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Bioplastics from Waste

Bioplastics from Waste Streams Fish scales to goggles Before you can enjoy a nice fish meal in a good restaurant the fish has to be scaled. But what happens to the tonnes of fish scales that end up as a byproduct each year? Whilst doing his masters at the Royal College of Arts (RCA, London, UK), design student Erik de Laurens got interested in finding local and sustainable ways of producing plastic-like materials. During his research he was inspired by a company that produces leather from fish skins, left over from the food industry. He realized some things are completely disregarded and yet have an enormous potential for production. Looking into history Erik was fascinated to learn that the tanning of fish skin was a process known for centuries. If fish skins could become leather, surely fish scales - the only byproduct of leather tanning- could become something too. Knowing that fish-scales in their composition were somewhere between horn and bone, both materials resembling plastics, Erik dived into old manufacturing books from the 19th century and adapted a technique of processing horn through heat and pressure. It turned out to work incredibly. During the process the fish scales release collagen which bonds the fish scales together. The material has the visual qualities of stone and the touch of Bakelite. It is moldable, biodegradable and recyclable. In order to test the material Erik designed 3 pairs of goggles and glasses inspired by swimming goggles and a table with an inlay of a fish. Currently Erik is looking for funding to push the development of this material further. (Photos courtesy Erik de Laurens) 30 bioplastics MAGAZINE [04/12] Vol. 7

Bioplastics from Waste Streams Bioplastics from chicken feathers In a scientific advance literally plucked from the waste heap, scientists described a key step toward using the billions of pounds of waste chicken feathers produced each year to make a new biobased thermoplastic. “Others have tried to develop thermoplastics from feathers,” said Yiqi Yang, Ph.D., who is an authority on biomaterials and biofibers in the Institute of Agriculture & Natural Resources at the University of Nebraska-Lincoln (USA). “But none of them perform well when wet. Using this technique, we believe we‘re the first to demonstrate that we can make chicken-feather-based thermoplastics stable in water while still maintaining strong mechanical properties.” One major goal to find alternatives for petroleum based plastics is to use agricultural waste and other renewable resources to make bioplastics. Starch, cellulose and proteins are derived from renewable resources and are biodegradable but are not readily processable thermoplastics. Chemical modifications mainly esterification, etherification and grafting of synthetic polymers such as methyl, ethyl and butyl acrylates and methacrylates are done to make these biopolymers thermoplastic. Two major limitations of bioplastics are low elongation and poor stability in water. Poultry feathers are inevitably generated and are available in large quantities at very low cost. Yang explained that feathers are made mainly of keratin, a tough protein also found in hair, hoofs, horns, and wool that can lend strength and durability to plastics. However, feathers are non-thermoplastic and chemical modifications are necessary to make feathers thermoplastic. Researchers in the Department of Textiles, Merchandising and Fashion Design, College of Education and Human Sciences at the University of Nebraska-Lincoln have chemically modified feathers to make them thermoplastic. Feathers were acetylated, etherified or grafted with vinyl monomers to develop thermoplastic products. After chemical modifications, the feathers were thermoplastic and could be compression molded into transparent films. The films obtained had high elongation and good stability in water. Among the different chemical methods studied, grafting provided a better opportunity to control the elongation and stability of the films. Grafting retains the main structure of the feather keratin and attaches thermoplastic polymers to the keratin backbone as side chains. This allows the feather films to be flexible and biodegradable. Chemically modified feathers would be suitable to develop inexpensive biobased and biodegradable products through extrusion, compression and injection molding. Potential products of what Yang‘s group terms ‘featherg-poly(methyl acrylate)’ plastic include films, packaging materials, fibers, resins for composites and other molded parts. The researchers have demonstrated the possibility of developing biothermoplastic products from feathers and are ready to commercialize the technology which would take 2-3 years from the time commercialization is pursued. (photo: bioplastics MAGAZINE [04/12] Vol. 7 31

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