Pigment Volume Concentration Research Articles

Heteropolyacids like new anticorrosion pigment in organic paints

Abstract This paper is focused on the heteropoly acids as another new possibility of dopant for conducting polymers which can be used as anticorrosive pigments for steel protection. The newly prepared pigments, silicotungstic and phosphotungstic heteropoly acids, were characterized by determination of oil number and density. The value of critical pigment volume concentration was determinated by these values. The pigment volume concentration was 0.5; 1; 3 and 5 % in epoxyester-resin witch was used as a binder. Organic coatings were applicated on steel panels which were tested by mechanical and corrosion tests. The main exam was exposition of testing sample in sulphur dioxide atmosphere. Another important exam was measuring the specific electrical conductivity and determination of corrosion loss. After 1584 hours, the samples were evaluated. Values of anticorrosion efficiency are increased for silicotungstic heteropoly acid pigment. But with long-term exposition, phosphotungstic heteropoly acid pigment has better and higher anticorrosion efficiency than the other sample.

Improvement in polyurethane coating performance through zinc aluminium phosphate pigment

Purpose This research aims to provide a comparative study of the effect of conventional zinc phosphate (ZP) and zinc aluminium phosphate (ZPA) representing second generation of phosphate-based anticorrosion pigments on the protective performance and physical mechanical properties of a solvent-borne polyurethane (PU) coating. Design/methodology/approach The two pigments were incorporated into the coating at optimum pigment volume concentration. To evaluate the protective performance, electrochemical impedance spectroscopy (EIS) was used. The effect of modification of ZP on the physical–mechanical properties of the coatings was studied through dynamic mechanical thermal analysis. Moreover, Micro Vickers hardness and pull-off tests were used to evaluate the hydrolytic coating degradation. Findings EIS revealed the superior protective function of coatings incorporated with ZPA compared to those formulated with ZP. This behaviour might be attributed to the release of sufficient inhibiting species because of partial dissolving of the anticorrosive pigments when an electrolyte penetrates into the coating. In addition, the effectiveness of modification of ZP on the physical–mechanical properties of coatings was shown. Research limitations/implications As a classical replacement for the toxic chromates, ZP has been widely used in the formulation of protective coatings. However, undesirable inhibitive function of the pigment arising from its low solubility has made modification necessary. Because of the modified solubility, second generation of phosphate-based anticorrosion pigments has been reported to reveal superior performance. Originality/value According to the literature, no report can be found studying the effect of the second generation of phosphate-based anticorrosion pigments on the physical–mechanical properties of PU coatings. The main goal of this work is to study the correlation between physical–mechanical properties and anticorrosion performance of the PU coatings.

Development of metoprolol tartrate-loaded sustained-release pellets: effect of talc on the mechanism of drug release

Talc is one of the most commonly used antiadherents in the coating film. However, the mechanism of influence of talc on drug release has yet to be fully understood. In this study, metoprolol tartrate (MT)-loaded Eudragit NE 30 D-coated sustained-release (SR) pellets were prepared using talc as an antiadherent in the layering and coating processes. Talc significantly reduced the stickiness of the layered or coated substrates, thus enhancing the process smoothness. Moreover, the incorporation of talc into the coating film significantly affected drug release. The water vapor permeability and drug permeability of free films increased as the concentration of talc increased. Importantly, talc had a dynamic effect on the drug release. The drug release rate of the pellets in the initial stage (within 2 h) increased with increasing talc concentrations, which exceeded the critical pigment volume concentration resulted in leaks formation in the coated film. However, subsequent swelling of the membrane and expansion of the copolymer network eliminated the influence of talc and the drug release was then controlled by the polymeric membrane. These results suggest that talc contributed to the reduction of the sticking of layered or coated substrates, and facilitated the manufacturing process and drug release properties.

Improvement of the anticorrosive properties of an alkyd coating with zinc phosphate pigments assessed by NSS and ACET

Abstract The effect of the addition of two anticorrosive phosphate pigments, standard zinc phosphate and modified zinc phosphate (zinc molybdenum phosphate modified with a surface treatment) on the corrosion protection of an alkyd coating on steel, has been investigated by means of a traditional accelerated test (salt fog spray test) and an electrochemical technique (accelerated cyclic electrochemical technique). Solvent-based alkyd coatings based on phenolic modified resins were formulated with different anticorrosive pigment concentrations (3%, 4.5% and 6%, expressed as anticorrosive pigment volume concentration in dry film volume, PVC) and finally characterised. An improvement in the anticorrosive properties is obtained with the addition of both pigments, the coatings formulated with modified zinc phosphate having better performance. Both techniques showed results that can be correlated.

Disposing waste latex paints in cement-based materials – Effect on flow and rheological properties

The effect of waste latex paints (WLPs) on fresh and hardened properties of cement-based materials is not well understood. In this project, WLPs were not randomly collected from waste collection sites; rather produced to ensure full traceability of composition, then stored in sealed or opened pail conditions to get expired. Test results have shown that rheological properties of cement pastes are directly affected by WLP constituents, substitution rates, and storage conditions. A series of charts were proposed to predict the variations in flow, yield stress, and plastic viscosity of pastes containing 4%, 8%, 12%, and 16% substitution rates of mixing water by WLPs. The indicative measures used for prediction included the gloss unit of paints and their pigment volume concentrations. The compressive strength slightly increased at relatively low WLP rates, but then dropped sharply at higher substitutions.

Design and synthesis of polymeric dispersant for water-borne paint by atom transfer radical polymerization

A series of chains of triblock amphiphilic copolymers were synthesized by atom transfer radical polymerization (ATRP) techniques and post modified to polymeric dispersant for waterborne paint. Poly(butyl acrylate (BA))-b-poly(hydroxy ethyl methacrylate (HEMA))-b-poly(methyl methacrylate (MMA)) triblock copolymers having predetermined molecular weights were synthesized by ATRP using CuBr, 2-bromoisobutyrate, and pentamethyldiethylenetriamine as a catalytic system in dioxane at 80 °C. The copolymers were further reacted with cyclic chlorophosphate and triethyl amine to form dispersible modified poly(BA-HEMA-MMA). The synthesized copolymers were structurally evaluated by Fourier transform infrared, 1H NMR, 31P NMR, gel permeation chromatography (GPC), energy dispersive X-ray spectroscopy, and their hydroxyl equivalent, respectively. The surface activity of modified copolymers as dispersing additives was investigated by the surface tension analysis and wetting ability test. The ability of additives to function as wetting and dispersing agents was evaluated by analyzing their mechanical, optical, chemical, and rheological properties of water-based paints at different pigment volume concentrations. The effects of the chain length of copolymers on dispersibility and optical properties were studied. The optical properties of paints suggested that the dispersibility of modified poly (BA)-b-poly (HEMA)-b-poly (MMA) (MPBHM) increased with an increase in the molecular weight of the copolymer.

Effect of zirconium conversion coating: Adhesion and anti-corrosion properties of epoxy organic coating containing zinc aluminum polyphosphate (ZAPP) pigment on carbon mild steel

Abstract An epoxy organic coating containing zinc aluminum polyphosphate (ZAPP) pigments with and without a hexafluorozirconic acid based conversion coating (ZrCC) pretreatment was applied on carbon mild steel (St 37) in order to investigate the corrosion resistance behavior and adhesion of the coating to substrate. Optimization of pigment volume concentration (PVC) and conversion coating application conditions was carried out and also the interaction of organic and conversion coating was studied using electrochemical impedance spectroscopy (EIS), salt spray and pull-off adhesion tests. Appropriate anti-corrosion properties was gained from organic coating samples with PVC = 30% and conversion coating applied from a solution with pH and acid concentration of 4.5 and 0.01 M, respectively. Results indicated that using conversion coating as a pretreatment before applying organic coating, improves adhesion of the coating to the substrate (by 1–2 MPa) and also provides an effective corrosion protection in long periods of immersion time. The highest corrosion resistance was obtained for pigmented organic coating sample with Zr conversion coating pretreatment after 4 weeks of immersion in NaCl 3.5 wt.%. Field emission scanning electron microscope and energy dispersive X-ray spectroscopy (FE-SEM/EDS) also proved the presence of about 5 wt.% of zirconium at the interface of coating and substrate not only at the onset of immersion but also after 4 weeks of immersion time. Results taken from this research, can clarify the key role of surface modification at interface of coating and substrate in adhesion and also the retention of anti-corrosion properties over the course of time even for an anti-corrosion pigment reinforced organic coating sample.

Corrosion – inhibiting properties of molybdenum-containing pigments in coatings

Purpose – This paper aims to synthesise anticorrosion pigments containing molybdenum for paints intended for corrosion protection of metals. Design/methodology/approach – The anticorrosion pigments were prepared by high-temperature solid-state synthesis from the appropriate oxides, carbonates and calcium metasilicate. Stoichiometric molybdates and core-shell molybdates with a non-isometric particle shape containing Ca, Sr, Zn, Mg and Fe were synthesised. The pigments were examined by X-ray diffraction analysis and scanning electron microscopy. Paints based on an epoxy resin and containing the substances at a pigment volume concentration of 10 volume per cent were prepared. The paints were subjected to physico-mechanical tests and to tests in corrosion atmospheres. The corrosion test results were compared to those of the paint with a commercial pigment, which is used in many industrial applications. Findings – The molybdate structure of each pigment prepared was elucidated. The core-shell molybdates exhibit a non-isometric particle shape. The pigments prepared were found to impart a very good anticorrosion efficiency to the paints. A high anticorrosion efficiency was found with the pigments Fe2(MoO4)3 and Fe2(MoO4)3/CaSiO3 and with Mg and Zn molybdates. Practical implications – The pigments can be used for the formulation of paints intended for the corrosion protection of metals. The pigments also improve the paints’ physical properties. Originality/value – The use of the pigments in anticorrosion paints for the protection of metals is new. The benefits include the use and the procedure of synthesis of the anticorrosion pigments which are free from heavy metals and are acceptable from the aspect of environmental protection. Moreover, the core-shell molybdates, whose high efficiency is comparable to that of the stoichiometric molybdates, have lower molybdenum contents.

Preparation and Numerical Simulation Investigation of High Reflectance Anti-laser-ablation Coating

An anti-laser-ablation coating using TiO2 as pigment and potassium silicate as binder (abbreviated as KS-T) was deposited on the aluminum alloy substrate by an air spray process. Factors influencing the reflectance of KS-T coating, including particle size, pigment volume concentration and coating thickness, were investigated. The reflectance of prepared KS-T coating could be up to 96.8% at the laser wavelength of 1064 nm. A three-dimensional finite element model based on the heat-conduction equation was developed to simulate the distribution of transient temperature filed. By monitoring the temperature variation at the backside center of aluminum alloy substrate during laser irradiation and comparing with the simulation results, it is found that KS-T coating could effectively protect the substrate from laser ablation. The simulation results demonstrated reflectance decrease of samples after a period of irradiation. The possible reasons for the reflectance decrease were proposed. The calculation results also showed that an obvious temperature drop emerged at the coating/substrate interface when interface thermal resistance (ITR) was considered. Eventually heat flux was prevented from flowing to the substrate and aluminum alloy kept a low temperature.

Geometry of a paint film: Basics revisited

Abstract “Pigment/binder geometry”: this is the title of a chapter in “Paint, flow and pigment dispersion”, the well known textbook [1] by Temple C. Patton that contributed to the coatings education of generations of paint chemists. The author had designed a graphical representation – the first one of this kind – of the volume repartition of the main components of a dry paint film as a function of the Pigment Volume Concentration, or PVC, of the paint. It was the source of inspiration for this article. His approach was however focused upon systems where the binder phase was an oil and would need to be refined and developed further when latex polymers are used instead. This is the object of the communication that follows. It is also the opportunity to re-visit a number of basic concepts.

Investigation of the mechanical properties of a photocatalytic pseudo‐paint

ABSTRACTPhotocatalytic oxidative paints (e.g., a paint containing nano‐TiO2) are used to break down volatile organic compounds to CO2 by photooxidation reactions. In this research, a photocatalytic oxidative pseudo‐paint was made with acrylic–styrene copolymer latex, TiO2 pigment, calcium carbonate extender, and TiO2 nanoparticles as a photocatalyst. To investigate the effects of the pigment, extender, and nanoparticles on the mechanical properties of the samples and their relationship to their photocatalytic activity, different contents of the particles were dispersed in the paint formulation. The tensile strengths (TSs) of the samples were measured as the mechanical properties. The samples were characterized by scanning electron microscopy analysis. We found that up to 3% nano‐TiO2 enhanced the mechanical properties of the pigmented resin, whereas beyond this, TS decreased. In samples containing 3% nanoparticles, the incorporation of 15% TiO2 pigment caused optimized mechanical properties, and beyond that, TS decreased because of particle agglomeration. In the absence of nanoparticles, the samples showed improvements in the mechanical properties with up to a 40% loading of pigment. The results reveal that the samples containing nano‐TiO2 and pigment showed the same trend for the mechanical and photocatalytic properties before the critical pigment volume concentration (CPVC). However, when the extender was incorporated or TiO2 particles were loaded beyond CPVC, the mechanical and photocatalytic properties correlation was compromised, and they were not directly correlated. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42885.

English

This study investigated the effects of silica (SiO2) morphology on emulsion paint properties by comparing the physical properties of emulsion paints produced with amorphous silica ( rice husk ash) with those of crystalline silica (silica flour) used as pigment extenders in the paint. Calcium carbonate was used as the reference standard in the study. Rice husk ash (RHA) was obtained by heating rice husks on a gas stove to obtain rice husk char which was subjected to controlled incineration in a muffle furnace at a temperature of 6500C and duration of 4hrs. The granular RHA obtained was ground to obtain powdery RHA of smaller particle size. The RHA powder, silica flour (SF) and CaCO3 were then sieved to obtain the same particle size range of 32-63microns (μm) used in the formulation of the emulsion paints. The extender levels in the formulations were varied from 2-12% by weight and the physical properties of the emulsion paint variants were determined. The results revealed that RHA-filled white emulsion paints (RHAWEP) had higher viscosities than those of silica flour due to the amorphous nature of silica in RHA which conferred on it, a thickening effect superior to that of crystalline silica. RHAWEPs had higher pigment volume concentration (PVC) values than those of silica flour and CaCO3 due to its lower specific gravity and this resulted in the flat (non-glossy) appearance of the RHAWEP dry films but semi-gloss appearance of those of SF and CaCO3.

Synthesis and investigation of the properties of tungstate-based anticorrosion pigments in coatings

Purpose – This paper aims to synthesize anticorrosion pigments containing tungsten for paints intended for corrosion protection of metals. Design/methodology/approach – The anticorrosion pigments were prepared by high-temperature, solid-state synthesis from the respective oxides, carbonates and calcium metasilicate. Stoichiometric tungstates and core-shell tungstates with a nonisometric particle shape containing Ca, Sr, Zn, Mg and Fe were synthesized. The pigments were examined by X-ray diffraction analysis and by scanning electron microscopy. Paints based on an epoxy resin and containing the substances at a pigment volume concentration (PVC) = 10 volume per cent were prepared. The paints were subjected to physico-mechanical tests and to tests in corrosion atmospheres. The corrosion test results were compared to those of the paint with a commercial pigment, which is used in many industrial applications. Findings – The tungstate structure of each pigment was elucidated. The core-shell tungstates exhibit a nonisometric particle shape. The pigments prepared were found to impart a very good anticorrosion efficiency to the paints. A high efficiency was demonstrated for the stoichiometric tungstates containing Fe and Zn and for core-shell tungstates containing Mg and Zn. Practical implications – The pigments can be used with advantage for the formulation of paints intended for corrosion protection of metals. The pigments also improve the paints’ physical properties. Originality/value – The use of the pigments in anticorrosion paints for the protection of metals is new. The benefits include the use and the procedure of synthesis of anticorrosion pigments which are free from heavy metals and are acceptable from the environmental protection point of view. Moreover, the core-shell tungstates, whose high efficiency is comparable to that of the stoichiometric tungstates, have lower tungsten content.

Modified poly(butyl methacrylate- b -glycidyl methacrylate) dispersant for solvent-based paint by Reverse Atom Transfer Radical Polymerization

Block copolymers of butyl methacrylate (BMA) and glycidyl methacrylate (GMA) were synthesized using reverse atom transfer radical polymerization. Azobisisobutyronitrile/copper (II) bromide/pentamethyldiethylenetriamine was used as a precursor. These copolymers had a constant block length but variable molecular weights of 7500, 10,000, and 15,000, respectively. The copolymers were further reacted with methyl ethanol amine to form dispersible modified poly(BMA-b-GMA) (MPBGA). The synthesized block copolymers were structurally evaluated by gel permeation chromatography, Fourier transform infrared spectroscopy, differential scanning calorimetry, and nuclear magnetic resonance. The ability of additives to function as wetting and dispersing agents was evaluated by analyzing their mechanical, optical, chemical, and rheological properties in solvent-based paints at different pigment volume concentrations. The effects of the chain length of copolymers on dispersibilty and optical properties were studied. The optical properties of paints suggested that the dispersibilty of MPBGA increased with an increase in the molecular weight of the copolymer.

Investigation of the anticorrosion efficiency of ferrites Mg1−xZnxFe2O4 with different particle morphology and chemical composition in epoxy-ester resin-based coatings

Abstract Mixed metal oxides with the ferrospinel structure ZnFe2O4, Mg0.2Zn0.8Fe2O4 and MgFe2O4 were synthesised by the high-temperature solid-phase process. A series of pigments containing the metals Mg–Zn–Fe was prepared from 4 different starting iron oxides: viz. goethite (FeOOH), hematite (Fe2O3), magnetite (FeO·Fe2O3) and specularite (Fe2O3). The properties of the ferrites as pigments were examined in a solvent-based epoxy-ester resin-based coating material at a pigment volume concentration PVCferrite = 10%. The anticorrosion efficiency of the paints with the ferrites was examined by exposing panels coated with the paints to atmospheres with SO2, NaCl, or condensed moisture. Furthermore, the physico-mechanical properties of paint films containing the pigments were evaluated by standardised tests. Ferrites prepared from the needle-shaped FeOOH or lamellar Fe2O3 emerged as pigments with the best anticorrosion properties. From the aspect of chemical composition, the paint films containing Mg0.2Zn0.8Fe2O4, i.e. combinations of the cations Mg–Zn, were assessed as the best.

Effect of polyaniline salts on the mechanical and corrosion properties of organic protective coatings

Abstract The aim of this work was to assess the effect of polyaniline salts (PANI-HA) with various dopant types on the mechanical and corrosion properties of organic protective coatings dependent on the pigment volume concentration. The doping acids used included phosphoric acid (H 3 PO 4 ), sulphuric acid (H 2 SO 4 ), hydrochloric acid (HCl), p-toluenesulphonic acid (PTSA), and 5-sulphosalicylic acid (CAS). The polyaniline salt types were described by their physico-chemical parameters. An epoxy ester resin was used as the binder for the organic coatings. The organic protective coatings included the various PANI-HA types. The prepared organic coatings were subjected to mechanical testing, corrosion tests and linear polarisation technique. Organic coatings achieved during mechanical tests comparable results regardless of the type of PANI dopant or PVC (pigment volume concentration) with the exception of organic coatings fulfilling the condition PVC = CPVC (critical pigment volume concentration) which exhibited decrease of mechanical resistance. The results of accelerated corrosion tests and techniques of linear polarisation testify that in particular the PVC parameter affects the resulting corrosion resistance. During those tests, the organic coatings exhibited improved corrosion resistance, particularly at low pigment volume concentrations (PVC = 0.1–5%) irrespective of the pigment used.

Assessment of the Properties of Paint Films Containing Surface-Treated Silicates

The objective of this paper is the surface modification of silica pigments layer of polyaniline (PANI), poly (p-phenylendiamine) (PPDA) and chemical layer of zinc ferrite ZnFe2O4. This layer promote adhesively-barrier properties of silica particles without surface-treated. This pigment was specified using physico-chemical parameters (oil absorption, critical pigment volume concentration, density, pH extract and the specific electrical conductivity of pigment extracts). An epoxy ester resin was used as binder for the organic coatings investigated. Organic coatings were prepared in the following volume concentration PVC = 10 %. Organic coatings prepared were subjected to measurement of physical-mechanical properties by the following tests: relative surface hardness, adhesion test, bend test, impact test. Organic coatings were subjected to the following corrosion tests: in an atmosphere of SO2 with water condensation. The results of mechanical and anti-corrosion tests provide evidence that was met premise increase adhesively-barrier properties of newly developed coating films.

Effect of precipitated calcium carbonate additions on waterborne paints at different pigment volume concentrations

Abstract Titanium dioxide (TiO 2 ) due to its high refractive index, is widely used in paint industry as a white pigment. In order to reduce this high cost of TiO 2 , a part of TiO 2 is generally substituted by some other industrial mineral fillers such as calcite and calcined kaolin; however, this substitution affects the quality of paints in terms of stability, coverage (opacity), brightness (gloss), scrub resistance (film toughness), etc. In the present paper, precipitated calcium carbonate (PCC) was substituted for TiO 2 in paint mixture at three different pigment volume concentrations (PVC). It was observed that substitution of TiO 2 by PCC depends on PVC value at which there is an optimum PCC amount. The quality of paints produced by PCC along with its rheological properties was evaluated based on standard features in both wet and dry paints such as viscosity, density, opacity and gloss values. Addition of PCC increases the opacity to a certain point. Similarly, scrub resistance and viscosity increases with the addition of PCC at all PVCs, however, viscosity is not as much critical for the paint production. On the other hand, there is no any systematic effect of PCC on gloss value of the paint. This study overall demonstrates that PCC can be successfully used to substitute TiO 2 only with a careful adjustment of PVC and other extenders used in the paint formulation.

Influence of pigment packing behavior on the adhesive requirements of aqueous paper coatings

The amount of adhesive included in an aqueous paper coating formulation is critical to the performance and appearance of the final product. While the time-honored “weight ratios” are typically used to formulate pigmented coatings for paper, pigment volume concentration (or alternatively, % void volume) has been found to be much more useful in determining the interactions of pigments with the adhesive on the properties of such aqueous coatings. In this study, slurries of commercial kaolin clay and ground calcium carbonate pigments used in papermaking applications were blended and then centrifuged to determine the maximum packing efficiency of the pigments. Isolated films of coatings made from selected pigment blends and increasing levels of latex adhesive were tested for void volume percentage and tensile modulus. Based on these results, a regression equation between pigment interstitial space and the mechanical strength of different coating films was established.

Anticorrosion efficiency of zinc-filled epoxy coatings containing conducting polymers and pigments

Abstract The dependence of the corrosion-inhibiting properties of zinc-filled organic coatings on the nature of the conducting polymers and conducting pigments added and on the pigment particles’ surface coating with conducting polymer layers were investigated. The following materials were selected to examine the corrosion-inhibiting properties of the conducting polymers: polyaniline phosphate (PANI), polypyrrole (PPy), natural graphite, and carbon nanotubes. Conducting pigment combinations for application in coating materials were formulated by applying pigment volume concentrations (PVC) of 0.3%, 0.5% and 1%, which were completed with Zn dust to obtain pigment volume concentrations/critical pigment volume concentrations (PVC/CPVC) = 0.64. Such conducting pigment/zinc dust combinations represented corrosion inhibitors to be used as ingredients in protective coatings. Solvent-based 2K epoxy resin based coating materials containing the corrosion inhibitors so formulated were prepared to examine their anticorrosion properties. The pigmented coatings were subjected to laboratory corrosion tests in simulated corrosion atmospheres and to standardized mechanical resistance tests. The protective coatings so obtained exhibited a higher efficiency than coating materials containing zinc dust alone. The coating material containing carbon nanotubes at PVC = 1% and the coating material containing graphite coated with polypyrrole (C/PPy) at PVC = 0.5% emerged as the best zinc-filled coating materials with respect to their corrosion-inhibiting efficiency. Treatment with the conducting polymers had a beneficial effect on the coating materials’ mechanical properties.