Halogen-free Flame Retardant Cyclotriphosphazene and Phosphoramidate Chemistry for Cotton, PET and PP
Fiber and Polymer Science Program
College of Textiles, North Carolina State University, Raleigh, NC 27606
Two novel generations of halogen-free phosphorus-based flame retardant monomers were developed and evaluated on cotton, nonwovens PET and PP. The first generation was based on phosphoramidate and the second on cyclotriphosphazene chemistry. Each monomer was graft polymerized into the substrates thermally or with the aid of a UV flood curing system. The influence of monomer concentration, photoinitiator concentration, UV exposure time and proximity of the specimen to the UV lamp on coating yield was evaluated through a design of experiment utilizing SAS JMP® Pro 10.
It was shown from the vertical flame test that cotton and nonwoven PET and PP treated with the phosphoramidate chemistry furnished self extinguishing properties with no melting or dripping in the case of PET of PP while cotton treated with monomers derived from cyclotriphosphazene chemistry did not ignite. Instead, a significant char structure formed in the area that was exposed to the flame. The structure-property relationships of monomers derived from the phosphoramidate and cyclotriphosphazene chemistry and flame retardancy mechanisms of the grafted polymers on the substrates will be discussed.