Search results for "X-Ray"
showing 10 items of 4234 documents
UV optical record and electron beam lithography in polymer films
2012
Possibility of UV optical record and electron beam lithography in different type of organic polymer films was studied. Mechanisms of molecular structure changes: photoisomerization, destruction, cross-linking and oxidation have been discussed. The results of UV illumination of polyurethanes, polyacrilates, and some block-copolymers are described. The element analysis of polyisoprene block copolymer was performed before and after UV illumination, and the changes in transmission spectra of the polymer film were measured. The resolution of electron beam lithography on polymer films was studied. In the polyisoprene block copolymer film the oxidation polymerization was ascertain at UV-illuminati…
Small angle X-ray scattering from amorphous polymers arising from heterogeneities
1973
The small angle X-ray scattering of glassy polymers (PET, PC, PVC, PMMA) and of polymer melts (PE) was studied. The dependence of the intensity scattered at small angles on the sample treatment suggests that neither the inherent structure of the pure polymer phase nor microholes are the origin of the scattering. In agreement with all experimental facts the scattering can be attributed to foreign particles such as for instance stabilizers in the polymer matrix. The consequence of this result is discussed with respect to the nodular structure of the amorphous phase and with respect to structural models of the amorphous phase. The nodular structure is not related to regions of different densit…
1995
Redoxactive liquid crystalline (LC) side group polymers were prepared by copolymerization of liquid crystalline acrylates and ferrocene-containing acrylates. The corresponding liquid crystalline ionomers were synthesized by a reversible redox reaction. The incorporation of tetra-alkylated ferrocene derivatives leads to LC polymers with reduced redox potential. These polymers can be oxidized under mild conditions to the corresponding ionomers, which are much more stable in solution than LC ionomers containing monoalkylated ferrocenium ions. Dynamic mechanical measurements and small angle X-ray scattering (SAXS) perfomed on LC ionomers prove the existence of ionic superstructures (clusters) w…
Morphology, rheology, and mechanical properties of a new nanobiocomposite
2015
Nanobiocomposites are a new class of biodegradable polymer materials with an ultrafine phase dispersion of the order of a few nanometers in a biodegradable polymer matrix that shows very interesting properties often very different from those of conventional filled polymers. In this work the morphology and the rheological and mechanical properties of a new nanobiocomposite made of a biodegradable copolyester based blend with an organomodified montmorillonite have been investigated to evaluate its possible use in several applications. SAXS diffractograms and TEM micrographs show that the in both the adopted processing conditions an hybrid intercalated/exfoliated morphology is observed. Rheolo…
Switching of Polymer Brushes
1999
Polymer coatings of brushlike monolayers composed of two different polymers, polystyrene and poly(2-vinylpyridine), are grafted by radical polymerization on the surface of silicon wafers. Thickness, grafting density, molecular weight of grafted chains, and the composition of the coatings were regulated by grafting time, monomer concentration, and additional initiator in solution. A typical dry film thickness is between 10 and 100 nm, and the molecular weights of the components range from 100 to 300 kg/mol. The fabricated coatings turn out to be sensitive to the composition of the environment. For instance after exposition to toluene the layer becomes hydrophobic and the top of the layer is …
2019
Abstract The preparation method of a polymer composite and the filler loading are amongst the factors that influence the properties of the final composites. This article studies the effect of these factors on the thermal stability and thermal degradation kinetics of poly(methyl methacrylate) (PMMA)/mesoporous silica (MCM-41) composites filled with small amounts of MCM-41. The PMMA/MCM-41 composites were prepared through in situ polymerisation and melt mixing methods, with MCM-41 loadings of 0.1, 0.3, and 0.5 wt.%. The presence of MCM-41 increased the thermal stability of PMMA/MCM-41 composites prepared by melt mixing, but in the case of the in situ polymerised samples, the MCM-41 accelerate…
Identification of Manganese(IV) Centers in Archaeological Glass Using Microsample Coatings Attached to PolymerFilm Electrodes
2001
Identification of MnO2 nodulae in archaeological glass by linear scan and differential pulse voltammetry using abrasive-conditioned microsamples attached to polymer film (Elvacite 2044) electrodes is described. Voltammetric responses for manganese-containing samples parallels to those obtained for β- and γ-MnO2 upon immersion of modified electrodes into NaCl, KCl and acetic/acetate aqueous media. The observed electrochemical response provides information on the open microporous structure of the MnO2 forms and the conditions of their formation during the weathering process of buried glass.
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.
Interaction between a water-in-oil microemulsion and a linear-dendritic poly(propylene oxide)–polyglycerol block copolymer
2011
We present small angle scattering and dielectric spectroscopy results on the influence of an amphiphilic diblock copolymer on the structure and dynamics of a microemulsion. We use a water-in-oil (w/o) droplet microemulsion based on the anionic surfactant AOT (sodium bis(2-ethylhexyl) sulfosuccinate), that forms spherical water droplets coated by a monolayer of AOT dispersed in the continuous oil matrix. The studied polymer consists of a hydrophobic poly(propylene oxide) (PPO) block and a hydrophilic hyperbranched polyglycerol with 74 glycerol units (NG74). Combining small angle neutron scattering (SANS) and small angle X-ray scattering (SAXS) we find that the droplet structure is preserved …
Martensitic phase transformation cubic-orthorhombic of NaCN and (NaCN)0.98 (KCN)0.02
1990
The ferroelastic cubic-orthorhombic transition of single crystals NaCN and (NaCN)0.98 (KCN)0.02 has been studied by x-ray diffraction. The domain configuration obtained is consistent with the Wechsler, Lieberman, Read-model for martensitic transformations.