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。
Spread monolayers of poly(styrene)−poly(ethylene oxide) diblock copolymers (PS m −PEO n, m = 38, n = 90, 148, 250, and 445) have been studied at the air−water interface by measuring the surface pressure−area (π− A ) isotherms at several temperatures. The π− A isotherms exhibit several regions which can be ascribed to…
Abstract High purity and a large amount of β‐modification can be produced in polypropylene (PP) by adding a bicomponent β‐nucleator consisting of equal amounts of pimelic acid and calcium stearate. Wide angle X‐ray diffraction (WAXD), scanning electron microscopy (SEM), static tensile tests, Izod impact tests, and ins…
Hydrotalcites, which are anionic clays, have been synthesized by the sol−gel technique from magnesium ethoxide, aluminum tri-sec-butoxide, and aluminum acetylacetonate. Initially a colloidal solution is obtained which gels and is thermally stabilized. The local and average structure are studied comparing the electron…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTSoluble Alkyl-Substituted Poly(ethylenedioxythiophenes) as Electrochromic MaterialsAnil Kumar and John R. ReynoldsView Author Information Department of Chemistry, Center for Macromolecular Science and Engineering, University of Flor…
A new class of porphyrins in which intervening ethynyl moieties connect aryl groups to the porphyrin 5- and 15-positions is described. The synthesis and optical spectroscopy of five new compounds are reported: [5,15-bis[(4‘-dimethylaminophenyl)ethynyl]-10,20-diphenylporphinato]zinc(II), [5,15-bis[(4‘-methoxyphenyl)eth…
Polymerization of l -lactide in dichloromethane at 25 °C using an initiating system comprising tris(2,6-di- tert -butylphenoxy)yttrium and 2-propanol was first order in monomer and initiator. A propagation rate constant of 1.92 × 10 3 L mol -1 min -1 was determined using in situ UV spectroscopy. In the first step the…
Supramolecular liquid-crystalline networks have been prepared by self-assembly of multifunctional H-bond donor and acceptor molecules through the formation of intermolecular hydrogen bonds. Two tricarboxylic acids, 1,3,5-tris(2-(2-(4-carboxyphenoxy)ethoxy)ethoxy)benzene ( 1 ) and 3,4-bis(2-(2-(4-carboxyphenoxy)ethoxy)…
Part I - Layered Solids and their Intercalation Chemistry. Part II - Molecular Sieves: Inclusion Chemistry and Reactivity. Layered solids and their intercalation chemistry (G. Alberti, U. Constantino). Graphite intercalation compounds (F. Okino, H. Touhara). Layered metal chalcogenides and their intercalates (J. Rouxe…
The spreading of aqueous mixtures of a number of surfactants, including “superspreading” trisiloxane surfactants, has been investigated as a function of surfactant concentration, substrate surface energy, temperature, humidity, and substrate roughness. The substrate surface energy, characterized in terms of the contac…
Over the past two decades the “pressure and material gaps” separating ultrahigh-vacuum surface science and technical catalysis has been bridged by coupling an apparatus for the measurement of reaction kinetics at elevated pressures with an ultrahigh-vacuum system for surface analysis. Studies with this combined method…
A combination of small-angle X-ray scattering and optical microscopy was used to investigate the influence of diluent mobility and polymer−polymer interactions on diluent segregation in a series of “model” melt-miscible poly(ethylene oxide) (PEO) blends. The amorphous polymeric diluents were selected with regard to th…
We report experimental data on the mechanical stability of the silica mesoporous material MCM-41. Using X-ray diffraction and nitrogen adsorption we show that the ordered mesoporous structure of MCM-41 can be affected considerably by mechanical compression at pressures as low as 86 MPa and essentially destroyed at 224…
We report atomistically detailed molecular dynamics simulations of benzene−polystyrene systems (0−84.2 wt % polystyrene). We have calculated solvent diffusion coefficients and have found that their composition dependence not only shows good agreement with experiment but also follows quite well the predictions by latti…
The phase behavior and miscibility of blends of poly(vinylidene fluoride) (PVF 2 ) and poly(1,4-butylene adipate) (PBA), both semicrystalline polymers, have been investigated using differential scanning calorimetry and light-scattering techniques. The phase diagram of this blend system exhibits a single glass transiti…
The synthesis and characterization of various optically active nanoscale-size tetranuclear assemblies held together by coordination bonds is described. Interaction of bis[4-(4‘-pyridyl)phenyl]iodonium triflate and bistriflates of chiral transition metal (Pd(II) or Pt(II)) bisphosphines resulted in the formation of chi…
The growth and planar to cellular and cellular to dendritic transition of crystals in Fe–C alloy melts have been successfully observed “in-situ” by use of a conforcal laser microscope combined with an infrared image furnace. The observations clearly indicated that an increase in the growth rate of planar crystals in a…
Infrared reflectance and Raman spectra of rubidium germanate glasses, x Rb 2 O·(1 − x )GeO 2, have been measured and studied as a function of Rb 2 O mole fraction in the range 0 ≤ x ≤ 0.60. The spectra of corresponding crystalline germanate phases, GeO 2 -quartz, GeO 2 -rutile, Rb 2 Ge 4 O 9, K 4 Ge 9 O 20, K 2 Ge 2 O…
We study the asymptotic limit, as \ 0, of solutions of the Cahn-Hilliard equation 1 under the assumption that the initial energy is bounded independent of . Here / = F', and F is a smooth function taking its global minimum 0 only at u -1. We show that there is a subsequence of {t e }o<e<i converging to a weak solution…
The solubility of paracetamol was studied at 25°C in mixtures of amphiprotic and aprotic solvents of varying polarity (ethyl acetate-ethanol, ethanol-water, dioxane-water). A plot of the solubility mole fraction of the drug versus the solubility parameter of the solvent mixtures reached a peak in dioxane-water, and tw…
The effect of film thickness on the organization kinetics of ultrathin (50−1000 Å thick) spin-cast polymer films was studied using poly(di- n -hexylsilane) and UV absorption spectroscopy. We found an extensive reduction in the crystallinity as well as a reduction in the rate of crystallization for film thicknesses bel…