Zhao Siheng, Xu Bo, Shan Hao, Zhang Qinglei, Wang Xiangdong
School of Chemistry and Materials Engineering, Beijing Technology and Business University, Beijing 100048, China.
Beijing Key Laboratory of Quality Evaluation Technology for Hygiene and Safety of Plastics, Beijing 100048, China.
Polymers (Basel). 2023 Apr 17;15(8):1917. doi: 10.3390/polym15081917.
This work investigated the effect of different valence states of phosphorus-containing compounds on thermal decomposition and flame retardancy of polyethylene terephthalate (PET). Three polyphosphates-PBPP with +3-valence P, PBDP with +5-valence P and PBPDP with both +3/+5-valence P-were synthesized. The combustion behaviors of flame-retardant PET were studied and the structure-property relationships between the phosphorus-based structures with different valence states and flame-retardant properties were further explored. It was found that phosphorus valence states significantly affected the flame-retardant modes of action of polyphosphate in PET. For the phosphorus structures with +3-valence, more phosphorus-containing fragments were released in the gas phase, inhibiting polymer chain decomposition reactions; by contrast, those with +5-valence phosphorus retained more P in the condensed phase, promoting the formation of more P-rich char layers. It is worth noting that the polyphosphate containing both +3/+5-valence phosphorous tended to combine the advantage of phosphorus structures with two valence states and balance the flame-retardant effect in the gas phase and condensed phase. These results contribute to guiding the design of specified phosphorus-based structures of flame-retardant compounds in polymer materials.
本研究考察了含磷化合物的不同价态对聚对苯二甲酸乙二酯（PET）热分解及阻燃性能的影响。合成了三种聚磷酸盐——含+3价磷的PBPP、含+5价磷的PBDP以及含+3/+5价磷的PBPDP。研究了阻燃PET的燃烧行为，并进一步探讨了不同价态磷基结构与阻燃性能之间的构效关系。结果表明，磷的价态显著影响聚磷酸盐在PET中的阻燃作用模式。对于含+3价磷的结构，更多含磷碎片在气相中释放，抑制聚合物链分解反应；相比之下，含+5价磷的结构在凝聚相中保留更多的磷，促进形成更多富含磷的炭层。值得注意的是，含+3/+5价磷的聚磷酸盐倾向于结合两种价态磷结构的优势，平衡气相和凝聚相中的阻燃效果。这些结果有助于指导聚合物材料中特定磷基结构阻燃化合物的设计。
