Improvement of mechanical properties of silica/phenolic composites and abrasive tools by modification of filler using diazonium salt with hydroxymethyl groups

Most important features that influence the properties of composites are the uniform mixing of components and interactions between surfaces of the individual components. Changing the type of interactions on these surfaces has a significant effect on improving the properties of the composites. In this work, we prepared active silica fillers with hydroxymethyl groups on the surface. We proved by Raman spectroscopy uniform distribution of the organic layer on the silica surface. The obtained materials were used as a filler in novolac composites and abrasive tools. Introducing active hydroxymethyl groups onto the surface of the filler allows for covalent bonds between the resin and the modified filler. The mechanical, thermal and thermomechanical properties of the materials were investigated. Flexural strength increased by 68% for novolac composite while 246% for model abrasive tool. Materials with modified silica have a higher cross-linking density. The addition of active filler to the polymer matrix allows to obtain a composite structure with higher stiffness and better damping properties. Therefore, it can be concluded that the use of a modified filler improves the properties of both novolac composites and model abrasive tools.