Mode II fracture toughening and healing of composites using supramolecular polymer interlayers

Abstract

Abstract. This study focuses on the transfer of the healing functionality of supramolecular polymers (SP) to fibre reinforced composites through interleaving. SPs exhibiting self-healing based on hydrogen bonds were formed into films and were successfully incorporated into carbon fibre composites. The effect of the SP interleaves on in-plane fracture toughness and the subsequent healing capability of the hybrid composites were investigated under mode II fracture loading. The fracture toughness showed considerable increase since the maximum load (P max ) of the hybrid composite approximately doubled, and consequently the mode II interlaminar fracture toughness energy (G IIC ) exhibited an increase reaching nearly 100% compared to the reference composite. The healing component was activated using external heat. P max and G IIC recovery after activation were measured, exhibiting a healing efficiency after the first healing cycle close to 85% for Pmax and 100% for G IIC , eventually dropping to 80% for P max while G IIC was retained around 100% even after the fourth healing cycle. Acoustic Emission activity during the tests was monitored and was found to be strongly reduced due to the presence of the SP.

Healing of carbon fiber reinforced plastics by Diels–Alder based polymers: Effects of healing agent concentration and curing cycle

“…Thus, the incorporation of 60, 120, or 180 gsm SHA in the mid‐plane region increases both P max and G IC . Similar satisfactory results have been reported in literature for CFRPs containing polymers with thermally activated healing functionalities …”

“…In addition, the examination of the cross‐section and the fracture surfaces of the samples under optical microscopy supported the investigation and led to qualitative considerations regarding the failure and healing mechanisms. It is underlined that this work complements previous works by the authors on the thermally activated fracture toughening and healing performance of CFRPs . More precisely, it utilizes a SHA of different nature, while the focus herein has shifted to the study of the effects of SHA concentration and selected curing cycle on the results.…”

“…In addition, the potential self‐healing ability of some other thermoplastics, reactive or not with the epoxy matrix, such as poly(ethylene glycol) methacrylate, ethylene vinyl acetate, and acrylonitrile butadiene styrene has been examined. Very recently, introduction of supramolecular polymers, which were previously known for their self‐healing character, on CFRP was proven a promising approach to provide non‐autonomous self‐healing . Finally, other two types of self‐healing mechanisms that are based on the shape memory effect exist and have been extensively reported in literature .…”

3D printing-assisted interphase engineering of polymer composites: Concept and feasibility

“…Thin electrospun nanolayers are incorporated to improve the interlaminar and interlayer properties of advanced composites without jeopardizing in-plane properties [3]. Self-healable interleaves may ensure the restoration of the property profile [4]. Thermosets, such as epoxy resins (EP) [5].…”

Failure Assessment and Evaluation of Damage Development and Crack Growth in Polymer Composites Via Localization of Acoustic Emission Events: A Review

“…Determination of the initiation delamination using AE features will be pushed forward whereby trying to adapt various clustering for time-scale, 80 and novel techniques (e.g., Hilbert transform) for frequency-scale descriptors. 81,82 FEM will be intensively used for the validation of AE results.…”