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101.
Polyvinyl chloride paste blending resins were prepared by a suspension polymerization process, and the optimum ingredients and technological conditions were studied experimentally. The effect of dispersant, surfactant, and agitator design on the particle morphology was discussed. In order to improve the thermal stability of the blending resin, stabilizer was added to the polymerization system, and a special after-treatment was adopted. The effect of blending resins on the rheological and gelation characteristics of the plastisols formed and on mechanical properties, thermal stability, and foamability of the finished articles is demonstrated. 相似文献
102.
Nova Isabella Castoldi Lidia Lietti Luca Tronconi Enrico Forzatti Pio 《Topics in Catalysis》2007,42(1-4):21-25
The reduction process of NOx species stored over Pt-Ba/Al2O3 Lean NOx Trap systems is analysed in this paper when H2 is used as a reductant. The effect of different experimental conditions (temperature, reductant concentration, adsorption
lengths, etc.) is addressed and discussed in relation to the selectivity and the efficiency of the reduction process. 相似文献
103.
Alessandro Martucci Sabrina Sartori Alessandro Muffato Lidia Armelao Elisabetta Di Bartolomeo Enrico Traversa Massimo Guglielmi 《Journal of the American Ceramic Society》2003,86(11):1965-1968
Na2 O· x Al2 O3 ( x = 9, 11)films have been obtained by sol–gel method. Crystallization processes during heat treatments have been investigated by X–ray diffraction analysis. A metastable phase with the mullite structure, λ–Na2 O· x Al2 O3 , has been observed starting from 800°C. Films remained stable after a heat treatment at 1000°C for 250 h. Impedance spectroscopy measurements showed that the films of λ-Na2 O· x Al2 O3 possess a large three–dimensional ionic conductivity at 400°C. 相似文献
104.
Lidia Castoldi Roberto Matarrese Chuncheng Liu Sara Morandi Luca Lietti 《Topics in Catalysis》2018,61(15-17):1672-1683
The formation of N2O has been studied by means of isothermal lean-rich experiments at 150, 180 and 250 °C over Pt–Ba/Al2O3 and Pt/Al2O3 catalysts with H2 and/or C3H6 as reductants. This allows to provide further insights on the mechanistic aspects of N2O formation and on the influence of the storage component. Both gas phase analysis and surface species studies by operando FT-IR spectroscopy were performed. N2O evolution is observed at both lean-to-rich (primary N2O) and rich-to-lean (secondary N2O) transitions. The production of both primary and secondary N2O decreases by increasing the temperature. The presence of Ba markedly decreases secondary N2O formation. FT-IR analysis shows the presence of adsorbed ammonia at the end of the rich phase only for Pt/Al2O3 catalyst. These results suggest that: (i) primary N2O is formed when undissociated NO in the gas phase and partially reduced metal sites are present; (ii) secondary N2O originates from reaction between adsorbed NH3 and residual NOx at the beginning of the lean phase. Moreover, N2O reduction was studied performing temperature programming temperature experiments with H2, NH3 and C3H6 as reducing agents. The reduction is completely selective to nitrogen and occurs at temperature higher than 250 °C in the case of Pt–Ba/Al2O3 catalyst, while lower temperatures are detected for Pt/Al2O3 catalyst. The reactivity order of the reductants is the same for the two catalysts, being hydrogen the more efficient and propylene the less one. Having H2 a high reactivity in the reduction of N2O, it could react with N2O when the regeneration front is developing. Moreover, also ammonia present downstream to the H2 front could react with N2O, even if the reaction with stored NOx seems more efficient. 相似文献
105.
Gheorghe Virgil Aldica Magdalena Lidia Ciurea Dorina Magdalena Chipara Ana Maria Lepadatu Karen Lozano Ionel Stavarache Stelian Popa Mircea Chipara 《应用聚合物科学杂志》2017,134(38)
Nanocomposites have been obtained by dispersing various amounts of vapor grown carbon nanofibers within isotactic polypropylene. Thermal investigations done by differential scanning calorimetry and dynamic mechanical analysis revealed the effect of the vapor grown carbon nanofibers on the melting, crystallization, α, and β relaxations. Direct current electrical features of these nanocomposites have been investigated and related to the thermal features of these nanocomposites. The effect of the loading with carbon nanofibers on the electrical properties of these nanocomposites is discussed within the percolation theory. The percolation threshold was estimated at about 5.5% wt carbon nanofibers. The temperature dependence of the direct current conductivity is analyzed in detail and it is concluded that the electronic hopping is the dominant transport mechanism. A transition from one‐dimensional hopping towards a three‐dimensional hopping was noticed as the concentration of carbon nanofibers was increased from 10% wt to 20% wt carbon nanofiber. The possibility of a differential negative resistivity is suggested. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45297. 相似文献
106.
Gold Nanoparticles and g‐C3N4‐Intercalated Graphene Oxide Membrane for Recyclable Surface Enhanced Raman Scattering
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Lulu Qu Na Wang Hui Xu Weipeng Wang Yang Liu Lidia Kuo T. P. Yadav Jingjie Wu Jarin Joyner Yanhua Song Haitao Li Jun Lou Robert Vajtai Pulickel M. Ajayan 《Advanced functional materials》2017,27(31)
Toxic organic pollutants in the aquatic environment cause severe threats to both humans and the global environment. Thus, the development of robust strategies for detection and removal of these organic pollutants is essential. For this purpose, a multifunctional and recyclable membrane by intercalating gold nanoparticles and graphitic carbon nitride into graphene oxide (GNPs/g‐C3N4/GO) is fabricated. The membranes exhibit not only superior surface enhanced Raman scattering (SERS) activity attributed to high preconcentration ability to analytes through π–π and electrostatic interactions, but also excellent catalytic activity due to the enhanced electron–hole separation efficiency. These outstanding properties allow the membrane to be used for highly sensitive detection of rhodamine 6G with a limit of detection of 5.0 × 10?14m and self‐cleaning by photocatalytic degradation of the adsorbed analytes into inorganic small molecules, thus achieving recyclable SERS application. Furthermore, the excellent SERS activity of the membrane is demonstrated by detection of 4‐chlorophenol at less than nanomolar level and no significant SERS or catalytic activity loss was observed when reusability is tested. These results suggest that the GNPs/g‐C3N4/GO membrane provides a new strategy for eliminating traditional, single‐use SERS substrates, and expands practical SERS application to simultaneous detection and removal of environmental pollutants. 相似文献
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