A simple arithmetic procedure was developed in order to be able to band-ratio dichroic measurements from simple attenuated total reflection (ATR)-IR spectroscopy to measure the surface molecular orientation of any pol...
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A simple arithmetic procedure was developed in order to be able to band-ratio dichroic measurements from simple attenuated total reflection (ATR)-IR spectroscopy to measure the surface molecular orientation of any polymer showing dichroism. This development eliminates the need to get a reproducible contact area or a reference band which does not show dichroism upon drawing. This method is universally applicable to any material showing dichroic IR bands. No assumptions are made regarding the structure of the sample in order to calculate the dichroic ratio. Furthermore, no special attachments are required for the dichroic measurements.
Thermal stability of [(CH3SiH)30(C6H5SiCH3)70]n a hydropolysilane copolymer, in vacuum and its crosslinking reactions with vinylic silanes as crosslinking agents was evaluated in order to obtain high yields of oxygen-...
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A nanostructured FeCrMoVM50 type steel was prepared via a chemical route. The process involved the thermal decomposition of organometallic precursors Fe(CO) 5 , Cr(CO) 6 , Mo(CO) 6 and V(CO) 6 , at 150°C ...
A nanostructured FeCrMoVM50 type steel was prepared via a chemical route. The process involved the thermal decomposition of organometallic precursors Fe(CO) 5 , Cr(CO) 6 , Mo(CO) 6 and V(CO) 6 , at 150°C for the formation of nanostructured M50 type steel powders. In addition to the thermal decomposition of these carbonyls, the results of the reduction of respective metal halides for the production of the same steel are also presented. The nanostructured steel powders obtained were also consolidated samples, were characterized using x-ray synthesized powders, as well as the consolidated samples, were characterized using x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high resolution electron microscopy (HRTEM). Possible mechanisms for the formation of nanostructured particles are also discussed.
Magnetic nanocomposite powders of Fe x N/BN ( x = 3 or 4) were prepared by thermochemical conversion of a FeBN-containing precomposite synthesized via an aqueous chemical route. Various characterization techniques...
Magnetic nanocomposite powders of Fe x N/BN ( x = 3 or 4) were prepared by thermochemical conversion of a FeBN-containing precomposite synthesized via an aqueous chemical route. Various characterization techniques were used to study the precomposite and composite materials. The results show that the conversion of the precomposite gel to the composite nanostructured material goes to completion around 400°C. Structural, chemical, morphological, and magnetic properties are presented.
Various polysilanes have been examined as self‐developed photoresists at 193 nm and the benefits of imaging these materials in controlled, reactive ambients have been determined. Plasticization of the irradiated poly...
Various polysilanes have been examined as self‐developed photoresists at 193 nm and the benefits of imaging these materials in controlled, reactive ambients have been determined. Plasticization of the irradiated polymer due to reaction with oxygen is avoided when dry, oxygen‐free ambients are employed. In addition, the redeposition of silicon from the ablated polysilane, which is prevalent in a one‐pulse imaging mode, is greatly reduced when NF3 or CF2Cl2 are used as exposure ambients. Laser desorption mass spectrometry indicates that thermally activated decomposition of the polysilanes at fluences >100 mJ/cm2 causes more extensive fragmentation of the desorbed molecules. This results in the formation of higher volatility products upon halogenation.
The homopolymerizations of a series of 3-n-alkyl-1-vinylimidazolium iodides are described in which the length of the quaternizing alkyl group was varied from methyl to n-propyl to n-hexyl to n-heptyl to n-dodecyl to n...
The homopolymerizations of a series of 3-n-alkyl-1-vinylimidazolium iodides are described in which the length of the quaternizing alkyl group was varied from methyl to n-propyl to n-hexyl to n-heptyl to n-dodecyl to n-hexadecyl. The preparations of these cationic monomers have previously been reported through reaction of 1-vinylimidazole with the corresponding n-alkyl iodide. All polymerizations were performed in aqueous solution at the same molar concentration of monomer using the free radical initiator 4,4′-azobis-4-cyanopentanoic acid. It was found that the short side-chain polyions (methyl and n-propyl) were water soluble, whereas the more hydrophobic intermediate side-chain polyions (n-hexyl and n-heptyl) were water insoluble. The long side-chain polyions (n-dodecyl and n-hexadecyl), on the other hand, being highly hydrophobic, appeared to form polysoaps and remained in aqueous solution. The solution behavior of these polyions in water, in aqueous salt solution, and in chloroform is discussed as well as is the critical micelle concentration of a long side-chain polyion and its corresponding monomer.
Ethyl α-chloroacrylate was polymerized by anionic and free radical initiation under a variety of conditions to yield polymers of differing tacticities ranging from predominantly syndiotactic to slightly isotactic on ...
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