Researchers publishing in ACS Sustainable Chemistry & Engineering developed a cushioning foam from cardboard waste.

Paper is one of the most common types of household waste. However, while paper is relatively easy to recycle, packaging materials like polystyrene are not.

Though it was already possible to make a foam from paper waste, these methods required several chemical pretreatment steps. The researchers now found a simpler way to make paper foam. They broke down cardboard scraps in a blender to create a pulp, then mixed it with either gelatin or polyvinyl acetate (PVA) glue. The mixtures were poured into moulds, refrigerated, then freeze-dried to form cushioning foams. Both paper-based foams served as good thermal insulators and strong energy absorbers, even better than some plastic foams.

The team then created a heavy-duty version of their wastepaper foam by combining the pulp, gelatin, PVA glue, and a silica-based fluid that hardens as force is applied. This version of the cardboard-based foam even withstood hits from a hammer without falling apart. Therefore, the foam could possibly be used in force-intensive deliveries, such as parachute-free airdrops.

Photo: Jinsheng Gou