The development of multifunctional UV-cured coating formulations combining sustainability, flame retardancy, and circularity remains a major challenge for advanced polymeric materials. In this work, a fully bio-based UV-curable vitrimeric formulation was developed by combining a vanillin-derived Schiff-base resin with DNA from herring sperm as a sustainable intumescent flame-retardant additive. DNA was incorporated at 10 and 20% w/w, and the resulting UV-cured coating formulations were investigated in terms of morphology, thermomechanical properties, flame-retardant performance, thermally activated scratch closure, and chemical recyclability. SEM observations revealed a heterogeneous morphology arising from the limited compatibility between DNA and the hydrophobic vitrimeric matrix, while DSC and DMTA demonstrated that DNA slightly increased the glass transition temperature and storage modulus without preventing network formation. TGA showed a marked increase in char residue. Cone calorimetry revealed progressive reductions of 38% in peak heat release rate, 46% in total heat release, and 73% in total smoke release for the formulation containing 20% w/w DNA relative to the unfilled formulation. PCFC results showed a similar trend. However, all formulations remained not classified in UL-94 vertical flame-spread tests. SEM-EDS analyses of combustion residues revealed a more compact, phosphorus-rich char, consistent with a predominantly char-forming contribution of DNA in the condensed phase. DNA incorporation did not prevent repeated thermally activated scratch closure or chemical recycling through transimination. Although scratch closure at 120 °C may be the synergic effect of dynamic bond exchange and thermally activated polymer mobility, these findings demonstrate the potential of DNA-containing imine vitrimers as sustainable UV-cured coating formulations with improved fire performance and circularity.
Lignin is an attractive renewable candidate for the development of sustainable Pickering stabilizers; however, its practical application is often limited by poor colloidal stability, strong self-association, and limited compatibility with polymer matrices. In this work, a zwitterionic functionalization strategy was developed by grafting poly(3-dimethyl(methacryloyloxyethyl)ammonium propane sulfonate) (DMAPS) chains onto Kraft lignin particles through a UV-induced thiol–ene reaction. The surface-modified lignin structures were subsequently employed as Pickering stabilizers in surfactant-free miniemulsion polymerization of methyl methacrylate and butyl methacrylate, yielding stable waterborne latexes and homogeneous composite coatings. Compared with unmodified lignin, the L/DMAPS hybrids improved filler dispersion, enhanced filler–matrix interactions, and promoted the formation of a more integrated microstructure. Accelerated UV-aging studies demonstrated significantly reduced oxidation, smaller changes in surface wettability, and improved resistance to photo-oxidative degradation. The optimal 1:1 L/DMAPS formulation provided the highest photostability, highlighting the synergistic combination of lignin UV-screening capability and zwitterionic surface protection. The zwitterionic modification transformed lignin from a conventional Pickering stabilizer into a multifunctional interfacial component that not only stabilized the miniemulsion but also improved polymer–filler interactions, leading to coatings with enhanced viscoelastic performance (higher storage modulus and Tg), reduced solvent uptake, and superior resistance to photo-oxidative degradation.
Achieving reliable adhesion across chemically diverse substrates remains a central challenge in adhesive science, because interfacial bonding and stress transfer depend strongly on substrate surface chemistry. Here, a multi-substrate strategy combines an optimized UV-curable thiol–ene adhesive with a gradient adhesion-promoting layer deposited by initiated chemical vapor deposition (iCVD). Among adhesives modified with a polysulfide oligomer (G4), the 10 wt% formulation shows the most balanced rheological and mechanical behavior, giving a lap-shear strength of 2.94 ± 0.20 MPa on glass. A nanoscale gradient copolymer, poly(1-vinylimidazole-grad-2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane-grad-allyl methacrylate), deposited by iCVD. Three monomers give three regions with distinct functions, namely an imidazole-rich base that anchors the coating to the substrate, a V4D4-containing region that is crosslinked during deposition, and an allyl-rich surface. Stage-wise spectroscopy supports the programmed compositional gradient, FTIR and control experiments are consistent with thiol–ene coupling at the adhesive–coating interface, and nanoindentation reveals a corresponding mechanical gradient. The coating improves adhesion across all substrates, raising lap-shear strength from 1.87 to 2.55 MPa on aluminum, 2.22 to 3.15 MPa on stainless steel, 1.92 to 2.55 MPa on polycarbonate (PC), 1.18 to 2.24 MPa on poly (methyl methacrylate) (PMMA), and 0.17 to 0.47 MPa on polytetrafluoroethylene (PTFE), while retaining high visible-range transmittance. This solvent-free approach offers a practical platform for UV-curable adhesives, microelectronics packaging, and transparent device assembly.
Coatings that provide effective anti-corrosion barriers are essential for protecting metal surfaces. However, over time, the coated substrate can become susceptible to localized corrosion, while physical damage, such as cracks and scratches, reduces the effectiveness of the protective coating. In this work, intelligent systems based on epoxy-silica coatings were developed to confer long-term protection against corrosion of the AA7075 aluminum alloy, using a strategy combining a dense and effective passive barrier against the permeation of oxidizing species, and active protection by incorporation of the inhibitors Ce(IV) and Ce(III). Different characterization techniques were used to identify structural changes in the modified epoxy-silica nanocomposites. Excellent long-term corrosion protection performance was obtained in 0.6 mol L−1 NaCl solution, with electrochemical impedance spectroscopy analysis showing that impedance modulus on the order of 10 MΩ cm2 was maintained over a period of 400 days. Detailed investigation of the modified coatings revealed their self-healing ability after film corrosion damage and exposure of artificially scratched coatings to accelerated corrosion and salt spray testing, confirming the effectiveness of the Ce(III) and Ce(IV) agents for the long-term protection of epoxy-silica coatings.
