Monomolecular P-N flame retardant

V-0 at 5 wt% loading

Integrates diethyl phosphite groups and piperazine into one molecule, achieving flame retardancy and mechanical reinforcement without compromising epoxy transparency.

Ao, Qin · Haobo, Han · Shuhui, Liang · Xueqian, Fan · Kai, Xu · 79057873 · Xu, Yue · Xu, Miaojun · Liu, Lubin

Chemical Engineering Journal 2026

Specifications

UL-94 rating

{'zh': 'V-0', 'en': 'V-0'}

Limiting oxygen index

{'zh': '36.4', 'en': '36.4'} %

Apparent activation energy of thermal degradation

{'zh': '184.7', 'en': '184.7'} kJ·mol⁻¹

Reduction in peak heat release rate

{'zh': '48.5', 'en': '48.5'} %

Reduction in total heat release

{'zh': '38.3', 'en': '38.3'} %

Increase in tensile strength

{'zh': '8.3', 'en': '8.3'} %

Increase in impact strength

{'zh': '6.0', 'en': '6.0'} %

Increase in flexural strength

{'zh': '11.5', 'en': '11.5'} %

Advantages

V-0 at 5 wt%

Only 5 wt% loading endows epoxy resin with UL-94 V-0 rating and a high LOI of 36.4%, demonstrating excellent flame retardant efficiency at a low dosage.

Enhanced thermal stability

The apparent activation energy of thermal degradation nearly doubles from 109.2 kJ·mol⁻¹ to 184.7 kJ·mol⁻¹, indicating greatly improved pyrolysis resistance.

Effective heat suppression

Peak heat release rate and total heat release are reduced by 48.5% and 38.3%, respectively, markedly lowering fire hazard.

Simultaneous mechanical reinforcement

While maintaining transparency, tensile, impact, and flexural strengths are increased by 8.3%, 6.0%, and 11.5%, respectively, achieving synergistic flame retardancy and reinforcement.

Applications

• flame-retardant epoxy modification：Achieves V-0 rating at a low loading without sacrificing transparency or mechanical properties.
• electronic packaging materials：Combines high transparency and flame retardancy for packaging requiring optical clarity and fire safety.
• aerospace composites：Improves mechanical strength while providing flame retardancy, meeting aerospace demands for safety and load-bearing capacity.
• high-performance adhesives：Good compatibility with epoxy matrix enhances bond strength while imparting flame retardancy.