Organic Phosphoric Acid Doped Polyaniline-Coupled g-C 3 N 4 for Enhancing Fire Safety of Intumescent Flame-Retardant Epoxy Resin

• Published in: Macromolecular rapid communications. Vol. 44; no. 12; p. e2300071
• Main Authors: Chen, Xilei, Piao, Junxiu, Dong, Huixin, Ou, Mingyu, Lian, Richeng, Guan, Haocun, Cui, Jiahui, Jiao, Chuanmei
• Format: Journal Article
• Language: English
• Published: Germany 01.06.2023
• Subjects: Amino Acids; Aniline Compounds; Epoxy Resins; Flame Retardants; Phosphoric Acids; Phosphorus; epoxy resin; phosphorous flame retardant; polyaniline; carbon nitride; fire safety
• ISSN: 1022-1336; 1521-3927
• DOI: 10.1002/marc.202300071

Two kinds of polyaniline coupled graphitized carbon nitride nanosheets doped with different organic phosphoric acids (CP@PA, with phytic acid; CP@NP, with amino trimethyl phosphonic acid) are developed by in-situ polymerization. According to the analysis of the section morphology and element distribution of epoxy resin (EP) composites, although CP@PA and CP@NP show completely different morphology, they can significantly enhance the dispersion of graphitized carbon nitride nanosheets in EP. Moreover, the different oxidation states of phosphorus contained in the CP@PA and CP@NP lead to varying effects on the fire safety of EP. The flame retardancy Index (FRI) is a dimensionless index to evaluate the performance of flame retardants. When used as a flame retardant, CP@NP (FRI = 3.22) is better than CP@PA (FRI = 1.29) in flame retardant, especially in suppressing thermal hazards. As a synergist of intumescent flame retardants (IFR), CP@PA (FRI = 26.12) is most effective in improving the comprehensive fire safety property of EP and achieves an "Excellent" rating. Therefore, two different flame-retardant mechanisms of CP@PA and CP@NP are summarized by analyzing the combustion behavior and changes of condensed phase. In summary, this research may be helpful to the design of nano synergies for IFR systems.