Researchers create single-use plastic replacement from sugar alcohol and wood powder
14 Apr 2023 --- US researchers have created a sturdy, lightweight material from sugar and wood-derived powders to replace single-use plastics. The material breaks down naturally in water.
The scientists used a rigid material designed from isomalt, a sugar alcohol, rather than polymers that are known to be brittle. They then investigated how to enhance the structure’s sturdiness for new applications.
“These sugar-based materials can be injection molded and manufactured just as easily as plastics, and this ease of manufacturing is one of the prime reasons that plastics are used so widely in short-term-use applications,” Scott Phillips, professor in the Micron School of Materials Science and Engineering at Boise State University, US, tells PackagingInsights.
“With additional research and development, it might be possible to consider using mass-produced sugar-based formulations for certain packaging instead of plastic.”
The findings were published in ACS Sustainable Chemistry & Engineering.
New research could use sugar to make single-use materials. Turning sugar into packaging
The researchers heated isomalt to a liquid-like state and mixed in either cellulose, cellulose and sawdust, or wood flour to produce three different materials. The materials were extruded into small pellets and molded into various objects, including balls, a dodecahedron, a chess piece and flower-shaped saucers using commercial plastics manufacturing equipment.
Phillips says that one of the research goals was to explore whether small molecules would bind with additives to create useful materials, much like polymers bind together with additives to form plastics.
All the tested additives doubled the strength of isomalt, creating materials that were harder than plastics, including PET and polyvinyl chloride, while still being lightweight.
“Select sugars are particularly effective binders and the combination of sugar binders plus additives can be used to tune the mechanical properties of the resulting materials in a way that is quite analogous to plastics,” says Phillips.
“Our first demonstration of this sugar-plus-additives combination makes rigid objects with density values similar to plastics. These rigid objects won’t be useful for flexible packaging at the moment, but we’re now working on other formulations that may provide flexibility that is more common in packaging.”
Rigid applications
Researchers are exploring plastic replacements for the packaging industry.
While the packaging applications are still in the beginning phases of research, Phillips explains that the material can be applied for more decorative purposes.
“The current formulations might be useful for packaging in which you want a rigid, decorative box, for example, or where the packaging might take the form of rigid, decorative beads or fake rocks.”
The researchers are currently focusing on rigid single-use and short-term-use objects.
“We think a lot about the temporary decorations used at large parties and events and the disposable party favors that guests use. Many of these items are made out of plastic and then discarded, but the sugar-based formulations might offer useful substitutes with substantial improvements in recyclability compared with plastics,” explains Phillips.
The researchers say that the material could be used for food service items and then crushed and sprayed with water to fall apart. But even if such items were tossed into the trash or somehow got into the environment, the slightest crack in the coating would start their collapse into sugars and plant-based additives, which the researchers say might be good for the soil.
Scalability for the future
Phillips compares the research to the process of making candy. He explains that sugar in baking can generate many different outcomes and textures – such as cotton candy versus hard candies.
“We’re combining these ideas from candy-making with concepts in materials science & engineering to create new materials. We sense that there’s a lot of room for further development and exploration to access sugar-based materials with a wide range of properties.”
He says while the material is not ready yet to replace all single-use plastics, the researchers will continue to explore the possibilities of the material.
“Having said that, scaling the approach seems feasible, especially since we purposely designed the preparation and fabrication protocols to mimic protocols used in the plastics industry.”
“Similarly, we chose inexpensive and readily available reagents, so massive quantities of starting materials can be purchased easily. We’re not conducting chemical reactions to make the materials — thus, we’re not generating chemical waste.”
By Sabine Waldeck
