Progress in Organic Coatings最新文献

In this work, the modified epoxy resins with phase sizes of silicone varying from a homogeneous structure to 9.35 μm were obtained by regulating curing. The effect of silicone phase size on the mechanical, thermal and ablative properties of epoxy resins was also investigated. The increase in the degree of pre-curing slowed down the exothermic effect of the curing process and reduced the number of precipitated silicone phases leading to a large-sized phase structure. Nevertheless, the increased grafting rate induces the formation of a homogeneous structure of the silicone in the epoxy resin. Nano-scale and homogeneous phases of silicone contribute to the formation of a dense antioxidant layer, which imparts excellent thermal stability and ablative resistance to the epoxy resin. The ablation rate of epoxy resins with homogeneous phase reached 0.0671 g/s and 0.014 mm/s, which is even lower than that of conventional ablative resins. Meanwhile, the excellent mechanical properties are expected to replace expensive thermal protection materials as the main component of the new generation of thermal protection systems.

To protect weathered ancient stone monuments from surface cracking and surface damage by powders, strong materials containing flexible chains are required. Herein, a facile strategy was proposed to produce hybrid octa-glycidyl polyhedral oligomeric silsesquioxane (GPOSS)-enhanced flexible siloxanes by the ring-opening reaction of GPOSS using three aminosiloxanes (bis(3-aminopropyl) terminated poly (dimethyl siloxane) (NH₂-PDMS), 3-aminopropyltriethoxysilane (APTS), and N-(6-aminohexyl) aminopropyl trimethoxysilane (AHAPTMS). This produced three different protective materials (POSS-PDMS, POSS-APTS, and POSS-AHAPTMS) that greatly improved the weather resistance of sandstone monuments, especially their resistance to water, salt, temperature, and humidity. All three protective materials presented an adhesion of up to 2.4 MPa. The resistance of freeze-thaw aging cycles was much higher for the protected sandstone (104–133 cycles) compared with the unprotected sandstone (20 cycles). The three protective materials improved the salt weather resistance of protected sandstone (9–60 cycles) compared with unprotected sandstone (3 cycles), with the long-chain aminosiloxane AHAPTMS providing the best protection. The hydrophobicity of three protective materials on the sandstone surface was improved. Furthermore, the water absorption, water vapor permeability, pore size distribution, mechanical strength, light transmittance, and glass transition temperature (T_g), were all improved. The three GPOSS-enhanced flexible siloxanes are novel and eco-friendly materials for protecting sandstone monuments.

The inevitable presence of fog causes a loss of light transmission in optical materials and leads to many unacceptable and serious consequences. A promising strategy for avoiding fog is to modulate the wettability of the material surface and further change the formed way of droplets. Although many works achieved high antifogging coatings, they are lack of the long-lasting antifogging at varied conditions. In this work, a high adhesion strength and persistent antifogging capability hydrophilic coating is obtained by utilizing silane coupling agents containing double bonds such as triethoxyvinylsilane (A151) and 3-(trimethoxysilyl)propyl methacrylate (KH570) with 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and then compositing with poly(vinyl alcohol) (PVA). The coating composed of A151 has a relatively uniform and flat surface structure, due to weaker hydrolysis ability of A151 promoted the smooth condensation speed, compared to KH570. Thanks to the hydrophilic and hydrophobic balance properties of the A151-modulated coating network, the resultant coating exhibits good antifogging performance in the range of 0 °C to 90 °C, which keeps a light transmission of about 85 %. Surprisingly, the coating shows excellent adhesion (350–700 kPa) to the substrate, which is significantly better than other conventional hydrophilic antifogging coatings, and the hydrophilic and hydrophobic modulation capability and the enhanced interfacial adhesion of A151 segments provide the basis of the coating for long-lasting antifogging, which would open up a new way of durable hydrophilic antifogging coatings.

In this study, we synthesized a high refractive index and photocurable monomer via the Fischer esterification reaction between 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene and 3-mercaptopropionc acid. The synthesized monomer was confirmed by Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR). Furthermore, we prepared UV-curable resins with different amounts of the synthesized monomer as a thiol component and evaluated their UV-cured solid-state properties, including refractive indices, volumetric shrinkage, and adhesion to PET films. An edge-lit light-emitting diode blacklight unit revealed that the luminance of the samples increased with increasing thiol content.

Wet-weaving and cluster braiding in industrial production processes generate irreversible defects and grooves in carbon fibre (CF) filaments, which reduce the service life and mechanical properties of the fibres. Additionally, the fibre surface covered with numerous inactive carbon-containing groups and presents chemical inertness, which limits the prospects of CF applications. Hence, the hyperbranched bio-based waterborne polyurethanes (SWPU) possessing the synergism of sulfamate and carboxylate complex hydrophilic units were adopted as sizing coatings to improve the flexural and tensile strengths of CF, as well as fibre surface roughness and wettability. The SWPU is designed on dihydroxymethylbutyric acid and sulfamates (A95) as per- and post-chain extenders, respectively, trimethylolpropane (TMP) as an intramolecular cross-linker, and plant-extracts castor oil (CO) replacing petroleum-based petrochemicals as the soft-segments. The construction of CO-TMP hyperbranched cross-linking networks and the strengthened hydrogen-bonding effects of the polar sulfamates positively affect the intermolecular interactions and configuration stability of SWPU sizing coatings. SWPU revealed favourable thermo-mechanical properties achieving a T5% decomposition temperature and toughness of 297.83 °C and 35.24 MJ/m³. The coating effects of the bio-based sizing agents not only repaired defects and improved surface roughness on CF, but the polar groups in SWPU comprising SO₃Na, carbamate and polyurea promoted the chemotactic activity and wettability of the fibres. The surface energy and tensile strength of the SWPU sized CF reached 43.75 mN/m and 5.68 GPa, respectively, which were 45.4 % and 30.7 % higher compared to original CF. The research contributes to the development and industrial production of high-performance, eco-friendly bio-based sizing coatings.

Superhydrophobic fabrics with multifunctions have enormous application potential in our daily lives, but still suffer from issues of poor durability, tedious coating process, and toxicity due to additional chemical treatments. In this study, we present an efficient and clean strategy for the preparation of robust, colorful and non-fluorinated superhydrophobic fabric coating with both antibacterial and antistatic properties via a facile one-step disperse dyeing process. The composite coating contains silicone-modified waterborne polyurethane (WPU) resin, hexadecyltrimethoxysilane (HDTMS), graphene oxide (GO), and disperse dyes. The disperse dyeing process under high temperature/steam pressure can not only realize fabric dyeing, form a firmly-bonded coating on the fabric surface, but also facilitate the in-situ reduction of GO (rGO). The rGO/HDTMS/WPU/dye coated fabrics exhibit colors with excellent color fastness and superhydrophobicity with impressively high stability against washing, abrasion, acid and alkali attacks, high temperature and extremely low temperature (i.e., liquid nitrogen) treatments. Moreover, the multifunctional coating demonstrates self-healing capability from chemical damages. The rGO in the coating matrix renders fabrics with antistatic and antibacterial ability against Staphylococcus aureus (antibacterial rate of over 98 %). This one-step multifunctional coating strategy is highly desirable for facile fabrication of fabric coatings by showing virtues of energy saving, emission reduction, carbon footprint reduction and environmental protection.

This study investigates the interlayer bonding mechanism between epoxy primers and polyurethane topcoats commonly used in marine coatings. Previous studies have focused on the physical bonding between the coatings, but this study focused on the theory of chemical bonding. Using E-44 and HP2000 as primers and MDI toluene solution to simulate a polyurethane topcoat, the changes in the molecular structure at the interface between the epoxy primer and the polyurethane topcoat after curing were revealed by sum-frequency vibrational spectroscopy (SFG) technique. The experiments showed that the hydroxyl (-OH) signals on the surface of the epoxy primer disappeared after contacting with the MDI solution, and the isocyanate (-NCO) and carbonyl (C=O) signals on the urethane topcoat were revealed, suggesting that a chemical reaction occurred between them. The results of SFG analysis were further supported by X-ray photoelectron spectroscopy, Raman spectroscopy, infrared spectroscopy and scanning electron microscopy. It was found that chemical bonding had a positive effect on the macroscopic properties of the coatings, indicating that the interlayer bonding between the primer and the topcoat could be significantly enhanced by chemical bonding, which provides new theoretical support for the interlayer bonding of the coating support system for marine environment.

Developing a superhydrophobic a superhydrophobic anti-icing coating with robust mechanical attributes and chemical resilience is essential for effective anti-icing protection. This study employed fluorine-modified epoxy resin as the resin matrix and Fe₃O₄@PPy as the photothermal filler to fabricate an ice-resistant superhydrophobic coating, renowned for its exceptional mechanical endurance and corrosion resistance. With its unique micro-nano structure, the resulting coating exhibited an impressive contact angle (CA) of 158.7° and a minimal sliding angle (SA) of <1°. Even after enduring 260 cycles of sandpaper abrasion and tape peeling tests, the coating retained a CA of 157.8° and 154.2° respectively, demonstrating remarkable mechanical durability. The Fe3O4@PPy coatings exhibit excellent ice resistance with water droplets frozen time prolonging to 524 s at −20 °C. Moreover, when exposed to a light intensity of 100 mW/cm², the coating rapidly heated to 82.4 °C, effectively facilitating de-icing and defrosting, while reducing ice adhesion strength by 88.4 %, underscoring its exceptional anti-icing efficacy. These findings underscore the potential of durable and chemically stable anti-·icing coatings to deliver sustained anti-icing benefits and hold promising practical applications.

Flexible polyurethane foams (FPUFs) are widely used in various industries due to its high rebound characteristics, but its inherent flammability significantly affects its application. In this study, inspired by the structure of shell nacre, an aerogel coating with gelatin, boric acid and tetrakis hydroxymethyl phosphonium sulfate (THPS) as raw materials was designed. Owing to the hydrogen bonding interactions among the above molecules, the aerogel coating exhibits strong interfacial adhesion to the FPUF substrate, and the peel strength even surpasses the intrinsic strength of the FPUF matrix. Moreover, the coated FPUFs exhibit exceptional flame retardant and thermal insulation properties. The LOI value reaches as high as over 80 % and easily achieves a UL-94 V0 rating. During combustion, the coated FPUFs illustrate extremely low heat and smoke release. Meanwhile, the coated FPUFs still maintain excellent resilience. In addition, the THPS endows coated FPUFs with excellent antibacterial properties and exhibits a highly inhibition against Escherichia coli and Staphylococcus aureus.

Hyperbranched and linear amino-polysiloxanes with different functional groups were synthesized from trifunctional, difunctional and amino siloxanes and characterized. The amino-polysiloxanes as curing agents were used for hydrogenated diglycidyl ether of bisphenol A coatings. The effects of amino-polysiloxanes with different functional groups and different branching degrees on the surface properties, mechanical properties, corrosion resistance and thermal properties of the epoxy resin coatings were investigated. The epoxy coatings with hyperbranched amino-polysiloxanes exhibit better reactivity, higher hardness, better wear and corrosion resistance, and higher thermal properties as compared to that with the linear amino-polysiloxane. The coatings with the hyperbranching polysiloxanes can maintain lowest-frequency impedance (|Z|_f=0.01Hz) above 10⁸ Ω·cm² after 30 days of the corrosion test, while coating with the linear polysiloxane only 10⁷ Ω·cm². Moreover, due to the introduction of trifluoropropyl, the fluorinated hyperbranched polysiloxane/epoxy resin coating (HBPSi-2Ph2F/EP coating) has the highest |Z|_f=0.01Hz, up to 4.26 × 10⁹ Ω·cm². The hyperbranched amino-polysiloxanes as curing agents for epoxy resins would be expected to find wide applications in high performance coatings.