Mechanically robust and thermally stable abrasive tools from phenolic resins reinforced with diazonium-modified zeolites

The contact area between the filler and the polymer is a critical region that influences to a great extent the filler-matrix adhesion and therefore the mechanical properties of the composite. Controlling the type of interactions at this interface has a significant effect on the properties of the composite materials. In this context, we prepared composites by covalent reaction of diazonium-functionalized zeolite with phenol-formaldehyde resin. Introducing the hydroxymethyl groups onto the surface of the filler via diazonium chemistry allows for covalent bonds between the resin and the modified filler. Such a modification resulted in higher flexural strength of the composites, better ability to dissipate mechanical energy during load and also better damping properties (which are strongly linked to the final product durability) compared with the composites bearing pristine zeolite filler. Moreover, application of modified filler accelerates the crosslinking of novolac resin used as a binder in abrasive tools. One key feature of the work was brought by thermogravimetric analysis-mass spectrometry results which indicate no release of toxic urotropine degradation products for composites containing modified fillers. This work demonstrates conclusively that diazonium-functionalized zeolite filler particles improve remarkably the thermal and mechanical properties of novolac-based composites. Such robust composites have high potential in the production of novel abrasive tools. POLYM. COMPOS., 40:3209-3219, 2019. (c) 2018 Society of Plastics Engineers