Adhesives for Field Repair of Graphite/Epoxy Composite Structures.
Abstract
Adhesive formulations were developed for the repair of damaged graphite/epoxy structures on board ship. These adhesives are formulated as two-part paste adhesives which can be cured at contact pressure at temperatures as high as 149C (300F). The adhesives were formulated from epoxy resins toughened by prereaction with carboxyl terminated butadiene acrylonitrile rubbers. Amine curing agents wre used. An adhesive formulated from the reaction product of Epon 828 epoxy resin (Shell Chemical Co.) and CTBN 1300X8 (B. F. Goodrich) using PACM-20 amine curing agent (Du Pont) had lap shear strengths at -55C (-67F) and room temperature of approximately 5000 psi. At 115C (220F) the lap shear strength was approximately 2800 psi. These values are competitive with the highest quality film adhesives. The environmental durability was impressive. Lap shear specimens after exposure to 140F, 95% RH under a constant tensile stress of 1000 psi for 21 days and for 60 days under a stress of 500 psi showed only a 2 percent and an 11 percent reduction, respectively, in ultimate tensile shear strength compared to unexposed control specimens when tested to failure at 115C (220F). (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1981
- Accession Number
- ADA107870
Entities
People
- David J. Crabtree