North Carolina State University Researchers Create Longer Lasting, Self-Healing Composites

North Carolina State University researchers have created a self-healing composite that is tougher than materials currently used in aircraft wings, turbine blades and other applications – and can repair itself more than 1,000 times. The researchers estimate their self-healing strategy can extend the lifetime of conventional fiber-reinforced composite materials by centuries compared to the current decades-long design-life. At issue are fiber-reinforced polymer (FRP) composites, which are valued for their high strength-to-weight ratio and are commonly used in aircraft, automobiles, wind-turbines, spacecraft and other modern structural applications. FRP composites consist of layers of fibers, such as glass or carbon fiber, that are bonded together by a polymer matrix, often epoxy. The self-healing technique developed by the NC State researchers targets interlaminar delamination, which occurs when cracks within the composite form and cause the fiber layers to separate from the matrix. The self-healing material resembles conventional FRP composites, but with two additional features. First, the researchers 3D-print a thermoplastic healing agent onto the fiber reinforcement, creating a polymer-patterned interlayer that makes the laminate two to four times more resistant to delamination. Second, the researchers embed thin, carbon-based heater layers into the material that warm up when an electrical current is applied. The heat melts the healing agent, which then flows into cracks and microfractures and re-bonds delaminated interfaces – restoring structural performance. In real-world scenarios, healing would only be triggered after the material is damaged by hail, bird strikes or other events, or during scheduled maintenance. The researchers estimate the material could last 125 years with quarterly healing or 500 years with annual healing. The study also shed light on why recovery slowly declines over time. With continued cycling, the brittle reinforcing fibers progressively fracture – creating micro-debris that limits rebonding sites. In addition, chemical reactions where the healing agent interfaces with the fibers and polymer matrix decline over time. Even so, modeling suggests the self-healing will remain viable over extremely long time scales. Jason Patrick, corresponding author of the paper and an associate professor of civil, construction and environmental engineering at North Carolina State University, has patented and licensed the technology through his startup company, Structeryx Inc. To identify growth opportunities in Composites Market: Trends, Opportunities and Competitive Analysis [2025-2031], please visit https://www.lucintel.com/composites-market.aspx