Flammability properties of paper coated with poly (methylenephosphine), an organophosphorus polymer.

The flame retardant properties of paper coated with either poly(methylenephosphine) ( PMP) or poly(methylenephosphine oxide) ( PMP-O) are evaluated. Paper sheets made from thermomechanical pulp were coated with PMP ( M_n = 27,000 g mol⁻¹, polydispersity index (PDI) = 1.47), PMP-O ( M_n = 30,000 g mol⁻¹, PDI = 1.24), or monobasic ammonium phosphate (MAP) to achieve an approximate loading of 0.8 mmol P/g paper. Thermal stability studies by thermogravimetric analysis show that the paper degrades in two main stages, with the second thermo-oxidative stage having a slower rate of degradation for paper treated with flame retardants. The flame retardancy of the sheets was evaluated by Technical Association of Pulp and Paper Industry Standard Method T461 cm-00 and by limiting oxygen index (LOI) according to ASTM D2863. After leaching with water, samples coated with PMP or PMP-O show no loss of flame retardancy, while those coated with MAP lose all flame retardancy. The LOI of paper coated with PMP (23.1%) or PMP-O (25.9%) is higher than those of uncoated paper (19.6%), but lower than MAP-coated paper (34.7%). Analysis of the char provided evidence that the flame retardant mechanism of PMP and PMP-O involves the formation of phosphorus oxides and acids. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]