Corrosion stands out as a leading factor contributing to the deterioration of industrial components, particularly in equipment utilized for oil and gas transmission and processing. Room temperature ...vulcanized silicone rubber (RTV) emerges as a promising solution for corrosion prevention due to its notable features including high hydrophobicity, adhesion, and thermal stability. This study focuses on enhancing anti-corrosion properties by applying coatings of RTV polymer with graphene oxide (GO) sheets (RTV-GO) or GO decorated with silicon oxide (RTV/GO-SiO2) onto X60 steel substrates. The investigation delves into the microstructure of the coating, surface hydrophobicity, adhesion to the substrate, and its efficacy in corrosion protection. Various techniques such as X-ray diffraction (XRD), atomic force microscopy (AFM), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR) were employed to analyze the nanocomposites. Furthermore, corrosion resistance was evaluated through open circuit potential analysis, potentiodynamic polarization, electrochemical impedance spectroscopy, and salt spray testing. Results indicate that incorporating GO and hybrid GO-SiO2 into the RTV polymer matrix not only enhances the interface strength between the coating and steel substrate but also boosts corrosion resistance by up to 10-fold compared to uncoated substrates.
The most important results obtained in this research are stated as follows:•By adding 0.1% Wt. of GO-SiO2 to the RTV matrix, the hydrophobicity of the nanocomposite coating increases significantly (up to 128 °).•Graphene oxide nanosheets with high surface area and low thickness act as a barrier against the diffusion of water and corrosive ions.•GO-SiO2 hybrid nanoparticles in the RTV polymer matrix significantly increase the adhesion of the nanocomposite coating.•RTV-based nanocomposite anti-corrosion coating containing graphene oxide sheets decorated with silica nanoparticles improved the corrosion resistance of the steel substrate up to ten times.
The sulfur curing system, peroxide curing system and their combinations were applied for the cross-linking of unfilled and carbon black-filled rubber formulations based on ...ethylene-propylenediene-monomer rubber. The results demonstrated that the type of curing system influenced the course and shape of curing isotherms. This resulted in the change of curing kinetics of rubber compounds. The cross-link density of materials cured with combined vulcanization systems was lower than that for vulcanizates cured with the peroxide or sulfur system. Good correlation between the cross-link density as well as the structure of the formed cross-links and physical–mechanical characteristics of the cured materials was established. Both filled and unfilled vulcanizates cured with combined vulcanization systems exhibited a higher tensile strength and elongation at break when compared to their equivalents vulcanized in the presence of the peroxide or sulfur curing system. It can be stated that by proper combination of vulcanization systems, it is possible to modify the tensile behavior of vulcanizates in a targeted manner. On the other side, dynamical–mechanical properties were found not be significantly influenced by the curing system composition.
Due to the rapid increase of waste vulcanized rubber products, the development of low-cost, efficient, and selective devulcanization processes is needed. In this paper, the devulcanization ability of ...Gordonia desulfuricans DSM 44462.sup.T was evaluated by a design of experiments. The aim of the experimental design was to investigate the importance of parameters influencing the bacterial growth, such as the glucose concentration (C), dibenzothiophene concentration (DBT), and initial biomass (optical density, OD) in biodevulcanization process. The complex viscosity (η*) was chosen as experimental response for the experimental design. A multiple linear regression was used to model the relationship between the response and the process variables. In addition, the crosslink density and gel fraction were measured. Furthermore, the automated ribosomal intergenic spacer analysis (ARISA) as a microbiological method was performed to assess the persistence of the inoculated strain during the experiments. Reduced regression models were obtained considering only the significant variables and interactions. The glucose concentration C and OD variables and C-DBT and DBT-OD interactions resulted to the relevant parameters for the process. The fingerprinting showed the persistence of G. desulfuricans DSM 44462.sup.T, despite the presence of other bacterial population after the VGNR sterilization. These results highlight the importance to support the physics analysis with microbiological analyses to evaluate the bacterial persistence during the treatment.
The inverse vulcanization produces high sulfur content polymers from alkenes and elemental sulfur. Control over properties such as the molar mass or the solubility of polymers is not well ...established, and existing strategies lack predictability or require large variations of the composition. Systematic design principles are sought to allow for a targeted design of materials. Herein, we report on the inverse vulcanization of norbornenylsilanes (NBS), with a different number of hydrolysable groups at the silicon atom. Inverse vulcanization of mixtures of NBS followed by polycondensation yielded soluble high sulfur content copolymers (50 wt % S) with controllable weight average molar mass (MW), polydispersity (Đ), glass transition temperature (TG), or zero‐shear viscosity (η0). Polycondensation was conducted in the melt with HCl as a catalyst, abolishing the need for a solvent. Purification by precipitation afforded polymers with a greatly reduced amount of low molar mass species.
Inverse vulcanized polymers of norbornenylsilanes with hydrolysable chloro‐ and ethoxy substituents were prepared and polycondensated to install defined amounts of M, D, or T siloxane bonds. The MW and TG of the soluble and branched polymers containing 50 wt % S could be varied systematically, whereas the elemental composition remained the same. Polymers with a sulfur content of 30 wt % could be prepared without low molar mass impurities.
Developing a highly active and low-cost non-precious metal electrocatalyst for oxygen evolution has been urgent for the clean energy system. Herein, the ternary metal sulfides MoCoNiS supported on ...nickel foam (MoCoNiS/NF) are successfully prepared using Mo doping Co-based metal-organic framework (Co-MOF) as precursor, which may be helpful for the good dispersion of different metal element. The uniform elements distribution of Mo, Co and Ni on MoCoNiS/NF is determined by all kinds of physical characterization. Mo doping may regulate the electronic environment around Co and Ni, suggesting the potential synergistic effects between different heteroatoms. Electrochemical test shows that MoCoNiS/NF exhibits the excellent OER activity than other single metal or binary metal sulfides as comparison samples, needing only 151 and 226 mV overpotential to achieve current density of 10 (η10 = 151 mV) and 100 mA cm−2 (η100 = 226 mV), respectively. The excellent stability of MoCoNiS/NF has been achieved. The remarkable OER performance of MoCoNiS/NF may due to the synergistic effects and good electrical conductivity as well as the three-dimensional structure of NF as substrate. Therefore, the rational design of MOF derived multi transition metal-based electrocatalysts will be an effective way for increasing OER performance.
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•Ternary MoCoNiS/NF is synthesized using Mo-doping Co-based MOF as precursor.•The synergistic effect and good dispersion of MoCoNiS can be achieved for OER.•MoCoNiS/NF has the superior activity for OER than mono or binary metal sulfides.•MOF derived multi transition metal-based electrocatalysts may be a promising strategy for OER.
Sulfur as a side product of natural gas and oil refining is an underused resource. Converting landfilled sulfur waste into materials merges the ecological imperative of resource efficiency with ...economic considerations. A strategy to convert sulfur into polymeric materials is the inverse vulcanization reaction of sulfur with alkenes. However, the materials formed are of limited applicability, because they need to be cured at high temperatures (>130 °C) for many hours. Herein, we report the reaction of elemental sulfur with styrylethyltrimethoxysilane. Marrying the inverse vulcanization and silane chemistry yielded high sulfur content polysilanes, which could be cured via room temperature polycondensation to obtain coated surfaces, particles, and crosslinked materials. The polycondensation was triggered by hydrolysis of poly(sulfur‐r‐styrylethyltrimethoxysilane) (poly(Sn‐r‐StyTMS) under mild conditions (HCl, pH 4). For the first time, an inverse vulcanization polymer could be conveniently coated and mildly cured via post‐polycondensation. Silica microparticles coated with the high sulfur content polymer could improve their Hg2+ ion remediation capability.
Marrying inverse vulcanization and silane chemistry yields solution‐processable high sulfur content polysulfide‐alkoxysilanes, which could be cured via polycondensation. With this strategy, coated surfaces and particles as well as crosslinked materials can be obtained. This method extends the applicability and control of materials prepared via inverse vulcanization.
In this concept review, the fundamental and polymerization chemistry of inverse vulcanization for the preparation of statistical and segmented sulfur copolymers, which have been actively developed ...and advanced in various applications over the past decade is discussed. This concept review delves into a discussion of step‐growth polymerization constructs to describe the inverse vulcanization process and discuss prepolymer approaches for the synthesis of segmented sulfur polyurethanes. Furthermore, this concept review discusses the advantages of inverse vulcanization in conjunction with dynamic covalent polymerization and post‐polymerization modifications to prepare segmented block copolymers with enhanced thermomechanical and flame retardant properties of these materials.
The detailed discussion of the fundamental and polymerization mechanism for sulfur copolymers is described from ring‐opening polymerization, inverse vulcanization, dynamic covalent polymerization. In this article, we highlight the segmented sulfur polyurethane with flame retardancy through post‐polymerization of sulfur copolymers. And we give the prospects for various applications of sulfur derived polymers.
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•Covalent crosslinks were introduced into ionic supramolecular network.•Permanent covalent crosslinks effectively enhance natural rubber.•The effects of covalent crosslinks on the ...self-healing were studied systematiclly.•Mechanical properties and self-healing effect of natural rubber was balanced.
Introducing covalent crosslinks into reversible supramolecular networks would effectively improve their mechanical strengths, but sacrificed the desired self-healing effect. So, it is a practical significance to explore the influence of irreversible covalent crosslinks on self-healing behavior to prepare self-healing rubbers with enhanced mechanical properties for further application. In this study, the trade-off of covalent crosslinks between the balanced mechanical properties and self-healing effect of a natural rubber/methacrylic acid/zinc oxide (NR/MAA/ZnO) supramolecular network system was studied. Zinc dimethacrylate (ZDMA) is in situ formed from MAA and ZnO during the mastication of NR, which introduce mass of ionic crosslinks to generate a reversible ionic supramolecular network at the initial stage of peroxide-induced vulcanization at 140℃. Then, free radicals continue to initiate covalent crosslinks to strengthen the NR matrix. The tensile strength of NR with slight covalent crosslinks could achieve 1.63 ∼ 3.86 MPa when vulcanization time keeps in 240 ∼ 360 s. At this time, primary continuous covalent crosslink network has little binding effect on rubber chains, and ionic interactions can be smoothly reorganized to ensure excellent self-healing behavior. The considerable self-healing efficiency of 67%∼95% indicates that the vulcanization time at 240 ∼ 360 s is an appropriate choice to achieve a win–win situation for the mechanical properties and self-healing efficiency of NR/MAA/ZnO composites.
The Cover Feature shows a novel insulating and flame‐resistant composite made from the sustainable building blocks canola oil, wool, and sulfur. More information can be found in the Full Paper by I. ...Bu Najmah et al.
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