Latex Paint Research Articles

C–H activation goes macro

Polymer Chemistry Methods to oxidize carbonhydrogen (C–H) bonds under mild conditions are showing increasing promise in streamlining small-molecule synthesis. Chen et al. report an application tailored instead to a macromolecule: polyethylene. The world's most common plastic has proven hard to tweak without damaging its structural integrity, but a ruthenium porphyrin catalyst is just selective enough to introduce hydroxyl and carbonyl substituents without disrupting the backbone. The oxidized polymers remained mechanically robust while showing improved adhesion properties and wettability by simple latex paint. Chem 7 , P137 (2021).

Bonding agents to mitigate interfacial strength loss during multi-layer concrete casting

Self-consolidating concrete (SCC) is very sensitive to interruptions or delays during the placement process. Current literature converges that interfacial bond strength between successive casting lifts could drop by up to 60%, compared with monolithic casting. In this study, two series of SCC mixtures were tested to assess the suitability of bonding agents to mitigate the drop in interfacial bond strength resulting from successive casting lifts. The slabs were cast in two layers separated by 60 or 120 min rest intervals; different bonding agents, including styrene–butadiene rubber (SBR), waste latex paint and cement/water and cement/SBR slurries were compared. The results showed that the application of polymeric bonding agents on top of the first cast is efficient to improve tensile strength and restore the integrity of the hardened member. This is attributed to the polymer particles that coalesce and fuse to form continuous close-packed films between the first and second SCC layers. The cement/water slurry did not lead to considerable improvement in pull-off strength between cast layers. Series of charts enabling the prediction of the drop in bond for a given SCC composition and rest interval as a function of the polymer dosage to the area of the cast slab are presented.

МОРФОЛОГИЯ ПЕЧЕНОЧНЫХ ВЕН КРОЛИКА

This article describes the features of the topography, drainage zones and the nature of the branching of the hepatic veins in the domestic rabbit. The studies were carried out in the laboratory of the Department of Biology and Soil Science of the Orenburg State University in the period 2020-2021. To study the venous outflow from the liver, sexually mature (six to seven months old) rabbits of the Butterfly breed were used. For this purpose, corrosive preparations of the hepatic veins (n=15) were obtained. To fill the venous system, Sherwin Williams Promar 400 latex paint was used. Corrosion was carried out in a 20-25% hydrochloric acid solution for seven days. The length and diameter of the vessels, the angles of their confluence and divergence were subjected to measurements. The obtained morphometric data were statistically processed using the Microsoft Excel program. Statistical study consisted in the construction of variational series, the determination of average values, the coefficient of reliability of the difference in average values. During the study, it was found that venous drainage is carried out through four independent hepatic veins, which form according to the main type and flow into the caudal vena cava. The caudate process of the caudate lobe and the left lateral lobe have independent venous vessels. The remaining lobes have common efferent venous trunks and have intraorgan communications within the main lobes. Morphometric parameters indicate the predominant development of the middle (4.48±0.18 mm) and left (1.51±0.11 mm) hepatic veins. It was determined that the drainage of each lobe is carried out by three veins of the third order, forming a three-level system of vascularization. The mastoid and caudate processes of the caudate lobe have different blood outflow systems that are not interconnected.

Catalytic C–H Oxidation Enhances Polyethylene Bonding

Selectively adding functionality to commodity plastics is an abiding challenge in polymer science. In this issue of Chem, Hartwig and co-workers describe a selective, catalytic oxidation of polyethylene C–H bonds by using high-valent ruthenium-oxo species. The transformation increases polyethylene’s adhesive properties without significantly modifying its thermal stability or mechanical strength.

Selective, Catalytic Oxidations of C–H Bonds in Polyethylenes Produce Functional Materials with Enhanced Adhesion

Summary The synthesis of functional and processable polyethylenes from simple vinyl monomers with controlled molecular weights and architectures has been a grand challenge of polymer chemistry. Post-polymerization modification of the homopolymers of ethylene is attractive for this purpose but has been hampered by the lack of efficient methods for the selective functionalization of C–H bonds in polyolefins. We report the selective, catalytic oxidation of C–H bonds in commodity polyethylenes with varying molecular weights and architectures. Remarkably, the functionalized materials, even at low levels of functionalization, exhibit physical properties that are absent in unmodified polyolefins, such as strong adhesion and the ability to be painted with common waterborne latex paint. Such observations indicate that selectively modified polyethylenes as described here may help to transform existing commodity plastics into more valuable and potentially more sustainable materials.

Improving the Accuracy of a Hygrothermal Model for Wood-Frame Walls: A Cold-Climate Study

A one-dimensional transient hygrothermal model was used to simulate eight different wood-frame wall assemblies. Simulations were compared with measured results from a two-year field study exploring the effects of exterior insulation on wall moisture performance in a cold-climate. The field study documented the moisture content, temperature, and relative humidity measurements in wall assemblies using oriented strand board (OSB) sheathing. Simulations were performed using generic design input values as well as input values based on measurements or sensitivity analysis. Laboratory material property measurements informed the choice of material property values in the improved model for OSB, asphalt-coated kraft paper, and interior latex paint. Simulations using improved input values typically agreed with field measurements within measurement error. The most significant model improvements were all related to vapor permeance. The vinyl siding used an effective permeance much lower than typically recommended. However, both the extruded polystyrene insulation and the asphalt-coated kraft paper facing on the cavity fiberglass insulation had higher permeance than literature values.

Efficacy of expanded polystyrene as fine aggregate in cement mortars modified with latex paint as an alternative to polymer admixture

Abstract In this present study, the effectiveness of expanded polystyrene (EPS) waste used as 20, 40 and 60% fine sand replacement in development of lightweight cement composite was evaluated. The cement mortar was strengthened by 10% low cost latex paint emulsion as an alternative to the more expensive polymer admixtures. Six different mix designs were produced and tested for compressive and split tensile strength according to BS EN standards. Scanning electron microscope (SEM) analysis was also conducted to analysis the micrograph of the samples. It was observed that as the EPS content, latex paint polymer admixture and curing days were increased, marginal increment in compressive strength was obtained. However, EPS fines were most effective in improving the split strength while latex paint admixture had comparatively less part to play in the strength development. The micrograph images showed that the EPS fines were uniformly distributed within the microstructure and the latex paint developed polymer films. These mechanisms coupled with the cement hydrate products were responsible for the enhanced strength observed in the samples.

Robot Nano Spray Painting - A Review

Since 1970s, robotic painting has been widely adopted to manufacturing and automobile industry, because of its many advantages over manual painting in its high efficiency, economy and keeping workers away from hazardous chemicals. During the automated painting process, the spray gun, the end-effector of the painting robot, is guided to paint the targeted surface along the planned trajectories. Nano-sized additives are placed in the latex paint to enhance the quality of paint. The purpose of this study is twofold: examine the trajectory planning of robot and discuss the most influential parameters to increase the quality and lifetime of paint. Multiple databases were searched for literature and limiting to last ten years. The keywords selected for the search were a combination of the Paint thickness, Robot Spray Painting, Trajectory planning, Simulation, Nano Paint, Characteristics of paint, State of the art technologies. From the literature survey, few works were carried out using the robot paint and no work was conducted using the CNT based Nano paints and analysing the environmental characteristics, surface characteristics are very limited. This study will identify the factors that enhance the paint characteristics and will be useful for coating and paint industry. The factors like distance, pressure and speed are considered and the parameters like surface roughness, thickness and film adhesion is considered. To optimize the control parameters to improve the quality of Robot Nano spray paint coating by Robot Trajectory planning. Examine the control parameters to increase life time of painting and shining characteristic in current scenario of industry.

Value-added waste latex paints in masonry cement for plastering applications

Polymeric latexes are commonly used in cement-based plastering and rendering works. This paper assesses the effect of recycled polymers obtained from waste latex paints (WLPs) on flowability and mechanical properties of masonry cement (MC) mortars, including whether such performance would be similar to that induced by virgin polymers. Three MC classes prepared with different cement-to-limestone ratios are produced in compliance to relevant EN 413-1 and ASTM C91 specifications. The WLPs were not obtained from waste collection sites, rather produced to monitor constituents and properties prior to use. Test results showed that water retention and rheological properties of mortars containing virgin or recycled polymers are remarkably higher than unmodified mixtures. The mechanical properties of WLP-modified mortars including compression, flexure, and pull-off adhesion strength were pretty similar, or even higher than equivalent mixtures containing virgin polymers. This was attributed the presence of ultrafine pigment and extender particles that improve packing density and infer nucleation benefits for the growth of additional hydrates. The dry curing regime applied for virgin and recycled polymer-modified mortars is particularly advantageous in construction sites, as this reduces the hassle of moist curing normally required for unmodified plasters while securing higher resistance against sorptivity and shrinkage cracks.

In-situ ultrasound-assisted control of polymeric membrane fouling

Membrane separation processes have been more widely applied to industrial activities, especially in water and wastewater treatment. However, there are still challenges associated with the use of membranes. Concentration polarization and fouling can cause significant permeate flux decay during the filtration process, hindering its efficiency and increasing cost. Among many strategies, the combination of membrane filtration with ultrasound (US) application has shown promising results in reducing membrane fouling. The main goal of this research was to identify the effect of US frequency, US power intensity and feed solid concentration on permeate flux during ultrafiltration of simulated latex paint effluent. Maximum increase in permeate flux of 19.7% was obtained by applying 20 kHz and 0.29 W cm−2 to a feed solution containing 0.075 wt% of solid. Overall, the application of US improves permeate flux by reducing fouling of ultrafiltration polymeric membrane.

Effect of surface covering on the release of formaldehyde, acetaldehyde, formic acid and acetic acid from particleboard

An important aspect for indoor air quality is the control of potential sources of organic pollutants. However, many building products, in particular wood-based materials, are coated under real conditions, while the emission behavior is usually examined without coating. For a reliable estimate of indoor air concentrations, it is therefore necessary to determine the influence of surface coatings on their emission behavior. In this work, the effect of various types of coatings (wallpaper, plaster, wall paint, latex paint) on particleboards with regard to the emission of formaldehyde, acetaldehyde, formic acid and acetic acid was investigated. The measurements were carried out in four steps. I: raw particleboard; II: particleboard with primer; III: particleboard with primer and top coating; IV: particleboard with primer and top coating after three months of storage. Applying the primer reduced the formaldehyde concentration in the chamber by 10–20%. With the final coating, the formaldehyde reduction was between 70% and 90% after 900 h. There was no increase in formaldehyde concentration after three months. Regardless of the coating, a constant decay in concentration was observed for acetaldehyde. The release of formic acid could be reduced by the primer for a short time, only the application of the final coating brought a lasting effect. The results were indifferent for acetic acid. One reason for this is that some of the coatings contained acetates. Overall, surface coatings make a significant contribution to reducing the emissions of wood-based materials. This is particularly evident where the substance formaldehyde is concerned.

Poly(acrylic acid) grafted soy carbohydrate as thickener for waterborne paints

Thickeners are widely used to change rheological properties of latex paints. Soy carbohydrate is an abundant, but a rarely utilized agricultural by-product. The grafting of poly(acrylic acid) onto soy carbohydrate particles forms gel particles that can change rheological properties of latex paints. The grafting polymerization of acrylic acid onto carbohydrate particles using ammonium cerium (IV) nitrate as initiator increased the particle size and viscosity of the aqueous particle dispersion. The viscosity increased with the increased amount of grafted poly(acrylic acid). Strain and frequency dependent moduli show a difference in dispersion-properties between the grafted soy carbohydrate and hydroxyl ethyl cellulose. The latex paint with poly(acrylic acid) grafted soy carbohydrate shows similar viscosity at low shear rate region and lower viscosity at higher shear rates when compared to the latex paint with hydroxyl ethyl cellulose. High-shear-recovery measurements of the latex paints predict sagging properties that are consistent with the ASTM sagging tests.

Sound absorption performance of diatom mud coating and its influence on indoor acoustic environment

The sound absorption coefficient of three different diatom mud and latex were measured. The models of two typical living rooms were established to study the influence of living room type, floor materials and curtains on indoor reverberation time, and the results were compared to the reverberation time with latex paint. The average sound absorption coefficient of three diatom muds was higher than that of latex in the measured frequency range. The improvement effect of diatom mud on the independent living room was more obvious. Ground materials and presence of curtains also affected the improvement effect of the diatom mud.

Electroplating sludge handling by solidification/stabilization process: a comprehensive assessment using kaolinite clay, waste latex paint and calcium chloride cement additives

This research examined the solidification/stabilization process of using a cement binder with actual electroplating sludge. An extensive comparative analysis was done with the cement–sludge mixture before and after the application of cement additives (kaolinite clay, waste latex paint and calcium chloride). The characterization analysis using the Fourier transform infrared spectrophotometer and X-ray diffraction analysis indicated the development of hydration at different cement mixtures. Through a comprehensive assessment of various cement additives, this study showed that the utilization of the admixtures in the cement binder could surpass the required standard unconfined compressive strength (350 kPa). Moreover, calcium chloride as its chemical additive (1704.5 kPa) was able to further aid the strength development against the control concrete (1151.5 kPa) at 28 days. In terms of the leaching tests, the use of cement additives has proved to successfully immobilize the heavy metals (Ag, Cu and Ni) in the cement–sludge matrix based on the toxicity characteristic leaching procedure. The results revealed an effective leaching resistance that leads to satisfying the stringent regulatory leaching requirements of the United States Environmental Protection Agency and the European Union Council (Ag ≤ 5.0 mg/L, Cu ≤ 0.6 mg/L and Ni ≤ 0.12 mg/L).

Descriptive Analysis of Cerebral Arterial Vascular Architecture in Dromedary Camel (Camelus dromedarius).

The artiodactyl brain has multiple levels of vascular pooling and the rostral epidural rete mirabile (RERM) at its base. The current study is the first of its kind to precisely demonstrate the arterial vasculature of the dromedary brain, utilizing a new casting method with colored latex and epoxy paint. In total, 35 freshly slaughtered dromedary heads were injected with colored latex or colored epoxy paint prior to dissection in order to reveal cerebral vasculature; Ten processed heads were chemically digested with 5% potassium hydroxide to obtain hard casts of cerebral arteries and anastomosing structures. The outcomes of this study ascertain the distinct vascular features of dromedaries that set them apart from other artiodactyls. In addition to the RERM, the dromedary possesses a well-developed ophthalmic and chiasmatic rete. The dromedary is similar to giraffe, goat, cat and pig in the contribution of middle meningeal artery to the rete mirabile; however, dromedaries have several arteries emerging directly from the cerebral arterial circle that supply the choroid plexus and pineal gland. Additionally, dromedaries exhibit a dominant basilar system that dominates the blood supply to the medulla oblongata, pons, and cerebellum. In our study, we were able to graphically prove the lack of connection between the areas supplied by vertebrobasilar system and carotid system in the dromedary. Furthermore, the vertebral artery does not branch into the basilar artery; instead, it acts as a contributing vessel to the ventral spinal artery that later fuse to form the basilar artery. This study employed the new casting method to illustrate a new arterial source to RERM and the various anastomoses among arterial sources supplying the brain in the dromedary. These anastomoses play an important role in maintaining an uninterrupted cerebral blood supply, decreasing the vulnerability of the fragile brain against ischemia and stroke, as well as, play an important role in maintaining blood pressure and flow in long-necked dromedaries when they raise or lower their heads.

The use of poly(3-hydroxybutyrate), C-phycocyanin, and phenolic compounds extracted from Spirulina sp. LEB 18 in latex paint formulations

Commercial paints are produced using components that can be harmful to the environment. In light of this, our study aimed to reduce these drawbacks by investigating water-based paints in which the latex resin (polyvinyl acetate [PVA]) was replaced with poly(3-hydroxybutyrate) (PHB) extracted from Spirulina sp. LEB 18. In addition, C-phycocyanin and phenolic compounds, both also extracted from this microalga, were added to the paints for coloration and antimicrobial properties, respectively. Characterization analyses indicate that paint with 9.2% PHB and 6.1% limonene performs better in the following aspects: density (1.47 g cm−3), solids (41.5%) and pigment contents (38.4%), hiding power (94.2%), abrasion resistance (123 cycles), adhesion (5–15% area removed), drying time (90 min), reflectance (90%), and emissivity (0.80). Moreover, the biocolorant C-phycocyanin, besides conferring color, also provides better coverage by the paints. At a concentration of 0.8%, the phenolic compounds are the most effective among the biocides tested. Overall, we found that it is possible to develop a product similar to commercial ones using natural substances extracted from microalgae, which have not yet been used in formulations of paint. Thus, this study contributes to a sustainable alternative for paint formulation.

Copper-containing glass ceramic with high antimicrobial efficacy

Hospital acquired infections (HAIs) and the emergence of antibiotic resistant strains are major threats to human health. Copper is well known for its high antimicrobial efficacy, including the ability to kill superbugs and the notorious ESKAPE group of pathogens. We sought a material that maintains the antimicrobial efficacy of copper while minimizing the downsides – cost, appearance and metallic properties – that limit application. Here we describe a copper-glass ceramic powder as an additive for antimicrobial surfaces; its mechanism is based on the controlled release of copper (I) ions (Cu1+) from cuprite nanocrystals that form in situ in the water labile phase of the biphasic glass ceramic. Latex paints containing copper-glass ceramic powder exhibit ≥99.9% reduction in S. aureus, P. aeruginosa, K. aerogenes and E. Coli colony counts when evaluated by the US EPA test method for efficacy of copper-alloy surfaces as sanitizer, approaching that of benchmark metallic copper.

Preventive Fungicidal Control of Cytospora leucostoma in Peach Orchards in Colorado.

In western Colorado, Cytospora leucostoma is ubiquitous in peach orchards and has developed into a major limiting factor of peach production. The pathogen is unable to invade healthy intact phloem tissue of the tree, but instead, it requires a wound as a mode of entry. Bark injuries caused by cold and pruning in commercial orchard systems provide infection courts that, in suitable environment conditions, can lead to many successful fungal infections. Preventive fungicide control is an integral component of management in tree fruit production. Eighteen fungicides were tested at selected label dose rates for C. leucostoma control. All treatments were initially tested in vitro in fungicide-amended media dishes. Successful treatments were then tested under controlled conditions on detached peach branch segments. Effective fungicides identified in the laboratory assays (thiophanate-methyl, captan, lime sulfur, and copper hydroxide) were further tested as spray applications in the field and as wound sealant applications in combination with latex paint and kaolin clay. Of the treatments evaluated, thiophanate-methyl, captan, 50% latex paint, thiophanate-methyl amended in 50% latex paint, captan amended in 50% latex paint, and lime sulfur were most effective in reducing C. leucostoma necrotic area. Copper hydroxide was ineffective in all field trials and in some instances, yielded larger necrotic areas than the nontreated positive control shoots.

Applied rheology and architectural coating performance

Paint rheology is understood to play a vital role in both product performance and customer acceptance. Consequently, the ability to formulate paints having the necessary flow properties is essential for paint technologists. Experienced formulators have said that as much as half the cost of new product development can be consumed in getting the rheology right. In fact, the quality-control viscosity measurement devices in everyday use in the development laboratory are of little help in this endeavor. Among other shortcomings, most such instruments apply shear stresses which are far from those involved in important coating flow processes. The rheological properties required for a successful coating must be defined with due regard to the prevailing conditions of stress involved in application and film formation. This requires that measurements should be taken over a wide range of shear stress and timescales. The task for the applied rheologist is to bridge rheology and technology, but it is often unclear how to connect rheological data with the “real-world” performance of paints, due to the complexity of coating flows. This review in part discusses the use of controlled-stress rheometry to characterize coatings, and presents ways of applying the results effectively to the analysis of paint flow. The methodology is fundamental but not unduly time-consuming, since the objective is to provide sound yet timely guidance to formulators. Thirteen commercial semigloss latex paints were analyzed rheologically to develop correlations to paint performance. Using the method of shear stress mapping, key regions of the non-equilibrium flow curve are identified for the control of paint flow processes. With this approach, simple but strong correlations were obtained of paint flow metrics to viscosity chosen at the relevant stresses. The fact of high correlation means one can expect that an appropriate viscosity adjustment will correspondingly improve performance. It is argued that shear stress, not shear rate, is the correct independent variable both for experimentation and for the graphical presentation and analysis of viscosity data. The yield stress parameter, particle flocculation, and sedimentation are also discussed, and an oscillatory shear method of direct measurement of yield stress is described.

Influence of the incorporation of granite waste on the hiding power and abrasion resistance of soil pigment-based paints

The large amount of solid wastes generated in the processing of ornamental stones is a matter of concern for the society. A possible solution is the incorporation of those wastes in civil construction paints, in order to promote improvements in their properties, and contributing to the sustainable development. The purpose of this paper is to study the influence of the granite waste, actuating as mineral filler, on the performance of poly vinyl acetate latex paints produced with soil pigments. It is emphasized that both the materials used and the manufacturing process adopted comply with the requirements of a social technology. To manufacture the paint samples, two types of soils were selected, and an experimental planning of mixtures was defined with varied proportions of soil, granite waste and poly vinyl acetate (PVA) resin. In such planning, the water ratio varied in each mixture in order to keep the viscosity within a constant range, considered ideal to apply the product. Next, experiments were performed to set the hiding power and the abrasion resistance of each mixture. It was verified that, in both types of soils used, the paints presented a better hiding power as the granite waste was added. Such result can be explained by the characteristics of the granite waste that promoted a gradual increase in the solid content of the mixtures. However, the waste and PVA interaction caused a decrease in the abrasion resistance of the paints, which is possibly due to the increase in the roughness of the paint film plus the increase in the pH of the mixture. It was also observed that none of the produced samples simultaneously complied with the hiding power and abrasion resistance of Brazilian standard specifications. The paint film that presented the best performance is constituted by 71% of granite waste and 29% of PVA resin.