Why is surface modification necessary for alumina fillers?

With the in-depth development and application of composite material research, fillers, as one of the components of composite materials, have increasingly received widespread attention. Filler is an important means of material modification, which not only greatly reduces the cost of materials, but also significantly improves various properties of materials, endows them with new features, and expands their application range.

Due to its strong heat resistance, stable crystal phase, high hardness, and excellent wear resistance, alumina is widely used as a reinforcing filler for various rubber, plastic, ceramic, refractory materials, etc. In addition, due to its high resistivity and good electrical insulation, it can be applied in integrated circuit substrates.

Why modify it? Due to the strong surface polarity of alumina and poor compatibility with the interface of organic resin matrix, it is difficult to uniformly disperse in polymers. Moreover, the difference in surface tension between alumina particles and organic resins makes it difficult for the polymer matrix to wet the particle surface, resulting in voids at the interface between the two, reducing the mechanical properties of the composite material and increasing the interfacial thermal resistance of the composite material.

High filling content can lead to improved material performance, but it also brings some problems. When aluminum oxide is used as a thermal conductive filler, due to its low thermal conductivity, a high filling amount can achieve good thermal conductivity, leading to an increase in the viscosity of the composite material and difficulty in meeting the construction flowability requirements, while also significantly reducing its mechanical properties. However, when the filling amount exceeds a certain value, the alumina particles are prone to agglomeration and will not have a good improvement in performance.

Therefore, it is necessary to carry out surface activation treatment on the filler, reduce the agglomeration between alumina particles, improve the interface compatibility between alumina powder and polymer matrix, improve their dispersion and filling uniformity in the polymer matrix, and thus obtain high-performance composite materials.

The above is the relevant content about alumina organized by alumina manufacturer Yangzhou Zhongtianli, hoping to provide some help to everyone. If you would like to learn more about alumina, please feel free to contact us. Yangzhou Zhongtianli New Materials Co., Ltd. is a technology enterprise specializing in the production of isopropanol aluminum, isopropanol aluminum trimer, secondary butanol aluminum, pseudo boehmite, high-purity arsenic, high-purity aluminum oxide, etc. It has multiple technologies and has received unanimous praise in the industry.