Title: Synthesis and characterization of the novel phosphonates- and phosphonothioate-piperazine as flame retardants for cotton Authors
Submitted to: Proceedings Of The American Association Of Textile Chemists And Colorists
Publication Type: Proceedings
Publication Acceptance Date: September 16, 2011
Publication Date: March 22, 2012
Citation: Nguyen, T.D., Chang, S., Condon, B.D. 2012. Synthesis and characterization of the novel phosphonates- and phosphonothioate-piperazine as flame retardants for cotton. Proceedings of The American Association Of Textile Chemists And Colorists. 105-110. Interpretive Summary: Phosphoramidates, a class of organophosphorous compounds, contains one P- N bond in the system. They prove to be better flame retardants on cellulose as compared to phosphates. To develop new phosphoramidate compounds, we incorporated piperazine unit with diethyl chlorophosphate and dimethyl chlorothiophosphate groups in an attempt to achieve high P-N content. Two new compounds were synthesized successfully in one step and formulated in aqueous solution and organic solvent to make twill fabric pass the 45 degree angle and vertical flammability testing. Different standard test methods were employed to verify our results and other instrumental analysis methods were utilized to study the mechanism of action of both compounds.
Technical Abstract: Tetraethyl piperazine-1,4-diyldiphosphonate (PDP) and O,O,O',O'-tetramethyl piperazine-1,4-diyldiphosphonothioate (PDSP) were synthesized in one simple step and their structures were confirmed by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy and elemental analysis (EA). Print cloth, twill, and 100% cotton fleece were treated with both PDP and PDSP compounds to provide different add-on values. The results of thermogravimetric analysis (TGA), limiting oxygen index (LOI), and flammability tests such as vertical (ASTM D6413-99) and 45º angle (ASTM D1230-01) of treated fabrics showed that both chemicals acted as good flame retardants. Microstructure and chemical composition on the surface of treated cotton specimens examined with different characterization methods, namely, micro cone calorimetry (MCC) and scanning electron microscope (SEM) helped understand the chemical binding and flame-retardant mechanism on cotton.