Waterborne Poly Research Articles

Migration of polydimethylsiloxane chain segments toward the surface of UV-cured waterborne poly(urethane-acrylate) films

Waterborne polyurethane (WPU) has poor water resistance and low surface hydrophobicity due to the incorporation of hydrophilic chain-extender. The water resistance and the surface hydrophobicity can be improved by incorporation of polydimethylsiloxane (PDMS), which is attributed to the migration of PDMS chain segments toward the surface of WPU film. However, whether the PDMS chain segments can migrate toward the surface of WPU film after UV-curing, resulting in higher hydrophobicity, needs further investigation? We prepared the different WPUA films by changing the molar ratio of aminopropyl-terminated polydimethylsiloxane (APT-PDMS) to hydroxyethyl acrylate (HEA), to deeply understand the migrating phenomenon of PDMS chain segments toward the surface of WPUA films. The migration cause of PDMS chain segments and the influence of chemical cross-linking on the migration were investigated by thermal annealing and solvent immersion of WPUA films. In addition, the migration activation energy and the relaxation time were studied by the migration rate of PDMS chain segments in the thermal annealing and the rheological behavior of WPUA film, aiming to elucidate the migration of PDMS chain segments depending on the chain motion and the fractional free volume. This investigation provides a simple and feasible strategy for improving the hydrophobicity of waterborne polyurethane.

Implementing miniemulsion photopolymerization for synthesis of waterborne biobased poly(thioethers) coatings

Herein, miniemulsion photopolymerization is implemented as a useful tool for synthesis of waterborne poly(thioether) dispersions from biobased monomers isosorbide-based dithiol (3R,3aR,6S,6aR)-hexahydrofuro[3,2-b]furan-3,6-diyl bis(3-mercaptopropanoate) and diallyl (3R,3aR,6S,6aR)-3,6-bis(allyloxy)hexahydrofuro[3,2-b]furan and their combination with the petroleum-based dienes diallyl terephthalate, 3,9-divinyl-2,4,8,10-tetraoxaspiro [5.5]undecane, and 1,4-bis(allyloxy)benzene. The synthetic process is optimized to achieve 30 % solids content latexes with weight average molecular weight ranging from 8.2 kg/mol to 136 kg/mol. The resulting poly(thioether) latexes yield consistent continuous polymer films after water evaporation at atmospheric conditions. Poly(thioether) films based on both biobased thiol and ene are soft and sticky, and thus, present insufficient mechanical properties for coating application. On the other hand, when biobased thiol was combined with petroleum based enes with aromatic and cyclic moieties within the structure, the obtained films are rigid and film forming. Only the film based on diallyl terephthalate diene present excellent balance of stiffness and flexibility, therefore with potential for coating application. Moreover, this film shows relatively good water sensitivity, with water uptake below 20 % after 11 days of water immersion and high gloss (above 80 gloss unit) measured at 60° angle of incidence. The properties are within the range of requirements for decorative coatings applications.

Preparation of UV-curable waterborne poly(thiourethane-urethane) acrylate based on thiol-click chemistry

Preparation of UV-curable waterborne poly(thiourethane-urethane) acrylate based on thiol-click chemistry

A crosslinked waterborne poly(urethane‐urea) oligomer enables mechanically strong waterborne polyacrylate–poly(urethane‐urea) hybrid films with superior film‐forming ability

AbstractIn this article, a crosslinked waterborne poly(urethane‐urea) (WPUU) is synthesized based on the terminal aromatic amine polyether (DP‐1000) and aliphatic isophorone diisocyanate. Then WPUU is compound with acrylate monomer by emulsion polymerization to produce waterborne polyacrylate–poly(urethane‐urea) (WPUUA) hybrid emulsions. Compared with waterborne polyacrylate (WPA) film, the film‐forming ability of WPUUA film is improved and the surface roughness Ra and Rq of WPUUA film decreases from 47.5 and 36.4 nm to 35.2 and 18.8 nm, respectively. Meanwhile, the mechanical properties of WPUUA films are significantly improved compared to WPA film. In addition, the performances of WPUUA hybrid films can be modified according to requirements by adjusting the molar ratio between DP‐1000 and polyisocyanate. As a result, these WPUUA hybrid emulsions have great application potential in waterborne coatings and other fields.

A crosslinked waterborne poly(vinyl acetate) for greenhouse gas fixation with improved elastomeric properties, shape-memory ability, and recyclability

The development of raw materials from methane and carbon dioxide holds significant potential to cut greenhouse gas (GHG) emissions and reduce the global carbon footprint. As an important monomer, vinyl acetate (VAc) can be produced by the consumption of acetic acid, which will potentially contribute to the reduction of GHGs emission. However, polymers based on VAc are usually prepared from emulsion polymerization in water which brings about the challenges of using modification processes to improve their properties. Here, a newly developed crosslink was able to establish covalently adaptable networks directly in water, enabling the formation of a poly(vinyl acetate) (PVAc) composite. As a result, PVAc emulsions using a monomer of 100% VAc could be transformed from a soft and weak adhesive polymer into an elastomeric polymer composite network with an elongation (775%) at break and flexibility. With the enhanced rubbery modulus, the polymer possesses characteristics for shape-memory material applications with 93% shape fixity and 99% shape recovery after repeated deformation and shape fixity for three times. The recyclability of the PVAc thermosets was demonstrated after granulating and remolding three times, representing an opportunity for designing a greenhouse gas fixing material.

Waterborne Poly(butylene succinate)-Coated Paper for Sustainable Packaging Applications

Waterborne Poly(butylene succinate)-Coated Paper for Sustainable Packaging Applications

Structure Property Relationship of Micellar Waterborne Poly(Urethane-Urea): Tunable Mechanical Properties and Controlled Release Profiles with Amphiphilic Triblock Copolymers.

Waterborne polyurethane (WPU) has attracted significant interest as a promising alternative to solvent-based polyurethane (SPU) due to its positive impact on safety and sustainability. However, significant limitations of WPU, such as its weaker mechanical strength, limit its ability to replace SPU. Triblock amphiphilic diols are promising materials to enhance the performance of WPU due to their well-defined hydrophobic-hydrophilic structures. Yet, our understanding of the relationship between the hydrophobic-hydrophilic arrangements of triblock amphiphilic diols and the physical properties of WPU remains limited. In this study, we show that by controlling the micellar structure of WPU in aqueous solution via the introduction of triblock amphiphilic diols, the postcuring efficiency and the resulting mechanical strength of WPU can be significantly enhanced. Small-angle neutron scattering confirmed the microstructure and spatial distribution of hydrophilic and hydrophobic segments in the engineered WPU micelles. In addition, we show that the control of the WPU micellar structure through triblock amphiphilic diols renders WPU attractive in the applications of controlled release, such as drug delivery. Here, curcumin was used as a model hydrophobic drug, and the drug release behavior from WPU-micellar-based drug delivery systems was characterized. It was found that curcumin-loaded WPU drug delivery systems were highly biocompatible and exhibited antibacterial properties in vitro. Furthermore, the sustained release profile of the drug was found to be dependent on the structure of the triblock amphiphilic diols, suggesting the possibility of controlling the drug release profile via the selection of triblock amphiphilic diols. This work shows that by shedding light on the structure-property relationship of triblock amphiphilic diol-containing WPU micelles, we may enhance the applicability of WPU systems and move closer to realizing their promising potential in real-life applications.

Bio-Based Waterborne Poly(Vanillin–Butyl Acrylate)/MXene Coatings for Leather with Desired Warmth Retention and Antibacterial Properties

This study presents a solvent-free, facile synthesis of a bio-based green antibacterial agent and aromatic monomer methacrylated vanillin (MV) using vanillin. The resulting MV not only imparted antibacterial properties to coatings layered on leather, but could also be employed as a green alternative to petroleum-based carcinogen styrene (St). Herein, MV was copolymerized with butyl acrylate (BA) to obtain waterborne bio-based P(MV–BA) miniemulsion via miniemulsion polymerization. Subsequently, MXene nanosheets with excellent photothermal conversion performance and antibacterial properties, were introduced into the P(MV–BA) miniemulsion by ultrasonic dispersion. During the gradual solidification of P(MV–BA)/MXene nanocomposite miniemulsion on the leather surface, MXene gradually migrated to the surface of leather coatings due to the cavitation effect of ultrasonication and amphiphilicity of MXene, which prompted its full exposure to light and bacteria, exerting the maximum photothermal conversion efficiency and significant antibacterial efficacy. In particular, when the dosage of MXene nanosheets was 1.4 wt%, the surface temperature of P(MV–BA)/MXene nanocomposite miniemulsion-coated leather (PML) increased by about 15 °C in an outdoor environment during winter, and the antibacterial rate against Escherichia coli and Staphylococcus aureus was nearly 100% under the simulated sunlight treatment for 30 min. Moreover, the introduction of MXene nanosheets increased the air permeability, water vapor permeability, and thermal stability of these coatings. This study provides a new insight into the preparation of novel, green, and waterborne bio-based nanocomposite coatings for leather, with desired warmth retention and antibacterial properties. It can not only realize zero-carbon heating based on sunlight in winter, reducing the use of fossil fuels and greenhouse gas emissions, but also improve ability to fight off invasion by harmful bacteria, viruses, and other microorganisms.

Hydrogen-Bond-Assisted Dye-Incorporated Waterborne Poly( urethane-urea) (WPU) for an Environment-Friendly Textile Dyeing Process

To propose a green dyeing strategy permitting the incorporation of chromophores via the promotion of physical bonding and a simple sewage processing procedure, a strategy for increasing the reactivity of a conventional disperse dye, namely, 1-amino-4-hydroxy-2-phenoxyanthraquinone (Disperse Red 60, R60), to isocyanate groups and miscibility with waterborne poly(urethane-urea) (WPU) was reported. The modified dye R60-OH was prepared by the alkylation of 3-bromopropan-1-ol. Subsequently, R60-OH was reacted with the trifunctional isocyanate (named R60-O-THDI), which provided additional hydrogen bonds between the dye and the polymer chain and rendered better color fastness. Polyester, nylon, and cotton fabric coated with R60 and R60-O-THDI-incorporated WPUs were investigated by colorimetric analysis, washing tests, and rubbing color fastness. R60-O-THDI exhibited the best rubbing and washing color fastness, indicative of a simple method to fabricate a water-based dye ink without grafting a chromophore onto a polymer backbone via the promotion of physical bonding. The proposed green dyeing strategy also permitted a simple sewage processing procedure to recover polyurethane from the suspension by changing the pH, rendering better color fastness on textiles, as well as less wastewater production.

A dynamic hard domain-induced self-healable waterborne poly(urethane/acrylic) hybrid dispersion for 3D printable biomedical scaffolds

Polyurethane (PU) with its efficient self-healing ability and high mechanical properties is highly anticipated but an arduous challenge to achieve.

In Situ Spontaneous Fabrication of Tough and Stretchable Polyurethane-Polyethyleneimine Hydrogels Selectively Triggered by CO2.

CO2 -triggered in situ hydrogels is developed from waterborne poly(ε-caprolactone)-based polyurethane (PU) dispersion and aqueous polyethyleneimine (PEI) solution without any other chemicals and apparatus (e.g., UV light). In the approach, nontoxic CO2 in air is used as a selective trigger for the hydrogel formation. CO2 adsorption onto PEI results in the formation of ammonium cations in PEI and the subsequent multiple ionic crosslinking between PU and PEI chains. Besides the amount of CO2 in air, the rate of hydrogel formation can be controlled by NaHCO3 in the PU-PEI mixture, which serves as a CO2 supplier. The PU hydrogels exhibit tough and stretchable properties with high tensile strength (2.05 MPa) and elongation at break (438.24%), as well as biocompatibility and biodegradability. In addition, the PU hydrogels exhibit high adhesion strength on skin and injectability due to the in situ formation. It is believed that these PU hydrogels have the ideal features for various future applications, such as tissue adhesion barriers, wound dressing, artificial skin, and injectable fillers.

Polyaniline-Grafted Chitin Nanocrystals as Conductive Reinforcing Nanofillers for Waterborne Polymer Dispersions.

Due to its intrinsic electrical conductivity, polyaniline (PANI) is one of the most promising conducting polymers for high-performance applications in a wide range of technological fields. However, its poor dispersibility in water and organic solvents markedly imparts its processability and electrical conductivity. Herein, we report a green and one-step approach to preparing stable colloidal dispersions of highly dispersible hybrid nanoparticles by polymerizing PANI onto chitin nanocrystals (ChNCs) as biotemplates, via initiation through the surface amino groups of ChNCs. Evidence of the grafting of PANI onto ChNCs was supported by transmission electron microscopy (TEM), as well as Raman and Fourier transform infrared (FTIR) spectroscopies. Nanocomposite films were prepared by mixing the PANI-g-ChNCs with a waterborne poly(vinyl acetate) latex dispersion followed by casting and film formation at room temperature. The mechanical properties were tested as a function of the PANI-g-ChNC content. In addition, it was shown that at a proper content of PANI in ChNCs, and over a critical loading in the PANI-g-ChNCs, a conductive film was obtained, without sacrificing the reinforcing effect of the rodlike nanofiller. As a potential application, conductive waterborne adhesives for wood were prepared and the performance of the adhesives was tested. This research provides a facile route to fabricating a new class of hybrid nanofiller from a biobased origin, stable in water and easy to mix with waterborne dispersions, combining the merits of the ChNC nanofiller with the conductivity of PANI.

Plant oil-based non-isocyanate waterborne poly(hydroxyl urethane)s

With the increasingly depletion of the petroleum resources and awareness of the importance of environmental issues, a quest for a newer, safer and greener route for plant oil-based non-isocyanate waterborne polyurethanes is becoming one of the major challenges in the polyurethanes industry. In this study, the carbonated linseed oil (CLSO) was prepared from epoxy linseed oil, which was used to polymerize with different diamines and hydrophilic moiety to produce green and safety cationic, anionic and nonionic plant oil-based non-isocyanate waterborne poly(hydroxyl urethane)s (NIWPUs). Meanwhile, aromatic diamines, aliphatic diamines and polyether diamines were used as chain extenders to tailor the performance of the resulting plant oil-based NIWPUs, which also further evaluate the robustness of the proposed preparation route. The results showed that all the NIWPU dispersions exhibited excellent storage stability. The cationic NIWPU films showed good mechanical properties (the highest tensile property was more than 9 MPa and the highest elongation at break was more than 200 %) and antibacterial properties (antibacterial efficiency toward Staphylococcus aureus and Escherichia coli above 98 %), anionic NIWPU films exhibited good mechanical properties (the highest tensile property was more than 8 MPa and the highest elongation at break was more than 300 %) and coating performance (the highest pencil hardness was 7H and the highest crosshatch adhesion was 5B), and nonionic NIWPUs showed tailorable cloud points. The technique reported here offers a number of advantages, including low cost, easy performance, environmentally friendly and economical process, opening new platform for the production of NIWPUs prepared from plant oil.

A self‐healing waterborne poly(urethane‐urea) on reversible covalent interaction for textile breathable coating

AbstractThe solvent‐free self‐healable waterborne poly(urethane‐urea) (SH‐WPU) product is environmentally friendly due to its lower volatile organic compounds emission during the coating process. This research revealed a strategy for breathable textile coating, that longer product life of SH‐WPU coated fabric based on the self‐healing dynamics that triggered by disulfide bond rearrangement upon temperature elevation (e.g., textile ironing). SH‐WPU was synthesized with 4,4′‐methylenebis cyclohexyl isocyanate as hard segment, (poly(propylene oxide)‐b‐poly (ethylene oxide)‐b‐poly (propylene oxide) triblock copolymer as soft segment. 4,4'‐Dithiodianiline (DTDA), and 2,2‐bis(hydroxymethyl)butyric acid were used as the chain‐extenders. The self‐healing efficiency was tested by simulated ironing condition. The SH‐WPU that contained 7.5 wt% of DTDA shown the highest recovery efficiency of stress at break by tensile test. The SH‐WPU coated fabric showed excellent recovery with the DTDA concentration from 4.5 to 7.5 wt% by the water pressure resistance test by disulfide and hydrogen bond rearrangement at elevated temperature. The results indicated the promising potential of SH‐WPU for breathable textile coating applications to not only overcome the damage under extreme weather conditions but also render the textile repairable by ironing.

Hydrophobic modification of water-borne poly(vinyl alcohol) electrospun nonwovens for advanced applications

A new approach for surface modification of hydrophilic and water-soluble polymeric nonwovens has been investigated. Here, the challenge was to prepare a highly water repelling material from a water-based system. This paradox was resolved by a novel concept of coating chemically reactive water soluble polymers with fluorinated silyl ethers, which was probed with poly(vinyl alcohol) (PVA) nanofibers. Key for getting high water repellence was the discovery that PVA had to be preheated to 180°C prior to silanization before coating with a mixture of tetraethyl orthosilicate (TEOS): n-decyltrimethoxysilane (DTMS): ethanol: H2O: HCl. As a result of this surface modification and additional annealing of electrospun PVA nanofibers, highly water repelling nonwovens were obtained which also showed very low roll angles and consequently high dimensional integrity upon contact with water. The nonwovens were characterized by means of thermogravimetric analysis, wide angle x-ray analysis, electron microscopy, capillary flow porometry, contact angle measurement, and energy-dispersive X-ray spectroscopy to gain in-depth insight into the mechanism of the surface transformation.

Structure and adhesion properties of waterborne poly(urethane urea)s containing small amounts of different graphene derivatives

Waterborne poly(urethane urea)s (PUDs) containing graphene derivatives with different morphologies and surface polarities were synthesized via in situ polymerization by using the acetone method. Small amounts (0.04–0.30 wt.%) of graphene oxide (GO), graphite nanoplatelets (GP) or milled graphite (MG) were mixed with polyadipate of 1,4-butanediol polyol and added during synthesis of the PUDs. The addition of graphene derivatives changed differently the degree of micro-phase separation of the poly(urethane urea)s (PUs) depending on the balance between the extent of covalent interactions between the surface functional groups on the graphene sheets and the isocyanate groups, and the number of stacked graphene sheets. Whereas MG mainly intercalated between the soft segments showing a typical behavior of nanofiller, GP and, particularly, GO showed different degrees of micro-phase separation due to more net covalent interactions with the poly(urethane urea) chains which caused higher crystallinity. The addition of graphene derivative decreased the glass transition temperature of the hard segments and increased the percentages of associated by hydrogen bond urethane and urea groups, more noticeably by adding GP and MG. Lower temperatures of decomposition and higher amounts of urethane and urea hard domains, and soft domains were found in PU + GO and PU + MG, and they showed an additional structural relaxation at 11–16 °C. PU and PU + GP had higher thermal stabilities than PU + GO and PU + MG and the addition of GP and, more markedly, GO imparted toughening to the poly(urethane urea). The T-peel strength values were higher in the joints made with PUD + GO due to the more net covalent interactions between the surface functional groups on the GO sheets and the poly(urethane urea) chains. On the other hand, the lap-shear strength of the joints made with PUD + MG and, in less extent, with PUD + GP noticeably increased.

An “inner soft external hard”, scratch-resistant, self-healing waterborne poly(urethane-urea) coating based on gradient metal coordination structure

To reduce pollution and maintain sustainable development, environmental friendly waterborne coatings as a replacement for conventional oil-based coatings have drawn lots of attention and been widely studied recently. It is a challenge to overcome the inherited weakness of waterborne coatings including poor scratch-resistance, low hardness and short lifespan. Herein, we have developed a scratch-resistant and self-healing waterborne coating of poly(urethane-urea), which contains a dual metal coordination structure of Zn(II)-carboxyl and Zn(II)-diamidepyridine by using the method of ions penetration. The addition of zinc ions has given dense metal coordination bonds on the coating surface, which has greatly increased the surface hardness (from B to 4H) and scratch-resistance, while the inner layer keeps excellent adhesion (>1.5 MPa) to substrates because of less metal ion penetration to the inner. What's more, the coating exhibits outstanding self-repairing performance, and the repair ability is better under hygrothermal condition. Atomic force microscope (AFM), dynamic mechanical analysis (DMA) and thermal analysis were used to characterize the self-healing and hardening mechanisms of the coatings. These results are expected to provide a useful method to improve the overall strength of waterborne coating.

Influence of the Surface Chemistry of Graphene Oxide on the Structure-Property Relationship of Waterborne Poly(urethane urea) Adhesive.

Small amounts—0.04 wt.%—graphene oxide derivatives with different surface chemistry (graphene oxide—GO-, amine-functionalized GO—A-GO-, reduced GO—r-GO) were added during prepolymer formation in the synthesis of waterborne poly(urethane urea) dispersions (PUDs). Covalent interactions between the surface groups on the graphene oxide derivatives and the end NCO groups of the prepolymer were created, these interactions differently altered the degree of micro-phase separation of the PUDs and their structure–properties relationships. The amine functional groups on the A-GO surface reacted preferentially with the prepolymer, producing new urea hard domains and higher percentage of soft segments than in the PUD without GO derivative. All GO derivatives were well dispersed into the PU matrix. The PUD without GO derivative showed the most noticeable shear thinning and the addition of the GO derivative reduced the extent of shear thinning differently depending on its functional chemistry. The free urethane groups were dominant in all PUs and the addition of the GO derivative increased the percentage of the associated by hydrogen bond urethane groups. As a consequence, the addition of GO derivative caused a lower degree of micro-phase separation. All PUs containing GO derivatives exhibited an additional thermal decomposition at 190–206 °C which was ascribed to the GO derivative-poly(urethane urea) interactions, the lowest temperature corresponded to PU+A-GO. The PUs exhibited two structural relaxations, their temperatures decreased by adding the GO derivative, and the values of the maximum of tan delta in PU+r-GO and PU+A-GO were significantly higher than in the rest. The addition of the GO derivative increased the elongation-at-break, imparted some toughening, and increased the adhesion of the PUD. The highest T-peel strength values corresponded to the joints made with PUD+GO and PUD+r-GO, and a rupture of the substrate was obtained.

Bioinspired, Highly Adhesive, Nanostructured Polymeric Coatings for Superhydrophobic Fire-Extinguishing Thermal Insulation Foam.

Lightweight polymeric foam is highly attractive as thermal insulation materials for energy-saving buildings but is plagued by its inherent flammability. Fire-retardant coatings are suggested as an effective means to solve this problem. However, most of the existing fire-retardant coatings suffer from poor interfacial adhesion to polymeric foam during use. In nature, snails and tree frogs exhibit strong adhesion to a variety of surfaces by interfacial hydrogen-bonding and mechanical interlocking, respectively. Inspired by their adhesion mechanisms, we herein rationally design fire-retardant polymeric coatings with phase-separated micro/nanostructures via a facile radical copolymerization of hydroxyethyl acrylate (HEA) and sodium vinylsulfonate (VS). The resultant waterborne poly(VS-co-HEA) copolymers exhibit strong interfacial adhesion to rigid polyurethane (PU) foam and other substrates, better than most of the current adhesives because of the combination of interfacial hydrogen-bonding and mechanical interlocking. Besides a superhydrophobic feature, the poly(VS-co-HEA)-coated PU foam can self-extinguish a flame, exhibiting a desired V-0 rating during vertical burning and low heat and smoke release due to its high charring capability, which is superior to its previous counterparts. Moreover, the foam thermal insulation is well-preserved and agrees well with theoretical calculations. This work offers a facile biomimetic strategy for creating advanced adhesive fire-retardant polymeric coatings for many flammable substrates.

Star-hyperbranched waterborne polyurethane based on D-glucose-poly(ε-caprolactone) core as a biomaterial candidate

Herein, a novel three-dimensional (3D) waterborne poly (ester-urethane-urea) (WPEUU) networks containig D-glucose-poly(ε-caprolactone) (GBPS) as a pentol star core were designed and synthesized. The structure and properties of the polymers were investigated by FTIR and 1HNMR spectroscopy methods and FE-SEM, DSC and TGA techniques in detail. In addition, the degree of polymerization (DPn = 12), the number average molecular weight (Mn ~ 7000 g/mol) and funtionality (f = 5) of pentol star were controlled and determined by means of 1HNMR. Physico-chemical characterization revealed that WPEUU compared with GBPS, showed a decrease in the degree of crystallinity (from Xc ~ 42% to Xc ~ 20%) and water contact angle (77.3° to 36.4°), which presented higher hydrophilicity, degradability and compatibility in vitro (14% VS 6% mass loss) and in vivo (30% weight loss) after four weeks degradation. The in vivo and in vitro degradations phenomen and surface morphology changes were compared by using FESEM micrographs. The skinny fibrous capsules (~5–7 µm) were observed around the WPEUU films. These results and low cytotoxicity to the L929 cells, also can be deduced that the prepared biodegradable and biocompatible WPEUU can be employed as potential biomaterial for biomedical applications in the future.