Polyurethane Composites Research Articles

Stretchable liquid metal grid/metallized polyurethane composites with switchable electromagnetic interference shielding and efficient infrared stealth performance

Intelligent electromagnetic interference (EMI) shielding materials with tunable electromagnetic shielding properties becomes a significant and urgent concern for information society. Hence, a switchable and low-reflectivity EMI shielding composite is fabricated by electroless nickel plating on the surface of polyurethane nonwoven fabric (Ni@TPU), and followed by combining with liquid metal (LM) grid. The synergistic combination of Ni@TPU and LM grid effectively facilitates the rational construction of hierarchical impedance matching. Meanwhile, it promotes destructive interference between electromagnetic waves reflected from Ni@TPU and the LM grid. As a result, an excellent low-reflectivity EMI shielding performance can be achieved. More importantly, the switchable EMI shielding performance can be easily realized by repeatedly stretching Ni@TPU/LM. In addition, the fluffy nonwoven fabric and LM grid with low infrared emissivity endow it with an outstanding infrared stealth performance. Such excellent low-reflectivity EMI shielding switch performance incorporated with flexible infrared stealth makes it possible to become smart EMI shielding material with a great promise to be employed in the application scenario of window in camouflage container.

Bio-Based Polyurethane Composites with Adjustable Fluorescence and Ultraviolet Shielding for Anti-Counterfeiting and Ultraviolet Protection.

Polyurethane and its composites play an important role in innovative packing materials including anticounterfeiting and ultraviolet protection, however, they are mainly derived from petroleum resources that are not sustainable. In this study, a 100% biobased thermoplastic polyurethane (Bio-TPU) was synthesized using biobased poly(trimethylene ether) glycol, pentamethylene disocyanate, and 1,4-butanediol. Subsequently, biobased tannic acid (TA) was employed to prepare biobased composites. The structures and properties of Bio-TPU and its composites were systematically evaluated. The results showed that the Bio-TPU/TA composite films had excellent and controllable fluorescence and UV-shielding properties. The fluorescence colors of the Bio-TPU/TA composite films could be adjusted to blue, green, and yellow by varying the TA content and adding coupling agents. Moreover, the UV transmittance of the Bio-TPU/TA composites decreased from 79.25 to 5.43% below 400 nm with an increasing TA content, indicating an excellent ultraviolet-barrier performance. Consequently, biobased TPU/TA composite films can be utilized as innovative anticounterfeiting materials and UV-shielding protection films. This study is expected to facilitate sustainable development in the polyurethane industry and broaden the high-end applications of polyurethane such as fashion, electronics, food manufacturing, pharmaceuticals, and finance.

Thermally conductive, mechanically robust alumina-incorporated polyurethane films prepared by ultraviolet light curing

Abstract The development of heat dissipating composite materials for electronic systems can be expedited using alumina particles as modifiable polymer-matrix fillers. However, these composites are difficult to synthesize given the tradeoffs between thermal conductivity, insulating characteristics, and conduciveness to processing. To that end, the present study is focused on synthesizing environmentally friendly polyurethane films that could be cured by ultraviolet light within minutes, without requiring high-temperature heat treatment. Through the optimization of alumina modification, hybridization of thermally conductive fillers, filler content, and stirring time on the thermal conductivity of the polyurethane composites, this study improves the process for sustainability, low-cost, and convenient preparation. The experimental results confirmed that the use of surface modification and hybrid fillers is effective for enhancing the thermal conductivity, with the value of the polyurethane integrated with 50 wt% Al2O3 and 5 wt% Al2O3–poly (catechol/polyamine) being 76.40 wt% higher than that of pure PU (0.44 W/mK). Additionally, the use of hybrid fillers resulted in superior mechanical and thermal properties (such as tensile strain, tensile strength, thermal expansion coefficient, and temperature resistance) compared with those of pure PU and films incorporated with only a single filler.

Improvement of Mechanical and Acoustic Characteristics of Halloysite Nanotube-Reinforced Polyurethane Elastomer Composites and Their Applications.

Polyurethane incorporated with nanofillers such as carbon nanotubes, basalt fibers, and clay nanoparticles has presented remarkable potential for improving the performance of the polymeric composites. In this study, the halloysite nanofiller-reinforced polyurethane elastomer composites were prepared via the semi-prepolymer method. The impact of different halloysites (halloysite nanotubes and halloysite nanoplates) in polyurethane composites was investigated. Scanning electron microscopy, X-ray diffraction, infrared spectroscopy, electronic universal tensile testing, and acoustic impedance tube testing were employed to characterize the morphology, composition, phase separation, mechanical properties, and sound insulation of the samples. The composite fabricated with 0.5 wt% of halloysite nanotubes introduced during quasi-prepolymer preparation exhibited the highest tensile strength (22.92 ± 0.84 MPa) and elongation at break (576.67 ± 17.99%) among all the prepared samples. Also, the incorporation of 2 wt% halloysite nanotubes into the polyurethane matrix resulted in the most significant overall improvements, particularly in terms of tensile strength (~44%), elongation at break (~40%), and sound insulation (~25%) within the low-frequency range of 50 to 1600 Hz. The attainment of these impressive mechanical and acoustic characteristics could be attributed to the unique lumen structure of the halloysite nanotubes, good dispersion of the halloysites in the polyurethane, and the interfacial bonding between the matrix and halloysite fillers.

Synergistic Reinforcing Effect of Hazelnut Shells and Hydrotalcite on Properties of Rigid Polyurethane Foam Composites.

Recently, the development of composite materials from agricultural and forestry waste has become an attractive area of research. The use of bio-waste is beneficial for economic and environmental reasons, adapting it to cost effectiveness and environmental sustainability. In the presented study, the possibility of using hazelnut shell (HS) and hydrotalcite (HT) mineral filler was investigated. The effects of fillers in the amount of 10 wt.% on selected properties of polyurethane composites, such as rheological properties (dynamic viscosity, processing times), mechanical properties (compressive strength, flexural strength, hardness), insulating properties (thermal conductivity), and flame-retardant properties (e.g., ignition time, limiting oxygen index, peak heat release), were investigated. Polyurethane foams containing fillers have been shown to have better performance properties compared to unmodified polyurethane foams. For example, the addition of 10 wt% of hydrotalcite filler leads to PU composite foams with improved compression strength (improvement by ~20%), higher flexural strength (increase of ~38%), and comparable thermal conductivity (0.03055 W m-1 K-1 at 20 °C). Moreover, the incorporation of organic fillers has a positive effect on the fire resistance of PU materials. For example, the results from the cone calorimeter test showed that the incorporation of 10 wt% of hydrotalcite filler significantly reduced the peak of the heat release rate (pHRR) by ca. 30% compared with that of unmodified PU foam, and increased the value of the limiting oxygen index from 19.8% to 21.7%.

Effect of the filler content on some physical and mechanical properties of virgin- and recycled thermoplastic polyurethane composites

Effects of thermoplastic polyurethane (TPU) types (Recycled (R) and Virgin (V)) composites with 15 wt% and 30 wt% oakwood flour addition were studied. Selected physical, mechanical, morphological, and thermal properties of resulting polymer composites were analyzed. Test samples were manufactured using injection molding, except that abrasion resistance specimens were manufactured using a compression molding process. The findings indicated that the types of TPU and filler contents played a significant role in the density and mechanical properties of the TPU test samples. The increased oak wood flour contents in both TPU types showed improvement in density, tensile modulus, hardness, flexural strength flexural modulus, dynamic impact strength, and yield strength of the composite while decreasing the elongation at break values. In addition, both TPU types and filler contents significantly affected the densities of V-TPU and R-TPU. The TPUs type, filler content, and cycle-rpm affected Taber’s abrasion resistance values. Weight loss, which increased with the number of cycles for the control samples, decreased with increasing wood flour content. This study aimed to provide an overview of the effect of the wood flour content in the manufacturing of thermoplastic-reinforced composites and to provide a basis for further research and development efforts.

Development and 4D printing of magneto-responsive PMMA/TPU/Fe3O4 nanocomposites with superior shape memory and toughness properties

This paper introduces 4D printing of composites of polymethyl methacrylate (PMMA) and thermoplastic polyurethane (TPU) reinforced with Fe3O4 particles for the first time. PMMA/TPU blends with 70/30 wt% are selected as matrix with the best compatibility based on dynamic mechanical thermal analysis. Fe3O4 nanoparticles are added to the blends with 10 %, 15 % and 20 % weight ratios. Their addition enables remote actuation of the materials in a high frequency alternating magnetic field. Field emission scanning microscopic images confirms a full dispersion of nanoparticles inside the polymeric matrix. Nanocomposites with 20 wt% of Fe3O4 can perfectly recover the permanent shape within 1.5 min in the magnetic field. They also reveal perfect shape memory properties in the hot water. Moreover, all samples display a perfect shape fixity ratio. The addition of TPU significantly enhances the toughness and flexibility of the PMMA matrix. It is found that Fe3O4 nanoparticles further enhance the mechanical strength by 10 % to 15 %, although they reduce the strain at break from 17 % to 14 %. Finally, a gripper is 4D printed and its excellent performance in the magnetic field is demonstrated.

Activated Carbon and Biochar Derived from Sargassum sp. Applied in Polyurethane-Based Materials Development.

Activated carbon (AC) and biochar (BC) are porous materials with large surface areas and widely used in environmental and industrial applications. In this study, different types of AC and BC samples were produced from Sargassum sp. by a chemical activation and pyrolysis process and compared to commercial activated carbon samples. All samples were characterized using various techniques to understand their structure and functionalities. The metal content of the samples was characterized by using an inductively coupled optical emission spectrometer (ICP-OES). A toxicity test was applied to investigate the effect of AC/BC on organisms, where Sinapis alba seed and Escherichia coli bacteria-based toxicity tests were used. The results revealed that the samples did not negatively affect these two organisms. Thus, it is safe to use them in various applications. Therefore, the samples were tested as fillers in polyurethane composites and, thus, polyurethane-AC/BC samples were prepared. The amounts of AC/BC mixed into the polyurethane formulation were 1%, 2%, and 3%. Mechanical and acoustic properties of these composites were analyzed, showing that by adding the AC/BC to the system an increase in the compression strength for all the samples was achieved. A similar effect of the AC/BC was noticed in the acoustic measurements, where adding AC/BC enhanced the sound adsorption coefficient (α) for all composite materials.

Impact performance of egg‐box core sandwich panels made from sisal fibers and castor‐oil‐based polymer

AbstractDeveloping sustainable composites for engineering applications is essential for minimizing environmental impacts and ensuring the long‐term viability of infrastructure and technological advancements. In this context, this work focuses on the manufacture and evaluation of the structural integrity of a sandwich structure composed of aluminum faces and egg‐box‐shaped, sisal fiber‐reinforced epoxy (SFE) or castor‐oil polyurethane (SFC‐O) composites. The sandwich panel is filled with a biobased foam and subjected to dynamic load (drop‐tower) test. For comparison, the base materials SFE and SFC‐O molded into the egg‐box‐shaped cores are also evaluated using Charpy impact tests to establish a potential correlation between their Charpy performance and the drop‐tower behavior of egg‐box sandwich structures. The findings reveal that SFC‐O laminates demonstrate superior Charpy impact resistance (~49%) compared to SFE laminates. Similarly, sandwich structures composed of egg‐box‐castor‐oil composite cores absorb approximately 42.5% more energy than those made with egg‐box‐epoxy cores. The impact behavior of the sandwich structures correlates directly with the impact resistance of the sisal fiber laminates. Overall, the results indicate that the castor‐oil polymer can effectively replace the epoxy polymer matrix phase, enhancing impact absorption and providing an environmentally correct and sustainable solution for fabricating sandwich panels.Highlights Castor‐oil polymer provides laminates with lower density relative to epoxy. Sisal‐castor‐oil‐based laminates possess higher impact resistance than those based on epoxy. Sisal‐castor‐oil‐based panels achieve higher absolute and specific drop‐tower impact properties. Panels subjected to drop‐tower impact tests reveal skin delamination, wrinkling and indentation. Debonding between the foam and egg‐box core is a typical failure mode for epoxy sandwich panels.

Enhanced thermal conductivity of UHMWPE by coating boron nitride and polyurethane composites

The development of textile wearable electronics has increased demands and requirements for thermal management materials due to integrated and miniaturized soft equipment. In this work, the surface of ultrahigh molecular weight polyethylene (UHMWPE) fibers was first decorated by polydopamine (PDA) to improve the surface activity and construct a steady interface layer. Then the boron nitride/polyurethane coating surface modified UHMWPE composite yarns with good thermal conductivity were produced using a coaxial wet forming process. The thermally conductive composite yarns demonstrated great mechanical properties (5.09 % strain, 0.79 N/tex strength) and thermal conductivity (0.54 ± 0.02 W·mK−1) with the BN/PU weight ratio of 1. Furthermore, the resistance to failure cycles was taken place, and the composite yarns kept good thermal conductivity after multiple cycles twisting, bending, washing, cooling and heating cycles. By the coaxial wet fabrication, the thermally conductive composite yarns were constructed, offering a viable and trustworthy method for creating polymer-based thermal interface materials with high thermal conductivity.

Effect of size and loading of waste single-used plastic (SUP) aggregates on a bio-based high density polyurethane composite

Abstract The utilization of waste single-use plastic (SUP) as fillers by containment in a polyurethane matrix was investigated as an alternative solution to the detrimental disposal of these waste materials. High-density bio-based rigid polyurethane composites were prepared by adding polyol, isocyanate, and additives, along with densified SUP, which served as aggregate fillers to enhance the bulk density and flexural strength of rigid polyurethane while increasing the thermal conductivity. The aggregated SUPs were prepared using agglomeration-densification machine and exhibited size variations of 12.44 mm (A), 14.12 mm (B), and 15.56 mm (C). The resulting aggregates were added to the rigid polyurethane matrix at varied loadings of 40%, 50%, and 60% v/v. The green composites were cured in heated hydraulic press at constant temperature and pressure. Based on the obtained results, it was found that the formulation with a SUP size of C and a loading of 60% produced the composite of highest bulk density due to relatively high density of agglomerated SUP as the size enlarges. Additionally, the SUP size of A and a loading of 50% (50A) exhibited the highest flexural strength value. This behaviour was attributed to the increased filler-matrix interfacial area achieved with the smallest size aggregates. However, a further increase in aggregate loading resulted in a decrease in this property as common attribute for composite materials. On the other hand, it was revealed that increasing the loading of SUP aggregates provided a lesser insulating effect due to the increase in thermal conductivity resulting from the presence of filled pores within the polyurethane foam. The findings of this study contributed to understanding the effects of aggregate size and loading on the mechanical and thermal properties of the composite material, providing valuable insights for the development of energy-efficient and environmentally-friendly polyurethane structures.

Hybrid lattice structure with micro graphite filler manufactured via additive manufacturing and growth foam polyurethane

The utilisation of lightweight structures is a common practice across a range of disciplines, including the construction of light steel frames, sandwich panels, and transportation infrastructure, among others. The advantages of lightweight structures include design flexibility, weight reduction, and the sustainability of materials that can be easily recycled. However, these advantages also present significant weaknesses. Compared to solid materials with compact weight, lightweight structures do not have the same characteristics. With the reduction in material weight, the strength of the lightweight structure decreases significantly compared to solid materials. In this study, the lightweight structure was made using additive manufacturing and reinforced with solid Composite Polyurethane Foam reinforced with graphite filler expanded into the lightweight structure. The results showed that in the compression test, the mixture with 2 % graphite filler had the highest value of 2.5 kN. The highest hardness test on the specimen with a 2 % graphite mixture was 19.8 HA. FT-IR testing showed that the carbon bonds from graphite in the 2 % specimen had the highest intensity. The test results showed that the addition of Polyurethane Foam into the structure could enhance material strength effectively without adding significant material weight.

Flame Retardancy and Thermal Stability of Rigid Polyurethane Foams Filled with Walnut Shells and Mineral Fillers.

Recently, the influence of the concept of environmental sustainability has increased, which includes environmentally friendly measures related to reducing the consumption of petrochemical fuels and converting post-production feedstocks into raw materials for the synthesis of polymeric materials, the addition of which would improve the performance of the final product. In this regard, the development of bio-based polyurethane foams can be carried out by, among other things, modifying polyurethane foams with vegetable or waste fillers. This paper investigates the possibility of using walnut shells (WS) and the mineral fillers vermiculite (V) and perlite (P) as a flame retardant to increase fire safety and thermal stability at higher temperatures. The effects of the fillers in amounts of 10 wt.% on selected properties of the polyurethane composites, such as rheological properties (dynamic viscosity and processing times), mechanical properties (compressive strength, flexural strength, and hardness), insulating properties (thermal conductivity), and flame retardant properties (e.g., ignition time, limiting oxygen index, and peak heat release) were investigated. It has been shown that polyurethane foams containing fillers have better performance properties compared to unmodified polyurethane foams.

Bio-Based Polyurethane Composites from Macauba Kernel Oil: Part 1, Matrix Synthesis from Glycerol-Based Polyol

Polyurethanes are the result of a reaction between an isocyanate and a polyol. The large variety of possible reagents creates many possible polyurethanes to be made, such as soft foams, rigid foams, coatings, and adhesives. This polymer is one of the most produced and consumed polymers in the world with an ever-increasing demand. Despite its usual petrochemical nature, research on bio-based polyurethanes flourishes due to the ease in creating bio-based polyols. This work covers the synthesis of a novel macauba kernel oil polyol by the epoxidation of the oil, followed by a ring-opening reaction of the epoxide with glycerol, used for the preparation of polyurethane foams using different NCO/OH ratios. The FTIR and H1 results confirm the formation of the epoxide and polyol, and the polymers in all NCO/OH ratios were confirmed by FTIR, showing great similarities between the samples, especially PU 1.0 and PU 1.2. Despite the TGs showing close behaviors for the three samples, their DTGs showed great difference between the samples, with PU 1.0 presenting a regular PU DTG profile with three degradation peaks while the other two sample presented five degradation peaks, indicating a higher crosslinking density in them.

Surfactant Regulated Chemical Modification of Rice Straw Powder for Biomass Composite Polyurethane Synthetic Leather

AbstractFor agricultural countries in Aisa, rice straw is a waste product, but also a valuable bioresource, with its recycling methods often drawing widespread attention. In this study, a novel multicomponent extraction method was proposed to perform comprehensive extraction of holocellulose and lignin from rice straw powder (RSP), resulting in modified rice straw powder (MRSP) with different micro‐morphologyies. The results indicate that the cosolvent tetraethylammonium chloride (TEAC) is more effective for extracting holocellulose and lignin compared to others, and different surfactants have decisive impacts on the extraction of holocellulose and lignin from RSP. Among them, anionic surfactants aid in the extraction of holocellulose, with sodium allylate sulfonate (SAS) being superior due to its greater changes in allyl polarity. Conversely, cationic surfactants facilitate the extraction of lignin, with octadearyl trimethyl ammonium chloride (OTAC) being superior due to the length of its alkyl‐carbon chain. And the quantized contribution of hydrophilic and hydrophobic groups of surfactants to the extraction of holocellulose and lignin, as well as, the different micromorphology of MRSP is obtained. Additionally, compared to the traditional PU (polyurethane) modified by eucalyptus wood powder (EWP/PU), the MRSP was used to prepare a series of biomass composite polyurethane synthetic leather (MRSP/PU), its tensile strength and peel strength of MRSP/PU coatings are greatly enhanced at the feedstock of 18 %.

Solvent-free preparation of carbon fiber reinforced dynamically cross-linked vanillin-based polyurethane composites with excellent self-healing and closed-loop recycling performance

Disposing of the wastes generated from the carbon fiber reinforced polymer (CFRP) composite materials after service failure has attracted great attention in recent years. CFRP composites prepared with dynamically covalent cross-linking polymers as matrix resins possess excellent self-healing and recyclability performance, providing an efficient solution to overcome this challenge. However, most of the dynamic cross-linking resins are typically made by high-cost petroleum-derived compounds with extensive use of organic solvents and environmentally unfriendly catalysts. Herein, catalyst-free self-healing and recyclable vanillin-based polyurethanes (V-PUs) via dynamic phenol-carbamate bonds were synthesized by a one-step solvent-free method with a biodegradable PCL as soft segment and biobased vanillin derivative as the chain extender. The optimized V-PUs exhibit Young's modulus of 1.92 GPa, stress at break of 64.98 MPa, glass transition temperature of 95 °C, and over 90 % self-healing and reprocessing efficiency. This excellent self-healing and reprocessing performance can be successfully transferred to the CFRP composite materials fabricated with the V-PUs as matrix resins by hand paste-vacuum bag pressing method. The interlayer shear strength (ILSS) of the composite material is 41 MPa, and the healing efficiency determined by ILSS reaches 85.34 %. Closed-loop recovery of the carbon fiber and matrix resin from the CFRP composite is realized through the solvent dissolution approach due to the dynamic character of the phenol-carbamate bonds, which is of great significance for the development of green economy and sustainable society.

Synthesis of bio-polyol-functionalized nanocrystalline celluloses as reactive/reinforcing components in bio-based polyurethane foams by homogeneous environment modification

Nanocrystalline Cellulose (NCC or CNC) is widely used as a filler in polymer composites due to its high specific strength, tensile modulus, aspect ratio, and sustainability.However, CNC hydrophilicity complicates its dispersion in hydrophobic polymeric matrices giving rise to aggregate structures and thus compromising its reinforcing action. CNC functionalization in a homogeneous environment, through silanization with trichloro(butyl)silane as a coupling agent and subsequent grafting with bio-based polyols, is herein investigated aiming to enhance CNC dispersibility improving the filler-matrix interaction between the hydrophobic PU and hydrophilic CNC. The modified CNCs (m_Ci) have been studied by XRD, SEM, and TGA analyses. The TGA results show that the amount of grafted polyol is strongly influenced by both its molar mass and OH number and the maximum amount of grafted polyol reaches up to 0.32 mmol per grams of functionalized CNC, within the explored conditions. The effect of different concentrations (1–3 wt%) of m_Ci on the physical, morphological, and mechanical properties of the resulting bio-based composite polyurethane foams is evaluated. Composite PU foams present compressive modulus up to 4.81 MPa and strength up to 255 kPa more than five times higher than those reinforced with unmodified CNC or with modified CNC in heterogeneous chemical environment. The improvement of mechanical properties of the examined PU foams, as a consequence of the incorporation of bio-polyols modified CNCs where polyol's OH groups interact with polyurethane precursors, could further broaden the use of these materials in building applications.

Environmentally Friendly Biocomposites for The Adsorption of Mancozeb Pesticide from Water

Objective: Developing polyurethane foams and composites incorporating petroleum catalyst residue (RC) and rice husk ash (RHA) to adsorb the pesticide mancozeb from water. Theoretical Framework: The annual global consumption of pesticides reaches 2.6 million tons, resulting in significant environmental impacts. Not only does this excess increase health risks, but the persistence of pesticides in water bodies emphasizes the need for effective alternatives for their removal, such as adsorption using polyurethane foams. Method: The polyurethane composites were synthesized with the incorporation of 20% and 50% of RC and RHA waste, respectively, in relation to the total mass of polyols. Characterization analyses were carried out using thermogravimetry, Fourier Transform Infrared Spectroscopy and X-ray diffraction. The composites were immersed in aqueous solutions of mancozeb at a concentration of 500 ppm, stirred for 24 hours at 150 rpm and the solution analyzed by UV-Vis. Results and Discussion: The foams showed chemical and dimensional stability. The composites synthesized with a high amount of waste incorporated achieved greater adsorption capacity. Research Implications: Este trabalho promove a economia circular ao desenvolver compósitos de poliuretano que incorporam resíduos para a remoção eficiente de pesticidas da água. Originality/Value: The results are promising for the use of waste in the production of sustainable polyurethane foams that can be applied in the water purification process.

A Soft, Fatigue‐free, and Self‐healable Ionic Elastomer via the Synergy of Skin‐like Assembly and Bouligand Structure

AbstractSoft ionic elastomers that are self‐healable, fatigue‐free, and environment‐tolerant are ideal structural and sensing materials for artificial prosthetics, soft electronics, and robotics to survive unpredictable service conditions. However, most synthetic strategies failed to unite rapid healing, fatigue resistance, and environmental robustness, limited by their singular compositional/structural designs. Here, we present a soft, tough, fatigue‐resistant, and self‐healable ionic elastomer (STFSI elastomer), which fuses skin‐like binary assembly and Bouligand helicoidal structure into a composite of thermoplastic polyurethane (TPU) fibers and a supramolecular ionic biopolymer. The interlocked binary assembly enables skin‐like softness, high stretchability, and strain‐adaptive stiffening through a matrix‐to‐scaffold stress transfer. The Bouligand structure contributes to superhigh fracture toughness (101.6 kJ m−2) and fatigue resistance (4937 J m−2) via mechanical toughening by interlayer slipping and twisted crack propagation path. Besides, the STFSI elastomer is self‐healable through a “bridging” method and environment‐tolerant (−20 °C, strong acid/alkali, saltwater). To demonstrate the versatile structural and sensing applications, we showcase a safety cushion with efficient damping and suppressed rebounding, and a robotic sensor with excellent fatigue crack tolerance and instant sensation recovery upon cutting‐off damage. Our presented synthetic strategy is generalizable to other fiber‐reinforced tough polymers for applications involving demanding mechanical/environmental conditions.

Influence of the Dispersion of Carbon Nanotubes on the Electrical Conductivity, Adhesion Strength, and Corrosion Resistance of Waterborne Polyurethane Composites

Due to the presence of many flammable substances in the working environments of the petrochemical industry, anticorrosive conductive coatings need to be used on metal equipment to avoid safety accidents like fires. However, existing conductive solvent-based coatings are volatile when exposed to flammable and toxic organic solvents. Thus, in this work, a series of eco-friendly anticorrosive waterborne polyurethane (WPU) composites with multi-walled carbon nanotubes (MWCNTs) were prepared via a low-cost and practical process; the dispersion of MWCNTs was revealed when present in different amounts, and the mechanism behind the conduction of WPU composites was determined. We concluded that low amounts of MWCNTs were well dispersed, generating a conductive network, and the WPU composite was not entirely covered by the MWCNT particles, so the electrical conductivity in certain parts of the coating was good. When the content of MWCNTs was excessive, some stretched MWCNTs dispersed to the top of the composite and many MWCNTs agglomerated at the bottom. Additionally, when the content of MWCNTs was increased, the electrical conductivity, corrosion resistance, and adhesion strength of the WPU composite decreased. Our results could provide a theoretical foundation for the preparation of anticorrosive conductive waterborne composites for protecting equipment in the petrochemical industry.