Preparation And Application Of Partially Delaminated Stearic Acid Montmorillonite

The partially delaminated Stearic Acid Montmorillonite (STA-MMT) was synthesized, using alkaline Ca- montmorillonite and Stearic acid(STA) as raw materials on the condition of circumfluence, water diversion and dispersion in organic solvent. Single factor analysis was performed to investigate the influences of the factors, such as the reaction time, the amount of Stearic acid, the dosage of ethanol in dispersant, the amount of solvent, the droping temperature of the STA solution, the anion exchange capacity(AEC) of the alkaline Ca-montmorillonite, and the partical size of the alkaline Ca-montmorillonite, upon the ignition loss test of organic STA-MMT clay. The optimum preparation condition was achieved: add dropwise 60mL haxmethylene alkyl solution of Stearic acid(4.50g) into a large beaker, which contains 5.00g 0.076mm alkaline Ca-montmorillonite and 75mL mixed anhydrous solution at 50℃; the anhydrous solution is mixed by haxmethylene alkyl and absolute alcohol with volume ratio of 9: 1. The organic content of the prepared product was about 36.25%.With characterization tools such as XRD, FTIR, SEM, TG/ DTA and DTS, it is confirmed that: the Stearic acid anion is intercalated in the layer; the MMT is partially delaminated as the d-spacing enlarges; the dispersibility of STA-MMT reaches the scale of 300nm in the solvent of ethanol. In comparison with montmorillonite modified by cetyltrimethyl ammonium bromide, this partially delaminated Stearic acid montmorillonite has such merits like: better gel properties, larger surface area, smaller partical size and better dispersibility in most of organic dissolvents.Furthermore, using partially delaminated Stearic acid montmorillonite as a precursor, hydrophobic wax/stearic acid montmorillonite(wax/ STA-MMT) was prepared by introducing hydrophobic wax into the hydrophobic phased interlayer of partially delaminated Stearic acid montmorillonite. Through single-factor analysis, the optimum preparation condition was obtained: at 55℃, add 5.00g wax into a large beaker, which contains 3.00g STA-MMT and 200mL mixed anhydrous solution of haxmethylene alkyl and absolute alcohol ( V_A: V_H=1 : 9), then stir for thermostat reactions over 5 hours. The organic content of the prepared wax/STA-MMT is 71.55%, with 36.30% contributed by wax. XRD and DSC characterization means were used to study the structure and melting point of wax/STA-MMT. Through characterizations it is shown that good compatibility exists between STA-MMT and wax; meanwhile the melting point of wax increased by 60.7℃.