Aluminum oxide surface modification

Due to the strong polarity of the surface of alumina, it is difficult to disperse uniformly in the polymer; in addition, its thermal conductivity is not high, so a high filling amount is required to obtain better thermal conductivity, which will lead to an increase in the viscosity of the composite material and it is difficult to meet the requirements. Construction fluidity requirements, but also greatly reduce its mechanical properties, so that its scope of application is limited.

The compatibility between the alumina particles and the organic resin matrix interface is very poor, and the alumina particles are very easy to agglomerate, and it is difficult to disperse evenly into the polymer matrix. Moreover, the difference in surface tension between alumina particles and organic resin makes it difficult for the polymer matrix to wet the surface of the particles, resulting in gaps at the interface between the two and increasing the interfacial thermal resistance of the composite material.

How to reduce the agglomeration between alumina particles, improve the interfacial compatibility between alumina powder and polymer matrix, and improve their dispersion in the polymer matrix, so as to obtain composite materials with excellent performance, become the filling material of alumina. Critical issues for applications in the field of materials.

Use the functional groups in the organic surface modifier molecules to adsorb or chemically react on the surface of the particles to modify the surface of the particles, and purposefully change the physical and chemical properties of the powder surface, such as surface energy, surface polarity, etc., to solve the problem of aluminum oxide. The trump card for the problem of poor powder dispersibility.

At present, the surface modifiers of ordinary alumina are mainly traditional silane coupling agents. However, when the short-chain silane coupling agent is used as a surface modifier, the effect on improving thermal conductivity is limited. Therefore, in order to overcome the shortcomings of short-chain silane coupling agents as surface modifiers, hexadecyltrimethoxysilane can be used to modify the surface of alumina.