Effect of dehydroxylation/amorphization degree of bentonite on the microstructure, thermal stability, and mechanical strength of basalt epoxy composites

Abstract

Calcination of smectite clays such as bentonite is tricky due to their 2:1 aluminosilicate structure. Low calcination temperature has minimal effect on the dehydroxylation, specific surface area (SSA), and crystalline nature of bentonite clays whereas high calcination temperature leads to removal of structural water (dehydroxylation) and amorphous nature but significant agglomeration of clay particles. The synergy between the dehydroxylation and amorphization of calcined bentonite clays in improving the thermal, mechanical, and wear properties of basalt epoxy composites was investigated. The process of dehydroxylation/amorphization of bentonite clay was characterized by XRD, FTIR, and BET. The performance of basalt epoxy composites with as received bentonite (ARB) clay were compared with calcined bentonites. The composites with calcined bentonite at 800 °C showed improved microstructure in HR-FESEM due to the synergy between dehydroxylation and amorphization of bentonite clays which further improves the thermal stability and mechanical performance of basalt epoxy composites.

Keywords

• Bentonite clay
• Dehydroxylation
• Specific surface area
• Basalt epoxy composite