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In this study, a mathematical model is proposed for prediction of CO 2 absorption from N 2 /CO 2 mixture by potassium threonate in a hollow-fiber membrane contactor (HFMC). CFD technique using numerical method of finite element was applied to solve the governing equations of model. Effect of different factors on CO 2 absorption was analyzed and for investigation of absorbent type effect, functioning of potassium threonate was compared with diethanolamine (DEA). Axial and radial diffusion can be described with the two dimensional model established in this work. The obtained simulation results were compared with the reported experimental data to ensure accuracy of the model predictions. Comparison of model results with experimental data revealed that the developed model can well predict CO 2 capture by potassium threonate in HFMCs. Increment of absorbent flow rate and concentration eventuate in enhancement of CO 2 absorption. On the other hand, capture of CO 2 will be reduced with increment of gas flow rate. According to the model results, potassium threonate can be considered as a more efficient absorbent as compared with DEA. ª 2015 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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The objective of this study is to investigate the effects of carbon nanotube (CNT) content, surface modification, and silane cross-linking on mechanical and electrical properties of linear low-density polyethylene/multiwall CNT nanocomposites. CNTs were functionalized by vinyltriethoxysilane to incorporate the ─O─C2H5 functional groups and were melt-blended with polyethylene. Silane-grafted polyethylene was then moisture crosslinked. Silanization of CNT was confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), and EDX analysis. Hot-set test results showed that silane cross-linking of polyethylene and incorporation of modified CNTs into polyethylene led to an increase in cross-linking density and the number of entanglements resulting in a decrease in elongation. It was found that the addition of pristine multiwall carbon nanotubes (MWCNTs) and functionalized MWCNTs does not affect silane cross-linking density. Silane modification resulted in a stronger adhesion of the silane cross-linked LLDPE to silanized MWCNTs according to scanning electron microscopy micrographs. Additionally, the electrical tests revealed that the silane modification of CNTs results in an improvement in electrical properties of nanocomposites, while silane cross-linking will not have an effect on electrical properties. Rheological properties of MWCNT/LLDPE nanocomposites have been studied thoroughly and have been discussed in this study. Moreover, according to TGA test results, modification of the MWCNTs led to a better dispersion of them in the LLDPE matrix and consequently resulted in an improvement in thermal properties of the nanocomposites. Crystallinity and melting properties of the nanocomposites have been evaluated in detail using DSC analysis. J. VINYL ADDIT.TECHNOL., 26:113-126, 2020. FIG. 11. Frequency response of the storage and loss modulus and the cross frequency for noncross-linked nanocomposites containing different amounts of pristine and functionalized MCNTs. [Color figure can be viewed at wileyonlinelibrary.com]

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