Magnesium hydroxide (MH) has advantages such as green and low cost in flame retardant application. However, the flame retardant efficiency is low, and often the amount of MH added is large in order to achieve the ideal flame retardant effect, which affects the mechanical properties of the composite material. In addition, the MgO produced by the thermal decomposition of MH has a certain smoke suppression effect, but the adhesion between MgO is poor, and the protective layer formed after combustion is thin and less sturdy, so it is often necessary to add the flame retardant co-efficient of the enhanced carbon layer into the composite material together with MH, which can also reduce the amount of MH to a certain extent.
In order to improve the compatibility between the magnesium hydroxide and the matrix, it is necessary to modify the MH such as surface grafting or coating to achieve better flame retardant efficiency.
1、Improve mechanical properties
Improve the mechanical properties of the composite material caused by the addition of MH, can take the role of lubricating particles with MH added into the matrix, or MH surface modification treatment. The EVA-MH-HPCTP composite was prepared by blending MH and hexaphenoxycyclotriphosphonitrile (HPCTP) as flame retardant with EVA, and the compatibility of the composite was significantly improved due to the bridging effect of HPCTP, and it has better processing performance. The EVA/MH/MWNT composites were obtained by applying multi-walled carbon nanotubes (MWNT) and MH to EVA composites. 2 wt% of MWNT was used to replace MH in EVA/MH/MWNT composites, and the exothermic rate and mass loss rate of MWNT could be significantly reduced by 50-60%, the burning time could be extended nearly two times, and the LOI value could be increased by 5%. The addition of MWNTs increases the melt viscosity of EVA composites during combustion, which makes the char layer harden. The mechanical strength and integrity of the char layer of MWNT in EVA/MH/MWNT nanocomposites improves the thermal oxidation stability, and...
Comments