Waterborne Polyurethane Research Articles

Development of fluorosilicon bivalve isocyanate microcapsules for multifunctional coatings with excellent self-repairing properties, enhanced hydrophobicity, and corrosion protection properties

This study first self-made TMP-IPDI tetramer, and then prepared a fluorine-modified silicon dioxide double shell isocyanate type self-healing microcapsule (CBS-X/TMP-IPDI@PU@F-SiO2) using TMP-IPDI tetramer, fluorescent agent 4,4-bis (2-disulfonic acid sodium styrene) biphenyl (CBS-X) as the core material, polyurethane (PU) as the single shell, and fluorine modified silicon dioxide (F-SiO2) as the double shell using interfacial polymerisation method. Then, it was added to waterborne polyurethane (WPU) to prepare self-healing coatings and coatings. The chemical structure, microstructure, self-healing self detection, and mechanical properties of TMP-IPDI, CBS-X/TMP-IPDI@PU@F-SiO2, and composite coatings were characterized by infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H NMR), scanning electron microscopy (SEM), particle size analysis (PSA), X-ray electron spectroscopy (XPS) analysis, contact angle testing, tensile testing, electrochemical impedance testing, and Ultraviolet photograph. The results showed that the TMP-IPDI tetramer was successfully prepared. The average particle size of CBS-X/TMP-IPDI@PU@F-SiO2 prepared is 29 μm. The contact angle, tensile strength, low-frequency impedance and Nyquist curve radius of the repaired spots increased with the increase of the amount of CBS-X/TMP-IPDI@PU@F-SiO2 in WPUs; the increasing trend slowed down when the amount of CBS-X/TMP-IPDI@PU@F-SiO2 was >5 %. When the CBS-X/TMP-IPDI@PU@F-SiO2 dosage is 5 %, the WPU coating has good self-repair and self-detection performance. The stress before and after repair were 12.89 MPa and 20.11 MPa, respectively, with a repair rate of 80.3 %. The contact angle at the repair site can reach 100.8°, and the coating has good corrosion resistance. The microcapsules prepared based on fluorine-modified silica (F-SiO2) as the wall material have good self-healing performance for WPU coatings, achieving secondary protection of the repaired material.

A multifunctional coating toward wearable superhydrophobic fabric sensor with self-healing and flame-retardant properties with high fire alarm response

The design of wearable fabric with ultrasensitive fire alarm response and piezoresistive sensor capabilities is urgently imperative to prevent burn injuries to people in the fire accident. Herein, a novel cotton fabric-based piezoresistive sensor comprising hydrophobic waterborne polyurethane, polyphosphazene (PPZ) microspheres encapsulated 1H,1H,2H,2H-perfluorooctyltriethoxysilane (FAS), and amino-functionalized carbon nanotubes (A-CNTs) was proposed via a roll coating approach, which achieve self-healing, flame-retardant property, and intelligent fire alarm response. The fabric sensor exhibited prominent flame retardancy because of the synergistic formation of a dense flame-retardant layer on the fabric surface by A-CNTs and PPZ. The char residue of the fabric sensor reached 20.4 wt% at 800 °C, and the limiting oxygen index was as high as 27.4 %. Interestingly, benefiting from the thermoelectric characteristic of A-CNTs, the fabric sensor triggered the fire alarm system within 2 s. More importantly, since the resistance changed with their deformations, the fabric sensor can also monitor a variety of human motions, and its sensitivity (GF) can reach 4.79. Additionally, the resulting fabric sensor exhibited self-healing performance. After physical damage, under near-infrared light irradiation, the healing agent FAS spontaneously migrates towards the surface of the fabric, effectively restoring the superhydrophobic property of the fabric. This work provides new insight into the design and application of multifunctional fabric sensors.

Multifunctional Fabric Leveraging Coating of Bio-based Waterborne Polyurethane

Multifunctional Fabric Leveraging Coating of Bio-based Waterborne Polyurethane

Organic solvent-free in-situ polymerization of waterborne polyurethane with amino-grafted silica for carbon dioxide separation

The novel mixed-matrix membrane (MMMs) by incorporating covalently amino groups grafted nano-silica (Amino-NP) into an eco-friendly, organic solvent-free waterborne polyurethane (OSF-WPU) matrix for the separation application of CO2/N2. This investigation focused on the gas permeance and separation performance of the MMMs. The optimized CO2/N2 separation factor reached [Formula: see text], with a CO2 permeance of [Formula: see text] GPU under conditions of 1.0 bar and 25∘C in a wet mixed-gas state. Incorporating even a tiny amount of Amino-NP efficiently enhanced CO2 permeability and CO2/N2 selectivity. OSF-WPU/Amino-NP MMMs demonstrated superior performance, emphasize their potential for stable long-term operation in practical CO2 separation applications.

A Superhuman Sensing Triboelectric Nanogenerator with Boosted Power Density and Durability via a Bio‐Inspired Janus Structure

AbstractTriboelectric nanogenerators (TENG) not only enable sustainable self‐powered sensing of devices, but also have superhuman noncontact/contact identification capabilities, which are propelling humanity toward the intelligent era. However, the inherently low dielectric constant of triboelectric materials as well as the mechanical mismatch between electrodes and dielectric materials severely limited their efficient and stable output performance. Taking inspiration from the asymmetric structure and function of human skin, a novel single‐electrode TENG is developed, whose electrode and dielectric layer are integrated in a Janus architecture. By tuning the balance between gravity and the internal noncovalent interactions, gradient dispersion of carbon nanotubes in waterborne polyurethane networks can be feasibly achieved, which can boost the device performance by reinforcement in both the charge trapping capacity of the dielectric layer and the charge transfer of the electrode layer. As a proof‐of‐concept, triboelectric sensing and deep learning are integrated to realize the evolution from perception to identification under both noncontact (motion prediction) and contact (material identification) modes. The bionic design strategy of gradient Janus film can offer valuable insights into improving the output performance and durability of TENG. Additionally, the proximal prediction and tactile identification functions are also desirable attempts for future human‐machine interfaces.

Stability of Ti3C2-MXene/Waterborne polyurethane composite emulsion and investigation of visible light-driven film self-healing performance

Intrinsic self-healing waterborne polyurethane (WPU) is an environmentally friendly, economically viable, and practical novel intelligent material. However, the key to achieving practical applications lies in the remote activation of repair in self-healing materials and the excellent mechanical properties of the matrix. In this study, we introduce quadruple hydrogen bonding in the polyurethane backbone. We have incorporated a novel two-dimensional sheet-like material, MXene, to achieve visible light remote-driven self-healing of material hydrogen bonds while enhancing the material’s mechanical properties. By utilizing the MXene supernatant, this approach not only resolves the issues of poor stability and easy sedimentation of MXene nanosheets in water-based polymers but also helps to prevent resource wastage. Our research results demonstrate that the composite film exhibits a tensile strength of 6.55 MPa and a fracture elongation of 604%. Additionally, quadruple hydrogen bonds in the WPU chains enable rapid self-healing of microcracks under visible light irradiation at 300 mW/cm2, with complete disappearance within 80 min.

Breathable and wearable graphene/waterborne polyurethane coated regenerated polyethylene terephthalate fabrics for motion sensing and thermal therapy

The functional utilization of recycled polymers has emerged as a current prominent and timely subject. Flexible wearable devices with high sensitivity to conductivity have garnered significant attention in the fields of human healthcare monitoring and personal heat management. One significant obstacle that needs to be addressed is the simultaneous maintenance of both sensing functionality and durability in composite fabrics. In this paper, a collection of durable, breathable, and flexible smart fabric was produced using the scratch coating method. The fabrics were created by utilizing a regenerated polyethylene terephthalate fabric as a base material, incorporating graphene microsheets (G) as a conductive agent, and applying a waterborne polyurethane layer as a surface protective coating. Furthermore, an investigation was conducted to assess their sensing performance and electrothermal performance. The composite fabric exhibits significant advantages in terms of high conductivity (592 S/m), wide strain range, high sensitivity (Gauge factor = 6.04) and fantabulous dynamic stability (2000 cycles) at a mass ratio of Graphene/WPU loading of 8:2. These sensors were successfully utilized to monitor various degrees of real-time human body movements, ranging from significant deformation bending of elbows to slight deformation swallowing. Furthermore, the sensors also exhibit a significant electric heating effect. Specifically, when a voltage of 10 V is applied, the sensors can reach a steady state temperature of 53.3 °C within a mere 30 s. This discovery holds potential for the development of wearable heaters that can be used for on-demand thermal therapy, functional protective clothing, and medical electric heating wearables.

Synthesis and Application of Silane-Modified Castor Oil-Based Waterborne Polyurethane as a Fluorine-Free and Durable Water Repellent

Synthesis and Application of Silane-Modified Castor Oil-Based Waterborne Polyurethane as a Fluorine-Free and Durable Water Repellent

Synthesis and Characterization of Nonionic Waterborne Polyurethane and Application to Wool Fabric Finishing

Synthesis and Characterization of Nonionic Waterborne Polyurethane and Application to Wool Fabric Finishing

A Novel Polyfunctional Polyurethane Acrylate Derived from Castor Oil-Based Polyols for Waterborne UV-Curable Coating Application.

Because of its unique molecular structure and renewable properties, vegetable oil has gradually become the focus of researchers. In this work, castor oil was first transformed into a castor oil-based triacrylate structure (MACOG) using two steps of chemical modification, then it was prepared into castor oil-based waterborne polyurethane acrylate emulsion, and finally, a series of coating materials were prepared under UV curing. The results showed that with the increase in MACOG content, the glass transition temperature of the sample was increased from 20.3 °C to 46.6 °C, and the water contact angle of its surface was increased from 73.85 °C to 90.57 °C. In addition, the thermal decomposition temperature, mechanical strength, and water resistance of the samples were also greatly improved. This study not only provides a new idea for the preparation of waterborne polyurethane coatings with excellent comprehensive properties but also expands the application of biomass material castor oil in the field of coating.

Low-Temperature Extrusion of Waterborne Polyurethane-Polycaprolactone Composites for Multi-Material Bioprinting of Engineered Elastic Cartilage.

3D bioprinting of elastic cartilage tissues that are mechanically and structurally comparable to their native counterparts, while exhibiting favorable cellular behavior, is an unmet challenge. A practical solution for this problem is the multi-material bioprinting of thermoplastic polymers and cell-laden hydrogels using multiple nozzles. However, the processing of thermoplastic polymers requires high temperatures, which can damage hydrogel-encapsulated cells. In this study, the authors developed waterborne polyurethane (WPU)-polycaprolactone (PCL) composites to allow multi-material co-printing with cell-laden gelatin methacryloyl (GelMA) hydrogels. These composites can be extruded at low temperatures (50-60 °C) and high speeds, thereby reducing heat/shear damage to the printed hydrogel-capsulated cells. Furthermore, their hydrophilic nature improved the cell behavior in vitro. More importantly, the bioprinted structures exhibited good stiffness and viscoelasticity compared to native elastic cartilage. In summary, this study demonstrated low-temperature multi-material bioprinting of WPU-PCL-based constructs with good mechanical properties, degradation time-frames, and cell viability, showcasing their potential in elastic cartilage bio-fabrication and regeneration to serve broad biomedical applications in the future.

Collaboration of Fenton reaction with a tannin acid-based hyperbranched waterborne polyurethane sizing agent for synergistic enhancement of the CF/PA6 composite interfacial properties

The adhesive strength between the sizing agent and carbon fiber (CF) plays a pivotal role in determining the interfacial properties of composites. Unfortunately, this critical aspect has been consistently overlooked. In this study, a hyperbranched waterborne polyurethane (HWPU) sizing agent was prepared by biogenetic derived raw materials including gallic acid as well as tannic acid. Meanwhile, iron ion was introduced onto the surface of CF by Fenton reaction, forming a heterogeneous structure to elevate the mechanical interlocking between the CF and resin. Chelation of TA with iron ion on the fiber surface effectively enhanced the adhesion between sizing agent and CF. The mechanical properties of the newly designed composites were systematically investigated. The results showcase a significant enhancement in both flexural strength and interlaminar shear strength (ILSS) compared to untreated CF, marking improvements of 54.3% and 60.0%, respectively. Furthermore, the interfacial shear strength (IFSS) test exhibited a 71.2% augment. In conclusion, this approach presented a highly promising concept aimed at improving the interfacial performance of CF composite materials.

Coordinate mechanical property and self‐healing performance by hydrogen bonding promoting microphase separation structures in waterborne polyurethanes

AbstractSelf‐repairing materials aim to replicate nature's repair mechanisms, but their current properties are inadequate for commercialization due to the trade‐off between repair and mechanical properties. An environmentally responsive low‐temperature self‐healing aqueous polyurethane with different sequence structures was developed in which the WPU‐MD/APDS system exhibited excellent performance. Statically, the incorporation of MD (1,8‐diamino‐P‐menthane) enhances hydrogen bonding within the system and facilitates reversible weak dynamic bonding; microphase separation enables aggregation of disulfide bonds in the hard‐phase domain, thereby improving disulfide bond exchange rates. Dynamically, the inclusion of MD introduces a rigid ring structure and promotes microphase separation with increased hydrogen bonding, leading to enhanced mechanical properties of the materials. The material exhibited tensile strength of 27.37 MPa, elongation at break of 1353%, excellent elastic recovery ability, and high tensile toughness of 136 MJ m−3; a sample with thickness of 0.2 mm lifted weight greater than its own weight into 40,000 times without damage recovery at 40°C. Rheological analysis confirmed its self‐healing property at room temperature.

Waterborne polyurethane polymer dispersions using castor oil and curcumin as bioresources: Synthesis, characterization, and antibacterial textile applications

AbstractThe main goal of this study is to make new waterborne polyurethane polymers (WPUCs) using bioresources like curcumin as a chain extender and castor oil as a polyol. We explored different mole ratios of curcumin during the synthesis of WPUC polymers. The WPUC dispersions were well‐defined and had nanoparticle sizes that ranged from 80.1 to 48.2 nm. Their zeta potentials were between −61.7 and − 52.2 mV, which showed that they were more stable. The absence of a phenolic hydroxyl band in the synthesized WPUC's IR spectrum indicated the insertion of curcumin into the PU chain. The coating of WPUCs on polyester/cotton (PE/C) blend fabric showed an improvement in colorfastness properties and reduced air permeability. The enhanced bending modulus (enhanced stiffness), improved abrasion resistance, and higher tensile strength were also observed. Furthermore, the WPUC‐coated fabric samples showed a bacterial inhibition percentage of 83.12%–99.9999% (p < 0.001) compared with blank fabric against bacterias' because of the inherent nature of curcumin. Inserting a higher amount of curcumin in the polymer chain of WPUC improved the antibacterial effects. Overall, our findings provide valuable insights for the possible antibacterial textile applications of synthesized WPUCs.

A novel method for the synthesis of solvent‐free and high‐solid‐content waterborne polyurethanes by introducing a small amount of polyethylene glycol

AbstractIn the study, the synthesis process involved the reaction of dimethylolbutyric acid and polytetramethylene ether glycol 1000 (PTMG1000) with hexamethylene diisocyanate (H12MDI), taking advantage of their mutual dissolution at high temperatures. The chain‐extension reaction with 1,4‐butanediol (BDO) was successfully conducted without the use of organic solvents. The emulsification reaction was carried out using the polyurethane prepolymer at 60% solids content, along with aqueous dispersions of polyethylene glycol (PEG) with varying molecular weights and amounts as interfacially active agents. Fourier transform infrared spectroscopy analysis suggested potential hydrogen bonding interactions between the PEG molecular chain and the polyurethane chain. Rheometer analysis demonstrated a significant reduction in viscosity with the addition of 1–5 wt.% PEG, accompanied by an increase in average particle size. This phenomenon was attributed to the formation of a hydrophilic lubrication layer of PEG around the water‐based polyurethane (WPU) microcells. Among them, WPU films containing 4 wt.% PEG4000 not only exhibited soft properties with a mechanical elongation rate exceeding 2000% but also showed excellent storage stability. The addition of long‐chain PEG facilitated the formation of a lubrication layer between the microcells, contributing to spatial stabilization and reducing particle aggregation at high solids content. It is noteworthy that this solvent‐free process, without any organic solvents, together with the adjusted PEG content, successfully synthesized waterborne polyurethanes with low viscosity and high solids content. This provides a new sustainable and environmentally friendly method for the future production of waterborne polyurethanes.

Organosilicon-modified double crosslinked waterborne polyurethane coatings

Conventional waterborne polyurethanes (WPUs) have limited their application as high-performance coatings due to low mechanical strength and poor solvent resistance. Organosilicon modification is important to improve the solvent and chemical resistance of WPUs. Herein, we prepared a double crosslinked WPUs with excellent performance using isophorone diisocyanate and polytetrahydrofuran as raw materials, and trihydroxy polyoxypropylene ether, pentaerythritol, and dihydroxy silicone oil as functional monomers. The solvent resistance and the mechanical properties of the coatings had improved after crosslinking of WPUs (tensile strength of 7.39 MPa, elongation at break of 1178 %). Furthermore, the coatings with excellent hydrophobicity (water contact angle of 94.5°). Meanwhile, medical gloves with organosilicon-modified WPUs showed excellent water, alcohol and salt immersion resistance. Based on the excellent comprehensive performance of organosilicon-modified WPUs, it is expected to be used as a surface coating in medical gloves.

Self‐healing waterborne fluorinated polyurethane‐acrylate based on photoreversible reaction and hydrogen bonds

AbstractThe development of self‐healing materials is an effective strategy to improve the service life of polymer materials. In this study, self‐healing waterborne fluorinated polyurethane‐acrylate (WFPUA) containing UV‐responsive coumarin groups was prepared by Pickering emulsion polymerization using modified cellulose nanocrystal as a stabilizer. The effect of double bond‐terminated waterborne polyurethane content on emulsion polymerization and latex film properties was mainly studied. Due to the dynamic reversibility of the coumarin groups and the synergistic effect of hydrogen bonds, the optimized sample (WFPUA‐30) had excellent mechanical properties and self‐healing properties. The tensile strength was 5.24 MPa and the elongation at break was 267%. The self‐healing efficiency of tensile strength and elongation at break after 6 h of repair was 86.52% and 93.20%, respectively. In addition, due to the presence of fluorine‐containing groups, the water and oil contact angles of the latex film could reach 101.7° and 82.1°, respectively. This work broadens the way for the manufacture of self‐healing and multifunctional waterborne polyurethane‐acrylates. © 2024 Society of Industrial Chemistry.

Waterborne polyurethane containing fluorosilicone coating: to endow leather with enduring hydrophobicity and mechanical properties

Natural leather-based materials possess a combination of air permeability, wear resistance, and plasticity. However, conventional leather products have inherent limitations that make them unsuitable for unconventional applications. Therefore, it is necessary to develop new capabilities in order to overcome these limitations. In this study, we explored the conversion of regular leather into a high-strength product with hydrophobic properties through surface engineering. To achieve this, we synthesized polysiloxane-modified fluorinated waterborne polyurethane emulsions as functional coatings using emulsion polymerization. The structure and properties of the treated leathers were characterized using techniques such as Fourier transform infrared, thermogravimetry, X-ray photoelectron spectroscopy, X-ray diffraction, and scanning electron microscopy. The results demonstrated that the synthesized polysiloxane-modified fluorinated waterborne polyurethane successfully penetrated and combined with the fibers of the leather, resulting in excellent hydrophobicity. The water contact angle increased to 124.3°. Furthermore, the tensile strength and tear strength of unfinished leather are 875 N and 114 N, respectively. The application of waterborne polyurethane-derived functional additives as coatings resulted in a significant increase in tensile and tear strength of the leather by 60 N and 16 N, respectively. In addition, the softness of the leather increased from 7.6 mm to 10.09 mm. Overall, the use of this functional waterborne polyurethane coating will contribute to the diversification of leather applications.

Waterborne 2-component polyurethane coatings based on acrylic polyols with secondary alcohols

We report the effects of increasing the molecular weight of a secondary alcohol-based polyol in a two-component waterborne polyurethane (2 K-WB-PUR) formulation. The system consists of an acrylic polyol latex and a water-dispersible polyisocyanate (hmPIC, Basonat HW1000 from BASF). The polyols investigated incorporated hydroxypropyl methacrylate as a comonomer to introduce the secondary –OH groups, in contrast to typical polyols which have primary -OH groups. Three molecular weights of this polyol were prepared (Mn ≈ 5100, Ð = 2.4; 10,300, Ð = 2.7; or 12,900 g/mol, Ð = 3.6) with a uniform Tg (∼20 °C) and hydrodynamic diameter (dh) ≈ 120 nm. The polyol and polyisocyanate were mixed with a molar NCO:OH ratio of 1.3:1. The particle size of the mixed dispersion was monitored by dynamic light scattering. The 5 K sample remained stable in dispersion over 7 days whereas the higher molecular weight formulations flocculated after 1 day. Fourier Transform Infrared (FTIR) measurements revealed that all NCO groups were consumed within 15–23 h for all dispersed samples. Fluorescence resonance energy transfer (FRET) experiments were carried out on samples in the dispersed state as well as on films formed from these dispersions. Very little molecular level mixing was observed in the dispersed phase for the samples. In the films, a large extent of mixing was observed in the 5 K sample whereas the extents of mixing for the higher molecular weight samples were reduced. The FTIR measurements recorded as the films formed showed that the NCO consumption in the 5 K film (t1/2 = 56 h) was comparable to an analogous 2 K-WB-PUR formulation based on a 5 K primary alcohol from a previous study. Surprisingly, the NCO consumption in the higher molecular weight samples was faster (t1/2 = 31, 32 h). We found that the composition of the resulting films formed from higher molecular weight polyols contained a greater relative ratio of polyurea to polyurethane.

General Semi-Solid Freeze Casting for Uniform Large-Scale Isotropic Porous Scaffolds: An Application for Extensive Oral Mucosal Reconstruction.

Ice-templated porous biomaterials possess transformative potential in regenerative medicine; yet, scaling up ice-templating processes for broader applications-owing to inconsistent pore formation-remains challenging. This study reports an innovative semi-solid freeze-casting technique that draws inspiration from semi-solid metal processing (SSMP) combined with ice cream-production routines. This versatile approach allows for the large-scale assembly of various materials, from polymers to inorganic particles, into isotropic 3D scaffolds featuring uniformly equiaxed pores throughout the centimeter scale. Through (cryo-)electron microscopy, X-ray tomography, and finite element modeling, the structural evolution of ice grains/pores is elucidated, demonstrating how the method increases the initial ice nucleus density by pre-fabricating a semi-frozen slurry, which facilitates a transition from columnar to equiaxed grain structures. For a practical demonstration, as-prepared scaffolds are integrated into a bilayer tissue patch using biodegradable waterborne polyurethane (WPU) for large-scale oral mucosal reconstruction in minipigs. Systematic analyses, including histology and RNA sequencing, prove that the patch modulates the healing process toward near-scarless mucosal remodeling via innate and adaptive immunomodulation and activation of pro-healing genes converging on matrix synthesis and epithelialization. This study not only advances the field of ice-templating fabrication but sets a promising precedent for scaffold-based large-scaletissue regeneration.