Polyvinyl chloride (PVC) is one of the extensive chemical materials, which is usually divided into two types: soft PVC and hard PVC.Among them, the hard PVC itself has self -extinguishing, but the soft PVC has added a large amount of plasticizer to improve the processing performance and plasticity, which has greatly reduced the flame retardant performance of the PVC system.At the same time, a large amount of toxic smoke will be produced during the combustion process, which seriously threatens people’s lives and property.
Inorganic flame retardant is the ideal non -risk -free flame retardant for application and development. The magnesium hydroxide flame retardant is one of the main products. It has the advantages of non -toxic, smoke suppression, no volatile, good thermal stability, and no corrosive gas., Meet the strict requirements of high efficiency, flame retardant, low smoke, and low toxicity of flame retardants.Magnesium hydroxide is widely used in the field of high polymer flame retardant due to high thermal decomposition temperature and efficient promotion of base materials.
Due to the large particle size of micron Magnesium hydroxide powder and its poor affinity with PVC system, the dispersibility is poor, which greatly reduces the mechanical properties of the system. The surface of modified micron-scale powder is coated with organic matter, which can enhance the compatibility with PVC system and improve the mechanical properties of the system to some extent. At the same time, due to the small particle size and high surface energy of the unmodified Magnesium hydroxide, the Magnesium hydroxide can easily agglomerate to form aggregates, resulting in uneven distribution of the powder in the PVC system, as a result, it has a lower oxygen index than the unmodified and modified micron Magnesium hydroxide flame retardants in the PVC system, while the modified Magnesium hydroxide powder has a lower surface energy, which overcomes the disadvantage of easy aggregation, as a result, the oxygen index of the Magnesium hydroxide was increased, and the effect of mechanical properties was greatly reduced, which showed the superiority of the nano-powder.
Nano-and micro-Magnesium hydroxide Magnesium hydroxide have different effects on the mechanical properties and flame retardancy of PVC system. Secondly, after surface modification, the compatibility and dispersion of Magnesium hydroxide in PVC system were improved to some extent, and the flame retardancy of the system was improved. At the same time, the influence on mechanical properties of the system can be reduced.