Epoxy resin (EP) is an important thermostat material, because of its excellent resistance to chemical corrosion and stability, good optical pass rate and adhesion is widely used in adhesives, coatings and advanced nanocomposive materials and other fields. However, EP's high flammability and low decomposition temperature make it prone to large amounts of CO, CO2 and toxic fumes during combustion, severely limiting ep applications. In order to improve the flame retardant performance of EP, expand its application field and add high-efficiency flame retardant to it, it has become one of the important directions to improve the flame retardant performance of EP
. In recent years, green halogen-free flame retardants have been shown to significantly improve the fire safety performance of polymer substates, with small smoke, no toxic and harmful gas production and so on, more and more attention in the field of flame retardants.
But while improving fire safety, the addition of green halogen-free flame retardants can significantly reduce EP transparency and limit ep applications in specific areas such as solar pavements, light-emitting diodes, multi-purpose coatings, etc. Therefore, while improving the safety performance of EP fire, the study of green halogen-free flame retardant materials, which can still maintain its transparency, is a difficult point and research hot spot in this field. Nanomaterials of different sizes have been shown to significantly improve polymer flame retardant properties, and magnesium borate (MBH) is an attractive new halogen-free flame retardant with application and research value in the field of flame retardant due to its low cost, environmental friendliness and excellent comprehensive properties.
In order to effectively improve the thermal stability and fire safety of the EP and maintain a high optical pass rate, the team of researchers Liu Zhiqi of Qinghai Salt Lake Institute prepared the MBH and added 1 wt% to 10 wt% of the MBH to epoxy resin to prepare the EP/MBH composite material through the high temperature curing method. The results show that the optical pass rate of composite materials in the wavelength range of 800 to 400 nm is still greater than 70% when MBH is added at 10 wt% due to the similar refractive index of MBH and EP. The addition of MBH increases the residual carbon footprint of EP/MBH composites and reaches the flame retardant level. Compared to EP, the flame retardant parameters of EP/MBH materials decreased significantly, with EP/5MBH composites being the most prominent, with a 30% to 50% decrease in thermal release rate peak (pHRR), smoke release rate peak (pSPR), CO release rate peak (pCOP), CO2 release rate peak (pCO2P), and fire spread index (FIGRA). The research of flame retardant structure shows that MBH flame retardant EP is a solid phase flame retardant, and MBH decomposes into magnesium borate in the flame retardant process, which acts as a coagulation flame retardant and prevents the spread of heat and flammable gas. For more information, see Salt Lake Research No. 4 of 2019 - Salt Lake Chemical Special Issue "Research Highlights": pp. 1-8.