Magnesium hydroxide is a green and environmentally friendly inorganic additive flame retardant. It has the advantages of good thermal stability, non-toxicity, easy availability of raw materials, low price, and no toxic and harmful gases during combustion. It can be widely added to such as Plastics, rubber, coatings and other polymer materials to improve their flame retardant properties.
Hebei Messi Biology Co., Ltd. has prepared a highly dispersed hexagonal flake flame-retardant magnesium hydroxide with small particle size and low surface polarity, and at the same time researched its flame-retardant application. The main content includes the following two aspects: First, in order to reduce the agglomeration of magnesium hydroxide particles and improve its compatibility with polymer materials, the hydrothermal method is used to prepare magnesium hydroxide with low surface polarity, good dispersion, and an average particle size of 1 μm. Left and right hexagonal flakes of magnesium hydroxide.
Hebei Messi Biology Co., Ltd. studied the effect of hydrothermal conditions on its crystal growth, especially on the growth of the less polar (001) crystal plane. It is found that reducing the initial particle size of the raw material and the solid content of the feed, increasing the OH- concentration in the hydrothermal medium and the hydrothermal temperature, and prolonging the hydrothermal time are all beneficial to crystal growth, but when the OH- concentration in the medium is greater than 8mol/L or the hydrothermal time When it exceeds 10h, the growth direction of the crystal will be changed, and the growth of (001) crystal plane will be shielded at the same time. The growth process of the crystal is explained by the theory of negative ion coordination polyhedron growth unit.
On the basis of optimizing the experimental conditions, a scale-up experiment was carried out on the preparation of hexagonal flake-shaped magnesium hydroxide, and the optimal hydrothermal conditions at two high feed concentrations of 20wt.% and 30wt.% were investigated. The second is to study the application of magnesium hydroxide flame retardant. The irregular crystalline form, the irregular crystalline form modified by stearic acid, and the hexagonal flaky magnesium hydroxide were added to polyethylene respectively, and the mechanical properties, flame retardancy, rheological properties, and crystallization behavior of polyethylene materials were investigated. Impact.
Hebei Messi Biology Co., Ltd. found that magnesium hydroxide can increase the oxygen index of polyethylene from 19.2% to 22.6%, enhancing its flame retardancy. And the hexagonal flaky magnesium hydroxide can effectively improve the tensile strength of the material, but the elongation at break drops seriously, from 231.65% to 28.78%, while the modified magnesium hydroxide has little effect on the mechanical properties of polyethylene. Since magnesium hydroxide has a heterogeneous nucleation effect on polyethylene, the crystallization rate of the material is accelerated, and the crystallinity decreases with the increase of magnesium hydroxide addition. In addition, the addition of different types of magnesium hydroxide will increase the pseudoplasticity of the material and reduce the rheological properties.