry. Metallocene catalyst systems exhibited a higher activity, produ…
This work experimentally and theoretically determines the molecular macrostructure of the polymer mixture that is developed (at relatively low conversions) in a solution polymerization of styrene (St) in presence of polybutadiene (PB). The reaction was carried out at 70°C in a batch-stirred tank reactor. From samples…
ABS was melt grafted with maleic anhydride at three different levels of 1, 2, and 3 wt %. These three different modified ABSs were melt blended with polycarbonate using a single-screw extruder to choose a suitable maleic anhydride grafting level on ABS for better performance. For the compatibility study, binary blends…
A series of novel triblock copolymers, consisting of a poly(ethylene glycol) center block joined by two blocks of random L-lactide/glycolide copolymers, are synthesized and their characteristics (spectral, thermal, and mechanical) determined. Polymer compositions and structures are assessed via 1H-NMR and 13C-NMR spec…
Two methods of obtaining electrically conductive fabrics by in situ polymerization of aniline were compared. Conductive fabrics were prepared by immersing the nylon 6 fabrics in 100% aniline or an aqueous hydrochloride solution of aniline followed by initiating successive polymerization in a separate bath (DPSB) or in…
Residual softwood sawdust was pretreated by a steam-explosion technique. It was used as a natural filler in polypropylene (PP)-based composites. Dynamic mechanical analysis and tensile properties of these materials were studied. The influence of filler loading, steam-explosion severity, and coating the fiber with a fu…
Guest desorption procedures for s-PS clathrate samples, leading to formation and regeneration of the nanoporous δ phase, are compared. An extraction procedure, based on supercritical carbon dioxide, allows an easy and fast recovery of the guest molecules operating under relatively mild conditions (90–200 bar, 40°C) an…
Oligomers were obtained from polyester samples by solvent extraction and dissolution methods. Dioxane, chloroform, and chlorobenzene were used for the extraction method, whereas dimethyl formamide and phenol : tetrachloroethane (1 : 1 mixture) were used for the dissolution method. The oligomers were separated and anal…
The bridging sulfido anions (μ-RS)(μ-S - ) [Fe 2 (CO) 6 ] 2 (μ 4 -S) ( 4a ) react with succinyl chloride in THF to give double and quadruple butterfly Fe/S clusters (μ-RS)(μ-RSS)[Fe 2 (CO) 6 ] 2 (μ 4 -S) ( 5a, R = Et; 6a, R = t-Bu) and [(μ-RS)Fe 2 (CO) 6 (μ 4 -S)Fe 2 (CO) 6 ] 2 (μ-S−S-μ) ( 5b, R = Et; 6b, R = t-Bu), u…
We examined the effect of the addition of homopolymers tetramethylbisphenol A polycarbonate, TMPC, and poly(norbornene−methyl- d 3 -carboxylate), NBMC, on the interlamellar spacing and the phase stability of symmetric poly(styrene- b -methyl methacrylate) diblock copolymer thin films on silicon substrates. The films w…
Solid-state deuterium NMR ( 2 H NMR) was used to study the dynamics of the tyrosine (Tyr) residue in silk fibroin from Bombyx mori ( B. mori ) and Samia cynthia ricini ( S. c. ricini ). Specifically deuterated cocoon silk was obtained by feeding silk worms with Tyr, labeled either at the C β carbon ([3,3- 2 H 2 ]Tyr)…
The synthesis and characterization of seven (Zn II ) 2 bis(porphyrin) molecules are described. The molecular structures of two bis(porphyrin)s ( 6 and 7 ) were determined by X-ray diffraction methods. Four of the compounds have their porphyrin moieties attached in a meta -fashion to a substituted benzene ring ( 1 − 4…
Polyaniline specimens, emeraldine sulfate, emeraldine hydrochloride, and emeraldine base, were characterized by infrared spectroscopy, X-ray photoelectron spectroscopy, elastic peak electron spectroscopy, and density measurements using helium pycnometry. This work has been stimulated by a considerable interest in pote…
The magnetic anisotropy of the two cyclic hexanuclear Fe(III) clusters [Li⊂Fe 6 L 6 ]Cl·6CHCl 3 and [Na⊂Fe 6 L 6 ]Cl·6CHCl 3, L = N(CH 2 CH 2 O) 3, was investigated. Based on a spin Hamiltonian formalism, the magnetic anisotropy was calculated exactly to first order, i.e., in the strong exchange limit, using Bloch's p…
The effect of water vapor concentration on the reaction rates of NH 3 oxidation and N 2 O decomposition catalyzed by calcined limestone was investigated by use of a fixed bed reactor under atmospheric fluidized bed combustion conditions. Both reactions were inhibited by the presence of water vapor. Inhibition of NH 3…
Aromatic polymers are widely used in products ranging from optical lenses to milk bottles because of their strength, thermal durability, and high glass transition temperatures. All of the commonly used routes employed to generate aromatic polycarbonates and polyesters generate large amounts of waste as by-products and…