A Highly Effective, UV-Curable, Intumescent, Flame-Retardant Coating Containing Phosphorus, Nitrogen, and Sulfur, Based on Thiol-Ene Click Reaction

Abstract

In this paper, a flame-retardant, UV-cured coating was prepared on the fiber composites’ (FC) surface via a thiol-ene click reaction using pentaerythritol tetra(3-mercaptopropionate) (PETMP), triallyl cyanurate (TAC), and 2-hydroxyethyl methacrylate phosphate (PM-2). The synergistic effectiveness of phosphorus (P), nitrogen (N), and sulfur (S) was studied in detail by changing the proportion of these reactants. Sample S4(N3P2)6, with a molar ratio of N and P elements of 3:2, and the thiol and vinyl groups of 4:6 had the highest LOI value (28.6%) and was self-extinguishing in the horizontal combustion test. It had the lowest peak heat release rate (PHRR) value (279.25 kW/m2) and total smoke production (2.18 m2). Moreover, the thermogravimetric analysis (TG) showed that the decomposition process of the coated composites was delayed. The conversion rate of the double bond and the thiol of S4(N3P2)6 was 100% and 92.0%, respectively, which showed that the cross-linked network structure was successfully formed. The tensile strength and the flexural strength of coated composites improved, and the transparency of the coating can reach 90%. These characteristics showed that the UV-cured coatings could be used in industrial production to effectively prevent fires.

A DOPO-Based Compound Containing Aminophenyl Silicone Oil for Reducing Fire Hazards of Polycarbonate

“…Due to the synergistic effect of the different FR elements, the compounds containing multi-elements display better efficiency for enhancing the fire safety of the PC matrix. Consequently, many works have focused on the synthesis of multi-in-one flame retardants, such as P/N [ 15 , 16 ], P/S [ 17 , 18 ], P/Si [ 19 , 20 ], P/S/N [ 21 , 22 ], etc. Chen et al [ 23 ] prepared PC-based composites blended with phosphazene-triazine bi-group flame retardant (A3); the PC/A3 composites reached a V-0 rating and 29.3% of LOI value in the case of 13.5% A3 loading level.…”