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Purpose: To evaluate the correspondence between output from a new artificial intelligence tool (AIT) and clinician evaluation regarding the immediate loading suitability of dental implants based on insertion torque curves recorded during implant placement in an in vitro test. The secondary aim was to analyze peak insertion torque (PIT) and variable torque work (VTW) values of the implants. Materials and Methods: The study was performed with four different densities of artificial bone blocks of solid rigid polyurethane without a cortical layer. Five types of implants with different macrogeometries were used. A total of 140 implants (7 implants of each type in the four polyurethane blocks) were inserted. Immediately after implant placement, the insertion torque curves were classified by the operator as suitable (S) or nonsuitable (NS) for immediate loading. The same curves were then analyzed by the new AIT, which classified them as belonging to the "YES" or "NO" class. For each implant, PIT and VTW values were also recorded. Results: The correspondence between clinician and AIT evaluation was 99.3%, with only one false negative reported by the algorithm analysis. The AIT was found to have a sensitivity of 98.95%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 97.8%. Mean PIT of the whole sample was 34.19 ± 19.43 Ncm, while mean VTW was 2,266.89 ± 1,993.73 Ncm. Statistically significant differences were found between implant systems in the whole sample and according to density of the polyurethane block. Conclusions: The AIT showed a high level of accuracy in the prediction of immediate loading suitability of dental implants based on the provided insertion torque curves. All the implants used in the in vitro test achieved good levels of primary stability, except when inserted in the least-dense polyurethane block. Clinical studies conducted with larger samples and more clinicians are necessary to confirm these results. [ABSTRACT FROM AUTHOR]

Polyurethanes have been extensively studied for their strong electromechanical response. Previous studies have mainly investigated the impact of electrical charges on these polymers' DC conductivity, which was measured on the order of 10−10 S/m. The movement of electric charges is responsible for the macroscopic deformation of polymer films under an electric field. However, this study focused primarily on electric fields below 107 V/m, where the electric current complies with Ohm's law. In this paper, we examine the electric current above this field value and observe a deviation in the current from linearity with the applied field, especially for a high electric field of 106–107 V/m. This change is known in polymers under high electric fields but has never been observed in polyurethane. This suggests the injection of electrode charges into the polymer material. This article provides the threshold at which the transition occurs from linear (Ohm's law) to nonlinear conduction as a result of injected electric charges. [ABSTRACT FROM AUTHOR]

Purpose: To assess whether a recently introduced implant placement micromotor that provides site-specific, operatorindependent cancellous bone density measurements can detect the presence of a cortical bone layer and measure its thickness and density. Materials and Methods: An in vitro experiment was performed on six double-layer polyurethane foam blocks mimicking the jawbone with different cortical thickness/cancellous density combinations. The densities were measured using the micromotor after either removing the cortical layer or leaving it intact, both with and without irrigation. Results: The results were compared by means of nonparametric statistical tests. Independent of irrigation, the micromotor detected the cortical layer when it was left intact and accurately estimated its thickness. The micromotor did not discriminate between blocks when they were considered separately, but it did when they were grouped into four or three classes. Conclusions: The present study suggests that the micromotor may represent a valid device to quantitatively assess bone quality and density. If the micromotor can quantitatively distinguish different cortical/cancellous bone combinations in humans, it may be a helpful tool for performing finely tuned, patient-tailored preparations of the implant seat, making tooth rehabilitation in challenging clinical conditions more predictable. [ABSTRACT FROM AUTHOR]

The accumulation of microplastics in various ecosystems has now been well documented and recent evidence suggests detrimental effects on various biological processes due to this pollution. Accumulation of microplastics in the natural environment is ultimately due to the chemical nature of widely used petroleum-based plastic polymers, which typically are inaccessible to biological processing. One way to mitigate this crisis is adoption of plastics that biodegrade if released into natural environments. In this work, we generated microplastic particles from a bio-based, biodegradable thermoplastic polyurethane (TPU-FC1) and demonstrated their rapid biodegradation via direct visualization and respirometry. Furthermore, we isolated multiple bacterial strains capable of using TPU-FC1 as a sole carbon source and characterized their depolymerization products. To visualize biodegradation of TPU materials as real-world products, we generated TPU-coated cotton fabric and an injection molded phone case and documented biodegradation by direct visualization and scanning electron microscopy (SEM), both of which indicated clear structural degradation of these materials and significant biofilm formation.

The field of hybrid engineered living materials seeks to pair living organisms with synthetic materials to generate biocomposite materials with augmented function since living systems can provide highly-programmable and complex behavior. Engineered living materials have typically been fabricated using techniques in benign aqueous environments, limiting their application. In this work, biocomposite fabrication is demonstrated in which spores from polymer-degrading bacteria are incorporated into a thermoplastic polyurethane using high-temperature melt extrusion. Bacteria are engineered using adaptive laboratory evolution to improve their heat tolerance to ensure nearly complete cell survivability during manufacturing at 135 °C. Furthermore, the overall tensile properties of spore-filled thermoplastic polyurethanes are substantially improved, resulting in a significant improvement in toughness. The biocomposites facilitate disintegration in compost in the absence of a microbe-rich environment. Finally, embedded spores demonstrate a rationally programmed function, expressing green fluorescent protein. This research provides a scalable method to fabricate advanced biocomposite materials in industrially-compatible processes.

Passive cooling is a cooling technology that does not require external energy input, with most passive cooling strategies having high manufacturing difficulty and cost. In this study, we prepared lightweight aerogels (0.093 g/cm3) with high porosity (91.3%), directional pores, enhanced elastic recovery performance, and lower thermal conductivity (0.046 W/mK) through simple mixing, directional freezing, and freeze‐drying. The prepared samples have a reflectance of 87% in the ultraviolet—visible—near‐infrared (UV‐Vis‐NIR) range (0.2–2.5 μm) and an emissivity of 93.6% in the atmospheric transparency window. After covering the box with axial and transverse aerogel samples, the temperature inside the box relative to the uncovered sample box decreased by 12.9 and 13.4°C, respectively. This work provides a feasible method for the research of simply prepared passive cooling materials. [ABSTRACT FROM AUTHOR]

This review's main focus is highlighting and recognizing the significant scientific advances of smart expandable lost circulation material, i.e., shape memory polymers (SMPs) composites as loss circulation material (LCM) for drilling applications as innovative and futuristic materials. This review highlights and explains ways of producing new smart materials for LCM, which can be programmed by its SMP cycle. It briefly describes loss circulation further on loss circulation material and its classification. Only very few SMPs used as LCM, like shape memory polyurethane, thermoset shape memory polymer, shape memory epoxy, etc., either used as Grout, mixed with xanthan gum, or medium-size particles combined with base fluid, while the next section focuses on shape memory polymer as loss circulation material with the shape memory effect and programming over treating wide fractures. The last section consists of conclusion, prospects, and recommendations. [ABSTRACT FROM AUTHOR]

Poly(N‐vinylcaprolactam) (PNVCL) is a thermoresponsive polymer, which presents a transition from hydrophilic to hydrophobic behavior close to the physiological temperature, being promising for biomedical applications. However, the production of finished products with PNVCL is difficult due to its high mechanical fragility in the solid state. In the present work, in order to prepare a thermoresponsive film with good mechanical properties, a blend of PNVCL with thermoplastic polyurethane (TPU) was prepared. Three compositions of PNVCL/TPU were studied with mass proportions of 90/10, 70/30, and 50/50, respectively. The films were flexible, miscible and presented different thermoresponsive behaviors, with changing from transparent to opaque varying from 31 to 40°C. Contact angle analysis showed significant changes in the hydrophilicity of the films' surfaces with temperature variation. Moreover, it was possible to induce a change in solid films from transparent to opaque by varying the temperature and verify the reversibility of this change. In addition, tensile tests were carried out, which proved, for PNVCL/TPU blends, the reduction of film brittleness with TPU increase. To the best of our knowledge, it is the first work that presents thermoresponsive properties of solid films formed by a blend of PNVCL and TPU. [ABSTRACT FROM AUTHOR]

Vat photopolymerization (VPP) of highly aromatic polyurethanes (PUs) expands the library of additive manufacturing (AM) materials and enables a vast array of ductile thermoplastics, rigid and flexible thermosets, and elastomers. Aromatic diisocyanates and various diols enable printing of rigid, highly aromatic cross‐linked parts, which offer high glass transition temperatures and tunable thermomechanical performance. The judicious control of molecular weight of the photo‐reactive telechelic oligomers allows for a fundamental study of the influence of cross‐link density in highly aromatic 3D PU printed objects. VPP AM produces objects with high resolution, smooth surface finish, and isotropic mechanical properties. Thermal post‐processing is critical in maintaining excellent thermomechanical properties with semi‐crystallinity as a function of cross‐link density. Due to the presence of two ester carbonyls in the bis(2‐hydroxyethyl) terephthalate chain extender, the printed parts are readily amenable to depolymerization with methanolysis to produce difunctional dimethyl dicarbamates under modest reaction conditions. Dimethyl dicarbamates serve as suitable monomers for subsequent polycondensation. [ABSTRACT FROM AUTHOR]

Soft strain sensors can accurately monitor the deformation of irregular and dynamic surfaces. However, traditional thin‐film strain sensors are generally not direction‐specific, and the sensor becomes unpredictable when stretched in different directions simultaneously. Here, a soft 1D strain sensor is reported that is only sensitive to axial deformation by rolling up a thin‐film strain sensor based on liquid metals (LM) and thermoplastic polyurethane (TPU) elastomer. The sensitivity of the 1D sensor can be regulated by rolling the 2D sensor at different angles. The 1D strain sensors have a large strain measuring range (>100%), high strain resolution (0.5%), fast responsiveness (<40 ms), and high reproducibility (over 2000 cycles), which are expected to adapt to various application scenarios with different sensitivity requirements. In addition, 1D strain sensors with different sensitivities can be braided into a three‐strand braid to provide measurements with three different sensitivities at the same time. [ABSTRACT FROM AUTHOR]

Highlights Boron nitride (BN) has excellent thermal conductivity (TC), however, it exhibits high surface energy, strong chemical inertness, poor interface compatibility with polymer matrices, and difficulty in even dispersion within‐polymer matrix, preventive effective construction of TC pathways. Four kinds of modified boron nitride/polyurethane composites (BTPUC) were prepared by different silane‐functionalized BN with polyurethane (TPU). Among them, 3‐trimethoxysilylpropylmethacrylate (TMSPMA)‐functionalized BN demonstrated better interface compatibility with TPU, significantly improving the mechanical properties and TC of the composites compared to the other three functionalized BN addition. The BN@TMSPMA/PU exhibited good TC and mechanical properties, with a TC of 0.865 W/mK, a tensile stress and a tensile strain of 9.65 ± 1.40 MPa and 759.88 ± 67.93%, respectively. It also showed good electrical insulation properties and mechanical durability. Therefore, the as‐prepared BN@TMSPMA/PU have broad prospects as flexible thermal‐management materials. The composites are constructed by TMSPMA‐modified BN and polyurethane by NIPS. The composites show good mechanical properties and cyclic failure resistance. The composites exhibit good thermal conductivity and electrical insulation. [ABSTRACT FROM AUTHOR]

Currently, waterborne polyurethane (WPU)/polyethylene terephthalate (PET) microfiber composites are typically produced using PET/alkali‐soluble polyethylene terebenzoate (COPET) as the island fiber. This involves dissolving COPET with alkali (NaOH) after WPU impregnation, resulting in significant alkali‐containing wastewater and weakening the composites' strength due to the strong alkali treatment. To address these issues, this study employs PET/PVA island fiber as the raw material, comprising 36 islands. PET serves as the water‐insoluble component, while PVA is the water‐soluble component, with a fiber ratio of 70 % PET to 30 % PVA. The PET/WPU microfiber composites are prepared via a water‐soluble method following WPU impregnation. The study examines the impact of water deweighting time, WPU impregnation amount, and water washing times on the deweighting rate of the composites. Scanning electron microscopy (SEM) characterized their microstructure. Findings indicate that with 30 % WPU impregnation, 80 °C water temperature, 40‐minute deweighting time, and three water washes, the deweighting rate of PET/WPU microfiber composites reaches 29.08 %, close to 30 %. SEM analysis confirms that PET/PVA island fiber composites were fully converted into PET/WPU microfiber composites, with most PET/PVA island fibers completely opened. The water‐soluble method presents a novel deweighting technology with significant environmental benefits and considerable research potential. [ABSTRACT FROM AUTHOR]

Radiopaque polyurethanes are extensively used in biomedical fields owing to their favorable balance of properties. This research aims to investigate the influence of particle concentration on various properties, including rheological, radiopacity, structural, thermal, and mechanical attributes, with a thorough analysis. The findings are benchmarked against a commercial product (PL 8500 A) that contains 10% weight barium sulfate. Two more thermoplastic polyurethanes (TPU) were formulated with two different concentrations of barium sulfate (10 wt.% and 20 wt.%) and compared to the commercially available product. FTIR demonstrated similar absorption bands among all samples, indicating that the fabrication method did not impact the TPU matrix. DSC indicated a predominantly amorphous structure for PL 8500 A compared to the other samples, while the kinetic degradation was more influenced by the higher barium sulfate content. The rheological analysis showed a decrease in the complex viscosity and storage modulus with the radiopacifier and an increase in the radiopacity, as demonstrated by the X-radiography. X-ray microtomography showed a more spherical particle format with a heterogeneous particle structure for PL 8500 A compared to the other polyurethanes. These findings enhance the comprehension of the structure–property relationships inherent in these materials and facilitate the development of customized materials for targeted applications. [ABSTRACT FROM AUTHOR]

Introduction Debridement plays a critical role in wound management. In addition to removing necrotic tissue, debridement can eliminate bacteria frequently harbored within the tissue. This study evaluated a novel debridement method that uses plasma-based radiofrequency technology to remove tissue and bacteria. Coblation is a technology that uses radiofrequency energy to excite the electrolytes in a conductive medium, such as saline, to create a precisely focused plasma. This plasma field contains highly energized particles that possess sufficient energy to break tissue molecular bonds, causing the tissue to dissolve at relatively low temperatures (typically 40 °C to 70 °C). Materials and Methods Eighteen deep dermal wounds measuring 22 mm × 22 mm × 3 mm deep were created on pigs. Wounds were inoculated with methicillin-resistant Staphylococcus aureus USA300 (MRSA USA300) in combination with shrapnel and then covered with a polyurethane dressing for 24 hours. Wounds were then randomly assigned to one of the 3 treatment groups: (1) Coblation, (2) surgical debridement, and (3) no debridement. Wounds were biopsied on days 0, 5, 9, and 12, and specimens were processed for MRSA counts using selective media. Statistical analysis was performed using IBM SPSS statistics 27 using one-way ANOVA. Results Comparison between coblation and surgical debridement showed a decrease in bacterial count in all assessment times. The lowest bacterial count in all assessment times was observed in wounds debrided with coblation showing a statistically significant (P  ≤ .05) decrease in more than 2 Log CFU/g on days 0, 5, and 9 compared to no debridement. On day 12, coblation-debrided wounds exhibited 6.10 ± 0.22 Log CFU/g, and this value represents 99.99% of reduction compared with non-debrided wounds (P  ≤ .05). More than 96% of reduction (P  ≤ .05) resulted in wounds treated with coblation compared with surgically debrided. Conclusions Reducing MRSA bacterial infection counts, especially of biofilm-associated organisms, in combination with shrapnel may have important clinical implications, especially for the military personnel. Further research into the use of this technology in wound management is warranted. [ABSTRACT FROM AUTHOR]

In this study, polypropylene glycol (PPG) and isophorone diisocyanate (IPDI) with molecular weights (Mws) ranging from 8000 to 18,000 were used as starting materials to synthesize silylated polyurethanes (SLPUs) according to alkoxysilanes. FT-IR, GPC, and DSC were used to analyze composition and structure of the synthesized SLPU. Shore A-type, C-type hardness testers, and UTM were used to measure hardness, tensile strength, and elongation, respectively. It was revealed that mechanical properties and viscosity increased as the Mw of PPG increased. In particular, PPG 12,000 and (3-aminopropyl) triethoxysilane SLPU showed excellent storage stability and good mechanical properties. When alkoxysilane was applied as a capping agent, it was found that methoxysilane had a faster curing speed than ethoxysilane. However, it had insufficient workability and storage stability. Mechanical properties of ethoxysilane were relatively superior to those of methoxysilane. [ABSTRACT FROM AUTHOR]

[Display omitted] Fluorescent microspheres are of significant interests due to their wide applications in biotechnology fields. However, their preparation presents several challenges, such as the need for dye labeling, the complexity of materials and often sophisticated preparation conditions. Here a simple process for hydrophilic and crosslinked polyurethane (CPU) microspheres, with carboxyl groups on the surface via one-step precipitation polymerization in 40 min, is presented. The microsphere size is easily adjusted by varying experimental conditions. CPU microspheres exhibit high thermal and pH stability with good redispersibility in water, and emit fluorescence without any modification or dye labeling. The emission mechanism is discussed. CPU microspheres are used as fluorescent probe to detect 4-nitrophenol (4-NP) based on their emission in UV light region, with excellent selectivity and sensitivity. In addition, they are reusable with detection limit unchanged after 7 cycles of reuses, a significant feature of this work. The mechanism of fluorescence detection is thoroughly explored and ascribed to the internal filtration effect. Based on the emission in visible light region, CPU microspheres are used as a model of PU microplastics (MPs) to visualize their biodistribution in HeLa and macrophage cells, as well as in zebrafish larvae, providing a reliable tracer for the visualization and tracking of PU MPs in organisms. [ABSTRACT FROM AUTHOR]

With environmental and health issues being raised, researchers have shifted their study from fluorinated to fluorine-free waterproof agents. However, most of the reported fluorine-free water repellents exhibit a significant drawback in their poor stability and durability of water repellency. In addition, the use of higher concentrations in these repellents results in the fabric becoming stiff, which negatively impacts the hand of the treated fabrics. To address these issues, dendrimer-like waterborne polyurethane prepolymers were initially synthesized using isophorone diisocyanate, polytetrahydrofuran, N -methyldiethanolamine, and trimethylolpropane as the primary materials. In this synthesis, sorbitan tristearate served as the dendrimer-like blocking agent, while single-ended bis-hydroxypropyl silicone oil was employed as functional monomers to enhance the hand and water repellency of the prepolymers. Then, dendrimer-like waterborne polyurethane was finished on the cotton fabric using a pad–dry–cure procedure. The test results showed that the water contact angle of dendrimer-like waterborne polyurethane film increased from 104.28° to 107.00° with the content of single-ended bis-hydroxypropyl silicone oil increasing, and the water contact angle of dendrimer-like waterborne polyurethane-finished fabrics reached 148.6° alone with a standard spray test rating of 90–95. In addition, the water contact angle of dendrimer-like waterborne polyurethane-finished fabrics was still greater than 140° even after five standard washes. The single-ended bis-hydroxypropyl silicone oil addition facilitated similar hand to the original fabric in dendrimer-like waterborne polyurethane-finished fabrics with high concentrations, surpassing market water repellents. This work is of great significance for improving the stability and durability of water repellency, and the hand of waterborne polyurethane fluorine-free water repellents in the textile industry. [ABSTRACT FROM AUTHOR]

Mattress comfort, often associated with firmness, is a complex construct influenced by factors such as material composition, construction, and personal preference. In this short communication paper, we indirectly investigated the effects of long-term mattress use on its hardness and sleep quality by observing the changes in the mattress. A mechanical durability test was performed on two structurally different mattress samples (with polyurethane core and pocket spring core) using a modified method based on the EN 1957 standard, aiming to understand the long-term effects of mattress characteristics on sleep quality. Preliminary results confirm that the mattress samples can maintain firmness and support during long-term use. The polyurethane foam mattress experienced initial compression but quickly stabilized, while the pocket spring mattress showed slight softening, maintaining overall firmness. For the polyurethane mattress, after the initial drop, the hardness value stabilized, varying between 7.53 and 9.03 N/mm, and at the end of the test, it stopped at 8.60 N/mm. The firmness rating stabilized at 4.3, showing minimal fluctuation between 4.0 and 4.6 throughout the process, while the total height loss was 3.79 mm. The hardness value of pocket spring mattresses generally decreased with increasing test cycles (it started at 5.86 N/mm and ended at 5.21 N/mm). The firmness remained relatively stable, varying between 7.3 and 7.1, and the total height loss was only 2.86 mm. The findings suggest that the firmness of a mattress can be changed with its use, highlighting the need for further research on a larger number of samples in the direction of the long-term implications of these changes on sleep comfort. [ABSTRACT FROM AUTHOR]

Background: Placing implants deep sub-gingivally may affect the accuracy of implant impression techniques and the fit of final restoration. Purpose: The aim of this in-vitro study was to evaluate the effect of soft tissue thickness on accuracy of conventional and digital implant impression techniques. Methods: Four parallel implant analogues (A, B, C, D) placed in each of two epoxy resin models representing edentulous mandible covered by flexible polyurethane material with two different thickness two mm and four mm. A total of sixty impressions performed, thirty impressions for each model divided into four groups (n = 15 per group) GI (C2mm) open tray impression with two mm implant depth, GII (C4mm) open tray impression with four mm implant depth, GIII (D2mm) digital impression with two mm implant depth, GIV (D 4 mm) digital impression with four mm implant depth. Impressions from open tray technique were poured to get stone casts while impressions from digital scanning technique were printed as three-dimensional printed casts. The six inter-implant distances between analogues were measured using Co-ordinate measuring machine, deviations compared to reference models were calculated. Data was collected, tabulated and statistically analyzed using One-way ANOVA test to detect significances between groups. Results: For conventional impressions there was significant difference between C2mm/C4mm (P < 0.001) regarding interimplant distance, while in digital impressions there was no significant difference between D2mm/D4mm AB(p = 0.110), BC(p = 0.066), CD(p = 0.710), AD(p = 0.084), AC(p = 0.067) and BD(p = 0.072). There was significant difference between conventional and digital impression techniques C2mm/D2mm, C4mm/D4mm (P < 0.001). Conclusion: Within the limitations of this in-vitro study digital impressions provide more accurate outcomes with implants placed deeper subgingivally than conventional impressions. Trial registration: Retrospectively registered. [ABSTRACT FROM AUTHOR]

This study introduces a series of novel passive‐cooling polyurethane materials (SiTPUs) by incorporating hydroxybutane‐terminated polydimethylsiloxane (OH‐PDMS)/polytetrahydrofuran (PTMG)‐mixed soft segments. Wide‐angle x‐ray scattering (WAXS) and small‐angle x‐ray scattering (SAXS) analyses revealed that with an increase in the OH‐PDMS content, the material exhibited enlarged grain sizes, reduced crystallinity, and the formation of larger‐sized microphase "structures with different compatibilities. The sample with a PDMS proportion of 40% (SiTPU‐40) demonstrates outstanding passive cooling performance, achieving a reflectance of 70.2% in the solar spectrum and a high atmospheric window emissivity of 91.6% without needing metal additives, resulting in a cooling effect of 10.8°C compared with that of pure thermoplastic polyurethane (TPU). Static contact angle tests indicated that introducing OH‐PDMS considerably enhanced the self‐cleaning performance of the material, with a PDMS proportion of 50% (SiTPU‐50) achieving the highest contact angle of 112°. Overall, this multi‐soft segment design optimizes passive cooling performance and enhances self‐cleaning capabilities, thus offering new possibilities for extensive material applications, especially in wearable technology and architectural surface coatings. [ABSTRACT FROM AUTHOR]

Polyurethanes (PUs) synthesized with blends of polycarbonate and polyester polyols (CD+PEs) showed intrinsic self-healing at 20 °C. The decrease in the polycarbonate soft segments content increased the self-healing time and reduced the kinetics of self-healing of the PUs. The percentage of C-O species decreased and the ones of C-N and C=O species increased by increasing the polyester soft segments in the PUs, due to higher micro-phase separation. All PUs synthetized with CD+PE blends exhibited free carbonate species and interactions between the polycarbonate and polyester soft segments to a somewhat similar extent in all PUs. By increasing the polyester soft segments content, the storage moduli of the PUs decreased and the tan delta values increased, which resulted in favored polycarbonate soft segments interactions, and this was related to slower kinetics of self-healing at 20 °C. Although the PU made with a mixture of 20 wt.% CD and 80 wt.% PE showed cold crystallization and important crystallinity of the soft segments, as well as high storage moduli, the intercalation of a small amount of polycarbonate soft segments disturbed the interactions between the polyester soft segments, so it exhibited self-healing at 20 °C. The self-healing of the PUs was attributed to the physical interactions between polycarbonate soft segments themselves and with polyester soft segments, and, to a minor extent, to the mobility of the polymeric chains. Finally, the PUs made with 40 wt.% or more polyester polyol showed acceptable mechanical properties. [ABSTRACT FROM AUTHOR]

Developing advanced engineering polymers that combine high strength and toughness represents not only a necessary path to excellence but also a major technical challenge. Here for the first time a rigid‐flexible interlocking polymer (RFIP) is reported featuring remarkable mechanical properties, consisting of flexible polyurethane (PU) and rigid polyimide (PI) chains cleverly woven together around the copper(I) ions center. By rationally weaving PI, PU chains, and copper(I) ions, RFIP exhibits ultra‐high strength (twice that of unwoven polymers, 91.4 ± 3.3 MPa), toughness (448.0 ± 14.2 MJ m−3), fatigue resistance (recoverable after 10 000 cyclic stretches), and shape memory properties. Simulation results and characterization analysis together support the correlation between microstructure and macroscopic features, confirming the greater cohesive energy of the interwoven network and providing insights into strengthening toughening mechanisms. The essence of weaving on the atomic and molecular levels is fused to obtain brilliant and valuable mechanical properties, opening new perspectives in designing robust and stable polymers. [ABSTRACT FROM AUTHOR]

A linear high‐sensitivity response is crucial for flexible electronic skin, particularly in precision detection for applications like intelligent robotics and human‐machine interactions. Prevailing strategies typically adopt a layered, multifaceted material design to cultivate this response, yet this approach often culminates in a diminished capacity to augment sensing stability. The root causes of these limitations are predominantly material mechanical mismatches and interface incompatibilities inherent in these designs. To address these challenges, an electromechanical integration strategy is introduced that simultaneously enhances linear highsensitivity and stability. This strategy is centered on constructing a robust, integrated mechanical and electrical interface within a polyurethane material system through an in situ growth and adhesion process. The iontronic pressure sensor exhibits a linear high‐sensitivity response (16.24 kPa−1, R2 = 0.999) within a wide range (0–300 kPa). Moreover, the sensor's integrated structure, self‐encapsulated through the adhesion between the electrode and dielectric layers, exhibits robust stability, even under complex mechanical stresses. The applications of the sensors in precision weighing and haptic feedback within intelligent gripping systems demonstrate their advantages of both linearity and stable sensing. This work delineates a strategic pathway for the fabrication of high‐performance flexible pressure sensors, contributing significantly to the field of advanced sensing technologies. [ABSTRACT FROM AUTHOR]

An ultrasensitive concentration‐dependent ESIPT mechanochromic mechanophore (MM) NaMz (4‐amino‐2‐(1H‐naphtho[2,3‐d]imidazol‐2‐yl)phenol), which exhibits real‐time and reversible multicolor mechanochromism in polyurethane is reported. NaMz has one single link point and can be obtained facilely by one‐step reaction. As the concentration of NaMz increased from 0.01 to 0.05 mol%, the intensity ratio IE/IK of enol emission to keto emission changed significantly and concentration‐dependent multicolor fluorescence (yellow, white, blue) can be realized. Then, a simple strategy, force‐tuning the aggregation state of NaMz molecules, to adjust the ESIPT process to achieve ultrasensitive colorful mechanochromism is proposed. Intriguingly, force‐tuned white light emitting can be realized for 0.035 mol%NaMz@PU. Because the extended conjugation structure, NaMz@PU shows a red‐shifted keto emission at 541 nm with a larger Stoke shift compared with PhMz‐NH2@PU, which is also the key to multicolor concentration‐dependent polymer mechanochromism of NaMz@PU. Control experiments of NaMz‐OH@PU and NaMz‐3OH@PU show that the aliphatic hydroxyl group on the naphthimidazole moiety impedes the planarization of molecular structure and thus hinders aggregation, further verifying that the multicolor concentration‐dependent mechanochromism of NaMz@PU is indeed caused by force induced disaggregation. The excellent color‐changing effect, real‐time reversible force‐optical coupling and precise regulation of this study will make a new contribution to polymer mechanochemistry. [ABSTRACT FROM AUTHOR]

The structure, morphology, and performance of polyurethanes are greatly influenced by the structure of chain extenders. In this study, two types of amine chain extenders, 1,3‐bis(3‐aminopropyl)‐1,1,3,3‐tetramethyldisiloxane (BAPD) and isophorone diamine (IPDA), were utilized in the synthesis of poly(dimethylsiloxane) (PDMS)‐based poly(urea‐urethane) elastomers (PDMS‐PUUs). The mechanical properties, morphology, and in vitro oxidative stability of the as‐prepared elastomers were controlled by altering the ratio of BAPD and IPDA. The results indicate that the overall phase mixing of PDMS‐PUUs improves after incorporating of BAPD into the hard segments. The hard segment, composed of IPDA with a rigid structure, plays a crucial role in maintaining the essential mechanical properties of the PDMS‐PUUs. Furthermore, PDMS‐PUUs based on mixed chain extenders exhibit relatively high boundary diffuseness and boundary thickness. Especially, the PDMS‐PUU sample synthesized from BAPD and IPDA with a molar ratio of 1/1 features the highest boundary diffuseness (0.094) and boundary thickness (0.395 nm), consequently displaying some remarkable properties, including enhanced cyclic tensile properties, superior strain recovery (92.6%), a low modulus (8.6 MPa), and high tensile strength (20.3 MPa). PDMS‐PUUs also exhibit good oxidative stability and biocompatibility, implying that the as‐prepared PDMS‐PUUs are proven to be biostable and capable of long‐term implantation. [ABSTRACT FROM AUTHOR]

Abstract\nIMPLICATIONS FOR REHABILITATIONIn this study, 3D printing-based solutions are sought to improve the durability of guide canes of visually impaired individuals. The financial inaccessibility of technological white canes is a challenge that this study addresses by integrating additive manufacturing. The proposed solutions are designing a ball caster tip with a suspension mechanism, manufacturing a barrier detection and vibration alert system, and a 3D-printed flexible cover for the guide cane. Each solution is specially prototyped for this study using Computer-Aid Design (CAD). It aims to produce accessories that can upgrade any regular cane to a more durable and comfortable state by easily clipping them onto any cane. The solutions were assessed under three criteria, for which the visually impaired consultee of the research was assigned weights for further evaluation. The assessment has been conducted based on each solution’s effectiveness, cost, and comfort. According to the evaluation of the visually impaired consultee, the ball caster with suspension mechanism yielded the highest score for the assessment criteria. Further recommendations have been made for each solution to decrease the volume occupancy and increase lifespan, durability, and comfort.Modular Computer-Aid Designing (CAD) of white cane accessoriesNovel ball caster module with a suspension mechanismSensitive barrier detection with ultrasonic sensors and alerting with vibration3D printing flexible thermoplastic polyurethane (TPU) cover for cane segment [ABSTRACT FROM AUTHOR]

Over the past few decades, polymers with dynamic covalent bonds have received a lot of attention due to their self‐healing, shape memory, and environmental adaptation properties. However, most of them require a change in catalyst or environmental conditions to achieve bond reduction and exchange reactions, and the harsh conditions are not conducive to the practical application of the material. However, the dr‐polyurea based polyurethane (PUU) can be prepared at low temperatures, and can be worn and rebuilt in a catalyst free and mild environment, thus showing excellent self‐healing function. In this paper, the unique dynamic reaction mechanism of hindered urea bond (HUB), the properties of related polymers and the development of frontier are reviewed. In addition, the performance research of HUB and the application prospect of innovative synthetic PUU are also reviewed. [ABSTRACT FROM AUTHOR]

The high extractives content in rice straw severely hinders surface adhesion, resulting in poor strength and dimensional stability of rice straw particleboard bonded with castor oil-based polyurethane (CPUR) resin. In this study, rice straw was pretreated with liquid hot water (LHW) at 150 °C for 20 min to reduce its extractives content for particleboard production with CPUR resin. The effects of LHW pretreatment on the chemical composition of the rice straws was evaluated. In addition, effects of CPUR resin dosage and density on mechanical properties and dimensional stability of the rice straw particleboards were investigated. The results indicated that LHW pretreatment significantly reduced the extractives and hemicellulose contents of the rice straw. The LHW pretreatment significantly improved the mechanical properties and dimensional stability of the rice straw particleboards. The overall performances of the rice straw particleboards were enhanced as the CPUR dosage increased. Increase of density led to upgraded mechanical properties but lowered dimensional stability of the rice straw particleboards. [ABSTRACT FROM AUTHOR]

Waterborne polyurethanes emulsions (WPU) based on polyethylene carbonate diol (PECD) were synthesized, characterized and modified by polypropylene carbonate diol (PPCD) and organosilicon KH-792. The mechanical, thermal and hydrolysis resistance properties of waterborne polyurethanes were comprehensively investigated. The results show that PECD based WPU has very excellent mechanical properties. The tensile strength and the elongation at break the PU was up to 73 MPa and 1040%, which was much higher than that reported for similar types of PPCD-based WPU. It was found that water absorption of PECD based WPU can be decreased dramatically, from 40.9% to 21.1%, after 50% PECD was replaced by PPCD, while tensile strength only decreased from 73.0 MPa to 63.4 MPa. The addition of KH-792 has great influence on PECD based WPU, when 1% KH-792 was added, the water absorption rate decreased from 21.1% to 11.88%, the mechanical strength remained at 63.3 MPa, the WPU film remained transparent after soaking in 80 ℃ hot water for 4 h. [ABSTRACT FROM AUTHOR]

Nanodiamond has been categorized among remarkable zero dimensional nanocarbon. This carbon nanoparticle has been applied as important nanofiller in the polymeric matrices. This state-of-the-art review article portrays fundamentals, physical properties, and prospects of nanodiamond filled thermosetting matrices. Among thermosets, most research efforts have been reported on the nanodiamond filled epoxy and polyurethane matrices. Consequently, the epoxy/nanodiamond and polyurethane/nanodiamond nanocomposites have been designed. The nanodiamond nanoparticle addition in polymers caused microstructural variations and enhancements in mechanical, thermal, wear, adhesion, and related advanced features. The property improvement was observed due to the nanofiller dispersion, matrix-nanofiller interactions, and interface formation. Type of thermosetting polymer, curing agent, nanodiamond content, nanodiamond functionalities, and processing method define the final nanocomposite architecture, morphology, and ensuing characteristics. Consequently, the high-tech epoxy/nanodiamond nanocomposites and polyurethane/nanodiamond nanocomposites exposed capability toward technological relevance like coatings, microwave absorption, and biomedical. As few thermosetting matrices have been used with the nanodiamond nanofillers so far, more comprehensive future efforts are needed to disclose the actual potential of thermosetting polymer/nanodiamond nanocomposites. [ABSTRACT FROM AUTHOR]

Optimization of impact sound insulation of wooden beam ceilings in Wilhelminian style houses, Part 2: Ceiling construction and flanking transmission The research deals with the influence of various parameters in the ceiling structure, such as cavity damping, screed thickness, impact sound insulation, fill and suspended ceilings, on the standard impact sound level of typical Wilhelminian style wooden beam ceilings. The measurements show that a thicker screed, softer impact sound insulation and a heavier fill significantly improve the impact sound level. Binding the fill with polyurethane instead of cement shows a significant improvement in the frequency range from 100 to 500 Hz. While cavity damping with mineral wool only contributes to a limited reduction in the standard impact sound level, decoupling the fill on an elastic intermediate layer delivers significant improvements. The measurements also show that the thickness of the paneling and the type of hangers in suspended ceilings have a significant impact on impact sound insulation. The investigations into flank impact sound transmission make it clear that flank transmission must be taken into account when planning higher requirement levels. Especially in the frequency range between 250 Hz and 800 Hz, the sound transmission of flanking components can play a significant role in the overall transmission. [ABSTRACT FROM AUTHOR]

Semi‐interpenetrating polymer networks (semi‐IPNs), composed of two or more polymers, forming intertwined network‐architectures, represent a significant type of polymer combination in modern industry, especially in automotive and medical devices. Diverse synthesis techniques and plentiful raw materials highlight semi‐IPNs in providing facile modifications of properties to meet specific needs. An initiator‐free synthesis of semi‐interpenetrating polymer networks via Bergman cyclization (BC) is reported here, acting as a trigger to embed a second polymer via its reactive enediyne (EDY) moiety, then embedded into the first network. (Z)‐oct‐4‐ene‐2,6‐diyne‐1,8‐diol (diol‐EDY) is targeted as the precursor of the second polymer, swollen into the first polyurethane network (PU), followed by a radical polymerization induced by the radicals formed by the BC. The formation of the semi‐IPN is monitored via electron paramagnetic resonance (EPR) spectroscopy, infrared‐spectroscopy (FT‐IR), and thermal methods (DSC), proving the activation of the EDY‐moiety and its subsequent polymerization to form the second polymer. Stress−strain characterization and cyclic stress−strain investigations, together with TGA and DTG analysis, illustrate improved mechanical properties and thermal stability of the formed semi‐IPN compared to the initial PU‐network. The method presented here is a novel and broadly applicable approach to generate semi‐IPNs, triggered by the EDY‐activation via Bergman cyclization. [ABSTRACT FROM AUTHOR]

Polyurethane (PU) belongs to a unique class of polymers. Different properties of PU such as mechanical strength and biocompatibility can be enhanced by co-polymerizing it with different bio and synthetic polymers. It finds huge applications as micro-reactors for the fabrication of metal nanoparticles (MNPs) owing to the synergistic properties of both polyurethane and fabricated metal nanoparticles. Metal nanoparticles fabricated polyurethane have gained much attention in the last few years. These types of nanocomposites hyphenate the mechanical properties of polyurethane with the high surface-to-volume ratio of metal nanoparticles. Here, this review article briefly evaluates different methods of synthesis of polyurethane-based metal nanocomposites and their characterization via different techniques to evaluate their properties. Applications of these polyurethane based nanocomposite materials have also been described critically in different fields depending upon their catalytic, antimicrobial and antifungal potential. Future directions of these nanocomposite materials have also been described in the field of designing of nano-filters and nano-devices in order to attain environmental remediation and sustainability. [ABSTRACT FROM AUTHOR]

With rapid economic development in China, new and aging road infrastructure is susceptible to premature distresses like potholes under environmental and traffic loading, posing safety risks. Although epoxy resins for crack repair materials exhibit favorable adhesion and mechanics, polyurethanes are emerging for roads to enhance the durability and wear resistance of epoxy resins. This paper summarizes polyurethane-modified epoxy resins for pavement repair, referring to their mechanical properties, adhesive properties, durability and toughness, corrosion resistance, and heat resistance. The polyurethane modification mechanism and the effect of curing agent on the properties of polyurethane-modified epoxy resins are discussed. Polyurethane-modified epoxy resins show potential to combine the strengths of both polyurethanes and epoxy resins for advanced pavement repair materials. [ABSTRACT FROM AUTHOR]

The effect of polyurethane content on the behavior of ballast was assessed based on large-scale direct shear and cyclic loading tests. The large-scale direct shear tests were performed at normal stresses (σn) of 40 to 120 kPa at a shearing rate (Sr) of 9 mm/min , while cyclic tests were performed at loading frequencies (f) of 16 to 32 Hz. The direct shear test results indicated that the increase in polyurethane content from 1.5% to 3.75% by weight of ballast has significantly improved the shear strength of ballast. However, the increment in shear strength is found to be insignificant for polyurethane contents greater than 2.25%, thus indicating 2.25% to be optimum for the stabilization of ballast. Further, the cyclic load tests were performed on unstabilized ballast and ballast stabilized with 2.25% polyurethane (PSB2.25%). The test results indicated that PSB2.25% has exhibited significantly reduced extent of vertical and lateral deformations, and had shown enhanced resilient modulus and damping ratio in comparison to unstabilized ballast (USB). Further, the vertical settlement of PSB2.25% at 2 million load cycles was observed to be less than the settlement of USB at 250,000 load cycles, which implies that the stabilized ballast continues to perform effectively even after higher load cycles. [ABSTRACT FROM AUTHOR]

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Polyurethanes are used in a wide range of biomedical applications due to their variety of physical–chemical, mechanical, and structural properties, and biotic and abiotic degradation. They are widely used in bio-imaging procedures when metallic-based filler particles are incorporated, making the final product radiopaque. It would be advantageous, however, if polyurethanes with intrinsic radiopacity could be produced in their synthesis, avoiding a series of disadvantages in the processing and final product and also presenting potential antimicrobial activities. This review's objective was to study the radiopacifying characteristics of nanoparticles, the physical principles of radiopacity, and the variety of medical applications of polyurethanes with nanoparticles. It was found in this study that the synthetization of radiopaque polyurethanes is not only possible but the efficiency of synthetization was improved when using atoms with high electron density as part of the backbone or when grafted, making them great multipurpose materials. [ABSTRACT FROM AUTHOR]

The latest studies agree that meniscal tears that require surgery should be repaired whenever possible to avoid early-onset osteoarthritis secondary to meniscectomy. Unfortunately, there are several limitations associated with meniscal sutures, making it difficult to put into practice the theory behind the concept of saving the meniscus. Meanwhile, there is an exponential growth in the use of tissue adhesives for surgery, but finding one suited to meniscal repair remains a struggle. This review has two main goals (1) to compile the various bioadhesives used in this field and (2) to list the criteria for an ideal meniscal bioadhesive. The review was conducted in PubMed, Google Scholar, and Web of Science in November 2023 without date restrictions. The inclusion criteria were: Studies published in English and focusing on meniscal repair using bioadhesives. The exclusion criteria were: Studies published in languages other than English. Adhesives used in combination with sutures, as the aim was to determine the adhesive's capabilities for meniscal repair alone. Synthetic adhesives such as polycyanoacrylates, polyethylene glycol, polyurethanes, and polyesters. Among the 11 bioadhesives found, fibrin is the only one that has been studied in humans. There are advantages and disadvantages to all the bioadhesives identified but none that fully meet the requirements for meniscal repair. The anatomy of meniscal tissue is complex and poses unique challenges that are compounded by arthroscopic stresses. The future of meniscal repair probably lies in combining the advantages of several bioadhesives, and this area should be the focus of future research. [ABSTRACT FROM AUTHOR]

The environmental problems caused by thermal reactions have prompted the search for new approaches. Photochemical curing, which uses light energy, offers a sustainable solution for polymerizing complex polymers, reducing energy consumption, and emissions. Current study involves cationic UV‐curing of biobased polyurethanes (PU) with a thermo‐responsive shape memory behavior on very low temperature almost equal to human body temperature. This product has a potential to be utilized as drug carrier or related biomedical applications, as well as self‐tightening materials against human body heat. Polymer has been designed from sesame oil, with slight modification through a facile epoxidation approach. Main objectives of this research were to prepare biobased PU recipe; to utilize a specially designed UV‐curing approach for this synthesis; and to develop shape memory properties upon sensing human body temperature. Prepared material has been analyzed through FTIR, SEM, TGA, DSC, water absorption capacity (WAC), and gel contents (GCs). Shape memory behavior has been tested in both air and water against a range of temperatures (35°C–80°C). At 35°C in 208 s, prepared sample, presented 96.60% Rr and 90.56% Rf, whereas at 80°C in 55 s Rr increased to 98.33% and Rf increased to 100%. Hydrophobic nature of sample was confirmed by 4.1% water absorption in 48 h. [ABSTRACT FROM AUTHOR]

A straightforward but effective approach to fabricate shape‐memory polyurethane thermosets by tailoring the soft phase composition of two‐ and four‐armed polycaprolactone (PCL) polyols is described. As the crystallization of the PCL soft phase has an effect on driving the self‐assembly of H‐bonds, a good balance of tensile performance and thermo‐healability can be achieved by regulating the ratio between PCL‐diol and PCL‐tetrol in the soft phase. The inferior ability of crystallization of the segments near the branching point gives rise to enhancement of the both overall healability and toughness of the network. Healings of punctured holes and cuts are assessed using optical microscopy (OM), field‐emission scanning electron microscopy (FE‐SEM), tensile analysis, and two‐electrode impedence characterization. The obtained network with the best healing behavior has a soft phase composition with the PCL‐diol/PCL‐tetrol molar ratio of 2/1, a tensile toughness of 64 MPa J−1 and a healing efficiency (estimated by recovery of tensile strength) of nearly 80%. Highlights: The composition of the soft phase of polyurethane networks was tailored.Two‐ and four‐armed polycaprolactones were used for the network structure.A good balance between mechanical and healing performance was obtained.Healing of complete cuts showed tensile strength recovery of nearly 80%. [ABSTRACT FROM AUTHOR]

In the domain of Horizontal Wind Turbines, the key role of blade material and process selection is discussed. Existing methodologies and manual manufacturing processes, while addressing this issue, suffer from complexity and environmental drawbacks. To mitigate these issues, the study introduces a comprehensive methodology for the selection, implementation, testing and analysis of materials and processes for small blade construction, taking into account various constraints. The research conducts a thorough exploration of manufacturing processes, considering factors such as time, affordability, machine accessibility, repeatability, elements to be manufactured, and adaptability to complex surfaces. A systematic comparison of materials and processes, along with proposed filtering methods, reveals that rotomolding/polyurethane casting exhibits superior performance due to improved energy capture and inertia. The study underscores the importance of careful material and process selection to optimize blade efficiency and highlights the need for further research to address mechanical, economic, environmental, scalability, and material advancement challenges. [ABSTRACT FROM AUTHOR]

The increasing need for ionic circuits has driven the demand for patterning methods with excellent wear resistance and ease of preparation. However, the traditional method of the circuits modified on the surface frequently suffers from wear and detachment during use. Herein, an interpenetrating network of poly(ionic liquid) and polyurethane is employed, creating a patternable ionic circuit that can resist the abrasion of sandpaper or taping. Hydrophobic ionic liquids are successfully polymerized inside the polyurethane to achieve a waterproof ionic circuit, simultaneously reducing the impact of environmental humidity. Additionally, this ionic circuit possesses the capability to perceive the multisignals of temperature, pressure, and pressing shapes with the assistance of artificial intelligence. The interpenetrating network provides a simple and practical solution for the fabrication of wear‐resistant and stable patterned ionic circuits. [ABSTRACT FROM AUTHOR]

This paper reviewed the blending modification of polylactic acid (PLA) from the aspects of degradable materials, nanomaterials and polyurethane, and its applications were summarized. Finally, the future development prospect in modification of PLA was proposed. [ABSTRACT FROM AUTHOR]

Silicon (Si) materials have attracted growing attention in lithium-ion batteries (LIBs) due to their remarkably high-theoretical capacity and abundance on Earth. Despite the excellent edges, the widespread application of silicon materials in LIBs has been severely limited by rapid capacity decay and an unstable solidelectrolyte interphase (SEI) due to their substantial volume changes (>300%). Here, we report a novel water-soluble binder (CW-20), comprising sodium carboxymethyl cellulose (CMC-Na) and waterborne polyurethane (WPU). Not only the novel binder can establish a cross-linked three-dimensional (3D) network through hydrogen bonding, which effectively maintains the electrodes' integrity, but also the binder can form a stable SEI layer, thereby improving the cycling stability and durability. Thus, the Si@CW-20 electrode maintains a specific capacity of 2626.2 mA h g-1 after 100 cycles at 0.1C. After 500 cycles at 0.5C, the Si@CW-20 electrode exhibits excellent stability, maintaining a high specific capacity of 1450.7 mA h g-1 with a capacity decline rate of 0.08% per cycle. Moreover, Si/C@CW-20 exhibits a capacity retention rate of 86.93% after 250 cycles at 1C. The cycling stability and durability of Si and Si/C anodes demonstrate significant potential for this strategy in facilitating the widespread implementation of high-capacity LIBs. [ABSTRACT FROM AUTHOR]

It remains enormous challenges to balance the conflict between high strength and toughness mechanical properties and excellent room‐temperature self‐healing abilities of polyurethane elastomers. In this work, we report a recyclable room‐temperature self‐healing polyurethane elastomer with excellent mechanical properties. The prepared polyurethane elastomer (PU‐DA‐Zn0.50) exhibits high tensile strength of 15.33 MPa, high toughness of 76.77 MJ m−3, and high elongation at break of 1604.46% by introducing isophorone diamine (IPDA), 1‐(3‐aminopropyl) imidazole (IMZ) and zinc ions into polymer system to form a dynamic double‐cross‐linked structure (hydrogen bonds and Zn2+‐imidazole coordination bonds). In addition, the tensile strength of fractured polyurethane can reach more than 80% of the original sample after 48 h of self‐healing at room temperature without external stimuli, which is attributed to the kinetics of rapid exchange of Zn2+‐imidazole coordination bonds at room temperature. It is worth noting that the balance between excellent mechanical properties and outstanding room‐temperature self‐healing ability can be optimized by adjusting the Zn2+‐imidazole coordination bond density in the system. Moreover, the dynamic nature of the double‐cross‐linking network endows polyurethane with favorable recyclability. The above remarkable comprehensive performances reveal a great potential of PU‐DA‐Znx elastomer in the fields of wearable flexible electronic devices such as bionic skin, human motion monitoring, and soft robots. [ABSTRACT FROM AUTHOR]

A series of CO2-based thermoplastic polyurethanes (TPUs) were prepared using CO2-based poly(polycarbonate) diol (PPCDL), 4,4′-methylenebis (cyclohexyl isocyanate) (HMDI), and polypropylene glycol (PPG and 1,4-butanediol (BDO) as the raw materials. The mechanical, thermal, optical, and barrier properties shape memory behaviors, while biocompatibility and degradation behaviors of the CO2-based TPUs are also systematically investigated. All the synthesized TPUs are highly transparent amorphous polymers, with one glass transition temperature at ~15–45 °C varying with hard segment content and soft segment composition. When PPG is incorporated into the soft segments, the resultant TPUs exhibit excellent self-healing and shape memory performances with the average shape fixity ratio and shape recovery ratio as high as 98.9% and 88.3%, respectively. Furthermore, the CO2-based TPUs also show superior water vapor permeability resistance, good biocompatibility, and good biodegradation properties, demonstrating their pretty competitive potential in the polyurethane industry applications. [ABSTRACT FROM AUTHOR]

Conventional waterborne polyurethane (WPU) has poor water resistance and poor overall performance, which limits its application in outdoor coatings. A solution to this problem is urgently needed. The introduction of fluorine-containing groups can effectively improve the water resistance of WPU. In this study, a new fluorinated chain extender (HFBMA-HPA) synthesized by free radical copolymerization and epoxy resin (E-44) were used to co-modify WPU, and five waterborne fluorinated polyurethane (WFPU) emulsions with different fluorine contents were prepared by the self-emulsification method. The effects of HFBMA-HPA content on the emulsion particle properties, coating surface properties, mechanical properties, water resistance, thermal stability, and corrosion resistance were investigated. The results showed that the WFPU coating had excellent thermal stability, corrosion resistance, and mechanical properties. As the content of HFBMA-HPA increased from 0 wt% to 14 wt%, the water resistance of the WFPU coating gradually increased, the water contact angle (WCA) increased from 73° to 98°, the water absorption decreased from 7.847% to 3.062%, and the surface energy decreased from 32.8 mN/m to 22.6 mN/m. The coatings also showed impressive performances in the adhesion and flexibility tests in extreme conditions. This study provides a waterborne fluorinated polyurethane material with excellent comprehensive performance that has potential application value in the field of outdoor waterproof and anticorrosion coatings. [ABSTRACT FROM AUTHOR]

This work shows that various polyurethanes (FPUs) prepared using biomass-derived furan diols can be applied as promising tribopositive materials. The elastic FPUs having appropriate glass transition temperature (Tg) could be incorporated into polyethylene terephthalate (PET) fabrics to form FPU/PET films. The optimal FPU-4/PET film showed promising triboelectric performance with output voltages (Vp–p) up to 405 V and a maximum power density (Pmax) of 32 mW cm−2. [ABSTRACT FROM AUTHOR]

Herein, inspired by the macrophage's defensive behavior of releasing free radicals to kill bacteria and viruses, a marine antifouling coating with dynamic surfaces is prepared by precise regulation of dynamic covalent bonds. Alkyl radical (R·) derived from oxime-urethane structure attracts and disrupts microbe cell membrane and pili between intimate cells, resulting in excellent anti-biofouling effect. Moreover, the newly exposed coating then continues to break, which ultimately results in the peeling of the layers, thus making barnacles, mussels and other fouling organisms less likely to adhere. [Display omitted] • Macrophage-inspired marine antifouling coating with dynamic surfaces is prepared. • Alkyl radical (R·) derived from oxime-urethane structure offers excellent anti-fouling performance. • The newly exposed coating continues to break making it less likely that fouling organisms will adhere to it. • This study presents a novel methodology for fulfilling the technological gap of marine coatings with dynamic surface. Macrophages can kill bacteria and viruses by releasing free radicals, which provides a possible approach to construct antifouling coatings with dynamic surfaces that release free radicals if the breaking of dynamic covalent bonds is precisely regulated. Herein, inspired by the defensive behavior of macrophages of releasing free radicals to kill bacteria and viruses, a marine antifouling coating composed of polyurethane incorporating dimethylglyoxime (PU x -DMG) is prepared by precise regulation of dynamic oxime-urethane covalent bonds. The obtained alkyl radical (R·) derived from the cleavage of the oxime-urethane bonds manages to effectively suppress the attachment of marine biofouling. Moreover, the intrinsic dynamic surface makes it difficult for biofouling to adhere and ultimately achieves sustainable antifouling property. Notably, the PU 50 -DMG coating not only presents efficient antibacterial and antialgae properties, but also prevents macroorganisms from settling in the sea for up to 4 months. This provides a pioneer broad-spectrum strategy to explore the marine antifouling coatings. [ABSTRACT FROM AUTHOR]

One of the major challenges in expanding the uses of polymer materials is the development of thermally driven, multifunctional, self‐healing water polyurethanes with superior mechanical properties. By adding nano‐inorganic fillers and incorporating phenol‐carbamate bonds into the molecular chains, a self‐healing waterborne polyurethane with strong mechanical properties as well as antibacterial, and antiseptic properties was created. Given that tannic acid (TA) can create an isocyanate‐group‐containing phenol‐carbamate network, the resulting TA‐based water polyurethane (TWPU) had great mechanical properties and superior thermal stability with tensile strength of 31.9 MPa and elongation at break of 1406.4%. The amount of dynamic phenol‐urethane linkages in the polyurethane backbone can also be adjusted and controlled to achieve excellent self‐healing efficiency. The coating's anti‐corrosion properties were good when the waterborne polyurethane was added to ZnO modified GO. Furthermore, the coating exhibited strong antibacterial capabilities due to the incorporation of nano‐zinc oxide. In this study, we create an environmentally friendly waterborne polyurethane that is antibacterial, antiseptic, and self‐healing using a straightforward and efficient design approach. [ABSTRACT FROM AUTHOR]