In situ preparation of intrinsic flame-retardant urea formaldehyde/carbon nanotubes nanocomposite foam: structure and reinforcing mechanism

ABSTRACT

Urea-formaldehyde (UF)/carboxylated carbon nanotubes (CNTs-COOH) nanocomposite foams were prepared via in-situ polymerization. Chemical bonding and hydrogen bonding interactions formed between CNTs-COOH and UF matrix. UF resin adhered onto the ektexine of CNTs-COOH and grafting ratio of 496.41% was achieved. UF/CNTs-COOH foam showed smaller cell size, narrower cell size distribution and lower water absorption compared with UF foam. Introduction of 0.25 wt% CNTs-COOH resulted in 58.43% increase in compressive strength. CNTs-COOH were pulled out with surface covered with UF resin under stress and the failure mode was the destruction of matrix around interfacial layer. UL-94V-0 rating was achieved for the composite foams.

Graphical Abstract

KEYWORDS:

• Urea-formaldehyde (UF)
• carbon nanotubes (CNTs)
• nanocomposite foam
• reinforcing mechanism
• intrinsic flame retardancy

Additional information

Notes on contributors

Chuanlong Li

Chuanlong Li is currently a master degree candidate at Sichuan University. His research work is mainly focused on the preparation of amino resin and foam with high performances.

Lin Ye

Lin Ye is a professor of Sichuan University. She is mainly engaged in the research and development of engineering plastics, water-based and environment-friendly polymer materials.

Xiaowen Zhao

Xiaowen Zhao is an associate professor of Sichuan University. She is mainly engaged in the synthesis, preparation, processing modification and structural characterization of polymer based blends or composites.