A review on self‐healing polymers and polymer composites for structural applications

Abstract

Polymer composites when employed for structural applications undergo dynamic stresses and strains that initiate fatigue‐induced microcracks, which by their coalescence cause the failure of the materials, thus limiting their service life. To overcome this hurdle, one of the recent approaches relies on the development of smart self‐healing polymers that, analogously to biological systems, can use damage as a trigger to activate the self‐repair phenomenon, thus extending their service life. This work reviews the self‐healing approach in polymer‐based materials for structural applications. It focuses on three main aspects, which are also explained with schematics that illustrate the mechanisms involved. The first aspect describes the different strategies adopted for self‐healing polymeric structures, the self‐healing agents used, as well as the reactions responsible for repairing the damage. The second part is focused on the methods used to disperse the self‐healing agents and catalysts within the polymer systems. The third section details the different self‐healing mechanisms and the effectiveness of self‐healing approaches in terms of mechanical and dynamical‐mechanical behavior of materials. Challenges and future research outlook highlighting the importance of relaxation time and fatigue characterization and to understand the mechanisms and possible improvements are also presented.

Monitoring and verification of micro‐strain generated inside the laminate subjected to thermal loading through fiber bragg grating sensors and classical laminate theory

“…In addition to detecting crack formation with the FBG sensor, another attractive sensing capacity of the FBG is the quantification of self‐healing [ 24 ] as well as impact localization for self‐healing. [ 25 ] The possible application of the FBG sensors can be even broadened to shape sensing for composite structures. [ 26,27 ]…”

“…In addition to detecting crack formation with the FBG sensor, another attractive sensing capacity of the FBG is the quantification of self-healing [24] as well as impact localization for self-healing. [25] The possible application of the FBG sensors can be even broadened to shape sensing for composite structures. [26,27] Measuring the strain on the individual layers within a composite laminate with an FBG sensor is the main versatility and advantage of the FBG sensor.…”

Low‐velocity impact and self‐healing behavior of CFRP laminates with poly(ethylene‐co‐methacrylic acid) filament reinforcement

“…By comparing with the traditional repairing methods, self-healing method does not involve any damaged-material-removal, mechanically fastened or adhesively bonded repairs. Therefore, self-healing epoxy composites [12][13][14][15][16][17][18] emerge as sustainable materials to improve the durability of CFRP composites, and to further enable resource and energy savings.…”

Poly(vinylidene fluoride)/molybdenum disulfide nanocomposite coatings: Studying the surface properties and corrosion protection

“…These coatings act as a physical barrier to separate metal surfaces from corrosive environments. [5][6][7][8] Due to its high mechanical strength, thermal stability, chemical resistance, hydrophobicity, and excellent electroactive properties, poly(vinylidene fluoride) (PVDF) is being used in a wide range of engineering applications. [9][10][11][12][13] PVDF has also been extensively used in the films and coatings industry.…”