106 / 2023-10-04 11:08:04

Synthesis of phosphorus-containing flame retardants and their application with polystyrene

Polystyrene; DOPO; Flame retardant

Phosphorus Material Chemistry and Applied Science > 1) Phosphorus chemistry in material science

Synthesis of phosphorus-containing flame retardants and their application with polystyrene

Yintong Zhao¹, Zhenhao Gao¹, Zhiwei Miao<sup>1,*

1</sup>State Key Laboratory and Institute of Elemento-Organic Chemistry, University of Nankai, Weijin Road 94, Tianjin, 300071

^*E-mail: miaozhiwei@nankai.edu.cn



Polystyrene (PS) materials are widely used in various fields of daily life, but it is relatively easy to burn, so in practical applications need to add flame retardants to improve the flame retardant properties of the material. The group designed and synthesised a new reactive flame retardant monomer DOPO-AC.^[1] It was found that when the addition amount of DOPO-AC was 5 wt%, the vertical combustion test (UL-94) could reach V-0 flame retardant grade, and the limiting oxygen index (LOI) value was 29.6%, which had excellent flame retardant effect and solved the problem of high flame retardant difficulty and large addition amount that generally existed in the flame retardancy of PS.^[2] In addition, the possible flame retardant mechanism of PS/DOPO-AC(Fig. 2a) copolymer is proposed: when PS/DOPO-AC copolymer burns, it produces flame-retardant phosphorus-containing substances, which are attached to the surface of the carbon layer of PS material to enhance the flame retardant effect, and PS/DOPO-AC copolymer can form a denser cross-linked carbon layer than pure PS. In addition, the flame retardant DOPO-AC produces in the process of combustion In addition, the flame retardant DOPO-AC produces water vapour and nitrogenous gases (e.g. NH₃) during combustion, which dilute the concentration of combustible gases and take away the heat inside the PS material, thus providing better flame retardancy.^[3]



Fig. 1 The synthetic route of DOPO-AC







Figure 2 a) Structural formula for PS/DOPO-AC b) Schematic diagram of the flame retardant mechanism of PS/DOPO-AC copolymer

Keywords: Polystyrene; DOPO; Flame retardant

References

[1] Q. Xiao, Q. He, J. Li and J. Wang, Organic Letters 2015, 17, 6090-6093.

[2] 申婷 and 杨玲, 中国塑料 2017, 31, 53-57.

[3] Z. H. Gao, J. Xie, H. Huang, Z. W. Miao, J. Appl Polym Sci. 2022; e52702.