Abrasion and scratch resistant resins and coating systems have received significant attention in recent years as they open new markets for organic coatings. To enhance the abrasion resistance of coating systems, boron nitride is being deployed in water-based systems. By adding surface active substances to an existing matrix an improvement of the surface hardness can be expected.
The prerequisite for the implementation of such mixed systems is a similar sedimentation behavior of all involved inorganic filler components. Due to an insufficient wettability, resulting from the diverging surface energies of boron nitride and the applied resin or coating system, the homogenous distribution of the particles in the resin matrix after sedimentation constitutes a major challenge.
The herein discussed research describes the surface modification of boron nitride particles to increase their wettability behavior. In a first approach the surface of the boron nitride particles is modified with silanes that carry different trialkoxy head groups. The head groups have been chosen with the intention to change the polarity of the particle as well as to provide an interface for covalent coupling of the resin matrix with the filler particles.
In a second approach boron nitride has been modified with a metal oxide layer to increase its polarity and also to improve the efficiency of the silylation reaction due to an increasing amount of accessible hydroxyl groups.
Both modifications lead to an improvement of the sedimentation behavior and seem to be promising options for industrial applications.
