Monitoring real‐time curing of epoxies in situ using single‐sided NMR. Issue 4 (21st January 2020)

• Record Type: Journal Article
• Authors: Kelley, Mackenzie; Abdol, Nastaran; Soroushian, Parviz; Keating, Kristina; Balachandra, Anagi M.; Meldrum, Tyler
• Is Part Of: Journal of polymer science. Volume 58:Issue 4(2020)
• Page Start: 616
• Page End: 623
• Publication Date: 2020-01-21
• Subjects: epoxy curing -- interfaces -- NMR relaxometry -- nondestructive -- single‐sided NMR; Polymers -- Periodicals; Polymerization -- Periodicals; Polymerization; Polymers; Periodicals; 547.7
• DOI: 10.1002/pol.20190117
• Languages: English
• ISSNs: 2642-4150

Abstract

Abstract: Adhesively bonded joints using epoxy are widely used in aircraft and aerospace structures. Quality control and defect detection during epoxy curing in such applications is critical. We used single‐sided nuclear magnetic resonance (NMR) to nondestructively probe and spatially resolve the change in the characteristic NMR relaxation time ( T 2 ) of epoxies during curing on a substrate. Time‐dependent T 2 values were fit to a Weibull function to model temporal changes in the NMR measurables. Our results demonstrate that the reduction in molecular mobility of various epoxy/curing agent mixtures occurs more rapidly at the interface than in the bulk. Further use of single‐sided NMR to acquire spatially resolved T 2 data will provide a route for elucidatory epoxy curing studies. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 616–623 Abstract : A nondestructive approach for monitoring real‐time curing of polymers on inorganic substrates using single‐sided nuclear magnetic resonance (NMR) is presented. Single‐side NMR measurements are used to nondestructively probe and spatially resolve changes in the NMR relaxation time, which reflects the physical properties as crosslink density, of epoxy as it cures. This approach can be widely applied in testing polymer–substrate interfaces, such as in the manufacturing of aerospace and defense technologies.