Thermo-mechanical properties of silane-modified composite materials based on klucel and glass microballoons

This research investigates how a filler-to-binder ratio and silane modification affect the thermal and mechanical behaviour of composites based on glass microballoons and Klucel intended as gap fillers for wooden artefacts. Scanning electron microscopy, thermogravimetric analysis and dynamic mechanical analysis were used to analyse the structure and selected properties of prepared gap fillers. The composites are lightweight due to the high amount of entrapped air in the microballoons, representing 80–94% of the composite volume fraction. Thermogravimetric analysis revealed a higher impact of silane modification than a filler-to-binder ratio on the thermal properties of the studied composites. Generally, both methyltrimethoxysilane (MTMOS) and (3-glycidyloxypropyl)trimethoxysilane (GOPTMOS) increased the thermal stability of samples with a 1:2 filler-to-binder ratio but did not affect those with a 1:3 filler-to-binder ratio. MTMOS increased the activation energies of modified composites, while GOPTMOS lowered them. Silane modification made the composites more elastic. The improved thermal and mechanical properties of composites modified with silanes indicate that such a treatment may be the right direction in developing lightweight gap fillers for wooden objects exposed outdoors.