SBIR-STTR Award

Fastening and joining technology has lagged behind the progress that has been made in other areas of composites for advanced air vehicles. Aerotech proposes the development of reversible polymeric adhesive bonding of composites using variable frequency microwave energy. With this method, composites are bonded using Poly Ether Ether Ketone (a high temperature thermoplastic) which is cured using variable frequency microwave energy applied at the bond line. When required, the polymeric adhesive can be reheated, causing the bond to disintegrate. Thus reversible bonding can be achieved. During Phase I, Aerotech and its partners, the DOE's Oak Ridge National Lab and Northrop Grumman, will demonstrate the technical feasibility of this process by bonding test specimens and subjecting them to a lap shear test and C-scans. During Phase II, volume production processes will be investigated. During Phase I, a theoretical study will be undertaken to examine the feasibility of a portable variable frequency applicator

Keywords:
curing microwave reversible applicator composites thermoplastic manufacturing variable frequency

This project is aimed at developing reversible bonding techniques for composite structures using thermoplastic adhesives and microwave energy. This allows manufacturers and maintenance personnel to bond, disbond and rebond composite components, leading to major advantages in the fabrication of integrated and unitized structures. During Phase I, over 200 glass/epoxy substrates were bonded, disbonded and rebonded, proving the feasibility of this technology. During Phase II, the technology will be extended to carbon substrates, and special formulations of thermoplastic adhesives for low (150 F) and high (250 F) end-use temperatures will be developed. Microwave amplifier-based applicator equipment will be developed to deposit MW energy into composite substrates in manufacturing and maintenance environments. A strong team has been assembled for this project: technical and business aspects of the technology will be the responsibility of Aerotech. The DoE's Oak Ridge National Lab and the University of Tennessee will assist in technology development. A major military/civilian aerospace industrial partner and a major automotive manufacturing partner will assist in "beta-testing" of the technology at their sites during Phase II for specific applications that have been identified.

Keywords:
reversible affordable thermoplastics microwave unitized bonding composites structures