Progress in Organic Coatings最新文献

In this study, insect-based resin, i.e., shellac, was spray-coated onto molded pulp product (MPP) as a water and grease-resistant food-grade barrier coating for packaging applications. The shellac was first crosslinked by curing at 125 °C for 210 min, and DSC confirmed the formation of a thermoset material. Moreover, the Tg of shellac increased after crosslinking, showing a decrease in free volume and a reduction in molecular mobility. The shellac-coated MPP was further crosslinked and then tested for different barrier properties. FE-SEM confirmed the uniform coating of shellac over the MPP, and the crosslinking showed the removal of micro holes from the coating and increased the interfacial bonding with the MPP. The crosslinked shellac coating showed a high water barrier, as Cobb and water vapor transmission rate (WVTR) showed while providing excellent grease resistance through KIT test, mustard oil penetration, and heptane transmission rate (HTR). Further, the crosslinked shellac was also under the migration limit with all the food simulants at room and elevated temperatures, showing the safe usage of different food products at different temperatures. The coating also improved the coated MPP's tensile index and bending stiffness.

Medical catheters might cause a high morbidity of catheter-associated urinary tract infections (CAUTIs) because of the bacterial adhesion onto the surface. In addition, the inherent hydrophobicity of catheter materials exacerbates mechanical friction, leading to tissue damage. Therefore, coatings with integrated antibacterial and lubricative properties are appealing approaches to mitigate these challenges. In this study, a kind of polyurethane (PU)-based coatings were developed and prepared on medical catheters, which were modified with a cationic antibacterial agent, quaternized ammonium-modified methyldiethanolamines (QMDEAs). Due to the reaction among castor oil tertiary alcohols, isocyanates and QMDEAs, a polymer cross-linked network was fabricated, in which a hydrophilic polymer, polyvinylpyrrolidone (PVP), was added to form a semi-interpenetrating network. The structures of the coatings were regulated by adjusting the lengths of alkyl chain of QMDEAs, concentrations of pre-coated solutions, ratios of QMDEA:isocyanate, and parameters of preparation process. Among the coatings we prepared, PU-C10–46 possessed the optimized performances, which reduced the dynamic friction coefficient by 91.38 % and had the antibacterial efficiency of 99.9 % with good biocompatibility. The in vivo anti-infective properties of PU-C10–46 were also demonstrated by an infected animal model. Furthermore, PU-C10–46 was produced in an industrial equipment, and the large-scaled industrial products also had the same performances. This work could provide a promising strategy to deal with the challenges of medical catheter-associated infection.

Waterborne blend, hybrid and block copolymer latexes containing hard and soft polymeric phases in different polymer particles, in the same polymer particles or in the same polymer chains are prepared in order to analyse how the coalescing aids added in order to produce continuous films at room temperature affect their final mechanical properties. The minimum film formation temperature is measured for the three latexes upon addition of Texanol and BDG coalescing aids, and the possibility of producing continuous films at room temperature with different amounts of the coalescing aids is analysed. The plasticizing effect of each coalescing aid is analysed by DSC and by measuring their partition coefficients between the water and the polymeric phases. Finally, the evolution of the mechanical properties of the films plasticized with BDG and dried for different times is related to the evolution of the coalescing aid remaining in the film after those drying periods and to the morphology of each film.

Elaborating the structure–activity relationship between hyperbranched polymer architecture and the resulting surface antifouling performance is critical for biomedical applications. In this work, a series of poly(2-methyl-2-oxazoline) (PMeOx)-based hyperbranched poly((poly(2-methyl-2-oxazoline) acrylate)-co-(S-(4-vinyl) benzyl S′-propyltrithiocarbonate))s (poly(PMeOxA-co-VBPT)s) with varying degrees of branching (DBs) were synthesized via reversible addition-fragmentation chain transfer polymerization and self-condensing vinyl polymerization (RAFT-SCVP) of poly(2-methyl-2-oxazoline) acrylate (PMeOxA) and S-(4-vinyl) benzyl S′-propyltrithiocarbonate (VBPT). The copolymers were anchored onto surfaces using a material-independent dopamine-assisted co-deposition method. We systematically investigated the hyperbranched structure effects of the copolymers concerning the surface compositions, hydration, morphology, and antifouling properties. Our results demonstrated that the hyperbranched structure provided surfaces with higher PMeOx chain density and superior antifouling properties compared to the linear counterpart. Furthermore, it was found that the antifouling efficacy of the hyperbranched PMeOx-based coatings depended on the surface PMeOx chain densities, which were determined by the DB and PMeOx content in copolymers. Specifically, the PMeOxA(3)-co-VBPT(1)/polydopamine (PDA) coating with optimized formulation displayed the highest resistance to protein, platelet, and cell adsorption (98.4–99.3 % reduction) compared to unmodified surface. Taken together, this work highlights the significant impact of hyperbranched architecture on surface anti-biofouling performances and provides valuable guidelines for manipulating surface properties in applications such as drug delivery, diagnostic, and biosensors.

We examined the effects of prolonged exposure to high temperature water on epoxy-based powder barrier coatings applied to steel panels, which are commonly used in many industrial applications including oil & gas pipelines. The coatings' performance was evaluated over 85 weeks at 65 °C using deionized water. We also compared the mass transport properties of free-standing coating films with the barrier performance of the coated steel panels. This research lays the groundwork for predicting cumulative damage and time-dependent barrier performance of a priori pristine coating systems. Although these coating systems are intended for decades of in-service use, we found that some degradation effects caused by permeant sorption within the coatings can be detected as early as 8 weeks in the ageing process. Despite the coatings' barrier performance, substrate oxidation was readily observed after 182 days, as shown by cross-sectional and focused ion beam milling analysis. Colorimetry measurements of the underlying substrate, conducted after coating removal, also revealed that the first 200 days of exposure were critical for the development of underlying corrosion reactions. This period is characterized by the likely degradation of the epoxy network and the onset of a steady state in mass transport mechanisms. We also analyzed the adhesion strength of the coated panels over time. The epoxy-based coating's pull-off strength declines rapidly due to water-induced plasticization, but the adhesion properties of the epoxy network show a slight recovery due to secondary cross-linking by Type II bound water. This study underscores the complexity associated with predicting the time-to-failure for epoxy coating systems. However, the data and analyses provided herein offer valuable insights into the implications of extreme exposure conditions, aiding in the construction of lifetime predictions using a stochastic process. In real-world scenarios, pipelines undergo various fluctuations in parameters like temperature and humidity, potentially leading to failure. A deterministic physical/chemical model under simplified conditions can serve as input for the probability distribution function of future failure events.

In the marine industry and freshwater aquariums, biofouling leads to adverse effects including increased energy consumption, reduced service life, and blurred windows that require resources and intensive labor to fix. Linalool is a representative monoterpene alcohol extracted from salvia with multiple bioactive properties and can hence be applied as an antifouling agent. In this study, a series of transparent antifouling coatings were prepared using linalool inspired by salvia, and experiments were performed to evaluate their antifouling performances and antifouling mechanism. The prepared coatings demonstrated a high level of transparency, making them suitable for application to windows. The antifouling ability offered by linalool and low surface energy (12.5 mJ·m⁻²) provided by fluorosilane conferred the antifouling performance of 96.7 % against Pseudoalteromonas xiamenensis and 97.3 % against Halamphora sp. More importantly, inhibition of the expression of mussel foot proteins by linalool reduced the adhesive strength of mussel adhesive plaques, which subsequently assigned resistance to mussel adhesion. The environmental impact of antifouling coatings prepared with linalool as the active ingredient was verified by experiments involving zebrafish survival and diatom growth, the coatings had no effect on the growth of organisms in the environment, proving their environmental friendliness. The convenient preparation, excellent antifouling activity, and optical transparency of these coatings demonstrate the potential applicability of monoterpene alcohols, represented by linalool, as an antifouling agent; additionally, it can be used in sensors for data extraction, underwater detection portals and other fields that need transparency.

The utilization of biomass resources for multifunctional bio-based waterborne polyurethane (WPU) development is receiving considerable attention. Phloretin (PRT) is considered to be a potential functional plant-based chain extender due to its unique molecular structure. Hereon, a commercial-grade castor oil-modified polyol was utilized as the soft segment. Through a molecular structure design strategy, PRT was incorporated into WPU skeleton to prepare a series of PWPU coatings with varying PRT contents. The results indicated that the addition of PRT resulted in a reduction in the length of cross-linking sites, an increase in the density of the cross-linking network, and significant enhancement of various properties, including mechanical properties, water resistance, adhesion, and anticorrosive performance. For instance, the PWPU-2 film exhibited a tensile strength of 38.2 MPa and an elongation at break of 608.8 %, while its toughness reached an even more remarkable value of 142.8 MJ/m³, surpassing all previously reported plant oil-based WPU systems. Interestingly, the water absorption rate of the PWPU-4 film decreased to 10.2 %, overcoming the challenge of simultaneously improving both water resistance and mechanical properties in plant oil-based WPU. Furthermore, the protective efficiency (IE) of the PWPU-10 coating reached up to 97.08 %. More importantly, the introduction of PRT had endowed PWPU coatings with a comprehensive range of UV shielding properties. The PWPU coatings prepared in this study have applications in various fields, such as anti-corrosion coatings, sunscreen coatings, and water-based ink connectors. These findings provided theoretical ideas for multifunctional WPU functional coatings.

Environmental sustainability and multifunctionality are now key drivers for smart coatings design and applications. In a circular economy that promotes durable materials, the challenge is to develop multi-functional one-pot coating materials. The eco-efficient self-stratification process allows the spontaneous formation of complex polymer multilayers in only one step of formulation, application, and curing. This leads to the simultaneous production of both an undercoat and a finishing coating with all the properties needed to protect a material. In addition, film formation in a single application step drastically reduces adhesion failures and contamination between layers. The original idea in this study was to conceive a self-stratifying and self-healing coating formulation using a bio-based epoxy resin and a PDMS-based vitrimer, by taking advantage of the self-healing properties of the vitrimers. This newly discovered class of polymers possess dynamic covalent bonds. This epoxy resin – dynamic PDMS blend was successfully applied on polycarbonate substrates by spraying and exhibited a type I stratification associated with room temperature self-healing properties. Furthermore, the coating showed great adhesion to the substrate, on the contrary to the dynamic-PDMS when applied directly onto polycarbonate. The stratification was observed with SEM-EDS imaging. The self-healing property was proven by optical microscopy imaging of scratches under different thermal treatments. FT-IR and wet contact angle were used to further characterize the synthetized dyn-PDMS.

Antimicrobial coatings play a crucial role in combating pathogenic microorganisms. However, developing long-lasting antimicrobial coatings presents substantial challenges. In this study, we developed a robust method for fabricating durable antimicrobial coatings using crosslinked, biocide-encapsulated core–shell polymer microspheres. These microspheres were prepared by emulsion polymerization, facilitating simultaneous synthesis and biocide loading. Designed with a hydrophilic shell and a hydrophobic core, the microspheres predominantly stored the hydrophobic biocides within the core, thus reducing the biocide concentration at the shell. This design, which is governed by Fickian diffusion, substantially slowed the rate of biocide migration from the shell to the external environment, thereby enhancing the coating's antimicrobial longevity. The synthetic process for these biocide-encapsulated microspheres was optimized to encapsulate biocides with a Log P range of 1–3, achieving an encapsulation efficiency exceeding 85 % for all tested biocides. Specifically, microspheres containing N-butyl-1,2-benzisothiazolin-3-one (BBIT) were used to develop an antimicrobial coating. The coating can be applied to various substrates, including glass, metal, wood, ceramics, and plastics. It exhibits excellent hardness, adhesion, mechanical strength, and solvent resistance on these surfaces. Antimicrobial tests and release analyses demonstrated that the coating maintains high biological activity for at least 10 months, effectively inhibiting bacterial and fungal growth. The release behavior of the coating adhered to the Peppas–Sahlin model, with diffusion as the predominant mechanism. The model predicted an antimicrobial retention rate of over 66 % after 1 year, confirming its sustained antimicrobial effectiveness.

Epoxy resin (ER) thermosets are widely applied in various fields due to their high mechanical strength, thermal stability and chemical corrosion resistance. However, the brittleness of ER thermosets and low thixotropic property of ER matrix largely limits their further development. Here, this article develops branched polyethyleneimine (PEI) functionalized carbon nanotube (PEI@CNT) as high-performance nanofiller for simultaneously strengthening and toughening ER thermosets. Benefiting from good dispersity and rich amine groups of PEI@CNT, effective interfacial bonding between PEI@CNT and ER is achieved. The ER thermoset with 0.5 wt% PEI@CNT shows increase in tensile strength by 24.8 % and fracture elongation by 30.0 % compared with pristine ER thermoset. The enhanced mechanical properties of PEI@CNT modified ER thermosets can be ascribed to the chemical interaction between PEI@CNT and ER matrix as well as the formed crack propagation, which can dissipate a lot of fracture energy, further improving the strength and toughness of the ER composites. More importantly, the thixotropic property of ER matrix is largely improved after adding the PEI@CNT filler. This work reports a high-performance nanofiller for enhancing mechanical properties of ER thermosets and processability of ER matrix.