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 formatio… Show more
“…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.…”
The development of heterogeneous covalent adaptable networks (CANs) embedded with carbon nanotubes (CNTs) that undergo reversible dissociation/recombination through thermoreversibility has been significantly explored. However, the carbon nanotube (CNT)‐incorporation methods based on physical mixing and chemical modification could result in either phase separation due to structural incompatibility or degrading conjugation due to a disruption of π‐network, thus lowering their intrinsic charge transport properties. To address this issue, the versatility of a macromolecular engineering approach through thermoreversibility by physical modification of CNT surfaces with reactive multidentate block copolymers (rMDBCs) is demonstrated. The formed CNTs stabilized with rMDBCs (termed rMDBC/CNT colloids) bearing reactive furfuryl groups is functioned as a multicrosslinker that reacts with a polymaleimide to fabricate robust heterogeneous polyurethane (PU) networks crosslinked through dynamic Diels‐Alder (DA)/retro‐DA chemistry. Promisingly, the fabricated PU network gels in which CNTs through rMDBC covalently embedded are flexible and robust to be bendable as well as exhibit self‐healing elasticity and enhanced conductivity.
“…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.…”
The development of heterogeneous covalent adaptable networks (CANs) embedded with carbon nanotubes (CNTs) that undergo reversible dissociation/recombination through thermoreversibility has been significantly explored. However, the carbon nanotube (CNT)‐incorporation methods based on physical mixing and chemical modification could result in either phase separation due to structural incompatibility or degrading conjugation due to a disruption of π‐network, thus lowering their intrinsic charge transport properties. To address this issue, the versatility of a macromolecular engineering approach through thermoreversibility by physical modification of CNT surfaces with reactive multidentate block copolymers (rMDBCs) is demonstrated. The formed CNTs stabilized with rMDBCs (termed rMDBC/CNT colloids) bearing reactive furfuryl groups is functioned as a multicrosslinker that reacts with a polymaleimide to fabricate robust heterogeneous polyurethane (PU) networks crosslinked through dynamic Diels‐Alder (DA)/retro‐DA chemistry. Promisingly, the fabricated PU network gels in which CNTs through rMDBC covalently embedded are flexible and robust to be bendable as well as exhibit self‐healing elasticity and enhanced conductivity.
“…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.…”
The dynamic covalent chain polyester oligomer PCG5 is prepared and applied to epoxy thermoset. Preliminary tests including pattern stamping, healing, shape memory, indentation, and adhesion test of the cured epoxy resin show that PCG5 can accelerate deformation, crack-healing, and transesterification rates at high temperatures. The transesterification rate and activation energy are quantitatively determined by a newly developed TGA method in the authors' group. This method is used to further realize a virtual acceleration mechanism of PCG5 in the transesterification reaction with cured epoxy resins, pointing out that the increase in cross-link density and ester concentration improves the mobility of structure units and collision of ester groups. Moreover, introduction of PCG5 doesn't sacrifice glass transition temperatures (T g ) of the cured epoxy resin and strengthens the fiber composites. An 85% recovery in storage modulus and an 88% recovery in tensile strength are achieved after 10 000 cycle's fatigue tests.
“…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.…”
Superhydrophobic surfaces have drawn worldwide attention because they can be used in diverse fields. However, many of them may not be able to be used in real life applications because of their poor durability and short life span. Self‐healing is a good strategy to increase the resilience and life span of a superhydrophobic surface. In this work, a facile and low‐cost method to fabricate the durable, environmental‐friendly, and self‐healing superhydrophobic material is proposed. Attributing to the low surface energy and superficial hierarchical nanostructure, this fluorine‐free polymer synthesized from commercial silicone oil and renewable beta‐pinene exhibits excellent water‐repellency (with contact angle of 170 ± 3° and sliding angle near 0°), which has potential application in oil–water separation. Furthermore, the as‐prepared superhydrophobic material also possesses great stretchability and simultaneously hydrophobic/mechanical self‐healing capability after withstanding repeatable scratches and abrasions. The new self‐healing superhydrophobic polymer is robust, environmentally benign, sustainable, and easy to fabricate, showing promising applications in various industries.
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