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

Abstract

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%.

Effect of Mixing Temperature, Ultrasonication Duration and Nanoparticles/Surfactant Concentration on the Dispersion Performance of Al2O3 Nanolubricants

“…Two absorption bands at 2852cm -1 and 2925cm -1 (Fig.8c) are due to the vibrational frequencies of CH 2 and CH 3 groups of oleic acid covering the surface of nanoparticles. The above observation results of FT-IR spectra con rmed that oleic acid chemically reacted with the particle surface, and the surface of Al 2 O 3 NPs was modi ed by oleic acid [61,62].…”

Hot aluminum substrate induced hexagonal‐tetragonal phase transitions in InSe and performance of Al/InSe/Cu2O pn tunneling devices

“…It is also worth of consideration, that even though the Al substrate was subjected to air contact for couple of minutes only, ultrathin formation of Al 2 O 3 passivation layer in the air is expected. The crystal structure of Al 2 O 3 can be hexagonal, 16 orthorhombic, 17 or tetragonal 18 . In case of tetragonal growth of Al 2 O 3 it could be a reason for the induced growth of similar structure of InSe.…”

“…The crystal structure of Al 2 O 3 can be hexagonal, 16 orthorhombic, 17 or tetragonal. 18 In case of tetragonal growth of Al 2 O 3 it could be a reason for the induced growth of similar structure of InSe. It is mentioned that hot Al 2 O 3 substrates induces high stress due to the difference of the thermal expansion coefficient between various films.…”

Effect of surface activation of alumina particles on the performances of thermosetting-based composite materials

“…[1][2][3] Nano-sized alumina powders which possess excellent structural properties are ideal candidates for preparing polymer composites. 4,5 However, there are some limitations related to the hydrophilic nature of alumina particles, which cause high water/moisture absorption and incompatibility with hydrophobic segments of polymeric matrices. 6 These drawbacks can be overcome by the surface modification/functionalization through reaction between modifying agent and large number of hydroxyl groups within the alumina structure.…”