Renewable resources

Popcorn is the classic cinema snack, but the crispy crunchy delight offers more than just an added pleasure to watching a movie on the big screen. The popcorn kernel is an ideal natural resource for eco-friendly composite materials that can be used to produce not only insulation, flakeboard, and packaging but also furniture and children’s toys. For these products, the manufacturing industry typically uses polystyrene materials like Styrofoam, whose production, use, and disposal pollutes the environment.

 

The idea of using innovative materials from re- newable resources to replace polystyrene orig- inates with Prof. Dr. Alireza Kharazipour, who is member of the Faculty of Forest Sciences and Forest Ecology at the University of Göttingen. His research in the technical bio-center concentrates on chemistry and the process technology of composite materials. A night out at the cinema with his wife in Göttingen inspired him to produce feather-light granulate from crushed corn. “In the dark, popcorn felt as light as Styrofoam balls”, recalls Prof. Dr. Kharazipour. “The next day I made popcorn at home.”

 

 

Soon his house began to reek of popcorn, so he had to move his experiments to the university’s lab. He mixed popcorn with wood chips to produce a flakeboard which has the same material stability but is up to 40 percent lighter. The Pfleiderer company in Gütersloh licensed his patent in 2011. By using his award-winning Balance Board, they manufacture kitchen furniture and equip AIDA cruise ships.

 

Meanwhile, Prof. Dr. Kharazipour’s team at the Büsgen Institute has developed about 40 products composed of 100-percent crushed corn which use protein as a binder. “These products are lightweight because popcorn granulate resembles cells filled with air”, explains the professor. “If grain maize expands to popcorn, the volume grows by 15 to 20 percent.”

 

While 19-mm-thick flakeboard weighs 650 to 700 kg/ m3, popcorn board weighs in at an ultralight weight of 70 to 200 kg/m3 “It costs less than plastics-based materials but it’s just as solid and it can easily be cut by a circular saw.” The material may be reused and it may even be home-composted.

 

 

Because of the fire-resistant properties of popcorn-based material, various plastics manufacturers have submitted applications to license the patent for flakeboard. In contrast to Styrofoam-based insulation materials which burn fiercely at temperatures between 600 to 900 degrees in a combustion chamber, pop- corn board is merely singed. “Since popcorn consists of starch, the polysaccharide surface caramelizes and turns hard as stone.”

 

Moreover, with lambda figures below 0.040, popcorn insulation boaffers less thermal transmittance than Styrofoam, and thanks to its acoustic absorption properties, it’s the perfect sound insulation for cinemas, studios, and theaters. Popcorn leftovers, which usually end up as organic waste, can be processed into insulation board – in the best sense of the circular economy. “The possibilities are multifaceted, and they haven’t by any means all been exploited to their full potential”, concludes Prof. Dr. Kharazipour.

 

Photos: © Prof. Dr. Alireza Kharazipour

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