Autonomous Solid Phase Microextraction for Explosives Detection and Identification

Military aircraft require corrosion inhibiting sealants around fasteners gaps to prevent fuel leaks, water ingress, and corrosion. Conventional selants must be wet-applied during assembly, which results in excessive labor costs and downtime. Limitationsof conventional polyether and polysulfide-based sealants include: the slowness of cure below room temperature, contraction during cure, and cumbersome application methods. A novel fastener sealant based on an expandable matrix resin with microencapsulatedcuring agents and chrome-free anticorrosive agents is proposed for this application. The sealant is designed to be pre-applied to metallic fasteners, form a thin, dry outer film surface and remain shelf-stable. Upon insertion into a hole, the shearingforces reflow the sealant and activate the base resin curing. The curing process will be accompanied by a controlled level of material expansion for effective sealing. The proposed sealant system should effectively protect aircraft structures from waterintrusion and associated corrosion processes. Pre-applied fastener sealants will be formulated with microencapsulated curing agents, low toxicity corrosion inhibitors and rheological additives and tested for adhesion to aluminum and composites, fuel andwater barrier properties, resistance to thermal and chemical degradation, and corrosion inhibiting properties. The physical performance will be compared to commercial sealants meeting MIL-S-81733.A pre-applied,chrome-free, expandable sealant havingexcellent corrosion inhibiting properties would provide the DoD with a cost-effective process for maintaining military aircraft. Potential commercial applications would include the manufacture and repair of civilian aircraft, automotive and marineproducts.