ABSTRACT
Polymers are highly promising materials for capturing carbon dioxide (CO2), a greenhouse gas. Hence in this work, we prepared phyllosilicate supported mesoporous polymer via reversible addition-fragmentation chain transfer (RAFT) polymerisation, which is the one among the controlled radical polymerisation. The mesoporous material anchored on dodecanethiol trithiocarbonate acts as a chain transfer agent (CTA) for the polymerisation of chloromethyl styrene and further conversion to quaternary ammonium compound which is effective to trap CO2 using tertiary amine. The synthesised porous phyllosilicate/polymer nanocomposites have been characterised by using various analytical tools. The CO2 sorption experiments were carried out by passing CO2 onto the synthesised porous phyllosilicate/polymer nanocomposites. The sorption kinetics was monitored by X-Ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FT-IR) spectra in the presence of carbonate were obtained by reaction of quaternary ammonium hydroxide and CO2. The phyllosilicate anchored macromolecular CTA (macro-CTA) and the surface-initiated polymer nanocomposites encompassed apparent surface areas of 94.5 and 26.8 m2 g-1, respectively. In addition, the total pore volumes calculated for the macro-CTA and polymer were found to be 0.27 and 0.095 cm3g-1, while the average pore sizes were 14.24 and 11.46 nm, respectively. The CO2 sorption capacity of the phyllosilicate/polymer nanocomposites, monitored at different temperatures, is the fastest for 25°C but slower for the sample treated at 50°C which may due to the dipole and quadrupole interaction.
ABSTRACT
We report rhodamine based fluorophore derivative for the stable dispersion of single-walled carbon nanotubes (SWCNTs), which can afford better fluorescent label to carbon nanotubes (CNTs). The nanotubes-fluorophore conjugates are helpful in achieving stable dispersion in polar and non-polar solvents with intense fluorescence. The product was characterized through NMR, Mass spectrometry, Raman, XPS, SEM, AFM and Fluorescence measurements. The formation of SWCNT-g- Rhodamine was confirmed by the presence of D and G bands in Raman spectrum. The alkyl and aryl groups in the range of 14.8, 17.6, 38.1 and 96.3 ppm confirms the grafting of the nanocomposite through NMR. The morphological studies were carried out intensively for analyzing SWCNTs stable dispersion and the results from EDAX measurements shows the elements weight% of C: 35.09 and N: 30.1 concludes that SWCNTs are completely grafted onto rhodamine derivatives. The application of SWCNTs fluorophore conjugates were analyzed by cell viability studies using MTT assay and exhibits less toxic compare to other functionalized CNTs. The viability of percentage increases with decrease in the concentration of SWCNT-COCl with 91.7% of live cells even after 24 h at a concentration of 250 µg for SWCNT-g-Rhodamine. The fluorescent images obtained during viability analysis shows enhanced fluorescence for living cells in case of SWCNT-g-Rhodamine compared to SWCNT-COCl, which clearly shows the utility of decorating nanotubes with fluorophore. This research work further extends its application for molecular sensing and other biological process.