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61.
62.
Sunirmal Pal Balaraju Banoth Goli Rahithya Ashish Dhawan Priyadarsi De 《Polymer》2012,53(13):2583-2590
Copolyperoxides of 2-(acetoacetoxy)ethyl methacrylate (AEMA) with styrene (St) and methyl methacrylate (MMA) of different compositions have been synthesized in the presence of 2,2′-azobisisobutyronitrile as a free radical initiator under 100 psi oxygen pressure at 50 °C. The rates of oxidative copolymerization reactions are determined from the oxygen consumption (Δp) against time plot. Highly exothermic thermal degradations of these copolyperoxides are studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) and degradation products have been characterised by electron-impact mass spectroscopy (EI-MS). The NMR spectroscopy and EI-MS analysis confirm the alternating peroxy bonds in the main chain. The monomer reactivity ratios are computed by the Fineman–Ross and Kelen–Tüdös methods, using compositions obtained from 1H and 13C NMR analysis. These copolymers can potentially be used as polymeric initiators for the radical polymerization of vinyl monomers, autocombustible fuel. Also, the β-carbonyl moieties along the side chain of the copolyperoxides can be utilized to prepare degradable polyperoxide–metal complexes. 相似文献
63.
This paper presents the corrosion inhibition performance of soluble self-doped copolymers of aniline and 4-amino-3-hydroxy-naphthalene-1-sulfonic acid synthesized by chemical oxidative polymerization method. The corrosion inhibition behaviour of the copolymers in 1.0 M HCl has been evaluated using Tafel Extrapolation method and electrochemical impedance spectroscopy (EIS) which was also used to propose the mechanism besides surface morphology. The results showed that the copolymer film exhibited the significant shifting in the corrosion potential and greater charge transfer resistance. The corrosion inhibition efficiency was found to increase from 50% to 90% by increasing the concentration of copolymer from 10 to 70 mg/l in HCl medium. Moreover, the copolymer showed the larger degree of surface coverage onto the iron surface, reflecting the higher inhibition for corrosion of the iron in highly acidic medium. 相似文献
64.
Mohd Taukeer Khan Manisha Bajpai Amarjeet Kaur S.K. Dhawan Suresh Chand 《Synthetic Metals》2010,160(13-14):1530-1534
The present study demonstrates the designing of copolymer poly(3-octylthiophene-co-3-hexylthiophene) (P3OT-HT) and study of the hole transport mechanism in it. Detailed structural, optical and thermal studies of P3OT-HT discuss its synthesis aspects. Current density–voltage characteristics have been studied at different temperatures (290–110 K) to understand the mechanism of hole transport in P3OT-HT. It has been established that current density in P3OT-HT thin films is governed by space charge limited conduction with traps distributed exponentially in energy and space. Hole mobility is both temperature and electric field dependent arising due to substituent functional groups attached the polymer backbone. 相似文献
65.
66.
X-ray studies of the stoichiometrically prepareda-Ga2Se3 and Ga2Te3 are reported after various stages of air-oxidation in the temperature ranges 250 to 825° C and 250 to 650° C respectively.
Diffractometric powder data of Ga2Te3 are also reported over the complete 2ϑ range with remarkable difference in the relative intensities of the (444) and (642) reflections. Ina-Ga2Se3 the oxidation proceeds by formation of the most stable phase, beta-gallium sesquioxide, complete oxidation occurring at 650°
C. For Ga2Te3 a mixture of Ga2TeO6 and TeO2 is obtained as the intermediate oxidation products in the range 500 to 600° C, while at 450° C some extra lines which could
be indexed on the super-lattice cell of Ga2Te3, along with Te and unchanged Ga2Te3 lines, are observed. Oxidation at the higher temperature of 650° C led to the disappearance of TeO2 lines leaving Ga2TeO6 as the final well-crystallised phase. 相似文献
67.
68.
Equations have been developed for calculating the size distribution of non-spherical objects by using photomicrographs prepared of sections or projections of samples. The equations contain the shape function characteristic of the shape of the objects in the sample which is also determined from the photomicrographs. The equations have been applied to the void size distribution determination in various sandstones and packed beds of beads, as well as to the particle size distribution determination of a sample of common salt. It has been found that the new equations resulted in plausible calculated size distributions in the case of highly anisotropic objects, whereas this was not the case when the sphere model was used as a basis for the calculations. In the case of the salt particles, however, the sphere model was almost equally adequate as the shape function method, because the shape function was, in this case, very nearly spherical. 相似文献
69.
Graphene oxide/ferrofluid/cement composites for electromagnetic interference shielding application 总被引:1,自引:0,他引:1
This paper deals with the preparation of graphene oxide-ferrofluid-cement nanocomposites to evaluate the electromagnetic interference (EMI) shielding effectiveness (SE) in the 8.2-12.4 GHz frequency range. It has been observed that incorporation of graphene oxide (30 wt%) along with an appropriate amount of ferrofluid in the cement matrix leads to a shielding effectiveness of 46 dB (>99% attenuation).The presence of graphene oxide and ferrofluid in the cement leads to strong polarizations and magnetic losses that consequently result in higher shielding effectiveness compared to pristine cement. The resulting nanocomposites have shown Shore hardness of 54 and dc conductivity of 10.40 S cm( - 1). SEM reveals the homogeneous dispersion of graphene oxide and ferrofluid in the cement matrix. 相似文献
70.
Ferrari A Cecchini M Dhawan A Micera S Tonazzini I Stabile R Pisignano D Beltram F 《Nano letters》2011,11(2):505-511
We employ simple geometrical rules to design a set of nanotopographies able to interfere with focal adhesion establishment during neuronal differentiation. Exploiting nanoimprint lithography techniques on cyclic-olefin-copolymer films, we demonstrate that by varying a single topographical parameter the orientation and maturation of focal adhesions can be finely modulated yielding independent control over the final number and the outgrowth direction of neurites. Taken together, this report provides a novel and promising approach to the rational design of biocompatible textured substrates for tissue engineering applications. 相似文献