Materials Literature
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Abstract Novel families of flexible, semiflexible and rigid crosslinked polyesters were prepared from modified natural oils such as soybean, rape‐seed and linseed oil. Maleinated oils were used as anhydride‐functional curing agents of epoxy resins such as bisphenol‐A‐diglycidylether and epoxidized natural oils. A new…
Enthalpy recovery data on poly(ether imide) from differential scanning calorimetry (DSC) is fit using the Moynihan−Tool−Narayanswamy model of structural recovery. A self-consistent phenomenological equation is used to describe the experimentally observed structure and temperature dependence of the relaxation time in b…
Highly exothermic direct reactions between elements boron and nitrogen at high pressures and temperatures yield technologically important forms of hexagonal and cubic boron nitride (BN). The crystal structures of the reaction products vary with pressure. Below 10 GPa, hexagonal BN is the product; cubic or wurzite BN f…
The synthesis and characterization of a series of bis(cyanide)( meso -tetraalkylporphyrinatoiron(III)), [Fe(T R P)(CN) 2 ] - where R is H, Me, Et, and i Pr, are reported. The 1 H NMR spectrum of the unsubstituted [Fe(T H P)(CN) 2 ] - shows a pyrrole signal at δ = −23.19 ppm (−25 °C) in CD 2 Cl 2, which is quite typica…
The supramolecular structures formed when anionic polyamidoamine starburst dendrimers, in the presence of low concentrations of spin probe surfactants, are added to aqueous solutions of nonlabeled cationic surfactants have been investigated by EPR spectroscopy. In order to obtain an overview of dendrimer/surfactant sy…
Birefringence is caused by both orientation of polymer chains and photoelasticity. These birefringences were compensated by random copolymerization of negative birefringent methyl methacrylate and positive birefringent benzyl methacrylate, but orientational and photoelastic zero birefringences were achieved with quite…
Plastic composite supports containing 50% agricultural products (oat hulls, soybean hulls, yeast extract, soybean flour, dried bovine erythrocytes, bovine albumin, and/or mineral salts) and 50% (wt/wt) polypropylene were produced by high-temperature twin-screw extrusion. The research employed two half sets of a five-f…
The tautomerism in solid phase was studied by near-edge X-ray absorption fine structure (NEXAFS) spectroscopy at the N K - and O K -edges and X-ray photoelectron spectroscopy (XPS) in the N1s and O1s regions for five N -salicylideneaniline derivatives: N, N‘ -disalicylidene-1,6-pyrenediamine (DSPY), N, N‘ -disalicylid…
Liposomes and immunoliposomes containing cytotoxic agents may be highly efficacious in intracavity therapy of malignancies confined principally to the peritoneal cavity. To assess the feasibility of this locoregional treatment, we prepared two derivatives of 5-fluorouridine (5-FUR), a highly cytotoxic metabolite of 5-…
We introduce a materials science tool for investigating refractory solids and melts: the electrostatic containerless processing system (ESCAPES). ESCAPES maintains refractory specimens of materials in a pristine state by levitating and heating them in a vacuum chamber, thereby avoiding the contaminating influences of…
The optical properties of a series of high refractive index polyphosphazenes were investigated. The wavelength-dependent change in refractive index (optical dispersion) associated with two selected polymers was examined using variable-angle spectroscopic ellipsometry. Values of the Abbé number for these polymers were…
Abstract Supramolecular structure of initially wet bacterial cellulose of Acetobacter xylinum has been investigated by X‐ray scattering including synchrotron radiation, transmission electron microscopy, and 13 C‐CP/MAS‐NMR‐spectroscopy. As a result a model is given of never dried swollen microfibrillar ribbons consist…
Many polymeric materials, including structural adhesives, exhibit a nonlinear viscoelastic response. The nonlinear free volume approach is based on the Doolittle concept that the “free volume” controls the mobility of polymer molecules and, thus, the inherent time scale of the material. It then follows that factors su…
Composite materials have become very attractive as personal and vehicle armors because of their light weight and high performance. Unfortunately, these materials are difficult to simulate numerically or analytically, and the only way to check their performance is experimentally. A first step could be the study of the…
Reactive species of nitrogen cold plasma could interact with a polymeric surface, leading to an important surface functionalization (mostly as amino group attachment) and consequently to a surface having a Lewis base character. Under certain conditions, the surface functionalization is not the only modification; a mor…
The synthesis of azobenzene-substituted polythiophenes (poly[3-(2-(4-((4‘-ethoxyphenyl)azo)phenoxy)ethoxy)-4-methylthiophene] (P3A), poly[3-((6-(4-((4‘-ethoxyphenyl)azo)phenoxy)hexyl)oxy)-4-methylthiophene] (P3B)) and poly[3-(((6-(4-((4-ethoxyphenyl)azo)phenoxy)ethyl)tri(ethoxy)oxy)-4-methylthiophene] (P3C) has led to…
Thermal factors of protein atoms as determined by X-ray crystallographic techniques show a tendency to be larger in side chains with unfavourable local conformations rather than in those displaying conformational energy minima. It follows that side chain atoms are more mobile if they are in a non-rotameric configurati…
The distribution of framework aluminum inside micrometer-size particles of the mesoporous molecular sieve MCM-41 has been investigated using transmission electron microscopic (TEM) images, after supporting platinum clusters inside the aluminum-containing region selectively via the ion exchange of Pt(NH 3 ) 4 2+ . The…
The synthesis and spectroscopic investigation of a number of push–pull ethenes in which the donor moiety is represented by a π-excessive five-membered heterocycle (pyrrole, indole and thiophene) and the acceptor group is a π-deficient heterocyclic azine ring (pyridine, pyrazine, pyrimidine, pyridazine) are described.…
To relax many of the assumptions used in continuum approaches, a general stochastic model has been developed. The stochastic model can be used not only for an accurate description of the fraction of solid evolution, and therefore accurate cooling curves, but also for simulation of microstructure formation in castings.…