Materials Literature
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This work studies the fire degradation of an intumescent for mulation Polypropylene (PP)-Ammonium Polyphosphate (APP)/Pentaerythri tol (PER) using the cone calorimeter. An intumescence model is described which introduces the notion of degradation front. From the weight loss data recorded by the cone calorimeter and th…
We have studied the crystallization, crystal structure, structure morphology, and magnetic properties of R/sub 6/Fe/sub 87/Nb/sub 1/B/sub 6/ with R=Nd, Pr, Dy, Tb and Nd/sub 3.5/Fe/sub 91/Nb/sub 2/B/sub 3.5/ melt-spun ribbons with a microstructure consisting of a mixture of exchange-coupled magnetically hard (R/sub 2/…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEnzymic Grafting of Amylose from Poly(dimethylsiloxanes)Volker v. Braunmuehl, Gerd Jonas, and Reimund StadlerCite this: Macromolecules 1995, 28, 1, 17–24Publication Date (Print):January 1, 1995Publication History Published online1 May 2002Published inissue 1 January 1995http…
The concentration range over which a self-assembted macrocyclic structure is stable is given by the critical self-assembly concentration (lower limit) and the effective molarity for cyclisation (upper limit); the relationships between these parameters, the size of the assembly and the properties of the component inter…
To assign infrared (IR) absorption bands related to Si‐H vibrations in porous silicon, harmonic frequencies for model clusters were calculated by an ab initio molecular orbital (MO) method using a 6–31 G * basic set. Vibrations associated with a group of interest can be obtained by terminating the cluster with pseudoa…
Four homologous mesogens of the hexakis(n-alkoxy)triphenylene series (HATn, n= 4,6,9,11), have been doped with the one electron oxidant NOBF4, and the electrical conductivity measured as a function of frequency in the hexagonal columnar Dh phase. The limiting low-frequency conductivities both parallel, σ‖, and perpend…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAlternating Ferro- and Antiferromagnetic Interactions in Unusual Copper(II) ChainsGiovanni De Munno, Miguel Julve, Francesc Lloret, Juan Faus, Michel Verdaguer, and Andrea CaneschiCite this: Inorg. Chem. 1995, 34, 1, 157–165Publication Date (Print):January 1, 1995Publication…
The conductivity of a polymer is determined by the availability of charge carriers and their mobility, and both terms are dominated by the trapping states in the polymer. The distribution in energy of these states may be studied by populating the states and observing the current that results from the relaxation of the…
Time-of-flight secondary ion mass spectrometry (TOF SIMS) and X-ray photoelectron spectroscopy (XPS) have been jointly used to study a two-step surface processing of AS4 carbon fiber: extraction of sizing in CH2Cl2 and functionalization with trimellitic anhydride. The combined information on molecular specificity obta…
The following theoretical equation has been obtained for measuring the rate of slow crack growth in polyethylene in terms of the crack opening displacement rate δ: δ̇=αy(1−y2)2ηdoE2α2cK4 Here δy is the yield point, K is the stress intensity, η is the intrinsic viscosity of the fibrils in the craze, E is Young's modulu…
The efficacy of various solid acid catalysts and exchanged clays in a single-pot synthesis of methyl tert-butyl ether (MTBE) from tert-butyl alcohol and methanol is investigated; dodecatungstophosphoric acid (HPA) supported on K-10 clay gives the best yield with highest selectivity for MTBE.
In reactions between the hexamolybdate [Mo6O19]2– and 1,4-diaminobenzene, terminal oxides are replaced by 4-aminophenylimido ligands and the first structurally characterised polyoxometallate to contain functionalised organoimido ligands, (Bun4)2[Mo6O17(NC6H4NH2)2]5, is also the first example of a trans-bis(imido) deri…
The main lines of a Continuum Damage Mechanics Modelling are reviewed, for applications to brittle materials treated as elastic damageable ones. The proposed damage models consider in the same framework the cases of initially isotropic materials like concrete and anisotropic composites. Attention is focused on the dam…
A series of sodium polyphosphate glasses of composition ${\mathrm{Na}}_{\mathit{n}+2}$${\mathrm{P}}_{\mathit{n}}$${\mathrm{O}}_{3\mathit{n}+1}$ have been studied using synchrotron-radiation x-ray-absorption spectroscopy. High-resolution P L-edge and K-edge x-ray appearance near-edge structure (XANES) as well as K-edge…
The time function of the Erying reaction rate theory of insulation life is modified to demonstrate a physical origin for temperature threshold. Various mechanisms by which trapped charges may be involved in degrading the polymer are examined, and incorporated into the life model through an alteration to the free energ…
Flashover mechanisms of silicone rubber used for outdoor insulation is presented and experimentally proven. A hydrophobic surface of silicone rubber wets and accumulates contaminants differently compared to conventional porcelain and glass insulators. This suggests that the flashover mechanism of silicone rubber insul…
β″-(bedt-ttf)4[(H2O)Fe(C2O4)3]·PhCN [bedt-ttf = bis(ethylenedithio)tetrathiafulvalene] is a superconductor [Tc 8.5(3) K]; from 9–300 K its magnetic susceptibility is dominated by the high-spin FeIII and obeys the Curie–Weiss law (C= 4.375 emu K mol–1, θ=–0.2 K).
Homogeneous Y‐Si‐O‐N glasses containing 15 or 20 eq% nitrogen (N) were prepared from compositions with Y/Si ratios in the vicinity of that of the lowest eutectic point on the Y 2 O 3 –SiO 2 phase diagram. The liquidus on the phase diagram shifted toward lower temperatures by incorporation of N. The density, the elasti…
To understand better the origin of protein rejection observed with surface-bound poly(ethylene oxide) (or PEO), we have measured fibrinogen adsorption for a series of linear and branched, low-molecular-weight PEOs bound to solid polystyrene surfaces. The results show that a dependence on molecular weight is found belo…
The relative time scales at which semivolatile gas and particle PAH approach equilibrium under both moderate and cool temperatures were investigated. Combustion particles were added directly from a diesel car and a wood stove to a 190 m^3 outdoor Teflon film chamber. The rate of migration of a gas-phase semivolatile P…