Submitted to: Journal of Materials Science and Applications
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/2/2014
Publication Date: 9/2/2014
Citation: Nguyen, M.M., Chang, S., Condon, B.D., Smith, J.N. 2014. Fire self-extinguishing cotton fabric: development of piperazine derivatives containing phosphorous-sulfur-nitrogen and their flame retardant and thermal behaviors. Journal of Materials Science and Applications. 5(11):789-802.
Interpretive Summary: This research has shown intumescent flame retardant for environmentally friendly halogen-free flame retardant which can be used to bring flame retardancy to cotton fabrics. Intumescent flame retardant system can be applied to decrease flammability of polymers. It is particularly useful to design and develop new environmentally friendly phosphorous, nitrogen, and sulfur containing flame retardant and formulations that enable textiles. Towards this goal novel compound was prepared via one single step synthesis and formulated in aqueous solutions to make cotton fabrics pass the vertical flammability tests. We achieved this ultimate result and in the process explained our design criteria, the chemistry to achieve the new compound, and employed standard test methods to verify our results. The new compound and their formulation will be of interest and use to professionals engaged in new materials designing in textile industries to create new marketable uses for cotton fibers and fabrics to serve emerging needs.
Technical Abstract: Recent studies have shown interest in flame retardants containing phosphorus, nitrogen and sulfur a combination small molecule with a promising new approach in preparing an important class of flame retardant materials. Tetraethyl piperazine-1,4-diyldiphosphonate (TEPP) and O,O,O',O'-tetramethyl piperazine-1,4-diyldiphosphonothioate (TMPT), based on Piperazine derivatives, were prepared successfully and their structures were proved by means of 1H, 13C and 31P NMR. Cotton twill fabric was treated with both compounds to provide different add-on levels. Thermogravimetric Analysis (TGA), microscale combustion calorimeter (MCC), vertical and 45º flame test and limiting oxygen index (LOI) were performed on the treated cotton fabrics and showed promising results. When the treated twill fabrics (5-7 wt % add-ons) were tested using the vertical flammability test (ASTM D6413-11), we observed that the ignited fabrics self extinguished and left behind a streak of char. Limiting oxygen index (LOI, ASTM 2863-09) was utilized to determine the effectiveness of the flame retardant on the treated fabrics. LOI values increased from 18 vol% oxygen in nitrogen for untreated twill fabric to a maximum of 30 vol% for the highest add-on of twill. Furthermore, Scanning Electron Microscope (SEM), Attenuated Total Reflection-Infrared (ATR-IR), and Thermogravimetric Analysis -Fourier Transform Infrared (TGA-FTIR) spectroscopy were employed to characterize the chemical structure on the treated fabrics, as well as, the surface morphology of char areas of treated and untreated fabrics. Additionally, Analysis of the release gas products by TGA-FTIR shows some distinctive detail in the degradation of the treated fabrics during the burning process.