Tearing Energy Research Articles

Tough and conductive nanocomposite hydrogels for human motion monitoring

Conductive hydrogels have received great attention owing to their promising applications in electrodes, supercapacitors, actuators, fuel cells, biosensors and biomedical devices and so on. However, it is still a challenge to achieve conductive hydrogels with integrated high performances, including high strength, large stretchability, high toughness, rapid self-recovery and good self-healing. In the present work, multiple physically cross-linked conductive hydrogels with integrated high performances were fabricated by in situ doping conductive PEDOT:PSS during the formation of dual physically cross-linked poly(N-hydroxyethyl acrylamide)/Laponite hydrogels. At the optimal condition, the conductive gels exhibit high tensile strength, high extensibility, high tearing energy, rapid self-recovery property without any external stimuli, high conductivity, good self-healing property, as well as sensitive strain sensing for monitoring human activities (e.g. the movements of the finger and wrist, and tiny breathing movements). Considering easy preparation and integrated high performances, our conductive gels have potential applications in wearable electronic sensors and bioelectronics.

Crack growth resistance in rubber composites with controlled Interface bonding and interphase content

The distinction between abrasion resistance of carbon black and silica reinforced tire tread compounds has drawn attention to the indispensable role of interfacial phenomena on crack growth resistance of rubber composites. Attempts to determine the dependence of interface bonding (from covalent to non-covalent) on crack growth resistance of rubber composites are insufficient without knowledge of the contributions resulting from the interphase (i.e. the volume of rubber chains with restricted mobility). For highly-filled rubbers, the interphase is mainly formed by strong filler-filler interaction and entrapment of rubbers among filler aggregates. Working on the silane-treated silica reinforced rubber, here the alkyl length and the grafting density of silane are systematically controlled to fabricate filler systems with desired surface energy, specified filler-filler interaction and definite trapped-rubber/interphase content. At equal surface energy of fillers one could then change the interface bonding from covalent to non-covalent and study the role of interface on the crack growth resistance. After analyzing the tearing energy of the resulting composites, it was found that the primary factor affecting the fracture strength of highly filled rubbers is the content of the trapped-rubber. The type of interface bonding shared a secondary contribution to the tearing energy values. A slip-stick fracture pattern was observed for the composite with the covalently-bonded interface. A mechanistic model ascribing the relation between the tearing energy and the controlling parameters of the fracture was also proposed.

Influence of highly dispersible silica filler on the physical properties, tearing energy, and abrasion resistance of tire tread compound

ABSTRACTRubber industry is facing a stiff challenge in the years to come. There are rising price for fossil fuel and shortage of resources. There is more stringent legislation to protect the environment and reduce the emission. Filler plays an important role in imparting useful properties to rubber products. In this article, the effects of new generation filler, on the physical properties, tearing energy, and abrasion resistance were investigated. The new generation filler, highly dispersible silica, has a dibutyl phthalate (DBP) absorption value of more than 180cc 100 g−1, more branched structure and relatively higher amount of small aggregates. Four different loadings of silica (up to 45 phr) were investigated. With increasing filler loading, the tensile strength and modulus at 300% elongation increased and the elongation‐at‐break decreased. The rebound resilience decreased and tan delta value improved with increasing silica content. The abradability continuously decreased with concomitant increase in the side coefficient force. The fatigue resistance was found to be better at higher silica loading. The silica particles due to its surface structure helps in crack arresting. The abradibility was related to tearing energy, loss modulus, and breaking energy. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47560.

Some factors affecting the flex life of polybutadiene rubber vulcanisate

Flex life of three different grades of polybutadiene rubber (BR) with highly linear chains, linear chains and long-branched chains was measured. The rubbers were reinforced with a precipitated silica nanofiller, the surface of which had been pre-treated with sulphur-bearing bis(3-triethoxysilylpropyl-)-tetrasulphane (TESPT) coupling agent. The rubbers were cured by reacting the sulphur in TESPT with the rubber chains to produce vulcanisates. The mechanical properties of the rubber vulcanisates such as tensile strength, Young’s modulus, elongation at break, stored energy density at break and tear energy were subsequently determined. The flex life of the rubber vulcanisates was also measured at a constant maximum strain amplitude and a test frequency of 3.17 Hz at ambient temperature. Additionally, the flex life of some unfilled rubber vulcanisates of similar Mooney viscosities cured with elemental sulphur was also measured. For the silica-filled rubber vulcanisate, the rubber with the highly linear chains had the longest flex life and the one with long-branched chains, the shortest flex life. It seemed that a correlation between the flex life and the molecular chains structure might exist despite the crosslink density of the rubber vulcanisates being different and the compounds having silica in them. For the unfilled rubber vulcanisates, the rubber with highly linear chains had the longest flex life and the one with linear chains the shortest flex life. Therefore, it was concluded that the flex life of the rubber vulcanisate was determined, to a large extent, by the molecular chains structure of the raw rubber, irrespective of whether the rubber had reinforcing silica filler, different crosslink densities and different initial viscosities or not. A similar trend was also observed for some of the mechanical properties. For example, the elongation at break was lower and Young’s modulus higher for the silica-filled rubber vulcanisates with long-branched chains than those measured for the silica-filled rubber vulcanisate with highly linear chains.

Mechanical Properties of a New Vinyl Polyether Silicone in Comparison to Vinyl Polysiloxane and Polyether Elastomeric Impression Materials.

Background:A new elastomeric impression material which is a combination of vinyl polysiloxane (VPS) and polyether (PE) elastomers called “polyvinyl ether silicone” (PVES) has been introduced with predictable accuracy and high-quality impressions. There is insufficient data on mechanical properties of this material.Materials and Methods:A comparative study of mechanical properties of VPS, PE, and PVES was carried out using light- and heavy-body consistencies of the three materials. Three standardized stainless steel molds were made to fabricate study specimens (n = 96). The specimens were tested for elastic recovery, strain under compression, tear energy, and tensile strength (TS) using the universal testing machine. Statistical analysis was done using two-way analysis of variance test.Results:Elastic recovery was higher in VPS as compared to other two materials. Strain under compression was higher for PE followed by PVES. Tensile energy was significantly higher in PVS while TS was higher in VPS, followed by PVES and PE.Conclusion:PVES tested was found to be more flexible with high tensile energy. This material can be preferred in cases with undercut areas favoring the removal of impressions without tear and distortion.

Relationship between dynamic fatigue crack propagation properties and viscoelasticity of natural rubber/silicone rubber composites.

In this paper, dynamic fatigue crack propagation properties of natural rubber/silicone rubber (NR/VMQ) composites are studied under constant tearing energy (G) input. Through dynamic fatigue crack growth testing, it is found that with the increase of VMQ fraction, NR/VMQ exhibits a lower crack growth rate (dc/dN). The viscoelastic parameters have been recorded in real-time during crack propagation, including the storage modulus E′, loss factor tan δ, and loss compliance modulus J′′, and their relationships with crack propagation behaviour have been established. The improved crack propagation resistance is attributed to the reduced J′′, resulting from the synergistic effect of increased E′ and decreased tan δ, and thus more energy dissipation occurred in the linear viscoelastic region in front of the crack tip, which consumed part of the energy for crack growth. Finally, good correlation between dc/dN and J′′ could be successfully established.

Thermoplastic PCL-b-PEG-b-PCL and HDI Polyurethanes for Extrusion-Based 3D-Printing of Tough Hydrogels.

Novel tough hydrogel materials are required for 3D-printing applications. Here, a series of thermoplastic polyurethanes (TPUs) based on poly(ɛ-caprolactone)-b-poly(ethylene glycol)-b-poly(ɛ-caprolactone) (PCL-b-PEG-b-PCL) triblock copolymers and hexamethylene diisocyanate (HDI) were developed with PEG contents varying between 30 and 70 mol%. These showed excellent mechanical properties not only when dry, but also when hydrated: TPUs prepared from PCL-b-PEG-b-PCL with PEG of Mn 6 kg/mol (PCL7-PEG6-PCL7) took up 122 wt.% upon hydration and had an E-modulus of 52 ± 10 MPa, a tensile strength of 17 ± 2 MPa, and a strain at break of 1553 ± 155% in the hydrated state. They had a fracture energy of 17976 ± 3011 N/mm2 and a high tearing energy of 72 kJ/m2. TPUs prepared using PEG with Mn of 10 kg/mol (PCL5-PEG10-PCL5) took up 534% water and were more flexible. When wet, they had an E-modulus of 7 ± 2 MPa, a tensile strength of 4 ± 1 MPa, and a strain at break of 147 ± 41%. These hydrogels had a fracture energy of 513 ± 267 N/mm2 and a tearing energy of 16 kJ/m2. The latter TPU was first extruded into filaments and then processed into designed porous hydrogel structures by 3D-printing. These hydrogels can be used in 3D printing of tissue engineering scaffolds with high fracture toughness.

Micro-mechanics based cohesive zone modeling of full scale ductile plate tearing: From initiation to steady-state

Ductile plate tearing, where the crack propagates multiple plate thicknesses, is targeted by the micro-mechanics based Gurson-Tvergaard-Needleman (GTN) model. The focus is on extracting detailed information on the fracture process that governs ductile crack initiation from a blunt pre-crack until the crack reaches steady-state propagation in order to enhance accuracy of the traditionally used cohesive zone traction-separation relations. The aim is to facilitate an accurate representation of the tearing process within the cohesive zone modeling framework as such simplistic models are largely exploited by engineers worldwide. Unfortunately, accuracy in the representation of crack propagation is often sacrificed for computation speed, but the present work allows correlating the cohesive zone modeling to a much more accurate, though computational expensive, micro-mechanics based (full 3D) model response. In the modeling of large-scale plate tearing, shell elements are typically employed to represent the engineering scale of the structure while the cohesive zone represents the micro-scale in terms of crack initiation and growth process. Thus, the cohesive zone essentially has to take over at the onset of the first localization (thinning far ahead of the crack tip). Calibration of the cohesive zone parameters has earlier been made in accordance with experimental observations such that the overall response of the system is well reproduced. But, the present work takes the calibration of the cohesive zone one step further and exploits details from a large-scale GTN model calculation. The goal is to match the response from the GTN model with the much less computation demanding cohesive zone modeling approach by incorporating knowledge of the loading history for individual cross-sections, in front of the pre-crack, through which the tearing crack propagates. The full 3D micro-mechanics based model set-up allows tracking of key parameters, such as peak traction and tearing energy, which goes into the cohesive traction-separation relation. The dependency on distance from the crack initiation site of the cohesive zone parameters is determined - from crack initiation to steady-state propagation - and followed up by a discussion on how to construct a traction-separation relation for ductile plate tearing.

VISCOELASTIC RESPONSE DURING CRACK PROPAGATION OF UNFILLED AND FILLED SBR

ABSTRACT The crack propagation behavior of unfilled and filled styrene–butadiene rubber (SBR) in steady and dynamic tearing was investigated using tensile tests on trousers samples and tear fatigue measurements on single edge notched tension (SENT) samples, respectively. For the unfilled sample, both types of measurements indicated that the tearing energy is dominated by the viscoelastic response of the polymer. This was demonstrated by the creation of crack growth master curves using the horizontal shift factors obtained from mastering the complex modulus. The tearing energy increased with increasing crack velocity and decreasing temperature as required by the time-temperature superposition principle. The crack growth master curves followed a power law with the same exponent for steady and dynamic tearing. This exponent agrees fairly well with the exponent predicted by linear viscoelastic crack propagation theory. For steady tearing at high crack propagation rates, systematic deviations from the master curves appeared, which were attributed to flash temperature effects. For the filled SBR, which contained 50 phr carbon black, only dynamic tearing was found to be dominated by the viscoelastic response of the polymer. For steady tearing, filler networking seemed to alter crack propagation rates significantly, so that the viscoelastic fingerprint was no longer visible. For the filled sample, additional measurements with a high preload were conducted. It was demonstrated that a single master curve can be constructed, only if the (static) preload contribution is neglected and the dynamic contribution of the energy density is used for the evaluation of the tearing energy. This master curve showed two distinct slopes at high and low crack velocities. It is argued that the higher slope at low crack speeds is relevant for lifetime predictions based on the integration of the Paris–Erdogan power law. Under conditions in which the viscoelastic crack propagation holds, very slow crack growth rates can be explored at reasonable testing times by measurements at elevated temperatures.

Mechanically tough and recoverable hydrogels via dual physical crosslinkings

ABSTRACTDevelopment of functional tough hydrogels with new network structures and energy dissipation mechanisms has great promise for many applications. Here, a new type of physical hydrogel crosslinked by hydrophobic association and hydrogen bonds was synthesized by a facile micellar copolymerization of hydrophobic methyl acrylate (MA) monomers and hydrophilic N‐hydroxyethyl acrylamide (HEAA) monomers in the presence of Tween80 micelles. Strong hydrophobic association between inner MA and Tween80 and hydrogen bonds between external polyHEAA and Tween80 provide two distinct crosslinkers to construct mechanically tough and recoverable network. Mechanical properties of polyHEAA‐MA@Tween80 hydrogels strongly depended on network components (HEAA, MA; Tween80 concentrations). At optimal conditions, the hydrogels can achieve fracture stress of 700 kPa, fracture strain of 1687 mm/mm, elastic modulus of 195 kPa, and tearing energy of 1598 J/m2. Due to the reversible nature of physical interactions, polyHEAA‐MA@Tween80 hydrogels can achieve fast stiffness/toughness recovery of 60%/33% without any external stimuli and resting time at room temperature. This work demonstrates a new design strategy to fabricate a new a single‐network hydrogel with high mechanical and self‐recovery properties by incorporating both hydrophobic association and hydrogen bonds in the network, which may provide alternative viewpoint for the design of multifunctional tough hydrogels. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 1294–1305

A highly tough and stiff supramolecular polymer double network hydrogel

Recently, we have constructed a high strength and thermoplastic supramolecular poly(N-acryloyl glycinamide) (PNAGA) hydrogel which can be developed as printable bioinks. However, the PNAGA hydrogel is low in stiffness and toughness, potentially limiting its application as load-bearing soft tissue scaffolds. In this work, we fabricate a supramolecular polymer double-network hydrogel based on hydrogen bonding crosslinked PNAGA and Fe3+-coordination crosslinked sodium carboxymethyl cellulose (CMC). The combined hydrogen bonding and ionic crosslinks contribute to high-strength nonswellable PNAGA/CMC-Fe hydrogels (Tensile strength of 2.9 MPa and compressive strength of 7.3 MPa at 80% strain without fracture) and stiffness (Young's modulus of 1.2 MPa and compressive modulus of 1.5 MPa). Furthermore, these reversible double physical crosslinks enable the PNAGA/CMC-Fe hydrogels to dissipate energy efficiently with a high toughness (12.3 MJ m−3) and tear energy (3700 J m−2), meanwhile imparting self-recoverability, anti-fatigue ability and self-healability to the network. This cytocompatible supramolecular polymer double network hydrogel with excellent multifaceted mechanical performances are promising to exploited as load-bearing soft tissue engineering scaffolds.

Fatigue crack growth in natural rubber: The role of SIC investigated through post-mortem analysis of fatigue striations

Fatigue striations are investigated in order to provide additional information on the role of SIC in the fatigue crack growth resistance in natural rubber (NR). Uniaxial fatigue tests were carried out with Diabolo samples under a wide range of loading ratios and loading levels. Fracture surfaces were analyzed by using SEM. Two striation regimes were identified: small striation patches with different orientations (Regime 1) and zones with large and well formed striations, where wrenchings are no longer observed (Regime 2). As fatigue striations were observed for all the loading ratios applied, they are therefore not the signature of SIC in the lifetime reinforcement. Nevertheless, increasing the minimum value of the strain amplified the striation phenomenon and the occurrence of Regime 2. Results obtained have been qualitatively put into perspective with crack propagation curves provided in Lindley (1973). The analysis carried out unifies the results obtained in the literature for relaxing and fully relaxing loadings (Rε⩽0) in the sense that increasing the loading, i.e. the tearing energy, leads to an increase in the crack growth rate and to a striation typology evolution, especially the striation size. For non-relaxing loadings, our results suggest that the striation typology may be governed by the loading ratio rather than the crack growth rate. Finally, as striations did not appear when the tests were performed at temperature superior or equal to 90 °C, the formation of striation requires therefore that the material is crystallizing.

Predicting failure in rubber membranes: An experimental-numerical approach

Abstract A material model to predict tearing of a rubber membrane in finite element analysis was developed. Using experimental data from uniaxial tension test and tearing of rubber sheets, we combined a cohesive traction law with a hyper-viscoelastic constitutive equation to create this material model. The resulting material model described hyper-viscoelastic behavior before damage, damage initiation, and damage evolution and consequent crack growth through a finite element mesh. The numerical simulations of tearing rubber sheets were found to be in good agreement with test data in terms of force-displacement response, onset of fracture and crack growth path. A key advantage of using this proposed material model is that there was no need to pre-define crack paths in the finite element analysis. Crack paths were controlled by the damage initiation and evolution laws as well as the tearing energy of the rubber.

Influence of TESPT on Tensile and Tear Strengths of Vulcanized Silica-filled Natural Rubbe

The effectof coupling agent on tensile and tear strengthsof vulcanized NR filledwith 50 pphr of precipitated silica (VN3) was investgated. The amount of coupling agent was varied from 0,1,2,3,4,5 to 8 pphr. In the absence of coupling agent bis[3-(triethoxysilyl)propyl] tetrasulphide (TESPT), the tensile strengthof silica-fille vulcanized NR was lower than the tensile strengthof unfilledvulcanized NR. The enhancement in the tensile strengthwas achieved only when TESPT was incorporated into the rubber compound. The dependence of tensile strengthon the amount of TESPT showed a similar trend as the dependence of tensile strengthon the crosslink concentration. This might imply that varying the amount of TESPT was analogous to varying the crosslink concentration of the rubber network. The effct of TESPT on tearing energy was very strking in silica-filed vulcanized NR. Without Si69, the crack propagated in a steady(smooth) manner where the tearing energy increases with increasing testspeed. When TESPT was added into the silica mix, the crack propagated sideways from the intended tear path producing the so called knotty tearing. The tearing energy was about a factor of ten higher than that without coupling agent in particular at low tear rates regions. The results here indicated clearly that in silica-filledvulcanized NR, coupling agent was essential to induce the strengthanisotropy necessary for the occurrence of knotty tearing. The result also showed that TESPT also influencedthe amount of hysteresisin silica-filledvulcanized NR. Both tensile and tear strengths were affected by the hysteresi

Polyurethane/clay nanocomposites with improved helium gas barrier and mechanical properties: Direct versus master‐batch melt mixing route

ABSTRACTThermoplastic polyurethane (TPU)/clay nanocomposite films were produced by incorporation of organo‐modified montmorillonite clay (Cloisite 30B) in TPU matrix by two different melt‐mixing routes (direct and master‐batch‐based mixing), followed by compression molding. In master‐batch mixing where the master‐batch was prepared by mixing of clay and TPU in a solvent, better dispersion of clay‐layers was observed in comparison to the nanocomposites produced by direct mixing. As a consequence, superior mechanical and gas barrier properties were obtained by master‐batch mixing route. The master‐batch processing resulted in 284 and 236% increase in tearing strength and tearing energy, respectively, with 5 wt % clay‐loading. Interestingly, in case of master‐batch mixing, the tensile strength, stiffness as well as breaking extension increased simultaneously up to 3 wt % clay‐loading. The helium gas permeability reduced by about 39 and 31% for the TPU/clay nanocomposites produced by mater‐batch and direct mixing routes, respectively, at 3 wt % loading of clay. Finally, the gas permeability results have been compared using three different gas permeability models and a good correlation was observed at lower volume fraction of clay. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2018,135, 46422.

Fatigue crack growth behavior of NBR, HNBR, HNBR ZSC compounds

Due to the insufficiency of reliable data, fatigue life calculations taking the crack propagation phenomena into account, remain scarce. Therefore, this work focuses on the characterization of fatigue crack growth behavior for materials NBR, HNBR and HNBR ZSC in different thermal ageing states at different temperatures. The experimental data base was analyzed using Fracture Mechanics principles, namely crack growth rate in relation with the tearing energy. The tests of the notched pure-shear specimen were performed on a METRAVIB DMA+300 fatigue testing machine. It is found that the crack growth rate is approximately proportional to the tearing energy in the steady propagation range. Furthermore, the test temperature and thermal ageing were observed to be able to weaken the shearing strength.

Resistance spot welding of MS1200 martensitic advanced high strength steel: Microstructure-properties relationship

This paper addresses the microstructure and tensile-shear mechanical performance of MS1200 Giga-grade martensitic advanced high strength steel resistance spot welds. The key phase transformations in MS1200 welds were lath martensite formation in the fusion zone (FZ) and upper-critical heat affected zone (HAZ), new ferrite formation in the inter-critical HAZ and martensite tempering in the sub-critical HAZ. The MS1200 welds were featured by a near matching hardness in the fusion zone and under-matching hardness in the heat affected zone (HAZ) compared to the base metal. At certain process window a complete nugget pullout and separation was observed with high post-necking tearing energy. The interfacial to pullout failure mode transition was explained in the light of FZ hardness as well as the HAZ softening associated with martensite tempering in the sub-critical HAZ. The load bearing capacity of MS1200 welds failed at interfacial mode was strongly depends on the FZ size as well as the FZ hardness. However, the peak load of welds failed at pullout mode was a function of HAZ softening as well as the plastic constraint in the HAZ associated with the hard upper-critical HAZ/FZ and martensitic BM.

Tearing energy and path-dependent J-integral evaluation considering stress softening for carbon black reinforced elastomers

For carbon black reinforced Ethylene-Propylene-Diene Monomer Rubber (EPDM) fracture mechanics investigations by using a Single Edge Notched Tension sample (SENT) are presented. Filled elastomers under cyclic loading typically display inelastic effects like permanent set, strong nonlinear S-shaped stress-strain behaviour and stress induced softening (discontinuous damage) as well as cyclic softening (continuous damage) better known as Mullins effect. These unique properties give this material class an interesting and a complex aspect regarding the experimental observations and numerical modelling of fracture mechanics. In simulations with homogenous material, the J-integral given as the evaluation of the Eshelby stress tensor along a path integral around the crack shows no dependency on the chosen integration path. In contrast, dissipative materials show strong path dependency of the J-integral. When the chosen path is near to the crack tip, this effect is pronounced, due to the inelastic effects, which are very high at the crack tip compared to the rest of the sample. In the process zone, the J-integral value depends strongly on the chosen path around the crack tip. This phenomenon occurs due to the intensity of inelastic effects near the crack tip. The path-dependency of J-integral using the variational formulation of a crack problem in a dissipative material has been given in [16]. Stumpf and Le have proposed a new formulation of the boundary value problem for elastoplastic cracked body using variational formulation, where the finite deformation was considered. For cyclic displacement controlled loading, the elastomers show typical stress softening behaviour, i.e. the force-displacement curve of each cycle is lower than the previous cycle and higher than the following cycle. This occurs due to the continuous damage, whereby the bondings between polymer chains and the filler particles are partially damaged. At small external amplitudes, the stress softening effect is significant only in the vicinity of the crack tip, because of the hysteresis which is large compared to the rest of the sample. The evaluation of the J-integral for an SENT sample under cyclic displacement controlled loading shows clearly that the resulting energy flux at the crack tip decreases from the virgin curve until the last repetition. The values found are in good agreement with experimentally evaluated tearing energy. Hence J-integral evaluation while considering a stress softening reflecting material model can be a promising approach used for estimation of the crack propagation or for lifetime prediction.

A study on the effect of electron acceptor-donor interactions on the mechanical and interfacial properties of carbon black/natural rubber composites

Abstract In order to fabricate carbon black/NR composites, various types of carbon black were added as fillers to a natural rubber (NR) matrix. The influence of the types of carbon black on the resulting composite was investigated by measuring its mechanical properties. In addition, to determine the relationship between the filler and the matrix, the adsorption and surface properties of the carbon black samples were examined using X-ray diffraction and Brunauer–Emmett–Teller isotherms. Mechanical properties of the carbon black/NR composites such as tensile strength and tearing energy were determined. The results showed that the mechanical properties of the carbon black/NR composites were considerably improved, owing to the increase in the London dispersive component of the carbon black surface free energy.

Super Bulk and Interfacial Toughness of Physically Crosslinked Double‐Network Hydrogels

AbstractConventional design wisdom prevents both bulk and interfacial toughness to be presented in the same hydrogel, because the bulk properties of hydrogels are usually different from the interfacial properties of the same hydrogels on solid surfaces. Here, a fully‐physically‐linked agar (the first network)/poly(N‐hydroxyethyl acrylamide) (pHEAA, the second network), where both networks are physically crosslinked via hydrogen bonds, is designed and synthesized. Bulk agar/pHEAA hydrogels exhibit high mechanical properties (2.6 MPa tensile stress, 8.0 tensile strain, 8000 J m−2 tearing energy, 1.62 MJ m−3 energy dissipation), high self‐recovery without any external stimuli (62%/30% toughness/stiffness recovery), and self‐healing property. More impressively, without any surface modification, agar/pHEAA hydrogels can be easily and physically anchored onto different nonporous solid substrates of glass, titanium, aluminum, and ceramics to produce superadhesive hydrogel–solid interfaces (i.e., high interfacial toughness of 2000–7000 J m−2). Comparison of as‐prepared and swollen gels in water and hydrogen‐bond‐breaking solvents reveals that strong bulk toughness provides a structural basis for strong interfacial toughness, and both high toughness mainly stem from cooperative hydrogen bonds between and within two networks and between two networks and solid substrates. This work demonstrates a new gel system to achieve superhigh bulk and interfacial toughness on nonporous solid surfaces.