Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China.
Molecules. 2021 Jan 11;26(2):340. doi: 10.3390/molecules26020340.
Nitrogen-containing flame retardants have been extensively applied due to their low toxicity and smoke-suppression properties; however, their poor charring ability restricts their applications. Herein, a representative nitrogen-containing flame retardant, polyheptanazine, was investigated. Two novel, cost-effective phosphorus-doped polyheptazine (PCN) and cobalt-anchored PCN (Co@PCN) flame retardants were synthesized via a thermal condensation method. The X-ray photoelectron spectroscopy (XPS) results indicated effective doping of P into triazine. Then, flame-retardant particles were introduced into thermoplastic polyurethane (TPU) using a melt-blending approach. The introduction of 3 wt% PCN and Co@PCN could remarkably suppress peak heat release rate (pHRR) (48.5% and 40.0%), peak smoke production rate (pSPR) (25.5% and 21.8%), and increasing residues (10.18 wt%→17.04 wt% and 14.08 wt%). Improvements in charring stability and flame retardancy were ascribed to the formation of P-N bonds and P=N bonds in triazine rings, which promoted the retention of P in the condensed phase, which produced additional high-quality residues.
含氮阻燃剂由于其低毒性和抑烟性能而被广泛应用；然而，其较差的成炭能力限制了它们的应用。本文研究了一种有代表性的含氮阻燃剂——聚己二嗪。通过热缩聚方法合成了两种新型、经济高效的磷掺杂聚己二嗪（PCN）和钴锚定 PCN（Co@PCN）阻燃剂。X 射线光电子能谱（XPS）结果表明三嗪中有效掺杂了磷。然后，通过熔融共混法将阻燃颗粒引入热塑性聚氨酯（TPU）中。引入 3wt%的 PCN 和 Co@PCN 可显著抑制最大热释放速率（pHRR）（48.5%和 40.0%）、最大烟雾生成速率（pSPR）（25.5%和 21.8%）和增加残留物（10.18wt%→17.04wt%和 14.08wt%）。炭化稳定性和阻燃性的提高归因于三嗪环中 P-N 键和 P=N 键的形成，这促进了 P 在凝聚相中保留，从而产生了更多高质量的残留物。
