Flame-retardant properties and mechanism of LGF/PBT/DOPO-HQ-conjugated flame-retardant composites

Junzhuo Sun; Daohai Zhang; Xiaoyu Shang; Fang Tan; Dongmei Bao; Shuhao Qin

doi:10.3389/fchem.2022.981579

Flame-retardant properties and mechanism of LGF/PBT/DOPO-HQ-conjugated flame-retardant composites

Front Chem. 2022 Oct 12:10:981579. doi: 10.3389/fchem.2022.981579. eCollection 2022.

Authors

Junzhuo Sun^{1

2}, Daohai Zhang^{1

2}, Xiaoyu Shang^{1

2}, Fang Tan^{1

2}, Dongmei Bao¹, Shuhao Qin^{1

3}

Affiliations

¹ School of Chemical Engineering of Guizhou Minzu University, Guiyang, China.
² Polymer Composites Engineering Research Center of Guizhou Minzu University, Guiyang, China.
³ National Engineering Research Center for Compounding and Modification of Polymer Materials, Guiyang, China.

Abstract

In this article, long fiber reinforced polybutylene terephthalate (LGF/PBT/DOPO-HQ) flame-retardant composites were prepared using 10-(2,5-dihydroxy phenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-HQ) as the conjugated flame-retardant. The effects of different flame-retardant contents on the combustion properties of the composites were investigated. The results showed that after adding 14% of DOPO-HQ, the flame-retardant effect of the composite reached the V-0 level of UL-94 fire rating with an ultimate oxygen index (LOI) of 26.4%. The average heat release rate (Av-HRR), peak heat release rate (PHRR), and total heat release rate (THR) decreased by 45.9, 56.5, and 32.6%, respectively. This shows that LGF/PBT/DOPO-HQ composite has good flame-retardant properties. Meanwhile, the flame-retardant mechanism of cohesive phase and gas-phase synergy during the combustion of flame retardants was analyzed by carbon layer morphology and dynamic thermal decomposition.

Keywords: composites; conjugated flame retardant; flame-retardant mechanism; gas-phase flame retardant; polybutylene terephthalate.