To maintain and evaluate the performance efficiency of nanotechnologies, stringent quality control methods are required. Here, we discuss the use of non-destructive testing (NDT) as an inspection tool for polymer nanocomposites.
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Well-established regulations have been used worldwide to certify the mechanical characteristics of advanced materials like polymer nanocomposites across different industries. To establish a relationship between production variables and material qualities, many inspection methods are used, investigating properties like stress, compression, bending, contact, and dynamic behavior.
Although destructive testing procedures are capable of assessing many substantial characteristics of a material, restrictions can limit the reliability of inspection data. In engineering domains involving electromagnetic and optics devices, determining the stability of nanomaterials like polymer nanocomposites is critical.
To overcome the issues associated with destructive testing, NDT is often employed to accurately evaluate characteristics on the nanoscale while also preserving the material sample.
Why Use NDT To Analyze Polymer Nanocomposites?
During the manufacturing of polymer nanocomposite structures, defects and impurities are sometimes unavoidable. As a result, non-destructive testing is essential for preventing failures and increasing the dependability of such nanomaterials during manufacturing and in-service evaluation.
Since this type of testing does not affect the polymer nanocomposite, each property can be examined. Limited testing, which evaluates just a fraction of the components, is unnecessary.
NDT methods may be used at many phases of product development and manufacturing, enabling producers to detect defects and replace faulty components before and after the product is deployed.
Another feature that makes non-destructive testing so effective for diverse applications is the accuracy of the inspection data, often attributed to the NDT's accessible and complimentary testing options. Subjecting the evaluated goods to a range of tests might eliminate the danger of inaccuracies or errors.
Non-Destructive Testing Techniques for Polymer Nanocomposites
For adhesively bonded nanocomposites, various NDT methods such as eddy current testing, fluid flow, ultrasonic testing (UT), vibration analysis, and dielectric constants are applied. The following are some of these techniques and their applications:
Polymer Nanocomposite for Structural Applications and Electromagnetic Techniques
The characteristics of carbon nanotubes have been used as a reinforcement in polymer nanocomposite systems to produce ultra-light engineering materials with improved mechanical and dielectric properties.
The industry has identified many prospective uses, such as electrically charged diffusive materials, nanosensors, and aerospace materials.
The electromagnetic characteristics of nanocomposite materials have been studied using eddy current-based and thermographic methods.
Ultrasound NDT to Monitor Nanocomposite Curing
Composite materials with thermosetting fiber (glass or carbon) reinforcement are common. Here, the fabric is soaked with adhesive or mixed polyester.
RTM and prepreg technologies are often paired with steam curing. Curing and glass transition temperatures determine the objects' ultimate attributes.
Realtime cure monitoring in manufacturing is performed using analytical methods and ultrasound. Ultrasonic cure monitoring in polymer nanocomposite is common for electronic equipment.
Optically and Non-Optically Excited Thermography
Aviation, sustainable sources, architectural, environmental engineering, and other sectors progressively use polymer nanocomposites with high adhesive bonding strength.
Pulsed thermal imaging, cyclic phase tomography, and lock-in fluoroscopy are examples of infrared thermography methods that have proven to have a lot of promise and benefits for testing and evaluating polymer nanocomposites.
Other sources of thermography, including beam, eddy current, radiofrequency, and ultrasound stimulated thermography, are attracting more interest for nanocomposites testing than traditional optical thermography.
Limitations of NDT
While beneficial, non-destructive testing does possess some limitations as an inspection tool. For example, the precision of the investigation can sometimes be influenced by a material's finish. Furthermore, some non-destructive testing methods are only suitable for relatively non-porous surfaces, and because polymer nanocomposites are porous, inspection data is limited.
Another issue with NDT methods is that many require an electrical power source, which restricts their use in remote, on-site locations.
Modifications in magnetic flux density can also have an impact on NDT inspection methods, and certain non-destructive testing tests are only practical on conductive materials. As polymer nanocomposites are often non-conductive, inspection data could be affected.
References and Further Reading
Taraghi, I., Łopato, P., Paszkiewicz, S., & Fereidoon, A. (2019). State-of-the-art nondestructive techniques for defects detection in nanocomposites foam-core sandwich panels containing carbon nanotubes: IR thermography and microwave imaging. Polymer Testing, 73, 352-358. Available at: https://www.sciencedirect.com/science/article/pii/S0142941818316842?via%3Dihub
Bonavolontà, C., Valentino, M., Meola, C., & Carlomagno, G. M. (2012). NDT of polymer nanocomposite for structural applications using electromagnetic techniques. International Journal of Applied Electromagnetics and Mechanics, 39(1-4), 363-368.Available at: https://content.iospress.com/articles/international-journal-of-applied-electromagnetics-and-mechanics/jae01483
Stark, W., & Bohmeyer, W. (2013). Nondestructive evaluation (NDE) of composites: Using ultrasound to monitor the curing of composites. In Nondestructive Evaluation (NDE) of Polymer Matrix Composites (pp. 136-181). Woodhead Publishing. Available at: https://www.sciencedirect.com/science/article/pii/B9780857093448500075?via%3Dihub
Ley, O., & Godinez, V. (2013). Nondestructive evaluation (NDE) of aerospace composites: application of infrared (IR) thermography. In Nondestructive Evaluation (NDE) of Polymer Matrix Composites (pp. 309-336e). Woodhead Publishing. Available at: https://www.sciencedirect.com/science/article/pii/B9780857093448500129?via%3Dihub