They may also consider dental composites. Regardless of the final choice, the polymer must harden quickly and bond well with the CFRP tube. “We are in the process of investigating which one would fuse better with the carbon fiber to make the two materials work together as one,” says Saadatmanesh.
While the project was initially aimed at repair of large bones, such as leg femurs, other potential applications have emerged, including stabilization of hard-to-set ribs and collarbones. “[For these bones] there is no other option,” says Saadatmanesh. “They are just left to heal by themselves, and it takes a long time and is very painful.” Researchers are also considering preventative reinforcement of bones weakened by osteoporosis and veterinary uses, including fracture repair for horses and other large animals that must bear weight as they heal.
The proposed technique is so promising that UA Venture Capital (UAVC), an investment firm that helps finance faculty-led innovations from the University of Arizona, has invested millions of dollars in MediCarbone, the company Saadatmanesh founded to accelerate commercialization. “We look for unique, world-changing technology, and clearly MediCarbone fits that description,” says Fletcher J. McCusker, UAVC founder and CEO. “The opportunity to repair bone intracorpus with minimum invasion could drastically change how broken bones are treated.”
Creating a New Class of Prepregs
Project: Semi-pregs with through-thickness permeability
School: University of Southern California
Location: Los Angeles
Principal Investigator: Steven Nutt and Mark Anders (co-investigator)
Through the years, researchers at the M.C. Gill Composites Center at the University of Southern California (USC)
have studied ways to make composites manufacturing more cost effective and efficient. “Although autoclaves impart robustness to prepreg processing, their high cost creates a bottleneck in production capacities,” says Mark Anders, a postdoctoral fellow at USC. “Therefore, manufacturers have looked to alternative, out-of-autoclave options, such as vacuum-bag-only (VBO) oven cure.”
One of the concerns with VBO processing is that it lacks the high pressures of autoclaves to suppress defects, so removal of entrapped air is critical to production of high-quality laminates. “Any time you lay up prepreg plies on top of each other, inevitably there will be air in and between them,” says Anders. “So the question then is how can you reliably get the air back out?”
Partial impregnation enhances air evacuation, but the concept hasn’t yet been fully optimized, says Anders. Partial impregnation is typically achieved by laminating resin films onto either side of a fiber reinforcement without fully saturating through the thickness, leaving dry evacuation channels at the ply center. These VBO prepregs utilize in-plane evacuation, or “edge breathing,” but the time required to evacuate air scales to the breathe-out distance squared. “For larger parts, debulking becomes impractically long,” says Anders.