Glass fiber and other reinforced composite fiber materials are light and strong, and are widely used in aviation, automobile, navigation, urban construction and sports equipment. However, because they are layered structures, interlayer separation may occur, and once internal damage occurs, it is difficult to detect and cannot be repaired by traditional methods. This is one of the important reasons that limit the wider application of composite materials.
According to the report of Physicist Organization Network on April 15, the research group of Independent Material System (AMS) of Beckman Institute of University of Illinois at Urbana-Champaign developed a new self-healing system, just like the vascular network in biological tissues, which is filled with chemical healing fluid, which can help strengthen fiber materials and realize repeated automatic healing. This self-repairing system has great potential in solving long-term risk problems, prolonging material life and improving reliability. Related papers were published in the recently published Advanced Materials magazine.
The self-healing system is a three-dimensional vascular network. Researchers use environmentally friendly polymers as "threads" to "sew" reinforced fiber materials to sew three-dimensional patterns with special textures, just like the vascular system in biological tissues. This sewing thread is temporary. After processing, it is heated and evaporated, leaving only a hollow vascular network. The blood vessel consists of two groups of isolated vascular systems, which are filled with different healing agents, one is epoxy resin and the other is sclerosing agent.
"When a fracture occurs, the originally isolated microchannel system ruptures, and the healing agent inside flows out into the fibrous material, just like a blood vessel ruptures. These two healing agents contact each other at the fracture site, forming a high polymer, just like a structural adhesive, connecting the damaged areas together. We have conducted many cycle tests, and basically all fractures can be successfully healed at 100%. " Jason patric, the first author of the paper, said, "The advantage of this self-repair method is that we don't have to detect the material structure, find out where there is damage, and repair it manually."
"This is the first time to prove the automatic healing of repeated cycles in reinforced composite fibers," said Scott Whyte, a professor of aviation engineering and one of the authors of the paper. "In the past, automatic healing has been demonstrated in polymer materials, but it is a different technology and cannot be used for reinforced fiber composites. The vascular technology we developed makes up for the missing link. "