Improved Performance in Multilayer Paper Composites Through the Incorporation of Inorganic Nanomaterials into Sodium...

Multilayer paper composites have been widely applied in industrial sectors and as sustainable concrete formwork in civil construction. These materials are produced by pressing paper layers bonded with a sodium silicate adhesive; however, their structural performance is often limited by the adhesive's low mechanical strength. Therefore, in this study, the effects of incorporating 0.5 wt.% nanoclay (NA), nanosilica (NS), and kaolin into sodium silicate on the physical, mechanical, and microstructural properties of the composites were evaluated. The composites were fabricated with 20 layers of recycled kraft paper and a final mass of 65 g/m² of reinforced sodium silicate applied by a glue line. The adhesive was applied using a paper coating machine, followed by pressing at 4.30 MPa. The results showed that the presence of nanomaterials had no measurable effect on the apparent density of the composites; nevertheless, the inclusion of 0.5% NA promoted a 25% increase in toughness. Thus, the use of nanomaterials is efficient at obtaining better-quality composites for numerous technological applications.