A transparent and intumescent phosphaphenanthrene/phenylpyrazole-containing epoxy resin system and its flame retardancy. (September 2021)

• Record Type: Journal Article
• Authors: Luo, Zijin; Chen, Zhe; Wei, Jun; Wang, Dongchao; Chen, Han; Chen, Rui
• Is Part Of: High performance polymers. Volume 33:Number 7(2021)
• Page Start: 760
• Page End: 773
• Publication Date: 2021-09
• Subjects: Transparency -- flame retardancy -- intumescent -- mechanisms; Polymerization -- Periodicals; Polymers -- Periodicals; 547.7
• DOI: 10.1177/0954008321992412
• Languages: English
• ISSNs: 0954-0083

Abstract

A novel intumescent flame retardant, PPMD, was designed from phosphaphenanthrene and nitrogen heterocycles through the two-step gut reactions of 1, 4-phthalaldehyde and 3-methyl-1-phe-nylpyrazol-5-ylamine. After determination of its structure by nuclear magnetic resonance and Fourier-transform infrared analyses, PPMD was added to an epoxy resin (EP) to facilitate a curing process. Thus, EP/PPMD samples with excellent transparency and flame retardancy were acquired. For example, the EP sample satisfied the UL-94 V-0 standard and achieved a limiting oxygen index value of 30.5% because of the incorporation of 5 wt% PPMD. The cone calorimeter test of the EP/5% PPMD sample revealed that its total smoke production (TSP) and total heat release (THR) values of EP/5% PPMD was only 22.5% and 56.4% of the control group, respectively. Moreover, the average effective heat of combustion (av-EHC) value of EP/5% PPMD was reduced by 34.1%, indicating that PPMD possessed high flame-inhibition activity and smoke suppression efficiency. The flame-retardant mechanisms of PPMD were also investigated in gas phase by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and in condensed phase by XPS and IR.