Synthesis of a Novel Flame Retardant Containing Phosphorus-Nitrogen Cotton by Grafting Poly Diethyl (Acryloyloxy) Ethylthiophosphoramidate onto Cotton via Atom Transfer Radical Polymerization, and Its Polymer/Clay Nanocomposite

In this research, a novel strategy for preparation of a flame retardant cotton fabric with a covalently attached diethyl (acryloyloxy) ethylthiophosphoramidate (DEAETPN) through surface initiated ATRP was investigated. Initially, new phosphorus containing flame retardant monomer (nitrogen and sulfur (DEAETPN) was prepared by reacting (2-hydroxy-ethyl)-thiophosphoramidic acid O, O’-diethyl ester with α-chlorophenyl acetyl chloride as an initiator. The initiator for ATRP using our novel method was covalently linked onto the cotton surface fibers. For this purpose, the surface of cotton fibers based-cellulose was modified with 3-aminopropyl triethoxysilane - a silane coupling agent. This functionalized cotton was then reacted with α-chlorophenyl acetyl chloride to prepare the Cotton-APTES-Cl macroinitiator. The metal-catalyzed radical polymerization of DEAETPN with macroinitiator was carried out in the presence of CuBr / 2, 2/-bipyridine (BPy) catalyst system in THF solvent at 70˚C to obtain poly (DEAETPN) segments grafted chlorinated cotton. Finally, the resulting nanocomposite obtained from Cotton-g-P (DEAETPN) graft polymer with montmorillonite modified in Carbon tetrachloride (CCl4) was prepared by a solution intercalation method. The chemical structure of all prepared compounds was confirmed by different techniques such as spectroscopy: FT-IR, 1HNMR, TEM, and SEM. The compound thermal behavior was also evaluated by DSC and TGA.