Paper mill waste recycled into foam
In a world increasingly concerned with waste, the smart manufacturers are identifying ways of utilizing the by-products of manufacturing and creating two products from one process. One example - a graduate student in agriculture at the Hebrew University of Jerusalem has developed a way of creating foam from the waste from paper mills, radically reducing waste from paper production and creating two products that are highly valuable and in demand.
In paper production, wood is chipped and mashed (mechanical pulping) or stewed in chemicals (chemical pulping) to separate the fibers in a water-intensive process. The fiber slush is then sprayed onto a continuously-moving mesh, the dimensions of which dictate the retention of fibers. While larger fibers are squeezed into paper, almost 50 percent of the finer fibers and water fall away to form a waste by-product that up till now has been wasted in millions of tons annually.
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Ph.D. student Shaul Lapidot and his laboratory colleagues at the Robert H. Smith Faculty of Agriculture, Food and Environment of the Hebrew University in Rehovot found that the waste finer fibers are a perfect feed-stock for nano-crystalline cellulose (NCC). This can be formed using relatively low energy and chemical input compared to paper-making itself. Furthermore, they developed a technique to process the NCC into composite foams.
These bio-foams in their virgin state are lightweight and highly porous, but with the addition of furan resin (a hemicellulose-based resin from raw crop waste from sugar cane, oat and rice hulls, and corn cobs), the foam is strengthened into something that rivals high-end synthetic foams currently on the market.
Foam is an under-appreciated product, valued for its high strength, weight reduction, energy dissipation and insulation. Commonly thought of as a packaging product, it in fact plays an inconspicuous role as a sandwich product in a host of everyday items such as furniture, cars, and insulation. It is conventionally manufactured using oil-based polymers such as polyurethane, polystyrene, polyvinyl chloride (PVC) and polyethylene terephthalate (PET). The discovery and development of a new industrial foam from renewable resources represents an exciting opportunity.
Lapidot's research led to his being awarded of one of the Barenholz Prizes at the Hebrew University Board of Governors meeting. The technology has already been licensed by Melodea Ltd from Yissum, the technology transfer company of the Hebrew University. The bio-foam joins mushroom styrofoam, biodegradable milk and clay foam, and environmentally-friendly surfboard TufFoam on the wave of new foam alternatives.