Search Results (165)

Background/Objectives: Early gut colonization by bifidobacteria, occurring more favorably in vaginally born infants than in those delivered via C-section, is crucial for maintaining overall health. The study investigated the health-promoting properties of Limosilactobacillus vaginalis BC17 both as viable cells and as postbiotics (i.e., cell-free supernatant and heat-killed cells), with the purpose of developing oral formulations to support intestinal health. Methods: The safety, effects on the adhesion of bifidobacteria and enteropathogens to intestinal cells, and anti-inflammatory properties of L. vaginalis BC17 viable cells and postbiotics were evaluated. Fast-disintegrating tablets were formulated by freeze-drying cell-free supernatant in combination with heat-killed or viable cells alongside maltodextrins. Results: The formulations were shown to be non-genotoxic and compatible with intestinal cell lines (Caco-2 and HT-29). BC17 viable cells survived in co-culture with intestinal cells up to 48 h and exhibited moderate adhesion to the cell lines. Notably, both BC17 viable cells and postbiotics enhanced the adhesion of beneficial bifidobacteria to Caco-2 cells by up to 250%, while reducing enteropathogens adhesion by 40–70%. Moreover, they exerted significant anti-inflammatory effects, reducing nitric oxide production in macrophages by 40–50% and protecting intestinal cells from SDS-induced damage. The formulations allowed administration of at least 10⁹ BC17 cells in infants and adults through easy and rapid dispersion in milk or water, or directly in the oral cavity without chewing, and preserved their functional properties for up to 3 months of storage. Conclusions: L. vaginalis BC17 viable cells and postbiotics, as well as fast-disintegrating tablets, showed promising functional and safety profiles. Although further in vivo validation is needed, this approach represents a compelling strategy for promoting gut health. Full article

In order to cope with the emergence of energy conservation and consumption reduction initiatives, we used an acrylic emulsion (as the adhesive), combined with silica aerogel (SA) and hollow glass microsphere (HGM) fillers, to synthesize thermal insulation coatings, which were found to have low thermal conductivity and excellent thermal insulation properties. These waterborne coatings are environmentally friendly and were synthesized without organic solvents. Comprehensive testing verified that the coatings met practical requirements. Specifically, the addition of 18% SA resulted in minimal thermal conductivity (0.0433 W/m·K), the lowest density (0.177 g/cm³), as well as a reduced gross calorific value. At a heating surface temperature of 200 °C, the 5 mm coating’s cooling surface temperature was 108.7 °C, yielding a 91.3 °C temperature difference and demonstrating remarkable thermal insulation performance. Furthermore, the coatings showed favorable results in terms of water resistance, corrosion resistance, wear resistance, and adhesion, achieving satisfactory engineering standards. In this work, the influence of different contents of SA on various properties of the coating was studied, with the aim of providing a reference for the modulation of the comprehensive performance of SA thermal insulation coatings. Full article

To obtain waterborne polymer-modified emulsified asphalt materials with better comprehensive performance, waterborne polymer modifiers including waterborne epoxy resin (WER)-reinforced styrene–butadiene–styrene block copolymer (SBS), waterborne acrylate (WA) or styrene butadiene rubber (SBR) emulsion were prepared. The mechanical strength, toughness, adhesion and impact resistance of these waterborne polymers were evaluated. Furthermore, the correlation between the performance indicators of the waterborne polymers was analyzed. Based on Fourier transform infrared (FTIR) spectroscopy and thermogravimetric (TG) analysis, the mechanism of WER-modified SBS and WA was characterized. The results show that adding 10%–15% WER can significantly improve the mechanical properties of the waterborne polymer. The performances of modified SBS and WA are better than that of modified SBR. When the content of WER is 10%, the tensile strength, elongation at break and pull-off strength of WER-modified SBS and WA are 4.80–6.38 MPa, 476.3%–579.6% and 1.62–1.70 MPa, respectively. The mechanical strength and breaking energy of the waterborne polymers show a significant linear correlation with their application properties such as adhesion, bonding and impact resistance. FTIR and TG analyses indicate that WER-modified SBS or WA prepared via emulsion blending undergo primarily physical modifications, enhancing thermal stability while promoting crosslinking and curing. Full article

To address the deficiencies of traditional emulsified asphalt-pavement maintenance material in cohesive strength, high-temperature rutting resistance, as well as adhesion to aggregates, this study developed waterborne epoxy resin-modified emulsified asphalt (WEA) binders using a two-component waterborne epoxy resin (WER) and systematically investigated their modification mechanisms and pavement performance. The results indicated that WER emulsions and curing agents could polymerize to form epoxy resin within the emulsified asphalt dispersion medium, with the modification process dominated by physical interactions. When the WER content exceeded 12%, a continuous modifier network structure was established within the emulsified asphalt. The epoxy resin formed after curing could significantly increase the polarity component of the binder, thereby increasing the surface free energy. The linear viscoelastic range of the WEA binder exhibited a negative correlation with the dosage of the WER modifier. Notably, when the WER content exceeded 6%, the high-temperature stability (rutting resistance and elastic recovery performance) of the binder was significantly enhanced. Concurrently, stress sensitivity and frequency dependence gradually decrease, demonstrating superior thermomechanical stability. Furthermore, WER significantly enhanced the interfacial interaction and adhesion between the binder and aggregates. However, the incorporation of WER adversely affects the low-temperature cracking resistance of the binder, necessitating strict control over its dosage in practical applications. Full article

Antibacterial microcapsules were prepared by using a compound of chitosan with an antioxidant of bamboo leaves (AOB) as the wall material and tung oil as the core material. The microcapsules were modified by adding them to waterborne coatings, and the modified waterborne coatings were coated onto Basswood samples. The performance of the obtained coatings was then characterised through a comparative analysis. The investigation focused on the effect of varying percentages of chitosan and AOB in microcapsules with a constant core-to-wall ratio on the performance of the waterborne on the surface of Basswood. The core-to-wall ratio of the microcapsules was established at 1:2, with the ratios of chitosan and AOB in the walls fixed at 9:1, 8:2, and 7:3, respectively. The results demonstrated that the gloss, impact resistance, and hardness of the coatings exhibited an increase with increasing ratios of AOB under varying M_chitosan:M_AOB (M_C:M_A) conditions. Conversely, the adhesion exhibited a decrease with an increase in AOB. The colour difference value exhibited minimal change. The self-healing rate of the coating exhibited an initial increase, followed by a subsequent decrease, in response to the increasing AOB concentration. The antimicrobial effect was optimised at a ratio of 9:1 for the combination of chitosan and AOB. The coating of Basswood containing 1.0% microcapsules and 9:1 M_C:M_A demonstrated superior performance, exhibiting a gloss of 9.7 GU, a colour difference ΔE of 31.03, a hardness of HB, an adhesion rating of grade 1, an impact resistance of grade 4, a self-healing rate of 19.09%, and a noteworthy antimicrobial effect against both Escherichia coli and Staphylococcus aureus. Full article

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

With increasing service life, concrete durability gradually deteriorates, requiring urgent repair and reinforcement. Conventional cement-based repair materials exhibit disadvantages such as high brittleness, low tensile strength, poor adhesion, and insufficient durability, making them inadequate for high-quality structural repairs. Based on the molecular structure–activity relationship, this study developed a novel waterborne epoxy–cement-based composite repair material using self-synthesized waterborne epoxy resin (WEP). The mechanism by which WEP improves the performance of cement-based materials was elucidated. The results indicate that WEP significantly influenced the early formation of silicate crystals. Furthermore, the addition of WEP enhanced material flexibility and adhesion, achieving flexural strength of 12.9 MPa and direct tensile bond strength of 2.13 MPa at 28 days, representing increases of approximately 30% and 58%, respectively, compared to the control group. Stress–strain curve analysis revealed that the ultimate strain of WEP-modified cement mortar reached 0.024%. SEM analysis revealed that cured WEP formed a dense cross-linked network with cement hydration products. This microstructural modification refined the pore structure, effectively addressing the material’s brittleness, ductility, and durability limitations. Full article

The increasing demand for sustainable materials in the coatings industry is driving the replacement of synthetic components with bio-based alternatives. In this study, Tagua powder, derived from the seeds of Phytelephas macrocarpa, was incorporated as a filler in a waterborne acrylic-based coating to evaluate its effects on abrasion and protective properties. Two different particle size ranges (40–63 µm and ≤40 µm) and concentrations (1 wt% and 3 wt%) were tested. Morphological analyses confirmed a homogeneous dispersion of the filler within the coating matrix, with larger particles inducing surface roughness. The results demonstrated that the addition of Tagua powder significantly improved abrasion resistance, with the coating containing 3 wt% of larger particles (40–63 µm), reducing mass loss by 24.5% after 1000 Taber abrasion cycles compared to the reference coating. However, due to its lignocellulosic nature, the filler increased water uptake, leading to a decrease in barrier properties. Coatings with 3 wt% filler exhibited a reduction in electrochemical impedance modulus by approximately one order of magnitude after 670 h of immersion in a 3.5 wt% NaCl solution, indicating lower corrosion protection. Despite this, the performance in filiform corrosion resistance remained comparable to the reference, suggesting that Tagua powder does not critically affect adhesion properties. These findings highlight the potential of Tagua powder as a functional bio-based filler, offering enhanced mechanical durability while requiring a strategic coating design, such as a multilayer system, to mitigate moisture sensitivity. This study provides valuable insights into the development of environmentally friendly coatings with improved wear resistance. Full article

Recent advancements in polymer materials have enabled the synthesis of bio-based monomers from renewable resources, promoting sustainable alternatives to fossil-based materials. This study presents a novel zwitterionic surfactant, SF, derived from 10-undecenoic acid obtained from castor oil through a four-step reaction, achieving a yield of 78%. SF has a critical micelle concentration (CMC) of 1235 mg/L, slightly higher than the commercial anionic surfactant Rhodacal DS-4 (sodium dodecyl benzene sulfonate), and effectively stabilizes monomer droplets, leading to excellent conversion and stable latex formation. The zwitterionic groups in SF enhance adhesion to hydrophilic substrates (glass, stainless steel, and skin). Films produced with SF exhibit outstanding water resistance, with only 18.48% water uptake after 1800 min, compared to 81% for the control using Rhodacal DS-4. Notably, SF maintains low water uptake across various concentrations, minimizing water penetration. Thus, the synthesized SF demonstrates improved adhesive properties and excellent water resistance in emulsion polymerization applications, highlighting its potential as a sustainable, high-performance alternative to petrochemical surfactants. Full article

In research aimed at improving the brittleness of WER (waterborne epoxy)-modified emulsified asphalt, commonly encountered issues are that the low-temperature performance of this type of asphalt becomes insufficient and the long curing time leads to low early strength. Matrix-emulsified asphalt was modified with WPU (waterborne polyurethane), WER, and DMP-30 (accelerator). Firstly, the performance changes of modified emulsified asphalt at different single-factor dosages were explored through conventional performance tests and assessments of its adhesion, tensile properties, and curing time. Secondly, based on a response surface methodology test design, the material composition of the composite-modified emulsified asphalt was optimized, and its rheological properties were analyzed by a DSR test and a force–ductility test. Finally, the modification mechanism was explored by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The results show that WER can improve the adhesion strength of modified emulsified asphalt and greatly reduce elongation at break. WPU can effectively improve the elongation at break of composite-modified emulsified asphalt, but it has a negative impact on adhesion strength. DMP-30 mainly affects the curing time of modified emulsified asphalt; EPD (composite modification) can effectively improve the high-temperature rutting resistance of matrix-emulsified asphalt, and its low-temperature performance is significantly improved compared with WER-modified emulsified asphalt. The EPD modification process mainly consists of physical blending. In the case of increasing the curing rate, it is recommended that the contents of WER and WPU be lower than 10% and 6%, respectively, to achieve excellent comprehensive performance of the composite modification. Full article

Eco-friendly waterborne coatings frequently exhibit poor corrosion resistance, high solvent content, and extended curing times, attributed to the excessive employment of hydrophilic groups and petroleum-derived polyols. In this work, aniline trimer (ACAT) and polyethylene glycol (PEG) were used as chain extenders. E-44 epoxy resin was subsequently utilized to modify the system and an aniline trimer-modified waterborne polyurethane (AT-WPU) dispersion was prepared and characterized. The chemical structure of the synthesized ACAT was characterized employing 1H NMR, ESI-MS, and FTIR spectroscopy. The structure and coating performance of the AT-WPU dispersion were investigated utilizing FTIR, particle size analysis, thermogravimetric analysis, DSC, TEM, SEM, and electrochemical corrosion testing. The results demonstrate that the aniline trimer-modified waterborne polyurethane dispersion was successfully synthesized. Additionally, the DSC analysis results and thermogravimetric graphs indicate that the glass transition temperature and thermal stability of the coatings increased with the addition of aniline trimer. As the aniline trimer content increased, the hardness and adhesion of the coatings were significantly enhanced. In the electrochemical corrosion assessment, the corrosion current density of AT-WPU-3 attained 7.245 × 10⁻⁹ A·cm⁻², and the corrosion rate was as low as 0.08 μm·Y⁻¹, indicating excellent corrosion resistance. The present study provides promising practical applications in the domain of metal material protection. Full article

This study explores the use of cellulose nanofiber (CNF)-stabilized Pickering emulsions for paper coatings, focusing on their rheological properties and effects on hydrophilicity and water vapor transmission rate (WVTR). Two types of Pickering emulsions, oil-in-water (O/W), were stabilized with 1 wt% CNF extracted from fique by-products. The oily phases of the emulsions were composed of poly(lactic acid) (PLA) and cocoa butter (CB). The physical stability, viscosity, and viscoelasticity of the emulsions were characterized. The emulsions were applied to the surfaces of Bond and Kraft papers using the rod-coating method. The coating process involved first applying a layer of the PLA emulsion followed by a layer of the CB emulsion. The coated papers were then evaluated by FE-SEM, contact angle, adhesion work, and water vapor transmission rate (WVTR). The results indicated that the coatings effectively produced a slightly hydrophobic surface on the papers, with contact angles approaching 90°. Initially, Kraft paper exhibited a WVTR value of 29.20 ± 1.13 g/m²·h, which significantly decreased to 7.06 ± 2.80 g/m²·h after coating, representing a reduction of 75.82%. Similarly, natural Bond paper showed a WVTR value of 30.56 ± 0.34 g/m²·h, which decreased to 14.37 ± 5.91 g/m²·h after coating, indicating a reduction of 47.02%. These findings demonstrate the potential of CNF-stabilized Pickering emulsions for enhancing the performance of paper coatings in terms of hydrophobicity and moisture barrier properties. The approach of this study aligns with global sustainability goals in packaging materials combining the use of PLA and CB to develop a waterborne coating to enhance the moisture barrier properties, demonstrated by a substantial reduction in water vapor transmission rates, and an improved hydrophobicity of coated papers. 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 saline soil areas, the concrete piers of concrete bridges experience long-term corrosion, mainly caused by chloride salts due to alternating temperature changes. Waterborne concrete coatings are prone to failure in this aggressive salt environment. Implementing coating protection measures can improve the durability of concrete and enhance the service life of bridges. However, the effectiveness and longevity of coatings need further research. In this paper, three types of waterborne concrete anti-corrosion coatings were applied to analyze the macro and micro surface morphology under wet–dry cycles and long-term immersion conditions. Various indicators such as glossiness, color difference, and adhesion of the coatings were tested during different cyclic periods. The chloride ion distribution characteristics of the buried concrete coatings in saline soil, the macro morphology analysis of chloride ion distribution regions, and the micro morphology changes of the coatings under different corrosion times were also investigated. The results showed that waterborne epoxy coatings (ES), waterborne fluorocarbon coatings (FS), and waterborne acrylic coatings (AS) all gradually failed under long-term salt exposure, with increasing coating porosity, loss of internal fillers, and delamination. The chloride ion content inside the concrete decreased with increasing depth at the same corrosion time, while the chloride ion content at the same depth increased with time. The chloride ion distribution boundary in the cross-section of concrete with coating protection was not significant, while the chloride ion distribution boundary in the cross-section of untreated concrete gradually contracted towards the concrete core with increasing corrosion time. During the corrosion process in saline soil, the coatings underwent three stages: adherence of small saline soil particles, continuous increase in adhered material area, and multiple layers of uneven coverage by saline soil. The failure process of the coatings still required erosive ions to infiltrate the surface through micropores. The predicted lifespans of FS, ES, and AS coatings, obtained through weighted methods, were 2.45 years, 2.48 years, and 2.74 years, respectively, which were close to the actual lifespans observed in salt environments. The developed formulas effectively reflect the corrosion patterns of different resin-based coatings under salt exposure, providing a basis for accurately assessing the corrosion behavior and protective effectiveness of concrete under actual environmental factors. Full article

Conventional waterborne polyurethane (WPU) has poor water resistance and poor overall performance, which limits its application in outdoor coatings. A solution to this problem is urgently needed. The introduction of fluorine-containing groups can effectively improve the water resistance of WPU. In this study, a new fluorinated chain extender (HFBMA-HPA) synthesized by free radical copolymerization and epoxy resin (E-44) were used to co-modify WPU, and five waterborne fluorinated polyurethane (WFPU) emulsions with different fluorine contents were prepared by the self-emulsification method. The effects of HFBMA-HPA content on the emulsion particle properties, coating surface properties, mechanical properties, water resistance, thermal stability, and corrosion resistance were investigated. The results showed that the WFPU coating had excellent thermal stability, corrosion resistance, and mechanical properties. As the content of HFBMA-HPA increased from 0 wt% to 14 wt%, the water resistance of the WFPU coating gradually increased, the water contact angle (WCA) increased from 73° to 98°, the water absorption decreased from 7.847% to 3.062%, and the surface energy decreased from 32.8 mN/m to 22.6 mN/m. The coatings also showed impressive performances in the adhesion and flexibility tests in extreme conditions. This study provides a waterborne fluorinated polyurethane material with excellent comprehensive performance that has potential application value in the field of outdoor waterproof and anticorrosion coatings. Full article