Thanks to the popularity of online shopping, an increasing number of goods are being shipped to buyers in cardboard boxes filled with eco-unfriendly EPS (expanded polystyrene) foam. Soon, however, such boxes could be upcycled into a greener alternative to EPS.
Not only is polystyrene derived from petroleum (the extraction and refinement of which is harmful to the environment), the foam made from it is very difficult to recycle, it's non-biodegradable, and it takes up a disproportionately large amount of space in landfills.
Seeking a more Earth-friendly alternative, Assoc. Prof. Jinsheng Gou and colleagues at Beijing Forestry University looked to cardboard waste. That waste could even include the very boxes in which EPS-packed products are shipped.
The scientists used a blender to break cardboard scraps down into a cellulose-fiber pulp, which was then mixed with either glycerol gelatin or polyvinyl acetate (PVA) glue. These mixtures were subsequently poured into moulds, refrigerated, and finally freeze-dried to form biodegradable cushioning foams.
Those foams proved to have good thermal insulating qualities, plus they absorbed impact energy even better than some petroleum-based foams.
Next, the researchers combined the pulp, gelatin and PVA glue with a silica-based shear-thickening fluid that hardens when subjected to force. The resulting heavy-duty foam was able to withstand being struck by a hammer without falling apart, raising hopes that it might someday find use in applications such as parachute-free cargo drops from aircraft.
A paper on the study was recently published in the journal ACS Sustainable Chemistry & Engineering.
Source: American Chemical Society
