Department of Chemistry
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Item Thermal Stability and Fire Retardant Studies of Polymeric Nanocomposites based on Layered Double Hydroxides(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-17) Raheel Ayub; FA18-R06-006; Dr. M. Shahid Nazir; LHR TP 5959Layered double hydroxide (LDH) has been used as nanofiller in different polymer industry and gained extra intention in 21th century due to substantially improved physical, electrical, mechanical and extraordinary flame retardant properties. LDH nanofiller have variable charge density, which allows various interactions with the host polymer matrices. In this study, MOF based LDH and MOF based CNTs/LDH nanocomposites were synthesized by using MOF and CNTs as precursor respectively, by co-precipitation method to improve flame retardant efficiency of polymer. Pristine LDH have limitations of toxicity, low limited oxygen index (LOI %), high peak heat release rate, and high loadings. Acidic modification of MWCNTs was synthesized by co-precipitation method with nitric acid (HNO3) and sulphuric acid (H2SO4). MOF based LDH and MOF based CNTs/LDH were confirmed by FTIR described peaks at at 2,927 cm-1, 1528 and 1048 cm-1 attributed to the vibration of aliphatic sp3 C–H, C = O and C–O respectively along with the broad peaks around 3000-3400 cm-1 of water molecules of LDH. Hollow dodecahedral structure of MOF based LDH and MOF based CNTs/LDH nanocomposites were confirmed by Scanning Electron Microscopy (SEM) represented greater surface active sites and synergistic effect for polymer. Thermal property of MOF based LDH and MOF based CNTs/LDH nanocomposites were confirmed by Thermo Gravimetric Analysis (TGA) which described initial weight loss at 137ºC attributed to the removal of water between the layers and maximum weight loss at above 450ºC due to nitrates and hydroxyl ions, significantly higher than pristine LDH. This work advances progress on the development of highly safe multifunctional polymeric nanocomposites for economical use and reduced life threat.Item Surface Etched Mixed Matrix Membrane for Desulfurization of Model Diesel Oil(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-17) Sadaf Ahmad; FA18-R06-001; Dr. M. Shahid Nazir; LHR TP 5959Fuel counts in basic necessity of modern life. However, fuel consumption has been turned into severe danger to the environment as well as human life due to the presence of sulfur components in fuel. Therefore, it has become essentially important to achieve ultra-low sulfur fuel. For this purpose, desulfurization has been vastly undergoing by using various techniques in recent decades. Polyoxometalates (POMs) are polyatomic anions comprising transition metal oxyanions associated with bridged oxygen atoms resulting in closed three-dimensional assemblies. POMs and their hybrid materials (such as POM-based porphyrin and POM based metal-organic frameworks (MOFs)), have been mostly reported in multidisciplinary research fields as brilliant candidates due to their characteristics properties. Specifically, hybrids of POM and porphyrin (~ POM@Porphyrin = POMOF) are outstanding materials for intended applications which being inorganic filler further incorporate in mixed matrix membranes (MMMs). MMMs generally fabricated through incorporation of inorganic fillers in polymeric matrix, have achieved great attention in recent research progress due to multiple applications in gas storage, catalysis, sensing, wastewater treatment, and biomedicine. The main objective of the current study is to use POMOF as a catalyst in desulfurization. Therefore, three POMOFs were fabricated by varying ratios (1:1, 2:1, 3:1) of cationic and anionic species. Characterization analyses such as UV/Vis, FTIR, and TGA showed successful synthesis of these POMOFs. The efficiency of POMOFs followed an order as 3 (95.5%)> 2 (85.5%)> 1 (70.3%). Among these three POMOFs, 3 exhibited excellent catalytic property in desulfurization. Furthermore, the desulfurization process could be recycled for ten times without a significant decrease in catalytic efficiency. Interestingly, POMOFs successfully accomplished desulfurization of model diesel oil and showed excellent renewability. To the best of our knowledge, such kind of POMOFs with special surroundings and bi-functional active sites are not reported.