Adhesion Resistance Research Articles

Glycidyl methacrylate co-polymer emulsion-based heat and water-resistant wood adhesive

This work aims to add an epoxy-ended co-monomer to polyvinyl acetate (PVAc) emulsion adhesive-based wood adhesive to improve its resistance to heat and moisture. Here, glycidyl methacrylate (GMA), vinyl neodecanoate (VeoVa), and vinyl acetate (VAc) emulsion copolymers have been created and evaluated as wood adhesives. To prepare the emulsion-based adhesive samples, a polyvinyl alcohol (PVA) solution, aluminium chloride solution, preservatives, and a plasticizer are added. Following that, the poly(VAc–VeoVa–GMA) based adhesive sample is compared with the VAc, VeoVa, and methyl methacrylate (MMA) (poly(VAc-VeoVa-MMA)) co-polymer-based adhesive. Tensile shear strength of wood joints under dry and wet conditions was tested in compliance with EN 204-205 standard to assess the adhesives’ performance. The EN 14257 standard, which defines the shear stress of wood joints at 80 °C, was used to assess the heat resistance of the wood adhesives. Tests on the hardness of films confirmed the results of differential scanning calorimetry, which indicated that the glass transition temperature in the GMA-based adhesive was significantly higher than in the MMA-based adhesive. After 6 h of bonding, EN 204 shows that the tensile shear strength of a GMA-based adhesive increased by 15.56% in a dry environment, by 16.67% in a wet environment and 37.84% heat resistance when compared to a co-polymer-based adhesive based on MMA. The approach that was developed provides a simple and useful way of developing adhesives with enhanced heat, water, and bonding strength resistance.

Effect of filling materials on the tribological performance of polytetrafluoroethylene in different wear modes

AbstractAs it is known, Polytetrafluoroethylene (PTFE) is one of the most preferred polymeric materials for tribological applications. This study investigates the performance of PTFE and its composites under different tribological conditions. The effects of short glass fiber (GF), carbon particle (CP) and bronze particle (BP) reinforcement agents and their hybrid filling with molybdenum disulfide (MoS2) on sliding, erosive and abrasive wear were examined. Sliding tests were carried out with a ball‐on‐disc test apparatus, erosive wear tests were carried out with solid particle erosion and abrasive wear tests were carried out with a scratch test. It has been found that reinforcement agents improve sliding and abrasive wear resistance but worsen the erosion resistance. The hardness and contact angle of the samples were associated with their wear performances. Topographic and morphological analyzes of worn surfaces were performed using optical profilometer and scanning electron microscopy (SEM), respectively, and wear mechanisms were discussed.Highlights Filling materials (glass fiber, carbon particle and bronze particle) increase the adhesion and abrasion resistance of PTFE, while decreasing its erosion resistance. The effect of hybrid addition of MoS2 solid lubricant on wear performances depends on the type of filler. There is a correlation between surface properties (hardness and contact angle) and wear performances. Optical profilometer and scanning electron microscopy were used to examine wear mechanisms.

Nanomechanical and Structural Characteristics of Nanodiamond Composite Films Dependent on Target-Substrate Distance

AbstractThis study explores the optimization of target-substrate distance (TSD) in coaxial arc plasma deposition technique for depositing nanodiamond composite (NDC) films on unheated WC–Co substrates, with a focus on enhancing properties relevant to cutting tool applications. TSD significantly impacted film growth and adhesion, while hardness and Young’s modulus remained stable within the 10–50 mm TSD range. Increased TSD led to reduced deposition rates and film thickness, but improved quality by eliminating macroparticles and reducing surface roughness. Notably, the NDC film deposited at 10 mm TSD exhibited exceptional adhesion resistance, a thickness of 11.45 μm, low compressive internal stress (2.8 GPa), and a surface roughness (Sa) of 280 nm, coupled with an impressive hardness of 49.12 GPa. This film also achieved a favorable deposition rate of 1.05 nm/s. In comparison, the film deposited at 15 mm TSD displayed a maximum hardness of 51.3 GPa, lower Sa of 179 nm, but a reduced deposition rate of 0.29 nm/s. The estimated C sp3 fraction correlated well with the nanoindentation measurements, while internal stress showed a consistent relationship with film adhesion. These findings suggest that a TSD of 10 mm is optimal for balancing hardness, adhesion, deposition rate, and surface roughness, making NDC films a promising candidate for cutting tool applications.

Zwitterionic sulfobetaine methacrylate (SBMA) coating on hydrophobic acrylic intraocular lens material to prevent the adhesion of lens epithelial cells: Effect of SBMA concentration

Posterior capsular opacification (PCO), known as a prevalent complication of cataract surgery, occurs because of the attachment and abnormal proliferation of remaining lens epithelial cells (LECs) after cataract surgery. To reduce the PCO occurrence by improving cell adhesion resistance, we attempted zwitterionic sulfobetaine methacrylate (SBMA) coating through ultraviolet-induced graft polymerization on the surfaces of intraocular lens (IOL) materials. In this study, the effect of the concentration of SBMA monomers in the coating solutions adjusted from 10 wt% to 30 wt% was investigated on the chemical composition, morphology, and hydrophilicity of the IOL material surfaces modified with SBMA. Additionally, the effect of SBMA concentration on preventing adhesion to protein and LECs on the surfaces of SBMA-modified IOL materials was evaluated in vitro. Grafting of zwitterionic SBMA on the surfaces of hydrophobic acrylic IOL materials was confirmed by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and water contact angle (WCA). To evaluate the long-term hydrophilicity of coating films prepared with different concentrations of SBMA on the IOL material surfaces, the WCA of IOL materials stored in phosphate-buffered saline solution was measured as a function of time. The coating film prepared at a concentration of 20 wt% of SBMA showed the lowest WCA after 28 days, showing the best long-term hydrophilicity. Also, that prepared at a concentration of 20 wt% of SBMA exhibited the highest anti-adhesion effect on proteins and LECs.

Deposition of modifiable MAO-PDA coatings on magnesium alloy based on photocatalytic effect

Micro arc oxidation-Polydopamine (MAO-PDA) composite coating is a functional corrosion resistant coating formed on the surface of magnesium alloy by combining MAO to form a porous ceramic layer and the spontaneous oxidation polymerization characteristics of PDA. The MAO-PDA coating is environmentally friendly and modifiable, providing a basic film layer for achieving self-warning, self-healing, conductivity and other modification functions, which has attracted widespread attention. A new type of MAO-PDA composite coating with good corrosion resistance was deposited on the surface of magnesium alloy by photocatalysis, which expanded the application range of magnesium alloy MAO surface treatment. Surface morphology, coating adhesion and corrosion resistance of the composite coating are characterized. Combined with Density functional theory (DFT) calculation, the possible mechanism is explored. The results indicate that the MAO layer containing Mg2TiO4 exhibits fewer pores and can better deposit PDA under ultraviolet (UV) light conditions, forming a magnesium alloy MAO-PDA composite coating with good corrosion resistance and modification friendliness. Band structure calculations confirm the photocatalytic effect of Mg2TiO4 under UV irradiation. As a result of the photocatalytic effect, reactive oxygen species (ROS) were generated in the pores and on the surface of the MAO sample, thus accelerating the local deposition of PDA.

The Future of Protection: Unleashing the Power of Nanotech against Corrosion

Corrosion and nanomaterials application gives a complete understanding of corrosion, a pervasive and costly problem that affects a variety of industries worldwide. This study investigates the negative effects of corrosion on infrastructure, safety, and product durability by examining its natural processes and various forms. Regardless of their relative effectiveness, intrinsic restrictions typically limit conventional corrosion control techniques. This article aims to investigate the topic of nanomaterials, which are rapidly emerging and have the potential to significantly reduce corrosion. This abstract delves into the fascinating world of nanomaterials, which range in size from 1 to 100 nanometres, and explores their remarkable powers. Nanomaterials offer substantial advancements in corrosion management, such as better coatings, self-healing mechanisms, and even "smart" coatings with sensing capabilities. The article focuses on the potential benefits of employing nanoparticles for corrosion management, drawing on recent research and imaginative applications. Nanotechnology enables the creation of novel solutions like superior barriers, increased durability, self-repairing capabilities, and targeted corrosion avoidance. However, hurdles remain as the abstract investigates the complexities of manufacturing costs, uncertainty about long-term efficiency, potential environmental effects, and scalability problems associated with adding nanomaterials to corrosion control systems. Understanding corrosion and nanomaterial applications provides essential insights into the fundamental mechanics of corrosion, as well as the significant impact of nanotechnology. This abstract aims to encourage academics, engineers, and policymakers to use nanomaterials to address the ongoing problem of corrosion. Its goal is to promote the use of nanomaterials in diverse industries by giving interdisciplinary insights and forward-thinking ideas that improve durability, safety, and sustainability. Corrosion, a relentless degrader of infrastructure and industrial assets, necessitates novel approaches to mitigate its negative impacts. Nanotechnology has lately emerged as a promising frontier in corrosion mitigation, presenting unrivalled opportunities for improved protection and a longer service life. This paper examines the current state of nanotechnology-based corrosion protection, discusses key obstacles and prospects, and makes recommendations for future advances. Nanotechnology's ability to manipulate materials at the atomic and molecular level has transformed the field of corrosion protection. Nanomaterials, which include nanoparticles, nanocomposites, and nanocoatings, have distinct features that make them particularly effective in inhibiting corrosion start-up and propagation. Nanotech-based solutions outperform conventional coatings in terms of adhesion, barrier characteristics, and chemical resistance, thanks to precise engineering and surface modification approaches. Despite tremendous advancements, broad implementation of nanotechnology-based corrosion prevention confronts challenges. Standardisation and regulation are critical for ensuring the safety, reliability, and environmental sustainability of nanomaterials and coatings. Academics, industry, and regulating authorities must work together to provide comprehensive criteria for material synthesis, characterization, and application. Initiatives that promote education and awareness are critical for accelerating the use of nanotechnology in corrosion protection. Training programmes and knowledge-sharing platforms can provide engineers and industry experts with the necessary skills and competence to properly implement nanotech-based solutions. Public communication efforts emphasizing the benefits of nanotechnology in maintaining infrastructure integrity can garner support from stakeholders and governments. The future possibilities for nanotech-based corrosion prevention are very promising. Advances in nanomaterial production techniques provide unparalleled control over material properties, paving the way for the creation of tailored coatings with superior performance characteristics. Integration with other emerging technologies, like artificial intelligence and the Internet of Things (IoT), has the potential to improve corrosion monitoring and management approaches. Furthermore, the creation of self-healing nanoparticles constitutes a significant advancement in corrosion protection. Inspired by biological systems, self-healing nanocomposites can repair corrosion-induced damage on their own, prolonging the service life of infrastructure assets and lowering lifecycle costs. Continued investment in research and development is crucial to realising nanotechnology's full promise for corrosion protection and ushering in a new era of resilience and dependability. Nanotechnology provides transformative corrosion control solutions that have the potential to revolutionise a variety of industrial sectors. By addressing important obstacles and capitalising on emerging opportunities, we can use nanotechnology to protect infrastructure, conserve resources, and assure long-term growth for future generations.

Effect of different HVOF coatings on the tribological behavior of PVD/HVOF duplex coatings

CrN film shows obvious differences in hardness, elastic modulus, and thermal expansion coefficient between film and substrate, suffering from poor adhesion and wear resistance. Here we combined PVD and HVOF technologies to produce CrN/WC-12Co and CrN/WC-10Co-4Cr coatings, and then compare their mechanical and tribological behavior with that of CrN film. We show that the PVD/HVOF coatings exhibit higher hardness, load carrying capability, and adhesion; the wear resistance also be improved greatly, especially for CrN/WC-10Co-4Cr. We discuss the wear mechanism of such duplex coatings and analyze the influence of different HVOF coatings on the deposition characteristic of CrN film.

Microstructure Evolution and Molten Salt Corrosion Resistance Dependent on Pre-Oxidation Treatment of NiAl Coatings

The chloride-infused molten salt shows the most potential as the medium for the upcoming generation of concentrated solar power system. However, the molten salt put for ward higher corrosion resistance demand on the critical components of concentrated solar power system. The application of NiAl coating proves to be a highly efficient method for preventing corrosion. In this paper, the microstructure, adhesion, and corrosion resistance of NiAl coatings on 310S stainless steel with/without pre-oxidation treatment were studied. The coating predominantly consisted of β-NiAl phase nanocrystals with an Al content of 41.0 at.%. Continuous α-Al2O3 oxide film was formed and no obvious cracks were observed after pre-oxidation. The adhesion strength of NiAl coating was increased by about 70% to 40.0 N through pre-oxidation. Importantly, the corrosion results of NiAl coatings by pre-oxidation treatment in the mixed salt of NaCl/MgCl2/KCl at 1073.15 K for 10 h showed no obvious diffusion of molten salt elements into the coatings. Compared to 310S stainless steel, the pre-oxidized coating sample exhibited a significant reduction of 50.2% in corrosion mass loss. The pre-oxidation of the NiAl coating creates an Al2O3 oxidation layer that effectively blocks corrosion, offering a new method for protecting stainless steels in concentrated solar power system plants.

Adhesive Zwitterionic Poly(ionic liquid) with Unprecedented Organic Solvent Resistance.

The resistance of adhesives to organic solvents is of paramount importance in diverse industries. Unfortunately, many currently available adhesives exhibit either weak intermolecular chain interactions, resulting in insufficient resistance to organic solvents, or possess a permanent covalent crosslinked network, impeding recyclability. This study introduces an innovative approach to address this challenge by formulating zwitterionic poly(ionic liquid) (ZPIL) derivatives with robust dipole-dipole interactions, incorporating sulfonic anions and imidazolium cations. Due to its unique dynamic and electrostatic self-crosslinking structure, the ZPIL exhibits significant adhesion to various substrates and demonstrates excellent recyclability even after multiple adhesion tests. Significantly, ZPIL exhibits exceptional adhesion stability across diverse nonpolar and polar organic solvents, including ionic liquids, distinguishing itself from nonionic polymers and conventional poly(ionic liquid)s. Its adhesive performance remains minimally affected even after prolonged exposure to soaking conditions. The study presents a promising solution for the design of highly organic solvent-resistant materials for plastics, coatings, and adhesives.

Acquired resistance to immunotherapy and chemoradiation in MYC amplified head and neck cancer

The proto-oncogene MYC encodes a nuclear transcription factor that has an important role in a variety of cellular processes, such as cell cycle progression, proliferation, metabolism, adhesion, apoptosis, and therapeutic resistance. MYC amplification is consistently observed in aggressive forms of several solid malignancies and correlates with poor prognosis and distant metastases. While the tumorigenic effects of MYC in patients with head and neck squamous cell carcinoma (HNSCC) are well known, the molecular mechanisms by which the amplification of this gene may confer treatment resistance, especially to immune checkpoint inhibitors, remains under-investigated. Here we present a unique case of a patient with recurrent/metastatic (R/M) HNSCC who, despite initial response to nivolumab-based treatment, developed rapidly progressive metastatic disease after the acquisition of MYC amplification. We conducted comparative transcriptomic analysis of this patient’s tumor at baseline and upon progression to interrogate potential molecular processes through which MYC may confer resistance to immunotherapy and/or chemoradiation and used TCGA-HNSC dataset and an institutional cohort to further explore clinicopathologic features and key molecular networks associated with MYC amplification in HNSCC. This study highlights MYC amplification as a potential mechanism of immune checkpoint inhibitor resistance and suggest its use as a predictive biomarker and potential therapeutic target in R/M HNSCC.

Experimental Evaluation of Ceramic Coatings for Die Protection in Low-Pressure Die-Casting Process

One of the most important factors in the LPDC process is the heat transfer during the solidification of the molten alloys, which is responsible for the resulting microstructure and, thus, the quality of the cast piece. The use of foundry coatings has been lately suggested as a proper strategy to control the heat transfer while protecting bonded moulds from aluminium adhesion by providing a barrier between the surface and the liquid metal. LPDC die coating failures usually come from the loss of adherence or excessive wear originated in the successive filling processes, which requires stopping production for the reapplication of the coating. In the present work, coatings with different insulation capabilities have been evaluated, in terms of adherence and wear tests, in order to select the most promising alternative for LPDC die coating. This study confirmed that surface preparation and cleanliness are vital for an adequate adhesion of the coatings to ensure their durability. The results evinced that the use of a primer layer provided a higher adhesion of the coatings and considerably improved their perfomance. The coating that presented the best results in terms of adhesion and wear resistance under different abrasive testing conditions was coating B3.

Research on cobalt-molybdic sulfide composite coatings deposited by magnetic jet electrodeposition under different magnetic field intensities

Co-MoS2 composite coatings were deposited by the magnetic jet electrodeposition under different magnetic field intensities. The growth orientation and deposition mechanism of Co-MoS2 composite coatings under magnetic jet electrodeposition were analyzed based on the weak adsorption theory of nanocomposite co-deposition. Research showed that the coating topography changed from a blade-like structure to a cellular structure, and the cellular structure became a granular protrusion structure with increase of the magnetic field intensity. Compared with Co-MoS2 composite coating in jet electrodeposition, the orientation of Co shifted from (110) to (101) as the magnetic field intensity increased in magnetic jet electrodeposition. The adhesion, microhardness, adhesion, corrosion and wear resistance of the composite coatings were enhanced, which was attributed to the influence of the magnetic field on the growth orientation of the composite coating and the coordinated lubrication effect in the Co-MoS2 composite coating.

Hydrophobic polyethylene film prepared by film blowing process for preservation of fried shrimp rolls

Hydrophobic coatings have wide applications, but face challenges in food flexible packaging in terms of poor adhesion and inadequate wear resistance. Health hazards and poor adhesion drive the search for novel hydrophobic coatings substitutes. Here, we introduced rationally synthesized carnauba wax-SiO2 microspheres as a component to composite polyethylene (PE) film construction, and created a wear-resistant hydrophobic composite PE film via the blown film technique. The resultant hydrophobic composite film demonstrated an enhanced water contact angle from 86° to above 100°, coupled with favorable mechanical properties such as wear resistance, tensile strength and effective barrier performance against water vapor and oxygen. Upon implementation in the preservation of a Cantonese delicacy, Chaoshan fried shrimp rolls, it was observed that at 25 °C, the carnauba wax-SiO2-PE composite packaging film extended the shelf life of the product by 3 days compared to pure PE film.

Wear-resistant and adherent nanodiamond composite thin film for durable and sustainable silicon carbide mechanical seals

In response to environmental concerns, there is a growing demand for durable and sustainable mechanical seals, particularly in high-risk industries like chemical, petroleum, and nuclear sectors. This work proposes augmenting the durability and sustainability of silicon carbide (SiC) ceramic seals with the application of a nanodiamond composite (NDC) film through coaxial arc plasma deposition (CAPD) in a vacuum atmosphere. The NDC coating, with a smooth surface roughness of Ra = 60 nm as substrate, demonstrated a thickness of 1.1 μm at a deposition rate of 2.6 μm/h. NDC film has demonstrated exceptional mechanical and tribological characteristics, such as a hardness (H) of 48.5 GPa, Young's modulus (E) of 496.7 GPa, plasticity index (H/E) of 0.098, and fracture toughness of H3/E2 = 0.46 GPa, respectively. These NDC films showcased commendable adhesion strength (>60 N), negligible wear, and low friction (≤0.18) during dry sliding against a SiC counter material. Raman analysis has confirmed the nanocomposite structure of NDC film, emphasizing the role of highly energetic carbon ions in enhancing film adhesion by forming SiC intermetallic compounds at the interface through the diffusion of silicon atoms from the substrate into the films. The abundance of grain boundaries and rehybridization of carbon sp3 to sp2 bonding is perceived to improve tribological performance. CAPD excels in synthesizing long-life eco-friendly NDC coatings for durable and sustainable mechanical seals, featuring smooth surfaces, superior adhesion, outstanding hardness, and wear resistance, making them high potential candidates for various tribological applications.

Preparation and Properties of Epoxy Adhesives with Fast Curing at Room Temperature and Low-Temperature Resistance.

Developing a highly efficient multifunctional epoxy adhesive is still an enormous challenge, which can rapidly cure at room temperature and has excellent low-temperature resistance performance and is crucial for the epoxy adhesive and electrical sealing fields during severe cold seasons. Herein, diglycidyl phthalate (DP) was synthesized with phthalic anhydride (PA) and epichlorohydrin (ECH) to enhance the curing rate and low-temperature resistance of bisphenol A diglycidyl ether (DGEBA) adhesive. The modified DP/DGEBA adhesives were systematically analyzed by gel time, mechanical properties, and aging resistance (time, temperature, and dry/wet treatment). The results showed that DP with highly active ester groups significantly accelerates the curing speed of DP/DGEBA. DP's rigid aromatic ring-benzene ring and flexible group-ester group gave the adhesive better low-temperature resistance. When the addition of DP was 10 wt % (based on the mass of DGEBA), the gel time of DP/DGEBA epoxy adhesives was reduced by 58 min compared to unmodified DGEBA epoxy adhesive, and after aging at low temperature (-20 °C) for 7 days, the tensile shear strengths of polyvinyl chloride (PVC) and aluminum plate increased by 76.2 and 80.6%, respectively. The results of non-isothermal curing kinetics and dynamic mechanical analysis suggested that when the amount of DP was 10 wt %, the reaction activation energy of DP/DGEBA epoxy adhesive decreased by 4.0%, and the cross-linking density increased by 8.9%. Moreover, the toughness of the modified adhesive was also improved. This study opens up a feasible way for the development of a low temperature-resistant epoxy adhesive cured rapidly at room temperature in practical application.

Selection of Crosslinking Agents for Acrylic Resin Used in External Coatings for Aluminum Packaging in the Beverage Industry

Paints and coatings are widely used in various applications such as walls, cars, packaging, and food products. The quality of food packaging is essential due to its direct or indirect contact with food. The demand for high-quality food packaging is increasing due to the higher production and consumption rates. However, containers used in the beverage industry often face problems like scratches and abrasions during transportation. This study aimed to investigate different formulations of external coatings for beverage cans to improve their physical resistance properties and prevent corrosion and surface damage problems. The study involved reacting an acrylic resin with six different amino resins, including methylated melamine, butylated melamine, glycoluril, methylated urea, butylated urea, and benzoguanamine, in various proportions. The results of 25 formulated samples were compared based on properties such as adhesion, durability, and chemical resistance. The outcomes of the study showed significant differences among the crosslinking agents. Among all the crosslinking agents, methylated melamine showed the most favorable results in the analyses, proving to be effective in almost all tests.

Study of frictional wear and desorption of nanoparticle‐rubber blend modified UHMWPE composites

AbstractTo address the issues of abrasive wear, impact wear, and soil adhesion that can lead to wear failure and excessive operational resistance in agricultural soil touching parts during farming. This study focuses on UHMWPE composites, modified by filling Nano‐SiC as a hard phase filler and XNBR as an elastic filler. These fillers were dispersed into the UHMWPE matrix through melt blending technology to create a high‐performance composite material for the surface protective material of soil touching parts. The study discovered that by adding hard and elastic fillers to the UHMWPE matrix, the density, hardness, flexural modulus and thermal stability of the materials were all increased. Specifically, the density increased by 5.67% and the flexural modulus increased by 107%. In the block on ring wear test the volumetric wear rate decreased by 98%, while in the mortar wear test the mass wear rate decreased by 64.64%. Additionally, the contact angle on the surface of the specimen after mortar erosion and wear increased to 102.76°, 18% higher than that of pure UHMWPE. These results demonstrate that the modified fillers can improve the abrasion and plastic deformation resistance and hydrophobic desorption of UHMWPE. UHMWPE composite material, serving as the surface protection for soil touching parts, resolves the issues of abrasion of soil abrasive particles and excessive soil adhesion resistance on these parts. This significantly prolongs the service life of soil touching parts of agricultural machinery and improves the operational efficiency and economy.Highlights Research on nanoparticles and elastomer‐modified composite materials. Research has shown the enhancement of UHMWPE composite materials by Nano‐SiC. XNBR improves the plastic deformation resistance of UHMWPE composites. Effects of Nano‐SiC and XNBR on the desorption behavior of composite materials. UHMWPE composites reduce soil contact wear and soil adhesion.

Fluorosilane emulsifying chlortrifluoroethylene ternary copolymerization design towards strong adhesion, anti-corrosion, fluorescent waterborne fluorocarbon coatings for tinplate substrate

Waterborne fluorinated ethylene and vinyl ether copolymer (FEVE) coatings are progressively replacing solvent-based FEVE coatings because of their environmental friendliness. However, their practical application is limited due to the poor adhesion, waterproofing, and corrosion resistance, as well as the environmentally unfriendly nature of the small emulsifiers used. Here, a novel waterborne FEVE coating with excellent adhesion, anti-corrosion, and fluorescent properties was developed using amphiphilic fluorosilane oligomer (PFSQ) as microreactors and chlorotrifluoroethylene (CTFE), isobutyl vinyl ether (IBVE), and glycidyl methacrylate (GMA) as copolymer monomers. The introduction of fluorosilane significantly enhances the hydrophobicity of the coating (the water contact angle increased from 69.3 ± 2.4° to 131.4 ± 1.1°). The epoxy groups in the GMA units of terpolymer facilitate bonding of the coating to the substrate, enhancing the adhesion of the coating to the tinplate substrate (the lap shear strength increased from 0.47 ± 0.04 to 0.92 ± 0.01 MPa). Moreover, the interaction between the epoxy groups of GMA and the silicon hydroxyl groups of PFSQ in the synergistic network leads to the intrinsic luminescence of the coating. In addition, the coating exhibits superior corrosion resistance. The molecular structure design provides a new idea for the development of multifunctional waterborne FEVE coating.

Moldable Tissue-Sealant Hydrogels Composed of In Situ Cross-Linkable Polyethylene Glycol via Thiol-Michael Addition and Carbomers.

Moldable tissue-sealant hydrogels were developed herein by combining the yield stress fluidity of a Carbomer and in situ cross-linking of 3-arm PEG-thiol (PEG-SH) and 4-arm PEG-acrylate (PEG-AC). The Carbomer was mixed with each PEG oligomer to form two aqueous precursors: Carbomer/PEG-SH and Carbomer/PEG-AC. The two hydrogel precursors exhibited sufficient yield stress (>100 Pa) to prevent dripping from their placement on the tissue surface. Moreover, these hydrogel precursors exhibited rapid restructuring when the shear strain was repeatedly changed. These rheological properties contribute to the moldability of these hydrogel precursors. After mixing these two precursors, they were converted from yield-stress fluids to chemically cross-linked hydrogels, Carbomer/PEG hydrogel, via thiol-Michael addition. The gelation time was 5.0 and 11.2 min at 37 and 25 °C, respectively. In addition, the Carbomer/PEG hydrogels exhibited higher cellular viability than the pure Carbomer. They also showed stable adhesiveness and burst pressure resistance to various tissues, such as the skin, stomach, colon, and cecum of pigs. The hydrogels showed excellent tissue sealing in a cecum ligation and puncture model in mice and improved the survival rate due to their tissue adhesiveness and biocompatibility. The Carbomer/PEG hydrogel is a potential biocompatible tissue sealant that surgeons can mold. It was revealed that the combination of in situ cross-linkable PEG oligomers and yield stress fluid such as Carbomer is effective for developing the moldable tissue sealant without dripping of its hydrogel precursors.

Green and Heavy-Duty Anticorrosion Coatings: Waterborne Epoxy Thermoset Composites Modified through Variation of Zinc Dust Loading and Incorporation of Amine-Capped Aniline Trimer and Graphene Oxide.

In this study, an array of environmentally friendly and heavy-duty anticorrosion composite coatings were prepared. The synthesis involved amine-capped aniline trimer (ACAT) produced by an oxidative coupling reaction and graphene oxide (GO) prepared based on Hummer's method, and later, the waterborne epoxy thermoset composite (WETC) coatings were prepared by thermal ring-opening polymerization of EP 147w, a commercial waterborne epoxy resin, in the presence of ACAT and/or GO with zinc dust (ZD). A synergistic effect was observed by replacing a significant amount of the ZD loading in the WETC by simultaneously incorporating a small amount of ACAT and GO. The electrochemical corrosion measurements of the as-prepared WETC coatings indicated that incorporating 5% w/w ACAT or 0.5% w/w GO separately replaced approximately 30% w/w or 15% w/w of the ZD, respectively. Moreover, the WETC coatings containing 5% w/w ACAT and 0.5% w/w GO simultaneously were found to replace 45% w/w of the ZD. A salt spray test based on ASTM B-117 also showed a consistent trend with the electrochemical results. Incorporating small amounts of ACAT and GO in WETC coatings instead of ZD not only maintains the anticorrosion performance but also enhances adhesion and abrasion resistance, as demonstrated by the adhesion and abrasion tests.