Surface Modification Of Aluminium Hydroxide And Brucite Powder

This dissertation deals with surface modification of inorganic nanometer and micrometer hydroxide (nanometer aluminium hydroxide, micrometer brucite), which could keep the inorganic particles away from aggregation and improve the compatibility between the inorganic particles and polymer materials. The surface modifiers used include small inorganic molecular stearate (zinc stearate, magnesium stearate, calcium stearate, etc.), small organic molecule (lauric acid) and polymer (polyethylene glycol). And it reveals the general rales on the modification of hydroxide and the type of interaction between modified agents and hydroxide.Polyethylene glycol (PEG) is successfully grafted onto nano-aluminium hydroxide surface using p-toluene sulfonic acid as the catalyzer through a one-step procedure. The effects of stearate amount, reaction temperature and mechanical force on the grafting are investigated. And the grafting mechanisms under different reaction temperatures are also investigated. On the basis, the surface modification of aluminium hydroxide by coating PEG is characterized through FT-IR and TGA. And the capability of the product is stable because the modifier and nano-aluminium hydroxide have been combined by chemical bond. Dispersity of modified nano-aluminium hydroxide also proved that the surface polarity of aluminium hydroxide has changed markedly.Small inorganic molecular stearates (zinc stearate, magnesium stearate, calciumstearate) are successfully grafted onto micrometer brucite (mainly magnesium hudroxide) surface by chemical adsorption . The effects of stearate amount, reaction temperature and mechanical force on the grafting are investigated. On the basis, the surface modification of brucite by coating stearate is characterized through FT-IR and TGA. And it proves that the stearate is absorbed onto the surface of brucite through chemical absorption. This research may offer a trial base and a theory base for the industrialization of the surface modification of brucite.The treated micrometer brucite been modified with lauric acid was studied. The effects of lauric acid amount, reaction time and reaction temperature on grafting are investigated. On the basis, the surface modification of brucite by grafting lauric acid is characterized through FT-IR and TGA. And it proves that the lauric acid is grafted onto the surface of brucite through condensation polymerization between lauric acid and brucite. This work may serve as the basis for further study on the surface modification of brucite by way of wet processing. To compare with raw brucite powder in LDPE (55:45 at the ratio of weight) , tensile strength, impact strength and elongation at break of PE increased from 9.2 MPa up to 11.4 MPa, from 17.1 KJ·cm^-2 up to 36.2 KJ·cm^-2, from 17 % up to 400 %, respectively.