A waterborne polyurethane coating functionalized by isobornyl with enhanced antibacterial adhesion and hydrophobic property

Ecofriendly dual-function cotton fabric with antibacterial and anti-adhesion properties based on modified natural materials

Ecofriendly fabrics with antibacterial and anti-adhesion properties have been attracted an increasing attention in recent years. Herein, natural menthol modified polyacrylate (PMCA) antibacterial adhesion agent was synthesized by esterification and polymerisation while natural pterostilbene-grafted-chitosan (PGC) antibacterial agent was prepared through Mannich reaction. The antibacterial and anti-adhesion cotton fabric was fabricated through durable PMCA dip finishing and then layer-by-layer self-assembly of PGC. The results showed that the antibacterial adhesion rates and antibacterial rates of the dual-function cotton fabric against Staphylococcus aureus and Escherichia coli reached up to 99.9 %. Its antibacterial adhesion rates improved by 36.1 % and 40.1 % in comparison with those of cotton fabric treated by menthol alone. Meanwhile against S. aureus, the dual-function cotton fabrics improved the antibacterial rates by 56.7 % and 36.4 %, respectively, from those of chitosan- and pterostilbene-treated fabrics. Against E. coli, the improvements were 89.4 % and 24.8 %, respectively. After 20 household washings, the dual-function cotton fabric maintained >80 % of its original anti-adhesion and antibacterial rates against both species. The dual-function cotton fabric also possessed safe and excellent wearability.

Self-Healing and Reprocessable Terpene Polysiloxane-Based Poly(thiourethane-urethane) Material with Reversible Thiourethane Bonds

Polyurethane materials will come into contact with different solvents in daily life, and at the same time, they will be subject to different degrees of collision, wear and tear. Failure to take corresponding preventative or reparative measures will result in a waste of resources and an increase in costs. To this end, we prepared a novel polysiloxane with isobornyl acrylate and thiol groups as side groups, which was further used in the preparation of poly(thiourethane-urethane) materials. Thiourethane bonds generated by the click reaction of thiol groups with isocyanates endow poly(thiourethane-urethane) materials with the ability to heal and reprocess. Isobornyl acrylate with a large sterically hindered rigid ring promotes segment migration, accelerating the exchange of thiourethane bonds, which is beneficial to the recycling of materials. These results not only promote the development of terpene derivative-based polysiloxanes but also show the great potential of thiourethane as a dynamic covalent bond in the field of polymer reprocessing and healing.

Solventless Photopolymerizable Paper Coating Formulation for Packaging Applications

Nowadays, packaging applications require the use of advanced materials as well as production methods that have a low environmental impact. In this study, a solvent-free photopolymerizable paper coating was developed using two acrylic monomers (2-ethylhexyl acrylate and isobornyl methacrylate). A copolymer, with a molar ratio of 2-ethylhexyl acrylate/isobornyl methacrylate of 0.64/0.36, was prepared and used as the main component of the coating formulations (50 and 60 wt%). A mixture of the monomers with the same proportion was used as a reactive solvent, yielding formulations with 100% solids. The coated papers showed an increase in the pick-up values from 6.7 to 32 g/m² depending on the formulation used and the number of coating layers (up to two). The coated papers maintained their mechanical properties and presented improved air barrier properties (Gurley's air resistivity of ≈25 s for the higher pick-up values). All the formulations promoted a significant increase in the paper's water contact angle (all higher than 120 °) and a remarkable decrease in their water absorption (Cobb values decrease from 108 to 11 g/m²). The results confirm the potential of these solventless formulations for fabricating hydrophobic papers with potential application in packaging, following a quick, effective, and more sustainable approach.

A facile, alternative and sustainable feedstock for transparent polyurethane elastomers from chemical recycling waste PET in high-efficient way

Polymers with excellent optical and mechanical performance fabricated from renewable resources, have been paid an increasing attention in recent years. Here, high-performing polyurethane elastomers with significant mechanical properties, crystallinity, excellent stretchability and good transparency are prepared by a synergistic molecular design in the soft and hard segments. Using the liquid glycolysis degradation product (LGOP) as a chain extender, polyurethane elastomer is synthesized from polyethylene terephthalate (PET) waste bottles. The results suggest that the degradation products from waste PET can be directly used as feedstock for preparing polyurethane elastomers with significant performance. The polyurethanes exhibited excellent optical transparency of near 90%, and can be stretched up to 670% without any treatment to return to original size. It is assumed that the symmetrical hard domain composed of aromatic rings and ester groups in LGOP creates sufficient chain fluidity for the dynamic exchange of hydrogen bonds and urethane. This paper has devoted to achieve a complete and mature system from waste PET to polyurethane products, to create a closed loop of waste PET plastic recycling and regeneration, and to realize the polyurethane industrial chain of raw material self-supply.

Inserting Menthoxytriazine into Poly(ethylene terephthalate) for Inhibiting Microbial Adhesion

Antimicrobial modification of poly(ethylene terephthalate) (PET) is effective in preventing the adhesion and growth of microorganisms on its surface. However, few methods are available to modify PET directly at its backbone to impart the antimicrobial effect. Herein, menthoxytriazine-modified PET (PMETM) based on the stereochemical antimicrobial strategy was reported. This novel PET was prepared by inserting menthoxytriazine into the PET backbone. The antibacterial adhesion test and the antifungal landing test were employed to confirm the antiadhesion ability of PMETM. PMETM could effectively inhibit the adhesion of bacteria, with inhibition ratios of 99.9 and 99.7% against Escherichia coli (Gram-negative) and Bacillus subtilis (Gram-positive), respectively. In addition, PMETM exhibited excellent resistance to Aspergillus niger (fungal) contamination for more than 30 days. Cytotoxicity assays indicated that PMETM was a noncytotoxic material. These results suggested that the insertion of menthoxytriazine in the PET backbone was a promising strategy to confer antimicrobial properties to PET.

Photocurable Coatings Based on Bio-Renewable Oligomers and Monomers

Due to long-term problems related to environmental protection, economic aspects, and waste management in the chemical industry, it is justified to develop renewable polymers as an alternative to synthetic polymers. Two kinds of acrylic bio-renewable components were used for the modification of acrylated epoxidized soybean oil (AESO). The bio-based compositions used as photocurable binders to obtain the photocurable coatings with satisfactory properties and high bio content were then prepared. The kinetic of curing reaction of the oligomers and monomers towards radical photopolymerization and the properties of the cured coatings were fully investigated; the results are discussed in relation with the compounds’ structures. Important information about how to design and obtain renewable photocurable coatings with satisfactory properties was provided in this study. In this study, AESO resin was modified with renewable oligomer or (math)acrylate monomer to increase the reactivity and reduce the viscosity of the photoreactive system in order to obtain renewable and viable alternatives to petroleum-based polymeric materials with perfect film-forming properties. It turned out that both photopolymerization rate and hardness of cured coatings were increased significantly with the addition of modifiers; the use of a thiol modifier and change of the photoinitiator concentration allowed to improve the adhesion, hardness, and control of the photo-curing process.

pH-Responsive Pickering high internal phase emulsions stabilized by Waterborne polyurethane

HYPOTHESIS

Waterborne polyurethane (WPU) is a common colloidal dispersion that can aggregate in the aqueous phase to form nanoparticles with hydrophobic polyurethane chains as the core and hydrophilic ionic groups as the shell. Considering their structure and pH-responsive functional groups, WPU nanoparticles could be ideal particulate emulsifiers for preparing pH-responsive Pickering high internal phase emulsions (HIPEs).

EXPERIMENTS

A series of anionic WPU with different content of 2,2-bis(hydroxymethyl)propionic acid (DMPA) side chains were synthesized via a polyaddition reaction. The DMPA content, size, ζ-potential, and interfacial behaviors of WPU were then investigated. Furthermore, the effects of particle concentration, internal phase fraction (ϕ), oil type, and pH values on the Pickering HIPEs' morphology, stability, and rheological behaviors were systematically studied. Finally, we demonstrated the emulsification-demulsification process of WPU-stabilized Pickering HIPEs and discussed its mechanism.

FINDINGS

Oil-in-water (O/W) Pickering HIPEs with tailored morphology and excellent pH-responsiveness were prepared from anionic WPU nanoparticles. The WPU concentration, ϕ, and oil type had a large impact on the formation and mean droplet size of the WPU-stabilized emulsions. Rheology analysis demonstrated that the strictly limited movement of droplets endowed the WPU-stabilized HIPEs with high stability, shear sensitivity, and excellent thixotropic recovery. By simply changing the aqueous-phase pH value, the WPU-stabilized HIPEs could undergo more than ten emulsification-demulsification cycles, as the physical and interfacial properties of WPU nanoparticles were pH-dependent. The excellent performance of the WPU-stabilized pH-responsive Pickering HIPEs exhibited their potential practical applications, such as for oil transportation and recovery, emulsion polymerization, and heterogeneous catalysis.

Sustainable UV-Crosslinkable Acrylic Pressure-Sensitive Adhesives for Medical Application

This study aimed to investigate the potential of photoreactive acrylate patches as systems for transdermal drug delivery, in particular, using more renewable alternatives and more environmentally friendly synthesis routes of transdermal patches. Therefore, the aim of this study was to develop a transdermal patch containing ibuprofen and investigate its performance in vitro through the pigskin. Transparent patches were prepared using four acrylate copolymers with an incorporated photoinitiator. Two types of transdermal patches based on the photocrosslinking acrylic prepolymers with isobornyl methacrylate as biocomponent and monomer increasing Tg ("hard") were manufactured. The obtained patches were characterized for their adhesive properties and tested for permeability of the active substance. It turns out that patches whose adhesive matrix is photoreactive polyacrylate copolymers have a higher cohesion than patches from commercial adhesives, while the modification of the copolymers with isobornyl methacrylate resulted in an improvement in adhesion and tack. This study demonstrates the feasibility of developing photoreactive acrylic-based transdermal patches that contain biocomponents that can deliver a therapeutically relevant dose of ibuprofen.

Graphene and water-based elastomer nanocomposites - a review

Water-based elastomers (WBEs) are polymeric elastomers in aqueous systems. WBEs have recently continued to gain wide acceptability by both academia and industry due to their remarkable environmental and occupational safety friendly nature, as a non-toxic elastomeric dispersion with low-to-zero volatile organic compound (VOC) emission. However, their inherent poor mechanical and thermal properties remain a drawback to these sets of elastomers. Hence, nano-fillers such as graphene oxide (GO), reduced graphene oxide (rGO) and graphene nanoplatelets (GNPs) are being employed for the reinforcement and enhancement of this set of elastomers. This work is geared towards a critical review and summation of the state-of-the-art developments of graphene enhanced water-based elastomer composites (G-WBEC), including graphene and composite production processes, properties, characterisation techniques and potential commercial applications. The dominant production techniques, such as emulsion mixing and in situ polymerisation processes, which include Pickering emulsion, mini-emulsion and micro-emulsion, as well as ball-milling approach, are systematically evaluated. Details of the account of mechanical properties, electrical conductivity, thermal stability and thermal conductivity enhancements, as well as multifunctional properties of G-WBEC are discussed, with further elaboration on the structure-property relationship effects (such as dispersion and filler-matrix interface) through effective and non-destructive characterisation tools like Raman and XRD, among others. The paper also evaluates details of the current application attempts and potential commercial opportunities for G-WBEC utilisation in aerospace, automotive, oil and gas, biomedicals, textiles, sensors, electronics, solar energy, and thermal management.

New type of borneol-based fluorine-free superhydrophobic antibacterial polymeric coating

A new type of superhydrophobic borneol-based polymeric coating has been prepared. The chemical composition of the polymer particles was analyzed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, which showed that the polymer did not contain fluorine, which can effectively avoid the cytotoxic risk of fluorine. By dynamic light scattering, scanning electron microscopy, and static contact angle measurement, the contact angle of the prepared coating gradually increased with increasing diameter of the polymer particles, and a superhydrophobic coating surface was finally obtained. Interestingly, after dissolving the superhydrophobic sample with tetrahydrofuran and making it a normal hydrophobic sample, the antiadhesion performance for E. coli was greatly reduced, and it could not effectively prevent E. coli adhesion. In addition, a long-term antiadhesion study of bacteria was performed. The superhydrophobic borneol-based polymer coating showed long-term resistance to E. coli adhesion. Therefore, the excellent antibacterial properties and cell compatibility mean that this series of polymer materials has great potential in the field of biomedicine.

Antifouling and Antibacterial Polymer-Coated Surfaces Based on the Combined Effect of Zwitterions and the Natural Borneol

The development and application of natural antibacterial materials have always been the focus of biomedical research. Borneol as a natural antibacterial compound has received extensive attention. However, the hydrophobicity caused by its unique structure limits its application range to a certain extent. In this study, we combine zwitterionic 2-methacryloyloxyethyl phosphorylcholine (MPC) with a complex bicyclic monoterpene structure borneol compound and prepare an excellent antifouling and antibacterial surface via the Schiff-base bond. The prepared coating has excellent hydrophilicity verified by the contact angle (CA), and its polymer layer is confirmed by X-ray photoelectron spectroscopy (XPS). The zwitterion MPC and borneol moieties in the copolymer play a coordinating role, relying on super hydration and the special stereochemical structure to prevent protein adsorption and inhibit bacterial adhesion, respectively, which are demonstrated by bovine serum albumin (BSA) adsorption and antibacterial activity test. Moreover, the water-soluble borneol derivative as the antibacterial surfaces we designed here was biocompatible toward MRC-5 (lung fibroblasts), as showed by in vitro cytotoxicity assays. Such results indicate the potential application of the as-prepared hydrophilic surfaces in the biomedical materials.

Fully organic compliant dry electrodes self-adhesive to skin for long-term motion-robust epidermal biopotential monitoring

Wearable dry electrodes are needed for long-term biopotential recordings but are limited by their imperfect compliance with the skin, especially during body movements and sweat secretions, resulting in high interfacial impedance and motion artifacts. Herein, we report an intrinsically conductive polymer dry electrode with excellent self-adhesiveness, stretchability, and conductivity. It shows much lower skin-contact impedance and noise in static and dynamic measurement than the current dry electrodes and standard gel electrodes, enabling to acquire high-quality electrocardiogram (ECG), electromyogram (EMG) and electroencephalogram (EEG) signals in various conditions such as dry and wet skin and during body movement. Hence, this dry electrode can be used for long-term healthcare monitoring in complex daily conditions. We further investigated the capabilities of this electrode in a clinical setting and realized its ability to detect the arrhythmia features of atrial fibrillation accurately, and quantify muscle activity during deep tendon reflex testing and contraction against resistance.

Reported wearable dry electrodes have limited long-term use due to their imperfect skin compliance and high motion artifacts. Here, the authors report an intrinsically conductive, stretchable polymer dry electrode with excellent self-adhesiveness for long-term high-quality biopotential detection.

Functional-modified polyurethanes for rendering surfaces antimicrobial: An overview

Antimicrobial surfaces and coatings are rapidly emerging as primary components in functional modification of materials and play an important role in addressing the problems associated with biofouling and microbial infection. Polyurethane (PU) consisting of alternating soft and hard segments has been one of the most important coating materials that have been widely applied in many fields due to its versatile properties. This review attempts to provide insight into the recent advances in antimicrobial polyurethane coatings or surfaces. According to different classes of antimicrobial components along with their antimicrobial mechanism, the synthesis pathways are presented systematically herein to afford polyurethane with antimicrobial properties. Also, the challenges and opportunities of antimicrobial PU coatings and surfaces are also discussed. This review will be beneficial to the exploitation and the further studies of antimicrobial polyurethane materials for a variety of applications.

Self-Assembly of Amphiphilic Linear-Dendritic Carbosilane Block Surfactant for Waterborne Polyurethane Coating

The traditional two-component waterborne polyurethane coating system cannot effectively inhibit the undesirable side reaction between polyisocyanate and water during curing hardening. It is difficult to avoid the microbubbles formed by this reaction during the film formation process, which severely degrades the appearance and decreases the performance of the film. Therefore, the addition of an amphiphilic Linear-Dendritic carbosilane Block Surfactant (LDBS) to the hardener can physically separate the polyisocyanate emulsion from water through self-assembly. The bubble-free film thickness (BFFT) of the two-component waterborne polyurethane coating in this study is approximately 1.5-fold greater than commercial waterborne polyurethane coatings in today’s coating industry. Fourier transform infrared spectroscopy (FT-IR) varied the effectiveness of LDBS for inhibition of the undesirable side reaction. The successful application of the waterborne polyurethane coating with LDBS on the 600 km/h high-speed maglev train provides a technical solution for large-scale industrialization of waterborne polyurethane coating and complete replacement of solvent polyurethane coating.

Improving environmental protection of waterborne polyurethane coating by adding TiO2/polyaniline/HNT/CNT nanocomposite

Nanostructures of titanium dioxide, polyaniline, halloysite, and carbon nanotubes have an excellent effect to improve environmental protection and surface properties of coatings like anticorrosion and self-cleaning attributes. In this research, we studied the individual effect of adding each nanostructure within the polyurethane matrix and also all nanostructure combinations with each other on the mentioned properties. To reach this aim, the polyurethane nanocomposites were prepared; then, anticorrosion and self-cleaning tests were carried out on the samples. FTIR spectroscopy and FESEM images were used to characterize the nanocomposite additives and coating influence. According to the obtained results, the polyurethane coating modified with titanium dioxide/polyaniline/halloysite nanotube/carbon nanotube nanocomposite showed very higher corrosion potential and resistance and lower corrosion current in the comparison with other coatings. Also, the mentioned polyurethane nanocomposite coating showed good hydrophilicity and it decolorized a dye contaminant with high efficiency which makes them appropriate candidate for the protection of the substrate against environmental destructive factors.

A facile preparation of a novel non-leaching antimicrobial waterborne polyurethane leather coating functionalized by quaternary phosphonium salt

The aim of this research is to develop a novel non-leaching antimicrobial waterborne polyurethane (WPU) leather coating material with covalently attached quaternary phosphonium salt (QPS). The structure of the QPS-bearing WPU has been identified, and their thermal stability, mechanical property, and antimicrobial performance have been investigated. The results reveal that the incorporation of QPS slightly reduces the thermal stability of WPU material but would not affects its usability as leather coating. Despite the presence of hydrophobic benzene in QPS structure, the strong hydration of its cationic groups leads to the increased surface contact angle (SCA) and water absorption rate (WAR) of the films, suggesting that the water resistance of the films needs to be improved for the purpose of leather coatings. Antibacterial tests demonstrate that when the QPS content is 20 wt%, QPS-bearing WPU shows effective antimicrobial activity against bacteria. The WPU containing QPS prepared in this study is a non-leaching antimicrobial material and has great potential application as leather coating.

Graphical abstract

Synthesis and antibacterial investigation of cationic waterborne polyurethane containing siloxane

Cationic waterborne polyurethane containing siloxane and quaternary ammonium salt in the side chain was synthesized, which showed an enhanced antibacterial property and hydrophobicity.

Interpenetrating polymer network-based nanocomposites reinforced with octadecylamine capped Cu/reduced graphene oxide nanohybrid with hydrophobic, antimicrobial and antistatic attributes

Designing of mechanically tough elastomeric materials encompassed with intrinsic surface hydrophobicity, antistatic and antimicrobial attributes is in skyrocketing demands, especially to protect the instruments which are submerged in water. Herein, the authors depicted the fabrication of interpenetrating polymer network-based nanocomposites containing different doses of octadecylamine capped Cu/RGO nanohybrid. The structures and morphologies of the synthesized nanohybrid and the fabricated nanocomposites were characterized by using FTIR, XRD, XPS, TGA, FESEM and TEM analyses. Most interestingly the nanocomposites showed good hydrophobicity (static contact angle: 119.2°-129.3°), low surface resistivity (~10⁷ Ω m) and strong antimicrobial activity towards Gram negative (Pseudomonas aeruginosa and Yersinia pestis) and Gram positive (Bacillus cereus) bacterial strains. The fabricated nanocomposites also exhibited antifungal (Candida albicans) activity. In addition, the fabricated nanocomposites showed excellent mechanical properties including high tensile strength (14.03-20.9 MPa), outstanding flexibility (1887-2470%), excellent toughness (249.89-510.1 MJ.m^-3), high scratch resistance (>10 kg) and high thermostability (281-288 °C). Therefore, the fabricated nanocomposites can be used as an effective thin film for many advanced applications.