N.U. Ahamad, S.U. Ahamed, M.M. Alam, M. Al-Mamun, M. Al-Amin, P. Rojita, M.M. Rahman
Shahjalal University of Science and Technology, Sylhet,
Bangladesh
Keywords: thermal property, modified carbon nanotubes, onset temperature, flame retardant
Summary:
In this research work, we studied the effect of incorporation of surface-modified multiwall carbon nanotubes (m-MWCNTs) on the thermal stability of polystyrene (PS) polymer. Multiwall carbon nanotubes (MWCNTs) were deliberately functionalized with silicon (in the form of 3-aminopropyl triethoxysilane, APTMS) and iron oxide (Fe3O4) nanoparticles. Prior to surface functionalization, MWCNTs were subjected to oxidation to create oxygenated groups (O-CNTs). Different samples of m-MWCNTs were incorporated into PS by solution blending at low concentration (0.1%) to prepare composite films. The as prepared composite films were employed to investigate their thermal properties in nitrogen by thermogravimetric (TG) analysis. The parameter used to study the thermal stability was the onset temperature, T5%. The FT-IR and Raman spectral analysis unambiguously revealed the successful modification of CNTs with oxygen containing groups. The morphology of the nanotubes, before and after the oxidation, was determined by SEM image and further analysed by EDS for elemental analysis. The chemical attachment of Si with O-CNTs was confirmed by FT-IR spectra and EDS, and the morphology of the Si functionalized MWCNTs was determined by SEM image. The APTMS bonded to O-CNTs also attached to Fe3O4 through crosslinking. Fe3O4 nanoparticles coated with polyvinylpyrrolidone (PVP) was found to well dispersed within PS film as confirmed by TEM image. The TGA results show that addition of Silicon improves the thermal stability by 21oC. Further addition of Fe3O4 to Si-CNT- improved thermal stability by 24oC. The role of Si and Fe3O4 are still unexplored and further research is required. The outcome of this study will be employed to develop environmentally benign fire retardant textiles with improved thermal stability and flammability in collaboration with interested textile industries in Bangladesh.