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Recently, advances in enhancing corrosion properties through various techniques, and the clinical application of biodegradable cardiovascular stents made from magnesium (Mg) alloys face challenges to corrosion resistance, blood compatibility, and biocompatibility. Drug-eluting stents (DES) offer a solution to enhance the corrosion resistance of Mg alloys while simultaneously reducing the occurrence of restenosis. In this study, WE43 Mg alloy was pretreated using electropolishing technology, and different polymers (PEG and PLLA) were used as drug-polymer coatings for the Mg alloy. At the same time, PTX, an anticoagulant, was incorporated to achieve drug coating of different polymers on WE43 Mg alloy. The corrosion resistance of different polymer-drug coatings was assessed using a plasma solution. Furthermore, in vitro and in vivo tests were used to evaluate the blood biocompatibility of these coatings. The results indicated the PTX-PEG-coated WE43 Mg alloy exhibited the highest corrosion resistance and the most stable drug release profile among the tested coatings. Its hemolysis rate of 0.6 % was within the clinical requirements (<5 %). The incorporation of PEG prevents non-specific protein adsorption and nanoparticle aggregation, enhancing the surface hemocompatibility of WE43 Mg alloy. Therefore, the PTX-PEG coating shows promising potential for application in the development of drug-coated Mg alloy.

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Biomedical-device-associated infection (BAI) is undoubtedly a major concern and a serious challenge in modern medicine. Therefore, the development of biomedical materials that are capable of resisting or killing bacteria is of great importance. In this work, a croconaine-functionalized polymer with antifouling and near-infrared (NIR) photothermal bactericidal properties was prepared and facilely modified on polypropylene (PP) to combat medical device infections. Croconaine dye is elaborately modified as a "living" initiator, termed CR-4EBiB, for preparing amphiphilic block polymers by atom transfer radical polymerization (ATRP). In the formed polymer coating, the hydrophobic block can strongly adhere to the surface of the PP substrate, whereas the hydrophilic block is located on the outer layer by solvent-induced resistance to bacterial adhesion. Under the irradiation of an NIR laser (808 nm), the croconaine dye in the coating achieved maximum conversion of light to heat to effectively kill E. coli, S. aureus, and methicillin-resistant Staphylococcus aureus (MRSA). This work provides a facile and promising strategy for the development of implantable antibacterial biomedical materials.

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Purpose: Titanium alloys are among the most widely used materials in medicine, especially in orthopedics. However, their use requires the application of an appropriate surface modification method to improve their properties. Such methods include anodic oxidation and the application of polymer coatings, which limit the release of alloying element ions. In addition, biodegradable polymer coatings can serve as a carrier for drugs and other substances. The paper presents the results of research on the physical properties of biodegradable polymer coatings containing nanoparticle hydroxyapatite on a titanium alloy substrate. Methods: A PLGA coating was used in the tests. The coatings on the substrate of the anodized Ti6Al7Nb alloy were applied by ultrasonic spray coating. The tests were carried out for coatings with various hydroxyapatite content (5, 10, 15, 20%) and thickness resulting from the number of layers applied (5, 10, 15 layers). The scope of the research included microscopic observations using scanning electron microscopy, topography tests with optical profilometry, structural studies using X-ray diffraction, as well as wettability and adhesion tests. Results: The results shows that with the use of ultrasonic spray coating system is possible to obtain the continuous coatings containing hydroxyapaptite. Conclusions: The properties of the coating can be controlled by changing the percentage of hydroxyapatite and the number of layers of which the coating is composed.

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Upconversion nanoparticles (UCNPs) are materials that provide unique advantages for biomedical applications. There are constantly emerging customized UCNPs with varying compositions, coatings, and upconversion mechanisms. Cellular uptake is a key parameter for the biological application of UCNPs. Uptake experiments have yielded highly varying results, and correlating trends between cellular uptake with different types of UCNP coatings remains challenging. In this report, the impact of surface polymer coatings on the formation of protein coronas and subsequent cellular uptake of UCNPs by macrophages and cancer cells was investigated. Luminescence confocal microscopy and elemental analysis techniques were used to evaluate the different coatings for internalization within cells. Pathway inhibitors were used to unravel the specific internalization mechanisms of polymer-coated UCNPs. Coatings were chosen as the most promising for colloidal stability, conjugation chemistry, and biomedical applications. PIMA-PEG (poly(isobutylene-alt-maleic) anhydride with polyethylene glycol)-coated UCNPs were found to have low cytotoxicity, low uptake by macrophages (when compared with PEI, poly(ethylenimine)), and sufficient uptake by tumor cells for surface-loaded drug delivery applications. Inductively coupled plasma-optical emission spectroscopy (ICP-OES) studies revealed that PIMA-coated NPs were preferentially internalized by the clathrin- and caveolar-independent pathways, with a preference for clathrin-mediated uptake at longer time points. PMAO-PEG (poly(maleic anhydride-alt-1-octadecene) with polyethylene glycol)-coated UCNPs were internalized by energy-dependent pathways, while PAA- (poly(acrylic acid)) and PEI-coated NPs were internalized by multifactorial mechanisms of internalization. The results indicate that copolymers of PIMA-PEG coatings on UCNPs were well suited for the next-generation of biomedical applications.

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The increasing global commitment to carbon neutrality has propelled a heightened focus on sustainable construction materials, with wood emerging as pivotal due to its environmental benefits. This review explores the development and application of eco-friendly polymer nanocomposite coatings to enhance wood's fire resistance, addressing a critical limitation in its widespread adoption. These nanocomposites demonstrate improved thermal stability and char formation properties by integrating nanoparticles, such as nano-clays, graphene oxide, and metal oxides, into biopolymer matrices. This significantly mitigates the flammability of wood substrates, creating a robust barrier against heat and oxygen. The review provides a comprehensive examination of these advanced coatings' synthesis, characterization, and performance. By emphasizing recent innovations and outlining future research directions, this review underscores the potential of eco-friendly polymer nanocomposite coatings as next-generation fire retardants. This advancement supports the expanded utilization of wood in sustainable construction practices and aligns with global initiatives toward achieving carbon neutrality.

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Modifying the interface between the lithium metal anode (LMA) and the electrolyte is crucial for achieving high-performance lithium metal batteries (LMBs). Recent research indicates that altering Li-metal interfaces with polymer coatings is an effective approach to extend LMBs' cycling lifespan. However, the physical properties of these polymer-Li interfaces have not yet been fully investigated. Therefore, the structural stability, electronic conductivity, and ionic conductivity of polymer-Li interfaces were examined based on first-principles calculations in this study. Several representative polymer compounds utilized in LMBs were assessed, including polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), and polyethylene oxide (PEO). Our research revealed that lithium fluoride is formed upon fluoropolymer degradation, explaining previously observed experimental results. Polymers containing nitrile groups exhibit strong adhesion to lithium metal, facilitating the formation of the stable interface layer. Regarding electronic conductivity, the fluoropolymers preserve a good insulating property, which diminished marginally in the presence of lithium, but that of PAN and PEO significantly reduces. Additionally, lithium diffusion on PTFE and PEO demonstrates low diffusion barriers and high coefficients, enabling easy transportation. Overall, our investigation reveals that the interfaces formed between various polymers and LMA have distinct characteristics, providing new fundamental insights for designing composites with tailored interface properties.

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The addition of nanostructures to polymeric materials allows for a direct interaction between polymeric chains and nanometric structures, resulting in a synergistic process through the physical (electrostatic forces) and chemical properties (bond formation) of constituents for the modification of their properties and potential cutting-edge materials. This study explores a novel in situ synthesis method for PDMS-%SiO2 nanoparticle composites with varying crosslinking degrees (PDMS:TEOS of 15:1, 10:1, and 5:1); particle concentrations (5%, 10%, and 15%); and sol-gel catalysts (acidic and alkaline). This investigation delves into the distinct physical and chemical properties of silicon nanoparticles synthesized under acidic (SiO2-a) and alkaline (SiO2-b) conditions. A characterization through Raman, FT-IR, and XPS analyses confirms particle size and agglomeration differences between both the SiO2-a and SiO2-b particles. Similar chemical environments, with TEOS and ethanol by-products, were detected for both systems. The results on polymer composites elucidate the successful incorporation of SiO2 nanoparticles into the PDMS matrix without altering the PDMS's chemical structure. However, the presence of nanoparticles did affect the relative intensities of specific vibrational modes over composites from -35% to 24% (Raman) and from -14% to 59% (FT-IR). The XPS results validate the presence of Si, O, and C in all composites, with significant variations in atomic proportions (C/Si and O/Si) and Si and C component analyses through deconvolution techniques. This study demonstrates the successful in situ synthesis of PDMS-SiO2 composites with tunable properties by controlling the sol-gel and crosslinking synthesis parameters. The findings provide valuable insights into the in situ synthesis methods of polymeric composite materials and their potential integration with polymer nanocomposite processing techniques.

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This article will focus on the issue of protection against the pathogenic biofilm development on steel surfaces within the food sectors, highlighting steel's prominence as a material choice in these areas. Pathogenic microorganism-based biofilms present significant health hazards in the food industry. Current scientific research offers a variety of solutions to the problem of protecting metal surfaces in contact with food from the growth of pathogenic microorganisms. One promising strategy to prevent bacterial growth involves applying a polymeric layer to metal surfaces, which can function as either an antiadhesive barrier or a bactericidal agent. Thus, the review aims to thoroughly examine the application of antibacterial polymer coatings on steel, a key material in contact with food, summarizing research advancements in this field. The investigation into polymer antibacterial coatings is organized into three primary categories: antimicrobial agent-releasing coatings, contact-based antimicrobial coatings, and antifouling coatings. Antibacterial properties of the studied types of coatings are determined not only by their composition, but also by the methods for applying them to metal and coating surfaces. A review of the current literature indicates that coatings based on polymers substantially enhance the antibacterial properties of metallic surfaces. Furthermore, these coatings contribute additional benefits including improved corrosion resistance, enhanced aesthetic appeal, and the provision of unique design elements.

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This paper describes the synthesis and use of multifunctional methacrylic monomers, which contain basic (amine) functional groups, including an example in which an acid-labile tert-butylcarbamate-protected glycine is used to form a novel methacrylic monomer. The "protected" amino acid-derived functional monomer (BOC-Gly-MA) is copolymerized with an epoxide functional methacrylic monomer (GMA), to deliver novel multifunctional polymers, which are processed into powder coatings and used to study filiform corrosion at the surface of an aluminum substrate. The BOC-Gly-MA-containing copolymers were shown to improve a coating's anticorrosion performance, presenting the lowest average filiform corrosion (FFC) track length, total FFC number, and total corroded surface area (CSA) of the coatings investigated. Further to this, a mode of action for the role of BOC-Gly functional polymers in corrosion protection is proposed, supported by both solution and polymer-aluminum interface studies, delivering new insights into the mode of action of pH-responsive polymer coatings.

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Degradable layer-by-layer (LbL) polymeric coatings have distinct advantages over traditional biomedical coatings due to their precision of assembly, versatile inclusion of bioactive molecules, and conformality to the complex architectures of implantable devices. However, controlling the degradation rate while achieving biocompatibility has remained a challenge. This work employs polyphosphazenes as promising candidates for film assembly due to their inherent biocompatibility, tunability of chemical composition, and the buffering capability of degradation products. The degradation of pyrrolidone-functionalized polyphosphazenes was monitored in solution, complexes and LbL coatings (with tannic acid), providing the first to our knowledge comparison of solution-state degradation to solid-state LbL degradation. In all cases, the rate of degradation accelerated in acidic conditions. Importantly, the tunability of the degradation rate of polyphosphazene-based LbL films was achieved by varying film assembly conditions. Specifically, by slightly increasing the ionization of tannic acid (near neutral pH), we introduce electrostatic "defects" to the hydrogen-bonded pairs that accelerate film degradation. Finally, we show that replacing the pyrrolidone side group with a carboxylic acid moiety greatly reduces the degradation rate of the LbL coatings. In practical applications, these coatings have the versatility to serve as biocompatible platforms for various biomedical applications and controlled release systems.

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Fluorinated ethylene propylene (FEP) vessels are of significant interest for therapeutic cell biomanufacturing applications due to their chemical inertness, hydrophobic surface, and high oxygen permeability. However, these properties also limit the adhesion and survival of anchorage-dependent cells. Here, we develop novel plasma polymer coatings to modify FEP surfaces, enhancing the adhesion and expansion of human mesenchymal stromal cells (hMSCs). Similar to commercially available tissue culture polystyrene vessels, oxygen-rich or nitrogen-rich surface chemistries can be achieved using this approach. While steam sterilization increased the roughness of the coatings and altered the surface chemistry, the overall wettability and oxygen or nitrogen-rich nature of the coatings were maintained. In the absence of proteins during initial cell attachment, cells adhered to surfaces even in the presence of chelators, whereas adhesion was abrogated with chelator in a protein-containing medium, suggesting that integrin-mediated adhesion predominates over physicochemical tethering in normal protein-containing cell seeding conditions. Albumin adsorption was more elevated on nitrogen-rich coatings compared to the oxygen-rich coatings, which was correlated with a higher extent of hMSC expansion after 3 days. Both the oxygen and nitrogen-rich coatings significantly improved hMSC adhesion and expansion compared to untreated FEP. FEP surfaces with nitrogen-rich coatings were practically equivalent to commercially available standard tissue culture-treated polystyrene surfaces in terms of hMSC yields. Plasma polymer coatings show significant promise in expanding the potential usage of FEP-based culture vessels for cell therapy applications.

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Structural color pigments offer an efficient, sustainable, and environmentally friendly approach to obtain waterborne polymer coatings. We developed polymer-based spherical photonic pigments to incorporate in aqueous dispersions of polymer nanoparticles used to obtain waterborne polymer films. Our spherical photonic pigments are assembled from polymer nanoparticles and are highly stable in water dispersion, maintaining their optical properties in the final polymer films. Unlike conventional dyes and pigments, which are prone to photobleaching because they are based on the absorption of light, photonic pigments rely on the selective reflection of light by their nanostructure and therefore are not photodegraded. Furthermore, different colors can be obtained from the same materials, changing only their nanostructure, in this case, the size of the polymer nanoparticles. Our novel spherical photonic pigments are noniridescent and can be incorporated in aqueous polymer nanoparticle dispersions without deteriorating their structure to produce waterborne polymer coatings with structural color. This approach for structural colored waterborne polymer coatings is efficient, simple, and environmentally friendly, offering excellent prospects for application in paints and coatings.

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The demand for electrically insulated microwires and microfibers in biomedical applications is rapidly increasing. Polymer protective coatings with high electrical resistivity, good chemical resistance, and a long shelf-life are critical to ensure continuous device operation during chronic applications. As soft and flexible electrodes can minimize mechanical mismatch between tissues and electronics, designs based on flexible conductive microfibers, such as carbon nanotube (CNT) fibers, and soft polymer insulation have been proposed. In this study, a continuous dip-coating approach was adopted to insulate meters-long CNT fibers with hydrogenated nitrile butadiene rubber (HNBR), a soft and rubbery insulating polymer. Using this method, 4.8 m long CNT fibers with diameters of 25-66 µm were continuously coated with HNBR without defects or interruptions. The coated CNT fibers were found to be uniform, pinhole free, and biocompatible. Furthermore, the HNBR coating had better high-temperature tolerance than conventional insulating materials. Microelectrodes prepared using the HNBR-coated CNT fibers exhibited stable electrochemical properties, with a specific impedance of 27.0 ± 9.4 MΩ µm2 at 1.0 kHz and a cathodal charge storage capacity of 487.6 ± 49.8 mC cm-2. Thus, the developed electrodes express characteristics that made them suitable for use in implantable medical devices for chronic in vivo applications.

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The use of nanoparticles (NPs) as reinforcements in polymeric coatings allows for direct interaction with the polymeric chains of the matrix, resulting in a synergistic process through physical (electrostatic forces) and chemical interactions (bond formation) for the improvement of the mechanical properties with relatively low weight concentrations of the NPs. In this investigation, different nanocomposite polymers were synthesized from the crosslinking reaction of the hydroxy-terminated polydimethylsiloxane elastomer. Different concentrations (0, 2, 4, 8, and 10 wt%) of TiO2 and SiO2 nanoparticles synthesized by the sol-gel method were added as reinforcing structures. The crystalline and morphological properties of the nanoparticles were determined through X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). The molecular structure of coatings was through infrared spectroscopy (IR). The crosslinking, efficiency, hydrophobicity, and adhesion degree of the study groups were evaluated with gravimetric crosslinking tests, contact angle, and adhesion tests. It was observed that the crosslinking efficiency and surface adhesion properties of the different nanocomposites obtained were maintained. A slight increase in the contact angle was observed for the nanocomposites with 8 wt% compared to the polymer without reinforcements. The mechanical tests of indentation hardness and tensile strength following the ASTM E-384 and ISO 527 standards, respectively, were performed. As the nanoparticle concentration increased, a maximum increase of 157% in Vickers hardness, 71.4% in elastic modulus, and 80% in tensile strength was observed. However, the maximum elongation remained between 60 and 75%, ensuring that the composites did not become brittle.

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This study investigates the osteogenic differentiation of umbilical-cord-derived human mesenchymal stromal cells (hUC-MSCs) on biphasic calcium phosphate (BCP) scaffolds derived from cuttlefish bone doped with metal ions and coated with polymers. First, the in vitro cytocompatibility of the undoped and ion-doped (Sr2+, Mg2+ and/or Zn2+) BCP scaffolds was evaluated for 72 h using Live/Dead staining and viability assays. From these tests, the most promising composition was found to be the BCP scaffold doped with strontium (Sr2+), magnesium (Mg2+) and zinc (Zn2+) (BCP-6Sr2Mg2Zn). Then, samples from the BCP-6Sr2Mg2Zn were coated with poly(ԑ-caprolactone) (PCL) or poly(ester urea) (PEU). The results showed that hUC-MSCs can differentiate into osteoblasts, and hUC-MSCs seeded on the PEU-coated scaffolds proliferated well, adhered to the scaffold surfaces, and enhanced their differentiation capabilities without negative effects on cell proliferation under in vitro conditions. Overall, these results suggest that PEU-coated scaffolds are an alternative to PCL for use in bone regeneration, providing a suitable environment to maximally induce osteogenesis.

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Customized bone scaffolds with osteogenic activities are desired for the regenerative repair of large-scale or irregularly shaped bone defects. This study developed a facile method to create osteogenic surfaces on three-dimensional (3D) printed scaffolds through coating-induced mineralization. The coating was synthesized using chemical vapor deposition of a polyelectrolyte containing oppositely charged groups. The opposite charges on the 3D scaffold played a crucial role in promoting the formation of nanoapatites without agglomeration, resulting in the retention of micro- and nanoscale pore openings needed for preosteoblasts to proliferate, differentiate, and migrate. The nanoapatite scaffold exhibited significant enhancement in osteoinductivity with a 107% increase in alkaline phosphatase expression and a 163% increase in osteocalcin activity compared to the pristine scaffold. The nanoapatite scaffold provided cues for preosteoblasts to grow along aligned features and migrate collectively. The findings of this study demonstrate the synergistic effect of oppositely charged polyelectrolytes and mineralized nanoapatites on promoting osteogenic activities on scaffold surfaces.

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A solvent-free route of initiated chemical vapor deposition (iCVD) was used to synthesize a bio-renewable poly(α-Methylene-γ-butyrolactone) (PMBL) polymer. α-MBL, also known as tulipalin A, is a bio-based monomer that can be a sustainable alternative to produce polymer coatings with interesting material properties. The produced polymers were deposited as thin films on three different types of substrates-polycarbonate (PC) sheets, microscopic glass, and silicon wafers-and characterized via an array of characterization techniques, including Fourier-transform infrared (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR), ultraviolet visible spectroscopy (UV-vis), differential scanning calorimetry (DSC), size-exclusion chromatography (SEC), and thermogravimetric analysis (TGA). Optically transparent thin films and coatings of PMBL were found to have high thermal stability up to 310 °C. The resulting PMBL films also displayed good optical characteristics, and a high glass transition temperature (Tg~164 °C), higher than the Tg of its structurally resembling fossil-based linear analogue-poly(methyl methacrylate). The effect of monomer partial pressure to monomer saturation vapor pressure (Pm/Psat) on the deposition rate was investigated in this study. Both the deposition rate and molar masses increased linearly with Pm/Psat following the normal iCVD mechanism and kinetics that have been reported in literature.

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To address the challenging issues of metal materials corrosion in industries, which has caused huge economic losses and security threats to many facilities in marine environments, functional polymer coatings have been widely used and regarded as one of the simplest and most effective methods to prevent such an undesirable event. In this study, a new type of coating filler consisting of graphene oxide/polyaniline/polydopamine (GO-PANI-PDA) nanocomposites has been successfully synthesized. The morphology, structure, composition, and corrosion resistance performance of the GO-PANI-PDA (GPP) nanocomposites were investigated via a series of characterization methods. The results from our electrochemical impedance spectroscopy, potentiodynamic polarization curve and salt spray experiment showed that the best corrosion resistance performance of the coating is from GPP 21 with the epoxy/GO-PANI:PDA ratio of 2:1, which exhibited a positive corrosion potential (-0.51 V) shift from epoxy/GO-PANI coating (-0.64 V). The corrosion current density (3.83 × 10-8 A/cm2) of GPP 21 is nearly an order of magnitude lower than that of epoxy/GO-PANI (7.05 × 10-7 A/cm2). The good anti-corrosion performance was fascinatingly observed in salt spray tests even without obvious corrosion phenomenon after 30 days of testing. Due to these remarkable properties, GPP nanocomposites can be an outstanding candidate for the rapid development of broadband shielding and anticorrosive materials.

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An anti-infective bilayer implant coating with selectively activatable properties was developed to prevent biofilm formation and to support the treatment of periprosthetic infection as a local adjunct to current treatment concepts. In a first step, Ti6Al4V discs were coated with a permanent layer of Poly(l-lactide) (PLLA) including silver ions. The PLLA could be optionally released by the application of extracorporeal shock waves. In a second step, a resorbable layer of triglyceride (TAG) with incorporated antibiotics was applied. The second layer is designed for resorption within weeks. Prior to approval and clinical application, a comprehensive evaluation process to determine mechanical/physical and microbiological properties is obligate. To date, none of the existing test standards covers both drug-releasing and activatable coatings for orthopedic implants. Therefore, a comprehensive test concept was developed to characterize the new coating in a pilot series. The coatings were homogeneously applied on the Ti6Al4V substrate, resulting in an adhesion strength sufficient for non-articulating surfaces for PLLA. Proof of the extracorporeal shockwave activation of PLLA was demonstrated both mechanically and microbiologically, with a simultaneous increase of biocompatibility compared to standard electroplated silver coating. Wettability was significantly reduced for both layers in comparison to the Ti6Al4V substrate. Thus, potentially inhibiting biofilm formation. Furthermore, the TAG coating promoted cell proliferation and bacterial eradication. In conclusion, the testing concept is applicable for similar biopolymer coating systems. Furthermore, the extracorporeal activation could represent a completely new supportive approach for the treatment of periprosthetic joint infections.

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Icephobic coatings interest various industries facing icing problems. However, their durability represents a current limitation in real applications. Therefore, understanding the degradation of coatings under various environmental stresses is necessary for further coating development. Here, lubricated icephobic coatings were fabricated using a flame spray method with hybrid feedstock injection. Low-density polyethylene represented the main coating component. Two additives, namely fully hydrogenated cottonseed oil and paraffinic wax, were added to the coating structure to enhance coating icephobicity. Coating properties were characterised, including topography, surface roughness, thermal properties, wettability, and icephobicity. Moreover, their performance was investigated under various environmental stresses, such as repeated icing/deicing cycles, immersion in corrosive media, and exposure to ultraviolet (UV) irradiation. According to the results, all coatings exhibited medium-low ice adhesion, with slightly more stable icephobic behaviour for cottonseed oil-based coatings over the icing/deicing cycles. Surface roughness slightly increased, and wetting performances decreased after the cyclic tests, but chemical changes were not revealed. Moreover, coatings demonstrated good chemical resistance in selected corrosive media, with better performance for paraffin-based coatings. However, a slight decrease in hydrophobicity was detected due to surface structural changes. Finally, paraffin-based coatings showed better resistance under UV irradiation based on carbonyl index and colour change measurements.