Adjust the frontal polymerization to achieve a variety of material properties

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Video: shows the rapid polymerization using monomers 1,5-cyclooctadiene and dicyclopentadiene. see more
Researchers at the University of Illinois at Urbana-Champaign have improved the frontal polymerization technology, in which a small amount of heat triggers a moving reaction wave to create a polymer material. The new method can better control its thermal and mechanical properties, thus allowing a wider range of materials.
The paper “Rapid Synthesis of Elastomers and Thermoset Materials with Adjustable Thermomechanical Properties” was published on ACS Macro Letters and was selected as the paper by the ACS editor.
Nancy Sottos, Maybelle Leland Swanlund chair and head of the Department of Materials Science and Engineering, said: “Most of the previous research has been on harder materials. This is the first time that frontal lobe polymerization has been used for synthetic rubber materials.” Beckman Senior The leader of the Autonomous Material System Group of the Institute of Science and Technology. “This new technology allows us to have more control and give the material good engineering properties in terms of strength and stiffness.”
The researchers used a mixture of two monomers, namely 1,5-cyclooctadiene and dicyclopentadiene, to make materials suitable for various applications.
Leon Dean, a graduate student of the Sottos Group under AMS, said: “These materials are chemically similar to those used in tires.” “Traditionally, the synthesis of rubber requires organic solvents, multiple steps and a lot of energy, which is not good for the environment. Ours Solvent-free manufacturing methods can speed up the production process and reduce energy consumption.”
Using this technology, researchers can create materials with a shape memory polymer feel. When the pre-deformed polymer is heated above its glass transition temperature, the shape memory effect occurs, which is the point at which the polymer changes from a hard glass-like material to a soft rubber-like material. The sequential change of the shape is caused by the difference in the glass transition temperature between the layers.
Qiong Qiong, a postdoctoral researcher at the Moore Group, said: “We made a hand-shaped layered material, in which the content of two monomers in each layer is different, so the glass transition temperature is also different.” “When you heat the polymer When it reaches the highest glass transition temperature and then cools down, it will form a fist. When the temperature is raised again, the fingers of the fist will open in turn.”
Researchers hope to further develop the technology by improving the control of polymer properties. Wu said: “Although we have demonstrated the tunability of multiple performances, it is still a challenge to adjust each performance separately.”
Dean said: “Expanding this technology will also be a challenge.” “Most of our work is done on a laboratory scale. However, in large-scale production, there is competition between bulk polymerization and frontal polymerization. ”
“This research fully demonstrates the strength of the Beckman Institute,” said Jeff Moore, the director of the Beckman Institute and the distinguished chairman of Ikenberry. “It brings together two groups that have different views on the issue but have common goals.”
Omar Alshangiti, an undergraduate student of Moore Group, also prepared most of the samples and measured all the parameters of the front-side polymerization process by studying suitable monomer combinations, making an important contribution to this research.
This research was supported by the AFOSR Center for Excellence in Self-Repair, Regeneration, and Restructuring; the US Department of Energy Office of Basic Energy Science, Materials Science and Engineering Branch Award; and the National Science Foundation Graduate Research Fellowship.
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Post time: Mar-01-2021