Ultra‐Fast Microwave Assisted Self‐Healing of Covalent Adaptive Polyurethane Networks with Carbon Nanotubes

Abstract

Vitrimers are a class of covalent adaptive networks which, unlike other covalent networks, can be thermally reprocessed, recycled, and are self‐healing. In this research, a polyurethane vitrimer network is prepared using 1,4‐phenylene diisocyanate and excess amount of polycaprolactone polyol. The dynamic nature of this network is provided by a dual effect of dynamic transesterification reactions as well as dynamic transcarbamoylation reactions. This vitrimer can be reshaped, be recycled, and heal potential defects at high enough temperatures. A fast healing strategy is developed by the addition of small amounts (0.05 wt%) of carbon nanotubes (CNTs) which enables the use of microwave radiation for an efficient fast healing process. Using this strategy the healing time decreases more than 30 times compared to using a conventional oven. CNTs also enhance the vitrimer mechanical properties and compensate for the mechanical property loss of the dynamic PU network in comparison to the permanent PU network.

Dynamic Covalent Polyurethane Network Materials: Synthesis and Self‐Healability

“…Of many approaches that have been explored to fabricate self‐healable heterogenous PU networks, three typical approaches are summarized here. Further, many reports describe the utilization of intrinsic hydrogen bonding of urethane (or carbamate) linkages labeled in PU copolymers for self‐healing [ 127–131 ] This section focuses on the integration of dynamic covalent bonds to achieve self‐healability and reprocessability.…”

Near-Instantaneously Self-Healing Coating toward Stable and Durable Electromagnetic Interference Shielding

“…First, the strong interactions between PPy and incident electromagnetic waves enable the microwave energy to be mainly converted to thermal energy (~ 50%), generating sufficiently high temperatures in a few seconds. Second, microwaves from oven heating radiate and penetrate the fabric three-dimensionally, which results in faster and more uniform temperature distribution, thus significantly shortening the heat exchange time within the whole coating layer compared to that of the traditional heat transfer method [49,52]. Therefore, the rapidly and uniformly heated PPy layer dramatically accelerates the migration of POTS molecules to the surface and thus regenerates the protective properties of the coating layer.…”

Magnetic Proximity Sensor Based on Magnetoelectric Composites and Printed Coils

“…This interesting research scenario actively promotes the production, optimization and application of innovative materials with tailored or improved functionalities [4]. Those materials include hydrogels, covalent adaptive network materials [5], photomechanical materials [6], shape-memory alloys, electroactive and magnetoactive materials [7], self-cleaning and self-healing materials, among others [1].…”