Phosphorus-Based Deep Eutectic Solvent

Flame-Retardant & Toughening Bidirectional

A green strategy that simultaneously modifies epoxy resin and carbon fiber to balance flame retardancy and mechanical performance.

Chunhong, Zhang · Hao, Liu · Xinyu, Chen · Yaohui, Wang · Yingnan, Wang · Shang, Lei

Composites Part B: Engineering 2026

Specifications

Flexural strength improvement

{'zh': '84.5', 'en': '84.5'} %

Fracture elongation improvement

{'zh': '214.8', 'en': '214.8'} %

Impact strength improvement

{'zh': '92.2', 'en': '92.2'} %

Peak heat release rate reduction

{'zh': '13.7', 'en': '13.7'} %

Total smoke production reduction

{'zh': '20.1', 'en': '20.1'} %

Flexural strength improvement (bidirectional)

{'zh': '42.9', 'en': '42.9'} %

Interlaminar shear strength improvement

{'zh': '107.8', 'en': '107.8'} %

Interfacial shear strength improvement

{'zh': '83.8', 'en': '83.8'} %

Advantages

UL-94 V-0 rating

The composite achieves a UL-94 V-0 rating, the highest flame retardancy classification, suitable for fire-sensitive applications.

Simultaneous mechanical enhancement

Flexural strength, fracture elongation, and impact strength are improved by 84.5%, 214.8%, and 92.2%, respectively, overcoming the typical trade-off between flame retardancy and mechanical properties.

Enhanced interfacial bonding

After bidirectional modification, interlaminar shear strength and interfacial shear strength increase by 107.8% and 83.8%, respectively, indicating stronger fiber-matrix adhesion.

Green and solvent-free

The process avoids the use of toxic organic solvents, being environmentally friendly, simple, and controllable.

Applications

• Carbon Fiber Composite Modification：For CF composite modification, simultaneously improving interfacial bonding and flame retardancy, replacing traditional organic solvent treatments.
• Flame-Retardant Epoxy Resin：For flame-retardant epoxy resin, achieving UL-94 V-0 rating while maintaining or improving mechanical properties.
• Lightweight Structural Materials：For lightweight structural materials, meeting flame retardancy and strength requirements while reducing weight.
• Interfacial Strengthening Agent：As an interfacial strengthening agent, improving interfacial shear strength between carbon fiber and resin matrix for better load transfer.