Surface Modification of Alumina Nanoparticles: A Dispersion Study in Organic Media

The alumina nanoparticles (NPs) have been synthesized from reaction between alum with ammonia and then calcined the precipitate at 1200 °C for 4 h. Its surface was modified by oleic acid (OA) and trimethoxyvinylsilane (TMVS) in o-xylene at 50 °C. The alumina NPs and its modified were characterized by XRD, FT-IR, SEM, EDX and TGA. The TGA analysis indicated that the grafting amount of OA and TMVS were 10.5 and 8.0% respectively. The dispersion of modified NPs was determined in monomers such as methyl methacrylate (MMA), butyl acrylate (BuA) and styrene (St) and in solvents such as ethanol, hexane and acetone. The experimental results showed that the highest dispersion was happened NPs modified by oleic acid in n-hexane, while the highest dispersion was observed NPs modified by TMVS in acetone. The results indicate that NPs modified by oleic acid formed a stable dispersion in MMA and BuA. The highest amount of dispersion happened NPs modified by oleic acid in MMA and BuA in initial weight of 5 and 2.5% respectively, while stable dispersion is formed in styrene when TMVS is used as modifier. The highest amount of dispersion was happened NPs modified by TMVS in styrene in initial weight of 2.5%.