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。
Homogeneous nucleation of crystallizing n -alkanes (CH 3 −(CH 2 ) n-2 −CH 3, 17 ≤ n ≤ 60) and some low-MW polyethylene (PE) fractions were studied using calorimetry and compared to reanalyzed PE data of Ross and Frolen. The undercooling and derived surface energy of the n -alkanes starts increasing for n as low as 25,…
Much experimental effort to realize possible uses of dendrimers has focused on the complexation of charged dendrimers to oppositely charged polyelectrolytes to form controlled delivery systems. Employing computer simulation and theory, we present a molecular-level picture of these guest−host aggregates and the conditi…
Nanoparticles of various dimensions of II−VI binary chalcogenides CdSe, PbSe, and Cu 2 - x Se, have been prepared by a very simple fast reaction between acetates or sulfates of Cd, Pb, and Cu and Na 2 SeSO 3 in the presence of complexating agents, using microwave irradiation. The nanoparticles were analyzed by X-ray d…
Facilitated transport of oxygen was investigated in ethyl cellulose membranes containing cobalt(II) meso-tetrakis (substituted phenyl) porphyrins [CoTPP, CoT(2-Cl)PP, CoT(4-Cl)PP, CoT(4-MeO)PP, and CoT(2,4-2MeO)PP] as fixed oxygen carriers. The oxygen permeability (P) and oxygen/nitrogen selectivity (P/P) of the membr…
The kinetics of polycondensation and copolycondensation reactions of bis(3-hydroxypropyl) terephthalate (BHPT) and bis(2-hydroxyethyl) terephthalate (BHET) as monomers were investigated at 270°C, in the presence of titanium tetrabutoxide (TBT) as a catalyst. BHPT was prepared by ester interchange reaction of dimethyl…
The [Cr2(azin)4Cl2]2- ion has been made and structurally characterized. Despite the long Cr−Cr distance (2.688(2) Å), there is strong coupling of all electron spins, presumably by superexchange via the bridging azin ligands (azin = anion of 7-azaindole).
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” opt…
Effect of ethyl and n-octyl branches on the properties of poly(ethylene adipate) (PEA) and poly(butylene succinate) (PBS) were investigated. Glass transition and melting temperature, crystallinity, melt viscosity, and spherulite growth rate were decreased with an increase in the degree of the chain branches. Introduct…
Wormlike dendrimers made of flexible and noninteracting segments were synthesized. Starting from a poly(methylhydrosiloxane) G 0 and using short propylsilane branches, the synthesis did not go beyond the second generation, as predicted from steric congestion. The starting polymer and the G 1 and G 2 dendrimers synthes…
Radiation induced grafting of acrylic acid onto polyethylene film was investigated. The grafted films rapidly adsorbed Cu2+, Cd2+, Th4+, and UO ions in high efficiency. The carboxylic acid groups on AAc-grafted PE film acted as a chelating site for the selected metal ions. Complex formation of metal ions and carboxyli…
The temperature-dependent resistivity behavior of carbon black–loaded polyethylene (PE) composites irradiated both at room temperature and 170°C above the PE melting point was studied. The irradiation doses were varied. At a given loading level, irradiation at room temperature corresponded to an energy treatment on a…
An analysis of the cylindrical brush of an isolated comb copolymer molecule, consisting of a semiflexible backbone and rodlike side chains, is presented. Using a mean-field approach and a simplyfying assumption, which is tested by computer simulations, we find that the persistence length of the brush, λ, scales as λ ∝…
Optical second harmonic generation (SHG) was used to study how mechanical rubbing modifies the surface structure of a polyimide (poly[4,4‘-oxydiphenilenepyromellitimide], PMDA-ODA) film and how the rubbed polyimide surface aligns a liquid crystal monolayer (4‘- n -octyl-4-cyanobiphenyl, 8CB) adsorbed on it. It was fou…
The Chandra spacecraft has been launched successfully on July 23, 1999. The payload consists of a high resolution X- ray telescope, two imaging detector systems in the focal plane and two transmission gratings. Each one of the two gratings can be put in the beam behind the telescope and the grating spectrometers are o…
Magnetic CoFe 2 O 4 spinel ferrite nanoparticles are synthesized by a microemulsion method using sodium dodecyl sulfate as the surfactant to form micelles. A statistical method of factorial design is used to establish a mathematical model from a series of synthesis experiments. This chemometric model quantitatively co…
The formation of alternating layers of positively charged gold and negatively charged silver colloidal particles on glass substrates via electrostatic interaction is described. The charging of the gold and silver colloidal particles is accomplished by self-assembly of 4-aminothiophenol (4-ATP) and 4-carboxythiophenol…
The thermochromic and solvatochromic properties of a series of fluorene-based conjugated polymers have been investigated. Both poly(2,7-(9,9-dioctylfluorene)) and poly(2,5-(thiophene)- alt -2,7-(9,9-dioctylfluorene)) have revealed interesting chromic properties which, on the basis of theoretical calculations, seem to…
Segment and domain orientation behaviors of a series of poly(butylene succinate) (PBS) –poly(tetramethylene glycol) (PTMG) segmented block copolymers containing different amounts of hard segment were studied with synchrotron small-angle X-ray scattering (SAXS) and infrared dichroic methods. Copolymers used in this wor…
K 2 MnSn 2 Se 6 ( I ), K 2 MnSnSe 4 ( II ), and K 2 Ag 2 SnSe 4 ( III ) were prepared by molten-salt (alkali-metal polyselenide flux) reactions at intermediate temperature (400−520 °C). Their crystal structures were determined by single-crystal X-ray diffraction techniques. Crystal data for I: space group P 4/ ncc, a…
Ce-doped BaTiO 3 (BTO:Ce) thin films prepared on MgO (100) substrates by pulsed laser deposition (PLD) at oxygen pressure of 1.2×10 -3 and 17 Pa have been studied by micro-Raman spectroscopy, x-ray diffraction (XRD) and atomic force microscopy (AFM). The film deposited at lower oxygen pressure has a larger lattice par…