Performance Properties Of Coatings Research Articles

Charge and Hydrogen Storage Capacities of Electrodeposited Graphene Derivatives

Graphene’s theoretical capacitance and physical hydrogen storage abilitiesmark it as one of the best candidates for energy storage application. Graphene oxide (GO) is easy to manufacture in bulk synthesis and can be considered as a precursor for graphene synthesis. The application of graphene on the surface of electrodes can be achieved by different techniques as drop-coating and electrodeposition. It has been reported that the electrochemical hydrogen storage is favored in samples with a well-developed porosity and a low content in surface oxygen complexes. Both features indicate that the unsaturated carbon atoms in the carbon materials have an important role for the hydrogen uptake. It has also been suggested that the total capacity of hydrogen storage is proportional to the interlayer distance and not to the carbon specific surface area.The present work presents an investigation of electrodeposited GO coatings (ED), which have subsequently been electroreduced to various degrees of rGO, and relate their charge capacitance and hydrogen storage capacity to the preparation mode, morphological structure, and surface chemistry. These properties were compared to those of drop-cast (DC) coatings of GO.The ED coatings were characterized by more accumulated graphene sheets imperfections as observed by cross section TEM analysis. These coatings, when reduced at -1.6 V vs Hg/HgO showed more efficient removal of phenolic groups than DC ones treated at the same potential (remaining contents of 2.1 and 18.1 %, respectively). They also showed lower charge transfer resistance (5.2 and 28 Ω cm2, respectively), higher capacitance (73.2 and 42.6 F/g, respectively), and higher hydrogen storage capacity (119 and 57 mAh/g, respectively). Moreover, they showed higher stability towards H2 charge/discharge cycles (retained hydrogen capacities of 95 and 40 % after 15 and 6 cycles for ED and DC coatings reduced at -1.5 V, respectively).The removal during the electroreduction process of phenolic groups located at the graphene sheets edges of the ED coatings and their higher pseudo-capacitance can explain their lower charge transfer resistance and their higher pseudo-capacitance, respectively. Their superior stability towards hydrogen charge/discharge cycles is suggested to stem from evolving hydrogen escape routes created during the ED process. The superior performance properties of coatings obtained by ED and subsequently electro-reduced make them promising electrode materials for energy storage.

Synthesis and Characterization UV-Curable Waterborne Polyurethane Acrylate/Al2O3 Nanocomposite Coatings Derived from Jatropha Oil Polyol

A new UV-curable waterborne polyurethane acrylate/alumina (UV-WPUA/Al2O3) coatings were successfully developed. The waterborne polyurethane acrylate (WPUA) dispersion was synthesized by reacting jatropha oil polyol (JOL) with isophorone diisocyanate (IPDI), 2,2-dimethylol propionic acid (DMPA), and 2-hydroxyethyl methacrylate (HEMA) via in-situ and anionic self-emulsifying methods. The WPUA/Al2O3 dispersion was formulated by various sonicating concentrations of alumina nanoparticles (0.3, 0.6, 0.9, and 1.2 wt%) into WPUA dispersion. The UV-WPUA/Al2O3 coatings were obtained with 75 wt% oligomers, 25 wt% monomer trimethylolpropane triacrylate (TMPTA), and 3 wt% of a commercial photoinitiator (benzhophenol) for UV-curing were used. The effect of Al2O3 nanoparticles on WPUA coatings was analyzed by FTIR, surface morphology, and coating performance properties such as pendulum hardness, pencil hardness, scratch resistance, and adhesion test. FTIR revealed the formation of JOL, neat UV-WPUA, and UV-WPUA/Al2O3 coatings, respectively. FESEM/EDX demonstrated that Al2O3 nanoparticles at the lower loading (up to 0.6 wt%) were well-dispersed correlated with contact angle (CA). The hardness property can reach 63.4% at the lower concentration of the Al2O3 addition 0.6 wt%. The adhesive strength, scratch hardness, and scratch resistance were greatly improved to 5B, 5H, and 2N, respectively. The preparation method offered in this study is an effective and convenient approach to producing UV-WPUA/Al2O3 coatings. The enhancement of the properties with the lesser concentration of Al2O3 nanoparticles (≤ 0.6 wt%) addition in this study shows a new promising potential as surface coating application for several major industrial areas, such as marine, transportation, and biomedical field with major economic and environmental benefits.

Композиция на основе линейно-лестничного силоксанового блок-сополимера для получения защитных покрытий с улучшенными физико-химическими свойствами

A one-component organosilicon composition based on a solution of the Lestosil SM-NT block copolymer containing an optimal ratio of linear polydimethylsiloxane and ladder phenylsilsesquioxane units in an organic solvent has been developed. As a curing system, a solution of heterosiloxane containing boron and zirconium atoms in the siloxane chain in alkoxysilane and special additives that improve the performance properties of coatings were used. The composition is intended for production of heat-resistant electrically insulating and moisture-resistant coatings with enhanced physical-chemical properties, used as protective materials in microelectronics and electronic products.

Methodological approach to assessing the effect of porosity on the operational properties of functional polymer powder coatings

Functional polymer powder coatings are considered, their advantages over traditional paint coatings are noted. The set of operational indicators of coatings is called, their dependence on both external and internal factors is estimated. Of the latter, the porosity of the coating material is distinguished. The analysis of the types of porosity is carried out, it is noted that it is a generalized indicator. In addition to porosity, the performance properties of coatings also depend on the shape, size, and tortuosity of the pores. Due to the fact that porosity has a significant impact on all the main technical properties of coatings, the study of this issue seems relevant from a practical point of view. Therefore, there is a need to develop an effective approach, highlighting the formalization of each of its stages as the main task. Since, in general, the coverage and the factors acting on it are a complex system, methods of system analysis and mathematical modeling are used. At the same time, in the aggregate of external factors acting on coatings during storage, transportation, and operation of products, atmospheric and actual operational ones are distinguished. Attention is drawn to the fact that their impact leads to a change in indicators, both porosity and the material of the frame (matrix) of the coating. The relations characterizing the influence of porosity, internal and external factors on the physico-chemical properties of polymer powder coatings are recorded in a general form.

Charge Capacitance and Hydrogen Storage Capacity of Drop Cast and Electrodeposited Reduced Graphene Oxide Coatings

Drop cast (DC) and electrodeposited (ED) graphene-based coatings on glassy carbon (GC) electrodes were subjected to various electro-reduction degrees. The ED coatings were characterized by more accumulated graphene sheets imperfections as observed by cross section TEM analysis. These coatings, when reduced at −1.6 V vs Hg/HgO showed more efficient removal of phenolic groups than DC ones treated at the same potential (remaining contents of 2.1 and 18.1%, respectively). They also showed lower charge transfer resistance (5.2 and 28 Ω cm2, respectively), higher capacitance (73.2 and 42.6 F g−1, respectively), and higher hydrogen storage capacity (119 and 57 mAh g−1, respectively). Moreover, they showed higher stability towards H2 charge/discharge cycles (retained hydrogen capacities of 95 and 40% after 15 and 6 cycles for ED and DC coatings reduced at −1.5 V, respectively). The superior performance properties of coatings obtained by ED and subsequently electro-reduced make them promising electrode materials for energy storage.

Obtaining a combined epoxy-acrylic dispersion

The current state of development of the economy of the Russian Federation causes the appearance of a number of urgent problems related to improving production and increasing the level of environmentally safe products, in particular paints and varnishes combined with high performance properties of coatings based on them. In this regard, the advantages and disadvantages of aqueous dispersions based on polymers in the presence of various modifiers that are widely used in the paint and varnish industry were analyzed. This article discusses the problem of stability conditions for mixed materials of epoxy-acrylic type and the establishment of a relationship between the composition of the film-forming base and the performance properties of coatings. The purpose of this study is to create new water-dispersion paints and varnishes based on mixed epoxy-acrylic film-formers for coatings with increased hardness, wear resistance, elasticity and adhesion. The analysis of the main types of water-based film-forming agents is carried out. It is proposed to use mixed systems of film-formers based on epoxy-acrylic dispersions. It was established by standard methods that by combining dispersions of acrylic and epoxy types it is possible to achieve a significant increase in the wear resistance of the compositions (almost 2 times) in comparison with the wear resistance of materials based on acrylic. The adhesion of coatings to substrates of various nature (except for brick) increases with an increase in the content of the epoxy component. In terms of performance, acrylic epoxy can be more effective than acrylic and can be used in humid environments. An increase in the performance properties of these materials in comparison with acrylate systems has been confirmed. It should be noted that an additional task in the development of any building materials is affordability. It is known that not all dispersions are cheap, for example, in the presence of silicone polymers, dispersions are expensive, so they are used only when necessary. To improve operational properties and reduce the cost of protective coatings, we proposed using composite materials, which included styrene-acrylic and epoxy aqueous dispersions. In the future, it is planned to create “smart” materials whose properties will depend on functional fillers.

Polyurethane polymers cured via azide-alkyne cycloaddition

Conventional thermoset polyurethane polymers are crosslinked by reaction of a polyisocyanate compound with a polyol. Herein are described alternative crosslinking polyurethanes (ACPUs) for coatings and related applications that cure by azide-alkyne cycloaddition. Commercial polyisocyanate resins including allophanate, isocyanurate, and biuret types were reacted with propargyl alcohol or 2-hydroxyethyl propiolate to yield polyurethane resins with terminal alkyne functionality. Various polyols, including polyether, polyester, and polyacrylic types were modified to convert their hydroxyl functionality to azide functionality. The best performance was obtained with an alkyne component based on Desmodur XP 2580 and an azidated polyol based on Setalux D A 870 BA. Clear, high-solids, two-component coatings were prepared with and without Cu(I) catalyst. The coating performance properties including pencil hardness, MEK double rubs, and glass transition temperature (Tg) were comparable to a conventional polyurethane control coating made from the precursor resins. Azide-alkyne formulations in the presence of copper catalyst exhibited faster curing kinetics than the polyurethane control. Propiolate-based systems showed significantly faster curing kinetics compared to the propargylated systems with or without Cu(I) catalyst. A study of azide:alkyne stoichiometry surprisingly showed that higher crosslink density of ACPUs may be obtained by formulating with 35–50 mol% excess azide component.

Regularities of formation of adhesive contact “sol-silicate paint - substrate”

Introduction. The use as a binder in the manufacture of silicate paints polysilicate solutions obtained by mixing liquid glass and silica sol is considered. To regulate the rheological properties of the paint, improve the filling and prevent the pigment part from sagging, it has been proposed to introduce glycerin into the binder composition. The results of studying the interfacial interaction between the paint and the substrate are given. Materials and methods. In developing the formulation of silicate paints based on polysilicate solutions, MK-2 microcalcite, marshalite, diatomite and talc of MT-GSM grade were used as a filler, and titanium dioxide as a pigment. Polysilicate solutions were obtained by reacting stabilized solutions of colloidal silica (sols) with aqueous solutions of alkali silicates (liquid glasses). Nanosil 20 and Nanosil 30 silicic acid sol were used, produced by the Promsteklocentr PC. Used potassium liquid glass with module M = 3.29. A thermodynamic method was used to assess the interfacial interaction. Results. Shown that the introduction of glycerol into the formulation of a sol of silicate paint promotes a decrease in the interfacial surface tension and a better wetting of the surface of the mortar substrate. An increase in wetting coefficient is observed. Coatings based on sol silicate paints with the addition of glycerin are characterized by increased crack resistance. An increase in tensile strength, maximum tensile properties, and decrease in the elastic modulus of paint membranes based on the composition with glycerol has been established. The values of the free surface energy of the coating based on the sol of silicate paint and the ratio of the polar to the dispersion component of the free energy of the surface are given. Coatings based on sol of silicate paint with the addition of glycerin are characterized by a large value of the free energy of the surface. In the process of moistening a decrease in the free surface energy is observed due to a decrease in the dispersion component. Conclusions. Studies have shown that the introduction of an additive of glycerin in the formulation of a silicate paint sol contributes to an increase in the performance properties of coatings based on it.

Synthesis of electroactive tetraaniline-based acrylic polyol by atom transfer radical polymerization for anticorrosive coating application

In this work, block copolymers of butyl acrylate and glycidyl methacrylate (GMA) having molecular weights 10,000 Da were synthesized with varied GMA block lengths by 10%, 20%, and 30% using atom transfer radical polymerization. The synthesized copolymers were further reacted with tetraaniline to formulate conductive polyol and further characterized by mass spectroscopy, UV–visible spectroscopy, 1HNMR, and FTIR. The block copolymers formed were evaluated by gel permeation chromatography, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry, and nuclear magnetic resonance (NMR) techniques for structural elucidation. These polyols were formed with 10, 20, and 30 wt% with isocyanate (HDI N-3300) to form a polyurethane. The effect of concentration of conducting polyol on anticorrosive coating performance properties, namely mechanical and optical properties, was further studied. The anticorrosive performance was evaluated by salt spray test and electrochemical impedance spectroscopy.

Amidoamine: Synthesis, disparity in cure with epoxy resins between bulk and solvent systems, and structure–property relationships of its epoxy‐based coatings

Amidoamines are widely used as crosslinkers for epoxy resins in protective coatings on metal substrates; however, their cure chemistry is not well elaborated in the technical literature. During cure, the epoxy–amine and epoxy–amide NH reactions could be accompanied by epoxy–hydroxyl etherification, epoxy–epoxy homopolymerization, and reaction between hydroxyls and amide moiety to form in situ ester and amine. To understand the epoxy–amidoamine cure chemistry and correlate it with coating performance properties, amidoamines of known structure are required. Therefore, amidoamines were synthesized by reacting dimer fatty acids with diethylene triamine. When these amidoamines were cured with epoxy resins, discrepancies were observed between systems cured at ambient and thermal conditions. The presence of solvents were seen to greatly affect the rate of epoxy–amidoamine cure at ambient, and before and after vitrification. Near‐IR and mid‐IR spectroscopy studies indicated that side reactions occurred to some extent during cure. No reaction was noted between the amide NH moiety and the epoxide group below 150°C whereas ester formation was noted above 120°C. Solvent‐based clear epoxy–amidoamine coatings formulated at an epoxy:amine equivalent ratio 1.15 passed basic organic coatings evaluation tests. POLYM. ENG. SCI., 59:E69–E81, 2019. © 2018 Society of Plastics Engineers

Depolymerization Study of PET Waste Using Aminoethylethanolamine and Recycled Product Application as Polyesteramide Synthesis

Recycling of poly(ethylene terephthalate) (PET) is a global concern due to generation of large volume of its post consumer waste and serious environmental problems caused as PET does not decompose in nature readily. Present research work aims at effective recycling of waste PET from soft drink bottles by aminolysis method and further utilization of the recycled product for high performance coating application. In the present study, we report aminoethylenethanolamine (AEEA) which till date is not studied much for chemical recycling of PET, having primary and secondary amine groups together with hydroxyl groups, for aminolysis reaction. The reaction parameters were optimized for conventional and microwave assisted technique by varying the ratio of raw materials, reaction time, temperature and power. The recycled oligomeric product was separated, purified and characterized for determination of amine value, hydroxyl value and by Fourier transform infrared spectroscopy, proton NMR (1H-NMR) spectroscopy. Further polyesteramides were successfully synthesized by partial replacement of neopentyl glycol by aminolyzed oligomeric product along with sebacic acid and phthalic anhydride. These resulting polyesteramides were further cured with commercial polyisocyanate curing agents and applied on mild steel panels. The cured coatings were evaluated for their optical, mechanical, chemical, thermal and anticorrosive properties. The partial replacement of recycled product of PET wastes exhibited comparative coating performance properties with respect to polyester polyol synthesized without any component based on recycled PET waste product.

Glycolytic depolymerization of PET waste using MP-diol and utilization of recycled product for UV-curable wood coating

Polyethylene terephthalate (PET) waste recycling has become a worldwide research interest for industries and academic institutes due its inevitable environmental impact. The main objective of current research work is to target efficient recycling of PET waste from mineral water bottles by the glycolysis method and subsequent use of the recycled product for value-added coating application. In the present study, we report on MP-diol (2-methyl-1,3-propanediol) which is not explored much for the chemical recycling of PET, having a branched aliphatic diol with two primary hydroxyls, for glycolysis reaction. The reaction parameters were optimized for microwave-assisted technique by varying the ratio of raw materials, reaction time, temperature, and power. The reaction parameters were optimized, and the recycled oligomeric product (OPETMPD) was separated, purified, and characterized by chemical and spectroscopic methods. Subsequently, dimethacrylated oligoesters of PET oligomer (UV oligomer) were synthesized by methacrylation of the glycolyzed PET product (OPETMPD). The synthesized UV oligomer was evaluated using chemical and spectroscopic methods. Ultraviolet (UV) radiation-curable formulations were prepared using synthesized UV oligomer and applied on wooden panels. The coatings were cured using UV-curing machine and evaluated for their performance properties. The partial replacement of UV oligomer in UV formulations exhibited comparative coating performance properties with respect to conventional UV formulation.

(UV/Oxidative) dual curing polyurethane dispersion from cardanol based polyol: Synthesis and characterization

This study reports the synthesis and property evaluation of UV/oxidative dual curing waterborne polyurethane dispersion prepared from cardanol-based polyol using different mode of curing. Cardanol-based polyol was prepared by reacting epoxidized cardanol with itaconic acid in presence of triphenyl phosphine catalyst. Structures of cardanol-based intermediates (both epoxidized cardanol and polyol) are confirmed by FTIR, 1H NMR and 13C NMR spectroscopy. The intermediates were characterized for various physicochemical properties such as hydroxyl value, acid value, epoxy equivalent weight (EEW), viscosity, color etc. Waterborne polyurethane oligomer was synthesized by reacting polyol, isophorone diisocyanate (IPDI), dimethylol propionic acid (DMPA) and 2-hydroxy methyl methacrylate (HEMA) in acetone as solvent. The prepolymer was neutralized with triethyl amine (TEA) and subsequently dispersed in deionized water and oligomer was obtained after removal of acetone. The coating films were formulated using suitable metal drier and/or photoinitiator blend based on different mode of curing, viz. oxidative curing, UV curing and (UV/oxidative) dual curing. The impact of curing process on properties of cured films was evaluated. Influence of curing process has been investigated by DMA, DSC and gel content analysis. The results showed that crosslink density plays an important role in deciding the final performance properties of cured films. The increase in crosslink density of UV/oxidative dual-cured system leads to an improvement in thermal, mechanical, chemical, water and solvent resistance properties along with other coating performance properties. In conclusion, the result of this study confirms that cardanol-based waterborne oligomer is suitable candidate for high performance environment-friendly coatings.

Effect of solvents on the curing and properties of fully bio-based thermosets for coatings

With the increasing concern about the depletion of fossil reserves and greenhouse gas emissions, it is desired to replace coatings which are made using petrochemical-based materials with renewable alternatives such as bio-based polymers. In this paper, fully bio-based thermosets for coatings were prepared from epoxidized sucrose soyate derived from sucrose and soybean oil fatty acid along with citric and malic acids found naturally in juices with the assistance of different solvents. The solvents with reasonable boiling point and good miscibility with citric acid and malic acid, such as water, ethanol, 1-propanol, 2-propanol, and 1,4-dioxane, were screened and used to investigate their effects on the curing and properties of the fully bio-based thermosets. The curing reactivity was studied by examining the gel time and nonisothermal curing process with DSC. The thermal and mechanical properties as well as coating performance properties were also investigated.

Features of interaction between styrene-acrylic film formers and modified kaolin

The processes of interaction in systems of kaolin with modifiers and styrene-acrylic film former are analyzed in the article. Researches were performed using infrared spectroscopy. The aim of the work was to assess the level of interaction processes in the investigated systems. In this paper the quantitative parameters of the main characteristic bands responsible for the stretching vibrations of reactive groups of kaolin and film former are determined. Maximum shift of the characteristic bands of the IR spectra and change their intensity are indicated. It is determine which of the investigated surfactants provide the most complete interaction of kaolin with styrene-acrylic film former. The results demonstrates that the interactions of the modifiers, fillers, and film former are proceed in presence of OH-groups of adsorbed water and linkages Si-O-Al of kaolin surface. The authors suggest the use of modified kaolin, which are characterized by the most complete interaction with the styrene-acrylic film former, as fillers for waterborne paints that provide higher performance properties of coatings.

Improving quality and performance properties of chemical coatings on steels and alloys by laser treatment

The subject of this paper is the Ni-P chemical coatings on steels and alloys. The research goal is to determine the capabilities of improving the quality and performance properties of the coatings under the rapid laser processing. Metal physical research methods - optical and electron-probe microscopy, hardness measurement, X-ray and electron microprobe analysis - are used. Anti-friction properties of the irradiated coatings are determined under testing on the tribometer. The study results have shown that the laser irradiation of chemical coatings can increase the hardness of the steel surface layers, advance the adherence strength of the coating to the steel substrate, lower the friction factor, and enhance the wearability of the coated steels.The results obtained allow reasonably choose modes of laser processing for chemical coatings leading to the consolidation and degassing of the steel surface layers, the increase of the coating adhesion to the substrate, the improvement of the surface morphology, the formation of a relatively perfect texture in the steel surface layers, and to the reduction of the burnout of alloying elements from the surface layers of materials.The studies show that the laser treatment of chemical coatings improves the quality of the surface layers of steels and alloys, increases the strength of coating adhesion to the metal substrate, increases the hardness, decreases the friction factor, and increases the wear resistance of steels with chemical coatings.

Influence of fillers dense packing to the performance properties of water-dispersion coatings

The considerable attention of scientists and practitioners is devoted to improving of coatings performance properties. Providing the most fillers dense packing in the polymer matrix of paint coating is one way of development in this area. Purpose of the article is creating a fillers dense packing of performance properties of water-dispersion coatings.Object of study – the water-dispersion styrene-acrylic coatings filled by Ukrainian carbonates. Research of film tensile strength was carried out according to GOST 18299, resistance of coating to wet abrasion – according to ISO 11998.The mathematical model let to determine that the maximum packing of particles in the coating will be achieved when the ra­tio of carbonate filler for plastics (CFP, the average particle size 1.8 microns) to chalk grade MMC-1 (1.0 microns) as 85.4 wt.% to 14.6 wt. % respectively. The maximum films tensile strength (5.52 MPa) and coatings resistance to wet abrasion (4.8 micron thickness loss) got from water-dispersion paints achieved when filled by carbonates CFP and MMC-1 at ratio 85.0 wt.% and 15,0 wt.% respectively. This is higher than the corresponding values in the case of each of the fillers alone and at other ratios that confirmed of getting the most dense packing of the particles in the coating.The influence of fillers packing density to coating performance properties from the water-dispersion paints has been determined. Getting the most dense packing of particles at specified ratio of carbonate filler allows to improve the performance properties of water-dispersion coating through a uniform wetting of the filler particles by polymer, strengthening the adhesive bond between binder and filler. This is to promote the continuous phase, resistance to cracking and destruction of coatings.

Effect of structure on coating performance properties of novel alkylenedioxydiphenol based epoxy resins

Although epoxy resins exhibit a wide range of useful properties for protective coatings on metal substrates, an increasing trend in the coatings industry toward more formable coatings places a severe burden on the traditional bisphenol. A based epoxy resins. Presented in this work are the results of experiments with a new series of epoxy resins based on alkylenedioxy diphenols demonstrating the relationship between coating performance properties (formability, chemical resistance, and adhesion) and structural parameters such as resin backbone flexibility, degree of phenol/formaldehyde crosslinkmg, and concentration of OH groups in the backbone of epoxy resins. Optimizing the three structural parameters for the new resins results in substantial improvements in coating performance properties over the traditional bisphenol A based resins.

Accelerated weathering for the testing of binders

The performance properties of coatings are predominantly governed by the binder material. Weathering is the most important and conclusive method of testing binders. Although valuable information is obtained from mechanical tests determining hardness, adhesion strength, flexibility, abrasion resistance, etc, they offer no direct relationship between the measuring data and the performance of the systems. It is only in special cases that electrical properties and, in particular, chemical resistance levels are of any interest.