Preparation and Modification of SiO_2 Spherical Particles

Nano-SiO2 spherical particles were prepared in the ethanol medium with ammonia as catalyst and tetraethoxysilane (TEOS)as silica source. The different diameters of the SiO2 spherical particles were obtained by changing ethanol dosage, the particle size distribution was in the range of 180 nm and 300 nm . During the reaction process,SiO2 spherical particles were modified by adding silane coupling agent (KH-570),and the presence of the peak value was 1 400 cm-1 in the infrared spectrograms with the increase of the concentration of silane coupling agent,it indicated that the strength of the characteristic peak of methy- lene (C-H)increased;KH-570 played a role in the modification of SiO2 particles,and furthermore,the organic functional group of KH-570 of the surface of SiO2 particles increased. The coating of the prepared SiO2 particles was operated in nitrogen with methyl acrylate,the presence of the characteristic peak of methylene (C-H)was 1 400 cm-1and the presence of the characteristic peak of ester group was 1800 cm-1 in the infrared spectrograms,it showed the surface of SiO2spherical particles was coated with methyl acrylate.