Search Results (23)

Water-based (meth)acrylic (co)polymer dispersions are produced on a large scale for various applications including coatings, adhesives, paints, and construction materials. A major benefit of waterborne polymer dispersions as compared to more traditional solvent-based alternatives is the low volatile organic compound (VOC) content, which results in an improved environmental profile. Following the trend of sustainability that has driven the growth of acrylic dispersions, recent research has focused on further enhancing the properties of these products by incorporating biobased materials such as polysaccharides (e.g., cellulose, starch, chitin, and chitosan), and proteins (e.g., casein, soy protein, and collagen). Amongst a large number of benefits, the incorporation of biomaterials can serve to decrease the amount of petroleum-based polymers in the formulation and can also contribute to enhance the physical properties of the resulting bio-composites. In this review, the beneficial role of these biopolymers when combined with waterborne acrylic systems is summarized. Recent advances in the use of these biobased and biodegradable materials are covered, aiming to provide guidance for the development of more sustainable, high-performance latex-based bio-composites with minimal environmental impact. Full article

This work deals with the coating properties of synthetic latices comprising two kinds of polymers, specifically polyacrylate and polypyrrole, which were simultaneously formed by semi-continuous emulsion polymerization using a “one-pot” synthesis strategy. In this procedure, both the emulsion polymerization of acrylate monomers and the oxidative polymerization of pyrrole occurred concurrently in one reactor. Polyacrylate latices differing in polypyrrole loading were prepared by applying various dosages of pyrrole, specifically 0, 0.25, and 0.50, based on the fraction of acrylate monomers. The effect of the in situ incorporated polypyrrole component (having the nature of submicron composite polypyrrole-coated polyacrylate latex particles) on the physico-mechanical properties and chemical resistance of the resulting heterogeneous coating films was investigated. The interaction of incorporated polypyrrole and anti-corrosion pigments (see ZnS, Zn₃(PO₄)₂, ZnFe₂O₄, MoS₂, and ZnO) on the corrosion resistance of coatings was evaluated by using the electrochemical linear polarization technique. The polyacrylate latex prepared with the lowest polypyrrole loading (achieved by polymerizing 0.25 wt. % of pyrrole related to acrylic monomers) was found to be the optimum binder for waterborne anticorrosive coatings based on their properties and protective function. Their compatibility with the selected types of pigments was studied for these latex binders. In addition, their influence on the anti-corrosion efficiency of polyacrylate paint films was evaluated using the linear polarization electrochemical technique. For high corrosion resistance, the ZnS and MoS₂ pigments, showing compatibility with polyacrylate latices containing the polypyrrole component, proved to be advantageous. Full article

In this study, we present the first characterisation of the polyvinyl acetate (PVAc) paints of commercial Spanish brand La Pajarita preserved in the studios of Joan Miró (1893–1983) in Mallorca, Spain. Investigation of several black and white paint samples using complementary analytical techniques (XRD, SEM–EDX, FTIR, and Py–GC–MS) allowed for the identification of pigments and binding media in studio materials, as well as in three artworks dating from the 1970s. Through comparative analysis, it was possible to find significant similarities between the composition of La Pajarita paints conserved in cans in the artist’s studio with black and white painted layers from three artworks by Miró. Miró’s use of La Pajarita paints is extensively documented in studio notes, photographs, and videos, and these paints are known to have been used by other significant Spanish artists. However, their composition has remained largely undiscovered until now. This research contributes to the knowledge of PVAc paints, providing evidence of their use by Joan Miró. The analytical results serve as a valuable reference for comparing and identifying these synthetic paints in other artworks, as well as aiding in attribution or dating studies. Furthermore, the study demonstrates the significance of materials found in artists’ studios as a fundamental resource for identifying the materials present in artworks. Full article

The escalating global emphasis on sustainability, coupled with stringent regulatory frameworks, has spurred the quest for environmentally viable alternatives to petroleum-derived materials. Within this context, the adhesives industry has been actively seeking renewable options and eco-friendly synthesis pathways. This study introduces geraniol, a monoterpenoid alcohol, in its unmodified form, as a key component in the production of waterborne pressure-sensitive adhesives (PSAs) based on acrylic latex through emulsion polymerization. Multiple formulations were developed at varying reaction times. The adhesives underwent comprehensive chemical characterization employing techniques such as Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Nuclear Magnetic Resonance (NMR), Gel Permeation Chromatography (GPC), and dynamic light scattering (DLS). The viscosities of the formulations were measured between 4000 and 5000 cP. Adhesion tests showed peel strength values of 0.52 N/mm on cardboard and 0.32 N/mm on painted steel for the geraniol-based formulations. The results demonstrate the potential for geraniol-based PSAs to offer a sustainable alternative to petroleum-derived adhesives, with promising thermal and adhesive properties. Full article

In 1969, Lynda Benglis withdrew her large latex floor painting, Contraband, from the exhibition Anti-Illusion: Procedures/Materials. Looking beyond the logistical problems that caused Benglis to pull the work, I suggest that it challenged the conceptual and formal parameters of the exhibition from its inception. Taking hints from feminism, modernist painting, camp aesthetics, psychedelic imagery, pop, and minimalism, Benglis’s latex pours unify an array of movements, styles, and political positions that have often been treated as antithetical. Although the refusal of traditional binaries was typical of the neo-avant-garde, Benglis’s work was “contraband” because it challenged the inflexible dictum that feminist art and modernist painting are mortal enemies. With Contraband, she drew on abstract expressionist techniques for communicating feeling by exploiting the dialectic of spontaneity and order in Pollock’s drip paintings. Simultaneously, she drew attention to gender through sexed-up colors and materials. Rather than suggesting that gender difference is repressed by abstract expressionist painting’s false universalizing, Benglis shows that modernist techniques for communicating feeling are crucial for the feminist project of understanding the public significance of seemingly private experience. Full article

Engineered living materials (ELMs) incorporate living material to provide a gain of function over existing materials, such as self-repair. The use of bacteria in ELMs has been studied extensively in concrete, where repair can be facilitated by bacterial ureolytic calcium carbonate (CaCO₃) precipitation; however, the study of bacteria in other construction materials is limited. We examined the ability of bacterial species to survive in common latex binder chemistries, a model paint formulation, and through the film-forming process. The longest survival was by bacterial spores of Bacillus simplex str. GGC-P6A, which survive in latex emulsions, a liquid coating composition, and in a dried film for >28 days. Surprisingly, our data show that non-spore-forming Escherichia coli survive at least 15 days in liquid composition, which appear to be influenced by the composition of the outer membrane, nutrient scavenging, and the ability to metabolize toxic acrylate. Spores of GGC-P6A were shown to grow in solid paint films from sites of damage, resulting in crack filling through carbonate precipitation, demonstrating the potential for self-repair through microbially mediated CaCO₃ precipitation without directed pH modification. These data suggest that a range of bacterial species, in particular members of Bacilli, may facilitate new applications of bio-augmented, self-healing coating systems. Full article

Infrastructure developments in recent decades have led to increasing demand for high-performance paints for construction and decorative purposes. Emulsion paint is water-based paint that is commonly used for coating the internal and external surfaces of a building. The quality and performance of this emulsion paint are highly dependent on its constituent components, such as binders, pigment, solvents, and additives. Emulsion paints initially used conventional formaldehyde-based binders and were, for some reason, prohibited from being used in paints due to health and environmental issues. The development of bio-based paints with natural rubber latex (NRL) has the potential to be developed as an emulsion paint binder. The results showed that NRL grafting of styrene monomer or MMA showed much better resistance to wet scrub and abrasion than PVAc at a monomer concentration of 20%, for styrene, and 30%, for MMA, with washability values reaching each of 11 and 12 cycles at 4% binder concentration. The NgSt20-4 and NgMMA30-4 binders’ abilities to overcome wet scrub and abrasion increased with increasing paint binder concentrations, reaching 22 and 23 cycles at 10% binder concentration. Overall, the combination of NRL grafted with MMA monomer and 30% PVAc showed better performance and could compete with commercial binders such as PVAc. Adding methyl methacrylate monomer increases the adhesion and cohesion properties of the binder and increases the binder’s resistance to scrubbing and wet abrasion. However, the combination of NRL grafted MMA and 30% PVAc showed the same effectiveness as NRL grafted MMA without PVAc, with more economical production costs. Full article

Graphene has stood out in several areas of research. The objective of the present work was an unprecedented study in the production of a commercial wall latex paint with graphene oxide incorporation. The developed paint was assessed by performance tests according to the Brazilian standards, and the characterization was performed using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR), thermogravimetric analysis (TGA), and contact angle analysis. The results indicated that GO addition led to a better dispersion of the paint compound mixture even at very low concentrations (1% and 2%). For the dry and wet paint coverage performance tests, the results were superior, 2% and 9%, respectively, when compared with the paint without GO addition. All performance tests were in accordance with the requirements of the Brazilian standards. Thus, it was concluded that GO-containing paint could be a promising building material to be used as a paint additive obtaining superior properties. Full article

Paints and coatings are required to quickly cure under a broad variety of environmental conditions and deliver solid long-term performance. Achieving a balance during all seasons between quick curing of a coating film, i.e., early rain resistance, while maintaining sufficient workability and open time for an optimized aesthetic appearance is a challenge for the architectural coatings industry. This article describes how the colloidal physics differs between the current standard mechanism to achieve early rain resistance by inhibited coagulants in winter paints and a new mechanism that provides all-season paints. A combination of advanced physical characterization methods, such as electrophoretic mobility, dynamic light scattering and confocal laser scanning microscopy, in combination with application tests, is used to provide a comprehensive mechanism of the early rain resistance achieved by such paints. In addition, it is shown that this new system can be transferred to wood coatings and organic renders. The key finding of this article is that all-season paints combining early rain resistance at cold and damp conditions with open time at high temperatures and dry conditions rely on fast paint film formation with high early integrity rather than coagulants triggered by base evaporation. Full article

Microbiological protection textile materials played an important role in the battle against the epidemic. However, the traditional active antimicrobial treatment of textiles suffers from narrow textile applicability, low chemical stability, and poor washability. Here, a high-strength adhesive nanosilver glue was synthesized by introducing nontoxic water-soluble polyurethane glue as a protectant. The as-prepared nanosilver glue could adhere firmly to the fiber surfaces by forming a flexible polymer film and could encapsulate nanosilver inside the glue. The as-prepared nanosilver had a torispherical structure with diameter of ~22 nm, zeta potential of −42.7 mV, and good dispersibility in water, and it could be stored for one year. Further studies indicated that the nanosilver glue had wide applicability to the main fabric species, such as cotton and polyester fabric, surgical mask, latex paint, and wood paint. The antimicrobial cotton and polyester fabrics were prepared by a simple impregnation–padding–baking process. The corresponding antimicrobial activity was positively correlated with nanosilver content. The treated fabrics (500 mg/kg) exhibited ultrahigh washing resistance (maintained over 99% antibacterial rates for 100 times of standard washing) and wear resistance (99% antibacterial rates for 8000 times of standard wearing), equivalent breathability to untreated fabric, improved mechanical properties, and good flexibility, demonstrating a potential in cleanable and reusable microbiological protection textiles. Full article

Lead in buildings can be found in certain materials such as paints or can be a result of contamination during the use stage. In situ methods for lead identification can be vital for the proper treatment of hazardous CDW (from repair works or selective demolition). A conventional handheld XRF (HHXRF) spectrometer can be used for this purpose, and this study analysed its reliability. A laboratory experiment was conducted to test different calibrations, and to establish a procedure for the conversion of the HHXRF lead concentrations into lead loadings. Model latex paint with a constant lead content was used on two types of surfaces (plasterboard and concrete). A field study was performed to identify and quantify the lead in paint on masonry walls in a public building. ICP-MS analysis was performed in order to verify the lead content. The coefficients of proportionality in the proposed model depend on various parameters: the contamination type, the layer thickness, the substrate, and the built-in calibrations. Despite the limitations of the HHXRF and the discrepancy of the mean lead loadings from the HHXRF and ICP-MS analysis, the HHXRF can be useful for the identification of lead in paint layers up to 1 mm, with a low limit of detection of the order of 0.01 mg/cm² at worst. Full article

The direct use of natural rubber latex (NRL) as a binder for emulsion paints did not produce emulsion paints with good opacity, washability resistance, and regulated touch drying time, even when mixed with polyvinyl acetate (PVAc). This study aimed to study the properties of opacity (hiding power), washability resistance, and set drying touch time of emulsion paint with a binder added from a mixture of modified natural rubber latex (NRL) and PVAc. NRL modifications included UV photodepolymerization with TiO₂ catalyst and grafting copolymerization of methyl methacrylate and styrene (NRL-g-(MMA-co-St)). NRL was mixed with PVAC at ratios of 0/100; 15/85; 25/75; 35/65; 50/50; 100/0% w/w before being used as a binder for emulsion paint. Emulsion paint samples had different binder contents, namely 2, 4, 6, and 8% w/w. Tests on paint samples included opacity using a UV-Vis spectrophotometer (EASYSPEC safas Monaco), washability using the Digital BGD 526 Wet Abrasion Scrub Tester, and drying time set using the ASTM STP500 procedure. The results showed that the opacity (hiding power), washability resistance, and set drying touch time met the emulsion paint standards for all binder levels, except the 100% w/w modified NRL composition. The higher level of NRL in the binder causes these properties to decrease and become unstable. The best opacity (hidden power), washing resistance, and drying touch time were obtained on modified NRL with a concentration of 15% w/w. The binder content in the paint was around 4% w/w, with an opacity of about 1.78% abs, washing resistance of 12 times, and the set drying touch time to 80 min. Full article

Polysaccharide coated nanoparticles represent a promising class of environmentally friendly latex to replace those stabilized by small toxic molecular surfactants. We report here an in situ formulation of free-surfactant core/shell nanoparticles latex consisting of dextran-based diblock amphiphilic copolymers. The synthesis of copolymers and the immediate latex formulation were performed directly in water using a photo-initiated reversible addition fragmentation chain transfer-mediated polymerization induced self-assembly strategy. A hydrophilic macromolecular chain transfer-bearing photosensitive thiocarbonylthio group (eDexCTA) was first prepared by a modification of the reducing chain end of dextran in two steps: (i) reductive amination by ethylenediamine in the presence of sodium cyanoborohydride, (ii) then introduction of CTA by amidation reaction. Latex nanoparticles were then formulated in situ by chain-extending eDexCTA using 2-hydroxypropyl methacrylate (HPMA) under 365 nm irradiation, leading to amphiphilic dextran-b-poly(2-hydroxypropyl methacrylate) diblock copolymers (DH_X). Solid concentration (SC) and the average degree of polymerization -$\overline{X_n}$- of PHPMA block (X) were varied to investigate their impact on the size and the morphology of latex nanoparticles termed here SCDH_X. Light scattering and transmission electron microscopy analysis revealed that SCDH_X form exclusively spherical nano-objects. However, the size of nano-objects, ranging from 20 nm to 240 nm, increases according to PHPMA block length. Full article

This article reports the design and manufacture of colored microcapsules with specific functions and their application in architectural interior wall coating. Utilizing reactive dyes grafted SiO₂ shell to encapsulate paraffin through interfacial polymerization and chemical grafting methods, this experiment successfully synthesized paraffin@SiO₂ colored microcapsules. The observations of surface morphology demonstrated that the colored microcapsules had a regular spherical morphology and a well-defined core-shell structure. The analysis of XRD and FT-IR confirmed the presence of amorphous SiO₂ shell and the grafting reactive dyes, and the paraffin possessed high crystallinity. Compared with pristine paraffin, the thermal conductivity of paraffin@SiO₂ colored microcapsules was significantly enhanced. The results of DSC revealed that the paraffin@SiO₂ colored microcapsules performed high encapsulation efficiency and desirable latent heat storage capability. Besides, the examinations of UV-vis and TGA showed that the paraffin@SiO₂ colored microcapsules exhibited good thermal reliability, thermal stability, and UV protection property. The analysis of infrared imaging indicated that the prepared latex paint exhibited remarkable temperature-regulated property. Compared with normal interior wall coatings, the temperature was reduced by about 2.5 °C. With such incomparable features, the paraffin@SiO₂ colored microcapsules not only appeared well in their solar thermal energy storage and temperature-regulated property, but also make the colored latex paint coating have superb colored fixing capabilities. Full article

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. Full article