Thermoplastic Polyurethane Matrix Research Articles

3D printing-directed flexible strain sensors of accordion-like architecture to achieve ultrastretchability with the assist of ultrasonic cavitation treatment

A new class of accordion-like cellular architecture with sinusoidal struts is designed to enhance the planar stretchability of cellular solids, aiming to fabricate flexible strain sensors with ultrastretchability. The combination manufacturing process of fused deposition modeling (FDM) 3D printing technique and ultrasonic cavitation-enabled treatment was introduced into the fabrication of flexible strain sensors made of thermoplastic polyurethane (TPU) substrate and carbon nanotubes (CNTs). A negative Poisson’s ratio (NPR) architecture made of TPU was firstly 3D-printed by FDM. The ultrasonic cavitation treatment was then conducted on the soft auxetic structure immersing in CNTs liquid, aiming to embed the CNTs into the surface layer of the flexible TPU substrate with NPR configurations. Instead of 3D printing the TPU matrix composite after hybridization inside the matrix material, the hybrid manufacturing procedure can ensure that the intrinsic excellent mechanical properties of TPU are not embrittled. Besides, the sinusoidal struts in accordion-like cellular architectures offer a design route to extend the material property chart to achieve ultrahigh stretchability in lightweight 3D printable flexible polymers for the applications that require combined stretchability, lightweight, and energy absorption such as soft robotics, stretchable electronics, and wearable protection shields.

High-Performance, Lightweight, and Flexible Thermoplastic Polyurethane Nanocomposites with Zn2+-Substituted CoFe2O4 Nanoparticles and Reduced Graphene Oxide as Shielding Materials against Electromagnetic Pollution.

The development of flexible, lightweight, and thin high-performance electromagnetic interference shielding materials is urgently needed for the protection of humans, the environment, and electronic devices against electromagnetic radiation. To achieve this, the spinel ferrite nanoparticles CoFe2O4 (CZ1), Co0.67Zn0.33Fe2O4 (CZ2), and Co0.33Zn0.67Fe2O4 (CZ3) were prepared by the sonochemical synthesis method. Further, these prepared spinel ferrite nanoparticles and reduced graphene oxide (rGO) were embedded in a thermoplastic polyurethane (TPU) matrix. The maximum electromagnetic interference (EMI) total shielding effectiveness (SET) values in the frequency range 8.2–12.4 GHz of these nanocomposites with a thickness of only 0.8 mm were 48.3, 61.8, and 67.8 dB for CZ1-rGO-TPU, CZ2-rGO-TPU, and CZ3-rGO-TPU, respectively. The high-performance electromagnetic interference shielding characteristics of the CZ3-rGO-TPU nanocomposite stem from dipole and interfacial polarization, conduction loss, multiple scattering, eddy current effect, natural resonance, high attenuation constant, and impedance matching. The optimized CZ3-rGO-TPU nanocomposite can be a potential candidate as a lightweight, flexible, thin, and high-performance electromagnetic interference shielding material.

High-performance flexible strain sensors based on biaxially stretched conductive polymer composites with carbon nanotubes immobilized on reduced graphene oxide

In this paper, reduced graphene oxide (rGO), decorated with immobilized carbon nanotubes (CNTs), was introduced into a thermoplastic polyurethane (TPU) matrix to obtain a conductive nanocomposite with 2 wt% nanofillers content. Hot-pressed composite sheets were then biaxially stretched into films to efficiently fabricate flexible strain sensors. The biaxial stretching process was shown to promote secondary dispersion and parallel alignment of the nanofillers, resulting in the sensors exhibited significantly higher sensitivity (GF = 150 for the rGO/TPU4×4 sensor with a stretching ratio of 4 × 4 relative to GF = 3.5 for the rGO/TPU1×1 sensor at 30% strain). Furthermore, due to the synergy of the CNTs and rGO nanoparticles, the rGO/CNT/TPU4×4 sensor had a lower resistivity (5.62 × 104 Ω·m), wider monitoring range (0.3 ∼ 400% strain), and higher stability compared with the rGO/TPU4×4 sensor. The ability of the sensor to recognize body movements and physiological activities was also shown.

Fabrication of wrinkled thermoplastic polyurethane foams by dynamic supercritical carbon dioxide foaming

Precise control and regulation of the cell structure in supercritical CO2 (scCO2) foaming is the key to boost the performance and extend the application of polymer foams. In this work, dynamic scCO2 foaming method is proposed to fabricate thermoplastic polyurethane (TPU) foams with unique wrinkly structures by introducing a continuous scCO2 flow field during scCO2 saturation. The scCO2 flow field applied on the TPU matrix generated intramolecular stress and resulted in the formation of wrinkles on the surface of cells. The structure of wrinkles was controlled by pivotal processing factors including foaming temperature, pressure, scCO2 flow rate, and scCO2 flow time. Attributing to the wrinkly structure, the wrinkled foams possessed superior compressive modulus, strength, recoverability, and energy absorption performance than conventional TPU foams, which make them a promising material for buffering and energy absorption applications. The dynamic scCO2 foaming method opens avenue for scCO2 foaming process involves dynamic field.

Flexible Fiber Membrane Based on Carbon Nanotube and Polyurethane with High Thermal Conductivity.

The development of high thermally conductive polymer composites with low filler content remains challenging in the field of thermal interface materials (TIMs). Herein, we fabricated a series of flexible fiber membranes (TMMFM) with high thermally conductive based on thermoplastic polyurethane (TPU) and acidified multiwalled carbon nanotubes (a-MWCNTs) via electrospinning and ultrasonic anchoring method. The SEM and TEM results demonstrated that the a-MWCNTs aligned along the fiber orientation in the membrane and anchored on the membrane surface strongly, which can establish the heat conduction path both in the horizontal and vertical directions. With the incorporation of 10 wt% a-MWCNTs, the horizontal direction (λ∥) and vertical direction (λ⊥) thermal conductivity value of TMMFM-5 was 3.60 W/mK and 1.79 W/mK, respectively, being 18 times and 10 times higher compared to pure TPU fiber membranes. Furthermore, the TMMFM maintained favorable flexibility of the TPU matrix because the small amount of a-MWCNTs only slightly hinders the mobility of the TPU molecular chain. The performance of the obtained TMMFM unveils their potential as a promising choice of flexible TIMs.

High content filling, toughness, and conductive performance of thermoplastic polyurethane/carbon nanotubes composites prepared by constructing the compact interface

Conductive polymer composites have drawn significant attentions. However, the low interface between nanomaterials and polymer matrix may result in the failure of function during the applications. Herein, we report a simple, effective, and scalable strategy for the fabrication of thermoplastic polyurethane (TPU)/carbon nanotube (CNT) composites with high content filling, good interfaces, and high toughness. The distribution of CNT in the TPU matrix was well regulated using a binary-solvent assisted non-solvent induced phase separation method to solve the interface problem. The results showed that the hydrogen-bonding was beneficial to the construction of a good interface, and the thermal stabilities of the polyurethane/carbon nanotubes composite films (PCCFs) were significantly improved. Most importantly, the as-prepared PCCF with 25% CNT exhibited a tensile stress of 20.3 ± 1.7 MPa, a strain of 1084.7 ± 206.9%, and toughness of 171.9 ± 39.8 MJ m−3, respectively, mainly ascribed to a microcrack, a CNT bridge, CNT orientation, and pulled-out CNT. The flexible films also showed good conductivity under strain of 0–200%. These findings suggested that the technique described herein is broadly applicable in the design and fabrication of a new kind of conductive and tough composites.

Effect of terbium(III) species on the structure and physical properties of polyurethane (TPU)

Herein, a study is presented, addressed to understand the influence of the terbium (III) species contained in a thermoplastic polyurethane (TPU) matrix. The studied terbium (III) species were terbium (III) nitrate, Tb(NO3)3·5H2O, and a terbium (III) complex, [TbL (NO3)2](NO3) (H2O), where L is a macrocyclic ligand derived from 2,6-pyridinedicarboxyaldehyde and ethylenediamine. SEM-EDXS showed that in both films the terbium (III) species were homogeneously distributed in the polymer matrix. The film doped with the nitrate salt displayed different physical properties, in comparison to the pristine TPU and the film containing the terbium (III) complex.Both TPU/TbIII films, exhibiting a green color emission, with a G/B ratio being temperature independent. By comparison of the emission of both films containing terbium (III) species, the TPU/TbIII complex film presented a more intense luminescence due to the antenna effect. TPU doped with the nitrate salt showed weak emission, indicating the lack of sensitizing groups.

Rational formulations of sustainable polyurethane/chitin/rosin composites reinforced with ZnO-doped-SiO2 nanoparticles for green packaging applications

Polysaccharide chitin (CH) was modified by antimicrobial natural gum rosin as a biocompatible agent within the thermoplastic polyurethane (TPU) elastomer to form the TPU/CH composite. This blend was then mixed with different ratios of ZnO-doped-SiO2 nanoparticles (ZnO-SiO2-NPs) to chelate chitin and to improve the properties of TPU nanocomposites. The topology and surface roughness of chitin and nanoparticles within the TPU matrix, besides their effect on the crystallinity degree of TPU were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD). The TPU nanocomposites are subjected to different measurements such as mechanical, thermal, hydrophobicity, flammability, water vapor, and oxygen barrier properties, as well as antimicrobial activity. The results showed that the major properties were improved when the nanoparticles were added, especially at 5 wt%. Furthermore, the TPU/CH blend reinforced with high contents of NPs (i.e., 5–7 wt%) exhibited efficient antimicrobial activities against Gram-negative, Gram-positive bacteria and, pathogenic fungi.

Rheological properties of cellulose nanocrystals isolated via mechanical methods in thermoplastic polyurethane matrix

Thermoplastic polyurethanes (TPU) are known for their versatility because they have both thermoplastic and elastomeric properties. Improvement of TPU properties can be accomplished by reinforcement with nanoscale fillers. Cellulose nanocrystals (CNC) are the most attractive nano-filler for reinforcement purposes in polymer matrices because of their high crystallinity and biodegradable materials. Mechanical methods to isolate CNC has sparked interest among researchers due to environmental demands (less solvent consumption). Lately, several researchers also have revealed some remarkable improvement of TPU through the addition of CNC. Thus, this study was aimed to produce CNC via mechanical methods for and to study the rheological properties of CNCs in the TPU matrix to gain insight interactions between CNCs and TPU. Isolation of CNCs via two methods: ultra-sonication (CNC-U) and nano-grinding (CNC-N) methods have been carried out. Then, the CNCs (0.5–2 wt%) were added into the TPU network employing the solution mixing method. The CNC was characterized via FESEM and the rheological behaviour was investigated on TPU/CNC solution. The main outcomes are that CNC-N has shown a higher aspect ratio (10–15), higher yield (>40%), and lower time and energy consumption than CNC-U. Rheological properties of TPU/CNC solution offer its structure-properties relationship via the increase in the concentration of CNCs. At 2 wt% concentration, TPU/CNC-N shows higher viscosity (19.5 Pa.s) than TPU/CNC-U (15.9 Pa.s). Thus, it was proven that the nanocomposite tends to act as a solid than liquid due to higher elastic behaviour. Furthermore, we can suggest the utilization of mechanical methods to produce a high yield of CNCs in notify the environmental issues.

Advanced dielectric elastomer based on optimized thermoplastic polyurethane–styrene ethylene butylene styrene blend: Experiment and simulation

AbstractIncreasing the actuation characteristics of dielectric elastomer actuators (DEAs) under low electric field strength without compromising the elasticity and breakdown strength is still one of the great challenges in application field. Herein, we propose a simple, efficient, and controllable strategy to prepare dielectric elastomers with intrinsically good integrated properties by introducing styrene ethylene butylene styrene (SEBS) in thermoplastic polyurethane (TPU). Combined with experiments and molecular dynamics simulation, we find that the SEBS is uniformly dispersed in TPU matrix and a good interface structure is formed by pi–pi interaction and entanglement. The above characteristics lead to the destruction of the hydrogen bond network of TPU and the formation of single aggregation structure. Consequently, much decreased Young's modulus (Y) and enhanced breakdown field (Ebr) are achieved. Especially, when the content of SEBS is 4.76 wt%, the blend shows a desirable Y of 2.4 MPa and a much improved Ebr (118 kV mm−1), which is about 59% lower and 42% higher than those of TPU, respectively. As a result, the maximum electrical strain area of the dielectric blend elastomer reaches 4.7%, which is 250% higher than that of pure TPU under the same electric field strength.

Highly efficient MXene/Nano-Cu smoke suppressant towards reducing fire hazards of thermoplastic polyurethane

A large number of toxic fumes evolved from polymeric materials are a great threat to human evacuation. The aim of this work is to dramatically reduce the generation of smoke and toxic gaseous products upon polymers burning. A highly efficient titanium carbide/nano-copper (Ti3C2Tx/Nano-Cu) hybrid smoke suppressant was synthesized by interficial adhesion and then incorporated into thermoplastic polyurethane (TPU) to fabricate TPU nanocomposites. The Ti3C2Tx/Nano-Cu hybrid was homogeneously dispersed in the TPU matrix and showed a strong interfacial interaction with the TPU host. Introducing the Ti3C2Tx/Nano-Cu hybrid into TPU led to enhanced high-temperature stability. Furthermore, the smoke production rate, CO production rate and total CO yield of the TPU nanocomposite containing 2 wt% Ti3C2Tx/Nano-Cu hybrid decreased by 66.7%, 51.8% and 52.9%, respectively, compared with those of pure TPU. The reduced fire hazards of the TPU were due to the physical barrier, the catalytic charring and the chemical conversion of Ti3C2Tx/Nano-Cu hybrid.

Fabrication of thermoplastic polyurethane with functionalized MXene towards high mechanical strength, flame-retardant, and smoke suppression properties

Recently, two-dimensional MXene demonstrated promising advantages to improve the flame-retardant performance of composites; however, its compatibility with polymer matrix is a great concern. In this study, MXene was first functionalized with phosphorylated chitosan (PCS) to obtain the PCS-MXene nanohybrid. The resulting nanohybrid was introduced into the thermoplastic polyurethane (TPU) matrix via solution mixing followed by the hot-pressing method, affording TPU/PCS-MXene nanocomposite. The resulting nanohybrid exhibited superior compatibility with the TPU matrix, enhancing mechanical performance of the TPU/PCS-MXene nanocomposite compared to the pristine TPU and TPU/MXene nanocomposite. Besides, the flame-retardant performance of TPU/PCS-MXene nanocomposite was greatly enhanced, while the smoke emission was effectively suppressed. As only 3 wt% PCS-MXene was introduced, peak heat release rate, total heat release, and total smoke production of the composite decreased by 66.7%, 21.0%, and 27.7%, respectively, compared to the pristine TPU. Systematical characterization was then carried out to investigate the enhancement mechanism of PCS-MXene, highlighting the crucial role of PCS combined with the catalytic effect of MXene. In brief, the compatibility issues of MXene were effectively addressed, and its flame-retardancy enhanced greatly via the PCS modification, the bio-based characteristic of which, in turn greatly benefits the further development of MXene-polymer composite.

Low friction thermoplastic polyurethane coatings imparted by surface segregation of amphiphilic block copolymers

This study aims to hydrophilize thermoplastic polyurethane (TPU) surface via selective segregation of amphiphilic block copolymers from bulk TPU matrix, namely “inverted grafting-to” approach. To this end, hydrophilic poly(ethylene glycol) (PEG) polymer chain was employed in either diblock (polycaprolactone-b-poly(ethylene glycol) (PCL-b-PEG)) or triblock (poly(ethylene glycol)-b-poly(propylene glycol)-b-poly(ethylene glycol) (PEG-b-PPO-b-PEG)) amphiphilic copolymer additives in polymer matrix. Greatly reduced water contact angles, as low as ca. 13°, from ≥90° for bare substrate proved the successful hydrophilization of TPU surface by this approach, although the degree of hydrophilization was significantly affected by the structure and concentration of embedded amphiphilic copolymers. Moreover, PEG-functionalized TPU surfaces in this approach displayed a reduction of coefficient of friction (COF) by two orders of magnitude. Given that TPU is a widely used material for urinary catheter or other medical devices, we demonstrated a first promising application as lubricious coating to TPU-based urinary catheter tubes.

Investigating Physio-Thermo-Mechanical Properties of Polyurethane and Thermoplastics Nanocomposite in Various Applications.

The effect of the soft and hard polyurethane (PU) segments caused by the hydrogen link in phase-separation kinetics was studied to investigate the morphological annealing of PU and thermoplastic polyurethane (TPU). The significance of the segmented PUs is to achieve enough stability for further applications in biomedical and environmental fields. In addition, other research focuses on widening the plastic features and adjusting the PU–polyimide ratio to create elastomer of the poly(urethane-imide). Regarding TPU- and PU-nanocomposite, numerous studies investigated the incorporation of inorganic nanofillers such as carbon or clay to incorporating TPU-nanocomposite in several applications. Additionally, the complete exfoliation was observed up to 5% and 3% of TPU–clay modified with 12 amino lauric acid and benzidine, respectively. PU-nanocomposite of 5 wt.% Cloisite®30B showed an increase in modulus and tensile strength by 110% and 160%, respectively. However, the nanocomposite PU-0.5 wt.% Carbone Nanotubes (CNTs) show an increase in the tensile modulus by 30% to 90% for blown and flat films, respectively. Coating PU influences stress-strain behavior because of the interaction between the soft segment and physical crosslinkers. The thermophysical properties of the TPU matrix have shown two glass transition temperatures (Tg’s) corresponding to the soft and the hard segment. Adding a small amount of tethered clay shifts Tg for both segments by 44 °C and 13 °C, respectively, while adding clay from 1 to 5 wt.% results in increasing the thermal stability of TPU composite from 12 to 34 °C, respectively. The differential scanning calorimetry (DSC) was used to investigate the phase structure of PU dispersion, showing an increase in thermal stability, solubility, and flexibility. Regarding the electrical properties, the maximum piezoresistivity (10 S/m) of 7.4 wt.% MWCNT was enhanced by 92.92%. The chemical structure of the PU–CNT composite has shown a degree of agglomeration under disruption of the sp2 carbon structure. However, with extended graphene loading to 5.7 wt.%, piezoresistivity could hit 10−1 S/m, less than 100 times that of PU. In addition to electrical properties, the acoustic behavior of MWCNT (0.35 wt.%)/SiO2 (0.2 wt.%)/PU has shown sound absorption of 80 dB compared to the PU foam sample. Other nanofillers, such as SiO2, TiO2, ZnO, Al2O3, were studied showing an improvement in the thermal stability of the polymer and enhancing scratch and abrasion resistance.

Vermicular Ni@RL-CS: Preparation, characterization and its applications in electromagnetic shielding

One-dimensional conductive materials are of great significance to the construction of conductive network in the polymer matrix due to their large aspect ratio. In this work, a nickel-plated rod-like calcium silicate composite (Ni@RL-CS) with unique vermicular structure was successfully fabricated by an electroless plating method. The structure and property of as-prepared Ni@RL-CS were characterized, and its electromagnetic shielding ability was evaluated through mixing with thermoplastic polyurethane (TPU). Results indicate that the Ni@RL-CS shows good electrical conductivity, magnetic property and strong dielectric loss ability. The Ni@RL-CS with a one-dimensional vermicular structure is easier to construct a continuous conductive network in TPU matrix, which greatly improves the electromagnetic shielding effectiveness of the TPU resin. TPU/Ni@RL-CS binary composite with 20 vol% Ni@RL-CS achieves ultrahigh specific EMI SE/thickness of 92.6 dB/mm in the frequency of X-band. By further hybridizing Ni@RL-CS with GNPs, the TPU/Ni@RL-CS/GNPs trinary composite exhibits excellent electromagnetic shielding performance. When the contents of Ni@RL-CS and GNPs are 10 vol% and 1.5 vol%, respectively, the specific EMI SE/thickness of the corresponding trinary composite reaches 74.6 dB/mm in the X-band owe to the dense conductive network, which is 56.5% higher than that of the binary TPU/Ni@RL-CS composite with the same content of 10 vol% Ni@RL-CS.. The synergistic effects of dielectric loss, magnetic loss, and the interfacial polarization loss are the main shielding mechanism. This work provides a strategy to prepare a functional filler based on an insulating inorganic material for electromagnetic shielding. The as-prepared Ni@RL-CS with the unique vermicular structure and outstanding electromagnetic shielding performance can serves as a functional filler to modify polymers for electromagnetic shielding applications.

Tribological behaviour of biocompatible TPU composites with reinforced titanium

ABSTRACT This paper elucidates the experimental investigation based on the tribological performance of abrasive wear for titanium microparticlereinforced biocompatible grade thermoplastic polyurethane (TPU) composites andits characterization. The biocompatible titanium is used as particulates in the composition of 0, 1, 2, and 4 wt% under the TPU matrix. The effect of filler material on different parameters like weight loss, wear index, specific wear rate, and wear coefficient on abrasive wear performance is evaluated under the study for biomedical implants. The ploughing of particles from the specimen surface shows, the higher wt% of titanium microparticles increases the hardness gradually in all samples. As a result, there is a decrease in wear coefficient, wear index, and specific wear rate from 0 to 2 wt%, but it increases in the sample of 4 wt%, which shows the higher weight loss from the specimen volume concerning the shore hardness of the composite.

Influence of the Halloysite Nanotube (HNT) Addition on Selected Mechanical and Biological Properties of Thermoplastic Polyurethane.

Halloysite nanotube (HNT) additions to the thermoplastic polyurethane (TPU) system were thoroughly evaluated in this study. The resultant composites have been designed for future personalized intervertebral disc implant applications, which requires additional technology to obtain the appropriate geometry unique to each patient. These requirements can be fulfilled using 3D printing. In this work, a technology was developed to produce filaments for fused deposition modeling (FDM). Nanocomposites were prepared using variable HNT content (1, 2, and 3 wt.%). The nanostructure of the resultant composites was confirmed using scanning transmission electron microscopy (STEM). Mechanical tests were used to measure the tensile modulus, stress, and elongation the composites and TPU matrix. Nanocomposites with 2% HNT content were able to withstand 26% increased stress and 50% increased elongation compared to pure TPU before fracturing in addition to a 13% reduction in the friction coefficient. A MTT cytotoxicity assay confirmed the cytotoxicity of all tested materials against human epidermal keratinocyte cells (HaCaT).

Interface engineering of graphene oxide containing phosphorus/nitrogen towards fire safety enhancement for thermoplastic polyurethane

The high flammability and generation of toxic volatiles during combustion are big obstacles for thermoplastic polyurethane (TPU). In this work, a 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) derivate containing phosphorus and nitrogen was synthesized and then grafted onto the surface of graphene oxide (GO-DOPO) by using a silane agent [(3-glycidyloxypropyl)trimethoxysilane] as the chemical bridge. Then the GO-DOPO was mixed with TPU by melt compounding to improve its flame retardancy. Tensile tests exhibited that the TPU/GO-DOPO nanocomposite maintained high ductility with a slight increase in tensile stress. The cone calorimeter tests exhibited that the incorporation of 2 wt% GO-DOPO into TPU presented a significant reduction in peak heat release rate (35.8%) and peak smoke production rate (50%), respectively, as compared with those of pure TPU. Meanwhile, the peak of CO production rate and the peak of CO2 production rate decreased by 57.1% and 35.9%, respectively. The investigation of the flame retardant mechanism for TPU nanocomposites revealed that the presence of GO-DOPO in TPU contributed to generating the compact, continuous and higher graphitized char layer exerted barrier effect in condensed phase, protecting the underlying TPU matrix. This work provides a feasible functionalization approach of GO to enhance the fire safety of TPU nanocomposites without sacrificing the superior mechanical properties, which facilitates the promising applications of TPU in various fields.

Visco-Poroelastic Electrochemiluminescence Skin with Piezo-Ionic Effect.

Following early research efforts devoted to achieving excellent sensitivity of electronic skins, recent design schemes for these devices have focused on strategies for transduction of spatially resolved sensing data into straightforward user-adaptive visual signals. Here, a material platform capable of transducing mechanical stimuli into visual readout is presented. The material layer comprises a mixture of an ionic transition metal complex luminophore and an ionic liquid (capable of producing electrochemiluminescence (ECL)) within a thermoplastic polyurethane matrix. The proposed material platform shows visco-poroelastic response to mechanical stress, which induces a change in the distribution of the ionic luminophore in the film, which is referred to as the piezo-ionic effect. This piezo-ionic effect is exploited to develop a simple device containing the composite layer sandwiched between two electrodes, which is termed "ECL skin". Emission from the ECL skin is examined, which increases with the applied normal/tensile stress. Additionally, locally applied stress to the ECL skin is spatially resolved and visualized without the use of spatially distributed arrays of pressure sensors. The simple fabrication and unique operation of the demonstrated ECL skin are expected to provide new insights into the design of materials for human-machine interactive electronic skins.

Functionalizing MXene towards highly stretchable, ultratough, fatigue- and fire-resistant polymer nanocomposites

Thermoplastic polyurethane (TPU) features many important industrial applications, but intrinsic flammability extremely impedes its practical applications. Current fire-retardant strategies often lead to improved flame retardancy but reduced mechanical properties (strength, ductility, and toughness). Hence, to date it has been unsuccessful to design advanced TPU materials that are strong, stretchable, tough, fatigue-and fire-resistant to meet increasing performance portfolio requirements. Here, we report a hybridized fire retardant (Zr-MXene) by in situ facilely loading zirconium amino-tris-(methylenephosphonate) (Zr-AMP) onto the titanium carbide (MXene) surface. Our results show that with 1 wt% of Zr-MXene, the resultant TPU nanocomposites demonstrate a record break strain (2060%) and toughness (316 MJ/m3) to date, in addition to increased tensile strength by 43.4% and improved fatigue resistance relative to the TPU matrix, because of favorable interfacial hydrogen-bonding. Moreover, the resultant TPU material exhibit significantly reduced flammability as a result of the combined physical barrier, catalytical carbonization and diluting effects of Zr-MXene. This work provides a promising strategy for the creation of multifunctional MXene and its polymeric nanocomposites, which hold great promise for many industrial applications.