Core-Shell Rubber Nanoparticle-Modified CFRP/Steel Ambient-Cured Adhesive Joints: Curing Kinetics and Mechanical Behavior

• Published in: Materials Vol. 17; no. 3; p. 749
• Main Authors: Okeola, Abass Abayomi, Hernandez-Limon, Jorge E, Tatar, Jovan
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 04-02-2024
• Subjects: Adhesive bonding; Adhesive joints; Bond strength; Bonded joints; Bonding strength; Bridges; Carbon fiber reinforced concretes; Carbon fiber reinforced plastics; Chemical bonds; Concrete; Concrete structures; Contact angle; Coupling agents; Curing; Energy; Epoxy adhesives; Epoxy resins; Fiber reinforced polymers; Glass transition temperature; Kinetics; Laminated materials; Mechanical properties; Moisture absorption; Nanoparticles; Polymer blends; Polymers; Reinforcing steels; Rubber; Shear strength; Shear tests; Substrates; Temperature; Tensile strength; Viscosity; Russia; repair; steel; strengthening; nanoparticles; silane; curing kinetics; adhesive; bridges; CFRP; core–shell rubber
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma17030749

Externally bonded wet-layup carbon fiber-reinforced polymer (CFRP) strengthening systems are extensively used in concrete structures but have not found widespread use in deficient steel structures. To address the challenges of the adhesive bonding of wet-layup CFRP to steel substrates, this study investigated the effect of core-shell rubber (CSR) nanoparticles on the curing kinetics, glass transition temperature (Tg) and mechanical properties of ambient-cured epoxy/CSR blends. The effects of silane coupling agent and CSR on the adhesive bond properties of CFRP/steel joints were also investigated. The results indicate that CSR nanoparticles have a mild catalytic effect on the curing kinetics of epoxy under ambient conditions. The effect of CSR on the Tg of epoxy was negligible. Epoxy adhesives modified with 5 to 20%wt. of CSR nanoparticles were characterized with improved ductility over brittle neat epoxy; however, the addition of CSR nanoparticles reduced tensile strength and modulus of the adhesives. An up to 250% increase in the single-lap shear strength of CFRP/steel joints was accomplished in CSR-modified joints over neat epoxy adhesive joints.