Thermally Labile Self‐Healable Branched Gel Networks Fabricated by New Macromolecular Engineering Approach Utilizing Thermoreversibility

Abstract

A new approach based on macromolecular engineering through thermoreversibility is reported to fabricate the engineered gel networks of thermally labile branched polymers exhibiting robust self-healing. This approach centers on the synthesis of linear polymers having Diels-Alder cycloadducts in the backbones (DALPs) through A + B step-growth polymerization of a difunctional furan and a difunctional maleimide. Reactive mixtures of the resulting DALP with a polyfuran at elevated temperature allow for the formation of engineered gel networks through random dissociation of backbone DA linkages of the DALPs by retro-Diels-Alder reaction, followed by their reconstruction in the presence of polyfuran (with functionality > 2) by Diels-Alder reaction. Optimizing the ratio of furan to DA linkages in the reactive mixtures yields thermally labile networks exhibiting excellent thermoreversibility. Effective self-healing demonstrated with reconstruction from two separate pieces and complete void filling on surface cuts as well as recovery of healing viscoelasticity suggest that the new macromolecular engineering approach offers versatility toward the development of thermally mendable thermosets.

Macromolecularly Engineered Thermoreversible Heterogeneous Self‐Healable Networks Encapsulating Reactive Multidentate Block Copolymer‐Stabilized Carbon Nanotubes

“…Herein, we report a new strategy to fabricate PU‐based dissociative CANs covalently embedded with CNTs stabilized with rMDBC (called rMDBC/CNT colloids). The strategy explores macromolecular engineering approach based on DA/rDA chemistry [ 14 ] utilizing rMDBC/CNT colloids as a multi‐crosslinkers for a reactive blend of a telechelic PU labeled with terminal furfuryl groups (Fu‐PU) and a bismaleimide (BM). As illustrated in Figure A, the partial cleavage of DA cycloadducts positioned on the backbone of the initially formed Fu‐PU‐BM linear copolymers could be favored for rDA reaction at elevated temperature.…”

Acceleration Effect of Dynamic Covalent Chains in a Hard Epoxy Resin on Its Thermally Induced Deformation and Healing Behavior

“…With DOI: 10.1002/mame.202100037 regard to this defect, another method involving reversible chemistry is developed. [15] Under external stimuli, such as heat, [16][17][18][19][20][21] light, [22] and force, [23] the healing process proceeds by breaking and reforming of the intrinsic reversible interactions in the polymers. Various intermolecular interactions have been identified in this process, including hydrogen bonding, [24][25][26] metalligand coordination, [27][28][29][30][31] supramolecular affinity, [32][33][34] and reversible covalent bonding, [10,[35][36][37] showing the multiple ways of healing.…”

Pinene‐Functionalized Polysiloxane as an Excellent Self‐Healing Superhydrophobic Polymer

“…The extrinsic healing process is limited by healing times due to the consumption of finely dispersed microcapsules [4] or vascular networks. [5] On the contrary, intrinsic self-healing polymers, which are based on the reformation of reversible covalent bonds [6][7][8][9][10] or non-covalent interactions [11][12][13][14][15][16][17] in polymer matrix, enable multiple selfhealing of synthesized polymeric materials.…”