Using remendable polymers for aerospace composite structures

Abstract

The work described in this research focuses on the development of a single-component remendable polymer suitable for integration into aerospace composite structures. The structural polymer can be used as a replacement matrix material in fiber-reinforced composites and allows for in-situ site-specific healing of delamination and matrix cracking when combined with a small volume fraction of heat-assisting materials such as magnetic particles. Whereas previous studies focused on the optimal volume fraction and composition of magnetic particles, and the healing of cracks in carbon-fiber composite coupons, current studies focus on the barriers to adopt this material in a aircraft manufacturing environment. These barriers include the (1) the extensive labor involved in producing a limited quantity of Mendomer (1-3 grams), (2) the evolution and entrapment of voids for all but exquisitely controlled environments, and (3) the low melting temperature (ca. 125°C) of the material when compared against high-temperature matrix systems. Proprietary steps have been formulated to increase raw material yield, reduce viscosity, and increase the glass transition temperature. Interests have also been motivated by reducing costs and adhering to conventional composite fabrication techniques. Research has also involved the investigation of automated damage detection to locate the site of damage for further healing, followed by automated healing since the ultimate goal of this research is to develop an autonomously healing composite system. However, a remendable composite is in itself valuable where its successful incorporation will reduce the need for part replacement and maintenance as well as increase the longevity and reliability of the structure.