High impact polystyrene (HIPS), which is widely used in the fields of household appliance casings, modern office supplies, building decoration, and home decoration, usually requires flame retardant modification. Currently, most halogen-free flame retardant modification formulas at home and abroad contain magnesium hydroxide, which has poor compatibility with the matrix HIPS and can easily cause a decrease in the performance of composite materials. It is necessary to use silane coupling agents to modify magnesium hydroxide to improve its impact on the flame retardant, mechanical, and processing properties of polystyrene materials.
When organic silane coupling agents are added to the material, the melt mass flow rate of the material decreases and the processing flowability of the material deteriorates. This is because although the coupling agent enhances the interfacial adhesion between the matrix resin and inorganic filler, it also hinders the sliding between molecules in the molten state of the matrix, resulting in an increase in the melt viscosity of the system.
When coupling agents are added to the material, the flame retardancy of the material is improved. Magnesium hydroxide treated with coupling agents has better compatibility with the matrix and fewer interface contact gaps, which is conducive to heat transfer.
After adding organosilicon, the tensile performance of the material deteriorates. After treating magnesium hydroxide with silane, the bending performance of the high material is significantly improved. This is because the compatibility between the silane treated magnesium hydroxide and the matrix is better, the interface contact is stronger, the defects are reduced, and the external force can be evenly dispersed under slow application.
When silane coupling agent is added to the material for modification, the impact strength of the material is improved. This is due to the hydrolyzable functional groups in silane coupling agents, which can decompose into Si when exposed to water&- OH groups can form hydrogen bonds with hydroxyl groups on the surface of magnesium hydroxide, and further undergo condensation or dehydration reactions through heating and drying to form partial covalent bonds, ultimately covering the surface of inorganic materials with silane, thus playing a good "bridge" role between polymers and fillers, improving the dispersion of fillers in the polymer matrix, and enhancing impact strength.
