A novel approach has been proposed to enhance the flame retardancy of ABS by a highly efficient intumescent flame retardant coating, which was prepared by aluminum- ethylene glycol methyl propionate cyclohexanediol phosphonate (EMPCP-Al), polyvinyl formal (PVFO) and melamine cyanurate with specific ratio. When the average thickness of coating achieved at 106 μm, the limit oxygen index value of ABS increased from 16.6% to 28.7%, its UL-94 rating reached V-0 level in the vertical burning test, and the peak value of heat release rate (PHRR) was decreased by 51.1% compared with that of pure ABS. TGA coupled with Fourier transform infrared spectroscopy was used to probe the degradation behavior of the flame retardant composites. In addition, the microscopic morphology and graphitization degree of the carbon layer which obtained after the thermal degradation of the flame retardant composites were investigated by scanning electron microscopy-energy dispersive X ray and Raman spectroscopy. Moreover, P element, N element and Al element in flame retardant coating exhibited benign synergistic flame retardancy in the gas phase and condensed phase. Furthermore, the flame retardant coating could effectively avoid the damage to intrinsic mechanical properties of ABS caused by high loading of flame retardant additives.
Yanli Dou,Aixun Ju,Zheng Zhong,Yutong Huo,Weiguo Yao
Unsaturated polyester resin (UPR) with excellent flame retardant is mainly obtained by adding large amounts of flame retardants, usually at the expense of mechanical properties. In this work, a reactive flame retardant containing phosphorus and nitrogen (DOPO-N) was successfully synthesized and incorporated in UPR as a crosslinker. The mechanical and flame-retardant properties of UPR composites were enhanced. UPR/30DOPO-N passed a UL-94 V-1 rating with a limiting oxygen index (LOI) of 30.8%. The tensile strength of UPR/30DOPO-N increased by 24.4%. On this basis, a small amount of modified HNTs (VHNTs) was added to further improve the flame-retardant properties of the composite. With the introduction of 3 wt% VHNTs, the composite passed the UL-94 V-0 rating. The peak of heat release rate (PHRR) and total heat release (THR) of it decreased by 60.7% and 48.3%, respectively. Moreover, the detailed flame-retarding mechanism of DOPO-N and VHNTs was investigated by thermogravimetric infrared spectroscopy (TG-IR), Raman spectra, and X-ray photoelectron spectroscopy (XPS). It was found that DOPO-N played a role in quenching the flame in the gas phase and cooperated with VHNTs to enhance the barrier effect in the condensed phase.
High-impact polystyrene is a widely-used construction material due to its superior comprehensive performance, but its susceptibility to fire can lead to the production of toxic and harmful gases. To address this issue, a novel, environmentally-friendly microencapsulated nitrogen‑phosphorus‑silicon flame retardant for high-impact polystyrene was prepared in this study. SiO 2 , produced by the hydrolysis condensation of tetraethyl orthosilicate , was used as the wall material, while melamine cyanurate was used as the core material. The microencapsulated nitrogen‑phosphorus‑silicon flame retardant was compounded with high-impact polystyrene and aluminum hypophosphite , and the composites were evaluated for their performance in terms of fire behavior, thermal stability, and morphology of the resulting carbon residues. When melamine cyanurate@SiO 2 and aluminum hypophosphite were added in a 1:4 ratio, the UL-94 rating of L5 reached V -0, and the LOI value increased to 27.0%. The conical calorimeter test results showed that the peak heat release rate of the L5 composite decreased by 78.7% compared to pure HIPS, and the corresponding total heat release rate decreased by 45.7%. Thermogravimetric analysis results illustrated that the amount of carbon residue increased significantly, from 2.46% to 22.26% of pure high-impact polystyrene. These findings indicate that the prepared microencapsulated nitrogen‑phosphorus‑silicon flame retardant is multifunctional, highly efficient, and can be applied to high-impact polystyrene.
危险品化学品经营许可证（带存储）