Epoxy resin (EP) is an important thermosetting material. Because of its excellent chemical resistance and stability, good optical transmittance and adhesion, it is widely used in adhesives, coatings, and advanced nanocomposites. However, EP has the characteristics of high flammability and low decomposition temperature, so that it will generate a large amount of CO, CO2 and toxic fumes during the combustion process, which seriously limits the application field of EP. In order to improve the flame retardant performance of EP, expand its application fields, and add efficient flame retardants to it, it has become one of the important directions to improve the flame retardant performance of EP matrix. In recent years, green and environmentally friendly halogen-free flame retardants have been proven to significantly improve the fire safety performance of polymer matrices. They have the characteristics of low smoke generation and no toxic and harmful gases, and have attracted more and more attention in the field of flame retardants.
However, while improving fire safety performance, the addition of green halogen-free flame retardants will seriously reduce the transparency of EP, limiting the application of EP in some special fields, such as solar pavement, light-emitting diodes, multi-purpose coatings, etc. Therefore, while improving the safety performance of EP fire, research on green halogen-free flame retardant materials that can still maintain its transparency is a difficult and hot research topic in this field. Nanomaterials of different sizes have been shown to significantly improve the flame retardant properties of polymers. Basic magnesium borate (MBH) is an attractive new halogen-free flame retardant because of its low cost, environmental friendliness and excellent comprehensive Performance, has application and research value in the flame retardant field.
In order to effectively improve the thermal stability and fire safety of EP and maintain a high optical transmittance, the team of Liu Zhiqi, a researcher from Qinghai Salt Lake Institute, prepared MBH and added 1 wt% ~ 10 wt% of MBH to the ring by high temperature curing Oxygen resin prepared EP / MBH composite material. The results show that due to the similar refractive index of MBH and EP, the optical transmittance of the composite material in the wavelength range of 800 ~ 400 nm is still greater than 70% when the MBH content is 10 wt%. The addition of MBH increases the amount of residual carbon in EP / MBH composite materials and reaches a flame retardant level. Compared with EP, the flame retardant parameters of EP / MBH materials have decreased significantly, and EP / 5MBH composite materials are the most prominent. Its peak heat release rate (pHRR), smoke release rate peak (pSPR), CO release rate peak (pCOP), The peak CO2 release rate (pCO2P) and fire spread index (FIGRA) are reduced by 30% to 50%. The flame retardant mechanism research shows that MBH flame retardant EP is a solid phase flame retardant mechanism. MBH is decomposed into magnesium borate during the flame retardant process, which plays the role of condensed phase flame retardant and prevents the spread of heat and combustible gases.