Study on the surface modification of inorganic flame retardant magnesium hydroxide and mechanism

摘要

1.Introduction Compared with other flame retardants, magnesium hydrate can break down at the temperature of 350℃ -400℃[1], and the decomposition product is magnesia & water which are pollution-free, and meanwhile a large amount of heat is absorbed during the process of breaking down[2,3]. So the high molecular polymer filled with flame retardant type magnesium hydroxide can slow down or stop the process of the burning effectively. As an environmental-friendly inorganic fire retardant, magnesium hydrate has wide potential application prospect and is the future sound of the leading flame retardant products. In order to play the role of its fire retardant function effectively, it must be modificated for its hydrophilic structure. The surface modification of magnesium hydroxide by silane coupling agent (KH-550, KH-560) and stearic acid was investigated in the experiment. By comparing the transmissivity of the above modificated samples in the liquid paraffin, the result shows that stearic acid is the most excellent modifier.And the optimal process conditions can be listed as follows: the dosage of stearic acid is 6%, and the modified temperature is 80℃, and the modified time is 60min. XRD, FTIR and TG-DSC are used to characteristic the modificated samples, and the analyzed result indicates the mechanism of surface modification is that stearic acid is attached to the surface of magnesium hydroxide by hydrogen bond formed between stearic acid and hydroxide radical of magnesium hydroxide, so the interconsistency between magnesium hydroxide and polymer gets improved.