Hebei Messi Biology Co., Ltd. stated that the initial decomposition temperature of basic magnesium carbonate (BMC) is 220°C, and the decomposition temperature range is 220-550°C. The heat absorbed during the decomposition process is 800kJ/kg, and the decomposition releases inert gases water vapor and carbon dioxide. With a weight loss of 52%, it has good prospects as a polymer environmentally friendly flame retardant.
6% stearic acid-modified basic magnesium carbonate was added to polypropylene at different amounts, and the effect of the added amount of basic magnesium carbonate on the mechanical and flame retardant properties of polypropylene was studied. The results show that basic magnesium carbonate can be used as a flame retardant in flame-retardant polypropylene. When the added amount of basic magnesium carbonate is 60 parts, the oxygen index of the polypropylene composite material reaches 32%, and the UL94 test reaches V0 level. As the addition amount of basic magnesium carbonate increases, the mechanical properties of the composite materials decrease significantly. When the addition amount of basic magnesium carbonate increases from 55 parts to 60 parts, the tensile strength, flexural strength and impact strength of the polypropylene composite material decrease from 20.51MPa, 28.56MPa, 34.14kJ/m2 to 18.71MPa and 27.57MPa respectively. , 19.87kJ/m2, among which the impact strength decreases most obviously. The combustion of basic magnesium carbonate polypropylene composite material is gradually carried out from the outside to the inside. On the surface of the composite material, the partially or completely decomposed basic magnesium carbonate and the magnesium oxide generated by the decomposition of basic magnesium carbonate catalyze the carbonization of the polypropylene to form carbon. The layer can block the exchange of oxygen and heat and enhance the flame retardant effect.
Synergists improve the flame retardant properties of composite materials, mainly by increasing the thermal decomposition temperature of basic magnesium carbonate, so that the heat absorption range of the flame retardant falls within the thermal decomposition temperature range of polypropylene as much as possible, thereby enhancing the flame retardant effect. . Different synergists can affect the color of composites. By compounding different synergists, the color, mechanical and flame retardant properties of composite materials can be further adjusted to meet different usage requirements. For example, when only 55 parts of basic magnesium carbonate is added as a flame retardant, the tensile strength of the composite material is 21.03MPa, 29.89MPa, 39.58kJ/m² (SHM2), the oxygen index is 28%, and it does not reach the vertical combustion level, and the product The color is earthy yellow. When using 35 parts of basic magnesium carbonate, the tensile strength, flexural strength and impact strength of the composite material are 24.53MPa, 39.75MPa, 11.78kJ/m (HMCOM4) respectively, the oxygen index is 27%, and the vertical combustion reaches V2 level. And the product is white in color.