Search results for "Microscope"
showing 10 items of 1412 documents
Functional templates for hybrid materials with orthogonal functionality.
2009
We demonstrate an integrated approach to prepare a nanostructured, multifunctional material with mutually exclusive, orthogonal properties. The hybrid material was obtained within a single step via self-assembly in solution. It consists of TiO(2) as a functional metal oxide and an amphiphilic block copolymer, poly(ethylene oxide)-b-poly(triphenylamine) (PEO-PTPA). Within the materials' synthesis, the block copolymer not only acts as a templating agent but also adds an electronic functionality to the resulting hybrid material. During the synthesis, a variety of self-assembled morphologies, ranging from spheres to wires, can be created. The obtained morphology depends on the weight fraction o…
Relationship between structure of drawn polymers and molecular motion
1971
In order to study the relationship between structure and molecular motion, drawn polymers are more suitable than isotropic samples since their morphology can be characterized more easily by quantitative methods such as small angle X-ray scattering (SAXS) and electron microscopy (EM). The effects of changes in morphological structure on molecular motion are demonstrated by comparing the results of the SAXS and EM measurements with the dynamic mechanical behavior of drawn polyethylene. In addition the NMR broad line spectra of these samples were analyzed and the influence of annealing conditions and external stress was investigated.
Self-Diffusion in Concentrated Colloid Suspensions Studied by Digital Video Microscopy of Core−Shell Tracer Particles
1998
Optical video microscopy and digital image processing have been used to study the self-diffusion of colloidal particles with a hard-sphere potential. The colloid particles consist of cross-linked polymers and are dispersed in a good solvent to avoid aggregation. To investigate single particle motion in highly concentrated dispersions, a host−tracer system, consisting of two different kinds of polymer particles, has been designed: the host particles are made of poly-t-butylacrylate (with ethanedioldiacrylate as cross-linker) and have the same refractive index as the employed solvent, 4-fluorotoluene. The tracer particles have a core−shell structure with a polystyrene core (cross-linked with…
An Appraisal by M.I.P of the Changes Induced in the Microstructure of Complex Sulfide Ores by Reactive Thermal Treatments in H2 and N2
1991
Summary Changes in the microstructure of complex sulfide ores resulting from reactive thermal treatments in either H2 or N2 were investigated qualitatively by combined scanning electron microscopy and X ray microanalysis, and quantitatively by mercury intrusion porosimetry (MIP) and mercury pycnometry. With increasing treatment temperature, we successively observed: 1) the development of fractures, preferentially at interfaces between the various mineral components, 2) the development of meso and macropores and the simultaneous swelling of the solids and 3) the crystallization or recrystallization of the metal or sufide phase products. In all cases the specific pore volume and mean pore dia…
The Nucleating Effect of a Semiflexible Liquid-Crystalline Polymer for the Crystallization of Poly(Phenylene Sulfide)
1995
Abstract Blends of poly(phenylene sulfide) and a semiflexible liquid-crystalline polymer have been prepared, in the whole range of concentration, by melt mixing. The effect of the LCP phase on the crystallization of PPS has been studied by non-isothermal and isothermal calorimetry. It has been found that the addition of only 2-5% LCP into PPS strongly increases the crystallization rate of the latter polymer. This effect has been interpreted as the result of an increased nucleation density. The morphology of the blends, studied by scanning electron microscopy, has shown that the two polymers are incompatible, although the phase dispersion is good. Under elongational flow, the dispersed phase…
Deposition and production of highly reproducible hybrid Cu[(tBu)4Pc]-polystyrene thin layers via spin casting
2012
This study focuses on the determination of a protocol for the production of a hybrid material composed of a polymer and a macrocyclic complex, namely polystyrene and a tetra-tert-butyl-copper phthalocyanine (Cu[(tBu)4Pc]), in order to obtain a layer thickness of about 100 nm and a controlled porosity in a highly reproducible way. Several methods were implemented and their reproducibility was evaluated through elements of characterization such as optical microscopy, atomic force microscopy and scanning electron microscopy. POLYM. ENG. SCI. 2013. © 2012 Society of Plastics Engineers
Evaluation of interfacial shear strength by tensile tests of impregnated flax fiber yarns
2011
Adhesion of flax fibers and polymer matrix as well as mutual bonding of elementary fibers in a technical fiber are among the principal factors governing the mechanical response of flax fiber-reinforced polymer–matrix composites. A method for evaluation of adhesion is proposed based on tension tests of impregnated fiber yarns, with subsequent characterization by optical microscopy of length distribution of fibers pulled out of the yarn fracture surfaces. An elementary probabilistic model is derived relating aspect ratio distribution of the pulled-out fibers to the fiber tensile strength distribution and the effective interfacial shear strength (IFSS). The method was applied to flax fiber/vi…
Use of transmission electron microscopy to obtain quantitative information about polymers
2005
In the polymer field the electron microscope is frequently used as a tool for obtaining purely qualitative data, but only rarely to obtain quantitative information. In order to discuss the potential of this instrument for the latter purpose it is convenient to separate the discussion into the following sub-sections.
Die Bestimmung der Molekulargewichtsverteilung von nichtkristallisierenden Polymeren mit dem Elektronenmikroskop, 6. Fehlerkorrektur der experimentel…
1977
A mathematical treatment is described, by means of which the effect of the measuring errors on the number molecular weight distribution of polymers, as obtained with an electron microscope (EM), can be eliminated. It is shown, that the difference in the nonuniformities of the measured and the corrected distribution would be negligible only in the case of samples with high average degrees of polymerization and sufficiently broad distributions. Otherwise differences of 10% or more can be found, depending on the size of the actual measuring error. This is shown by means of four practical examples. For a practical application the measuring error may not exceed some critical value, which, though…
<title>Holographic recording in polymer composites of organic photochromes and chalcogenides</title>
2008
Recently a number of organic and inorganic materials have been studied for direct surface-relief formation during the exposure process by a light or e-beam. It is very promising for practical application enabling the possibility to simplify the surface-relief formation technology. In this report the method of preparation of thin polymer-chalcogenide and polymer-azobenzene composite films is described, and some features of photoinduced changes of optical properties and holographic recording of these materials are studied. Films of composites were obtained from solution of arsenic sulphide, Disperse red 1 and polymers in organic solvents. The solution was spread on glass substrate and dried. …