Materials Literature
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We present a promising coarse-graining strategy for linking micro- and mesoscales of soft matter systems. The approach is based on effective pairwise interaction potentials obtained from detailed atomistic molecular dynamics (MD) simulations, which are then used in coarse-grained dissipative particle dynamics (DPD) si…
Ferrocene has been encapsulated within a symmetric ether-amide dendritic shell and its redox potential monitored in a variety of solvents. The dendritic effect generated by the branched shell is different in different solvents. In less polar, non hydrogen bond donor solvents, attachment of the branched shell to ferroc…
The dipole moments of four photochromic derivatives of indolinospirobenzopyran have been studied in their spiro and their open merocyanine form, in dioxane. Determinations have been done by electrooptical absorption measurements (EOAM). To prepare either a pure spiropyran or a pure merocyanine form solution, the exper…
The esterification kinetics of lactic acid with methanol without addition of catalyst and catalyzed by ion-exchange resins are presented in this work. The effect of catalyst type, stirrer speed, catalyst size, catalyst loading, initial reactant ratio, and temperature on reaction kinetics was evaluated. Experimental re…
Metallic nickel was electrodeposited from aqueous nickel(II) acetate dissolved in the lyotropic liquid crystalline phases of Brij 56 and Brij 78 surfactant templates to form metal films with hexagonal arrays of nanometer-sized channels. The applicability of these materials as inexpensive, large area and low-resistance…
Oxidized single-walled carbon nanotubes (SWNTs) have been reacted with cadmium selenide (CdSe) nanocrystals, capped with mercaptothiol derivatives, as well as with titanium dioxide (TiO 2 ) nanocrystals, functionalized with 11-aminoundecanoic acid to form nanoscale heterostructures, characterized by transmission elect…
Low-molecular-weight poly(ethylene terephthalate) (PET) (viscosity-average molecular weight was subjected to solid-state polymerization (SSP) in the temperature range between 230 and 250°C for up to 20 hr under high vacuum The procedure of SSP allowed us to obtain a number of PETs ranging in M η from 43 to 300 kg/mol.…
The chemical polymerization of aniline was carried out in acetonitrile/water media by the use of benzoyl peroxide as an initiator. Among the acids chosen as dopant the highest yield was obtained in HCl with 24.8% and the highest conductance was observed in H2SO4 with 0.082 S cm−1. The effect of HCl, benzoyl peroxide a…
The formation of odoriphores in polyethylene (PE) is of concern to industries involved in the packaging of items such as foodstuffs and pharmaceuticals that are sensitive to organoleptic contamination. Hitherto, traditional strategies such as increasing the level of antioxidant, reducing contact between the resin and…
The peculiarities and kinetics of segmental dynamics in a few semi-crystalline poly(oxymethylene) (POM) samples and in poly(oxymethylene-co-oxyethylene) with 1.5% ethylene oxide units were studied over the temperature range from 110 to 430K. Differential scanning calorimetry (DSC) and laser-interferometric creep rate…
Controlled analyte permeability, calcification resistance and biocompatibility are among the many prerequisites necessary for the fabrication of outer membranes for implantable biosensors. In this study, multilayered films of polyelectrolytes (i.e., NafionTM, a perfluorinated ionomer, and Humic Acids (HAs), naturally…
Mg(OH)2 and ammonium polyphosphate (APP) based flame retarded polyethylene (PE) and polypropylene (PP) compounds were prepared in a plastograph and the influence of additive systems on the microstructure, mechanical, and melt characteristics of the compounds was investigated by DSC, Raman microscopy, and rheological m…
The correlation between impact resistance and crystalline morphology was studied on specimens prepared from three different polypropylene (PP) homo- and copolymers, obtained by injection molding. The crystalline morphology was varied using three different nucleating agents. Linear elastic fracture mechanics was applie…
It is difficult to enrich isotope components of small abundance to a high concentration by means of gas centrifuge cascades. A nonsteady-state approach is studied for the separation of end components and middle components. Unlike ordinary conventional separation cascades, which have two withdrawals at the two ends of…
Reactor powder of a number of commercial ultra-high molecular weight polyethylenes synthesized on heterogeneous Ziegler–Natta catalyst in a conventional slurry process have been investigated with the help of scanning electron microscopy (SEM), wide-angle x-ray scattering (WAXS), differential scanning calorimetry (DSC)…
The kinetic model proposed by Chen and Wu (Chen, S.A.; Wu, K.C. Kinetics of polyesterification. II. Foreign acid-catalyzed dibasic acid and glycol systems. J. Polym. Sci. 1982, 20, 1819–1831.) for the formation of unsaturated polyester resins by reaction between diols and anhydrides has been modified to take into acco…
Micromold with microchannels was employed in assembly of directional free-standing single-walled carbon nanotube (SWNT) strings at room temperature. The new postgrowth assembly approach could, in principle, apply not only to a wide range of SWNTs in their soluble or dispersible forms, including small diameter (0.7-0.8…
Many normally ductile semi-crystalline polymers, such as polyamide-6 (or 6,6) (Nylon), high density polyethylene (HDPE), and isotactic polypropylene (iPP) are known to be brittle under impact loading. Some general principles for improvement of toughness of semi-crystalline polymers that rely on the reduction of plasti…
Polyanilines (PANI) were synthesized from peroxidase-catalyzed polymerization of aniline with and without the presence of a template in the aqueous buffer solution of pH 4.3. The template used was poly(vinylphosphonic acid) (PVP). Solid-state 13C and 15N CP/MAS NMR techniques were applied to characterize the structure…
The influence of cooling rate from the melt on the polymorphism and crystallinity is investigated as a function of isotacticity and stereo-defect distribution in polypropylenes. Detailed analysis of wide angle x-ray diffraction patterns shows that crystallinity in the materials used is nearly independent of the experi…