Effects of Surface Treatment of Co3O4 Particles on the Properties of Polymethylphenylsiloxane Based Nanocomposites

Abstract

Polymethylphenylsiloxane (PMPS) was filled with Co3O4 nano-particles to prepare nanocomposites with thermal absorption properties (also called as endothermal properties). The surfaces of the nano-particles were treated by covalently bonding them to polybutylmethacrylate (PBMA) by an emulsion grafting method, and their surface characteristics after treatment are reported. The effects of treating the Co3O4 nano-particles on the interfacial properties, thermal properties (thermal stability of materials) and endothermal properties of the nanocomposites were investigated by means of a dynamic wetting instrument, transmission electron microscopy (TEM), differential thermogravimetry (DTG) and by a calibration test of the heat flow transducer. The results indicate that PBMA had been grafted onto the surfaces of the Co3O4 nano-particles successfully, and the grafting ratio reached about 6.6%. After the grafting treatment the hydrophilicity of the Co3O4 particles decreased and the hydrophobicity increased. The miscibility between Co3O4 particles and PMPS was increased, and their dispersion in PMPS was also improved. Compared with pure PMPS resin, the thermal stability of the untreated Co3O4/PMPS composites decreased, but increased to some extent for treated Co3O4/PMPS composites. The calibration test of the heat flow transducer revealed that the nanocomposite with grafted Co3O4 nano-particles had much better endothermal properties than the one with untreated Co3O4 nano-particles.