P, N, Si synergistic flame-retarding water polyurethane coating with superior flame retardancy and hydrophobicity

Abstract

Water polyurethane with ame retardant and hydrophobic properties was synthesized by in situ polymerization using 9,10-dihydro-9-oxa-10-[N, N-bis-(2-hydroxyethyl-amino-methyl)]-10phosphaphenanthrene-10-oxide (DOPO-DAM) as ame retardant modifying agent, hydroxyl-terminated polydimethylsiloxane (PDMS) as hydrophobic modifying agent. FT-IR and TEM characterized the chemical structure and morphology of modi ed WPU. The effects of DOPO-DAM and PDMS dosage on the performance of modi ed WPU were investigated. The tensile strength for the modi ed WPU lms rst increased and then decreased with increasing of DOPO-DAM dosage. Incorporating DOPO-DAM and PDMS into WPU signi cantly enhanced ame retardancy, as evidenced by the reduction in peak heat release rate, total heat release rate, total smoke production, effective heat of combustion, and carbon dioxide production rate. The scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy con rmed that the good ame retardancy of modi ed WPU was due to the synergistic effect of P, N and Si elements. Afterward, modi ed WPU as a nishing agent was coated on polyester fabric. The experimental results of LOI and the vertical burning test indicated that when the dosage of DOPO-DAM was 6 wt% in modi ed WPU, after-ame time, after-glow time, damage length and LOI values of the coated polyester fabric were 7.0 s, 0.0 s, 8.5 cm and 26.2%, respectively. In addition, with the increased PDMS dosage in modi ed WPU, the water contact angle of the coated fabrics showed an upward trend and remained stable. The addition of PDMS not only improved the ame retardancy of the coated fabric but also had a good effect on hydrophobicity.