High Weather Resistance Research Articles

ITO/Cu-mesh transparent conductive film with high weather resistance and electromagnetic interference shielding effectiveness

ITO/Cu-mesh transparent conductive film with high weather resistance and electromagnetic interference shielding effectiveness

Compartmentalization into Outer and Inner Shells of Hollow Nanospheres for Antibiosis Based on Chemistry and Physical Damages.

There is a substantially ascending demand for nonantibiotic strategies to overcome the resistance of bacterial infections. Here, the discovery of a distinctive antibacterial structure is reported. The novel structure of nanoparticle strategy is proposed for appreciable bacteria killing by the smart design of the delayed addition of crosslinkers into the reaction mixture. [2-(methacryloyloxy)ethyl]trimethylammonium chloride solution (MTCl), a water-soluble ionic liquid (IL), has narrow-size material distribution, good whiteness, and high weather resistance. The quaternary ammonium salt is utilized to efficiently permeate cell membranes through electrostatic interaction, accordingly, boasting a beneficiary of antibacterial properties. More importantly, it allows bacteria to attach the nanomaterials easily, especially the double-shelled nanosphere. In light of the introduction of 9-amino(9-deoxy)ep-quinine (QNNH2) on its inner shell, it blocks the nucleic acid and glucose metabolism in bacteria, which is betterment of the antibacterial activity of double-shelled structure nanoparticle compared to other structure of nanomaterials. This physical/chemical/biological triple antibacterial process eliminates the need for traditional antibiotics, and the fabrication strategies and material properties described here provide insights into the design of antibacterial nanomaterials based on chemical and physical effects.

A dual-selective thermal emitter with enhanced subambient radiative cooling performance

Radiative cooling is a zero-energy technology that enables subambient cooling by emitting heat into outer space (~3 K) through the atmospheric transparent windows. However, existing designs typically focus only on the main atmospheric transparent window (8–13 μm) and ignore another window (16–25 μm), under-exploiting their cooling potential. Here, we show a dual-selective radiative cooling design based on a scalable thermal emitter, which exhibits selective emission in both atmospheric transparent windows and reflection in the remaining mid-infrared and solar wavebands. As a result, the dual-selective thermal emitter exhibits an ultrahigh subambient cooling capacity (~9 °C) under strong sunlight, surpassing existing typical thermal emitters (≥3 °C cooler) and commercial counterparts (as building materials). Furthermore, the dual-selective sample also exhibits high weather resistance and color compatibility, indicating a high practicality. This work provides a scalable and practical radiative cooling design for sustainable thermal management.

Influence of particle size distribution on biocarbonation method produced microbial restoration mortar for conservation of sandstone cultural relics

Biocarbonation of reactive magnesia based on microbially induced carbonate precipitation (MICP) process is a sustainable geotechnical reinforcement technology for strength development and permeability reduction. This method can be used to produce microbial restoration mortar (MRM) for the application of stone cultural relics restoration. In this paper, the influence of particle size distribution on the strength and porosity of MRM was examined. By mixing fine and coarse sandstone powder in various proportions, nine different particle size distributions were obtained to investigate the restoration performance, including the unconfined compressive strength (UCS), porosity, and color difference. The results indicate that the well-graded particle size distribution can lead to the UCS improvement and porosity reduction of MRM. The findings also imply that adding fine sandstone powder to the coarse sandstone powder can provide extra bridging contacts within the soil matrix. These bridging contacts can be easily connected by the precipitated hydrated magnesium carbonates (HMCs) minerals, consequently resulting in more effective bonding and filling within the pore matrix. The microstructural images of MRM confirm the formation of HMCs, which exhibited a dense network structure, filling out the gap and bonding the sandstone powders. Furthermore, the microbial restoration mortar showed a high weather resistance to dry-wet cycles, acid rain, and salt attack, which is attributed to better stability and strength of HMCs than the original calcic cemented minerals in sandstone.

Investigating the strength and durability properties of alkali activated red mud for tailings pond embankment material

This article investigates the applicability of alkali-activated red mud (RM) as a geo-material for the construction of tailings pond (TP) embankments. A series of unconfined compressive strength (UCS) and direct shear tests (DST) are carried out to examine the mechanical performance of RM activated with sodium hydroxide (NaOH). While doing so, the influence of NaOH concentrations, curing conditions and curing period are also investigated. Furthermore, durability tests are performed to examine the weathering resistance of stabilized RM specimens against extreme environmental conditions. Finally, the effectiveness of alkali activated RM (as an embankment material) is demonstrated with the help of numerical analysis performed on a model TP. Based on the experimental results, the compressive strength of bare RM is improved from 0.34 MPa to 5.6 MPa, 0.57 MPa to 10.55 MPa and 0.97 MPa to 29.34 MPa under controlled ambient curing (CAC, 25±2 °C), open air curing (OAC, 25±7 °C) and dry curing (DC, 60 °C) conditions respectively. On the other hand, effective friction angle and cohesion of bare RM is found to increase from 16.76° to 52.85° and 6.58 kPa to 391.11 kPa respectively, after alkali activation. Furthermore, alkali activated RM specimens exhibit a significantly high weathering resistance than bare RM against 12 cycles of alternate wetting and drying. The numerical analysis reveals a notable increase in the factor of safety values when alkali activated RM is utilized for the construction of TP, indicating its potential as an embankment material.

Design of core-shell SiO2 nanoparticles to create anti-reflection and anti-fouling coatings for solar cells

Amphiphobic coatings with the anti-reflective property offer a promising strategy to mitigate the degradation of photovoltaic conversion efficiency in solar cells caused by fouling and reflection of incident light. Despite advancements in developing transparent and liquid-repellent coatings, achieving integration of both properties still poses a significant challenge. In this work, a unique nanostructure coating with extremely low roughness and surface energy is constructed by integrating fluorinated cluster core-shell structured silicon sols (BASSF) into a self-made silicon precursor (SP) using a template-free two-step base/acid-catalyzed reaction. The exceptional anti-fouling performance of the S-P@BASSF coating is a result of the chemical inertness of the polymer and the unique structure of the sol-gel particles. This innovative approach provides a potential solution for fabricating high-performance coatings and materials. The coating is capable of recovering to 97 % of its initial efficiency swiftly, even after severe dust contamination. The coating exhibits remarkable anti-reflective property due to the combination of sol particles with varying refractive indices. The coating also displays high weathering resistance, maintaining contact angles with water (≥105°) and diiodomethane (≥85°) even after prolonged exposure to UV lamps, high temperature and high humidity weather. The results obtained in this study show that nanocomposite coatings via the preparation of smooth, high refractive index and low reflectivity have great potential for outdoor applications such as energy harvesting and optical instruments under wet conditions.

The influence of anhydrite III as cement replacement material in production of lightweight masonry blocks for unreinforced non-load bearing walls

Lightweight cellular hollow concrete (LCHC) block is a type of masonry unit that has excellent thermal and acoustic performance, fire resistance and high weathering resistance, and manufactured by precast technique. This work presents an experimental study, which investigates the effects of volumetric partial replacement of Portland cement by calcium sulfate anhydrite on precast properties, especially hardening time of the products, thermal insulation properties and mechanical properties of the blocks. LCHC block is produced by the mixing of Portland cement (PC), anhydrite III (ANH), expanded perlite (EP), pumice (PU) and calcite (CA) for building applications. The physical and mechanical properties of LCHC blocks having various replacement levels of ANH are studied. Experimental studies were carried out on both 10x10x10 cm3 cube specimens and 19x19x39 cm3 block specimens. In this research work, LCHC blocks with 16 different mixture batches were cast into a mould with vibro-compacting, de-moulded immediately and transferred to a storage area for curing up to 28 days in normal air condition. The unit weights and compressive strengths of the cube specimens decreased as the ANH replacement level increased, depending on the decrease in the cement ratio. However, it was observed that the compressive strength of the block specimens increased up to the volumetric replacement level of 1.86 %. As expected, the thermal conductivity values of the specimens decreased with the decrease in unit weight. The most notable change on the specimens occurred in the hardening time. The hardening process of the specimens can be completed up to 90 times faster than the control mixture. In addition, within the scope of the study, three formulations are presented in which the compressive strength and the elastic modulus of the wall sections made with LCHC blocks can be calculated, and thermal conductivity value of masonry block unit can be calculated.

Application of Chemical Technology of Water-Based Acrylic Dipping Paint in Art Painting Creation

In order to better sort out the superiority of water-based acrylic in painting art, explore and understand the uniqueness of water-based acrylic painting materials and apply this to art creation. The author proposes a chemical process based on water-based acrylic dipping paint, by discussing the coating and film properties of water-soluble acrylic dip paint, combined with the practical application of a casting tank; summarizing the countermeasures to solve the disadvantages of common paint films; and proving that the paint has a good comprehensive performance by comparing with other dipping paints. Experimental results show that based on the chemical process of water-based acrylic dipping paint, it has waterproof, high gloss, gloss retention, color retention, high weather resistance, and good corrosion resistance in the process of art painting; the physical parameters are better than other dipping paints, such as gloss can reach 70∼80%. Conclusion. In art painting, water-based acrylic dip paint is a kind of comprehensive performance paint with waterproof, high gloss, gloss retention, and color retention.

Self-Healing Behaviors of Core–Shell-Structured Microcapsules Cement-Based Materials Immobilized with Microbes by Expanded Perlite

To improve the weather resistance of Bacillus mucilaginous L3 in cement-based materials, we used the expanded perlite as an immobilization carrier of B. mucilaginous L3, and prepared core–shell-structured microcapsules using a metakaolin-sodium silicate mixed solution as the coating shell. Such immobilization by microcapsules can ensure the high weather resistance of B. mucilaginous L3 in cement-based materials, and was characterized by relevant methods. The cement-based materials containing self-healing microcapsules demonstrated high weather resistance, and can heal the largest cracks width of 0.85 mm. The expanded perlite offered the microbes with attachment sites and a survival and protection space. The self-healing grains coated with high-activity metakaolin can contact well with the substrate in the concrete, which showed excellent integrity. The minerals separated out by the self-healing microbes were high-purity calcite-like calcium carbonate and exhibited high healing ability.

Advantage analysis of aluminum honeycomb composite used in motorhomes

In the light weight, high weather resistance and environmental protection requirements of the panel used for the motorhome, aluminum honeycomb composite, new material with mature the quality improvement and material upgrading of the panel used for the motorhome. In this paper, the existing problems of the panel used for the motorhome and the properties of aluminum honeycomb composite are discussed, the advantages of applying aluminum honeycomb composite to the board of the motorhome are analyzed. The application of aluminum honeycomb composite materials to motorhomes will meet the requirements for improving the quality of panels, such as reduced in weight, environmentally friendly, non-combustible, recyclable, improved weather resistance and increased service life.

Development of value‐added polyethylene grades with extended service lifetime: Weathering resistant flame retarded materials for outdoor applications

AbstractThe current article deals with the development of different novel, tailor‐made polyolefin formulations exhibiting both low flammability and high weathering resistance, so as to provide value‐added polyethylene grades with extended service lifetime. Two low‐density (LDPE) and one linear low‐density (LLDPE) polyethylene grades were modified via melt compounding with an additive system comprising: (a) a nitrogen‐phosphorous intumescent system for flame retardance and (b) a hindered amine light stabilizer and a benzophenone‐type UV absorber for UV/heat stabilization, at a total loading of 30–35 wt%. The target was to reach V0 classification in UL94V flammability tests, while to a large extent maintaining the mechanical properties, such as, tensile and impact strength of the investigated polymers, thus ensuring that the additives do not interfere significantly with the material quality. Subsequently, the compounds were subjected to separate artificial UV and heat aging at 100°C for 1500 h; the formulations showed good flame retardance, even after prolonged artificial weathering, but there was an observable, although acceptable, decrease in the mechanical properties. Nevertheless, all the results show that the developed polyethylene compounds are very promising for outdoor applications, such as, irrigation piping and profiles, where long‐term weathering stability is important, and where flame retardance is important for safety during storage.

Ag-doped phosphate glass with high weathering resistance for RPL dosimeter

Ag-doped phosphate glass employed in the commercial dosimeter named FD-7 is used globally as one of the most reliable dosimeter materials. The luminescence phenomenon is well known as radiophotoluminescence (RPL). In this work, a new RPL glass material was developed for dosimeters that are used under high humidity conditions. The glass material that contains Ag2O as an activation center was produced by the melt-quenching method. The radiation properties and the optimal amount of Ag2O concentration required for achieving the best performance of the glass were evaluated using the RPL read-out system employing the photon counting method. On exposure to UV laser light radiation, the new RPL glass developed in this work emitted light of an approximate wavelength of 650 nm after radiation exposure, and the RPL intensity was proportional to the exposed dose. In addition, the glass material exhibited high reusability owing to the repeated operation of irradiation and reset. On conducting the weathering resistance test for a long duration, it was found that the new RPL glass exhibited the same RPL intensity and appearance as its initial values.

Влияние окружающей среды влажных субтропиков на цветовые характеристики защитных полимерных покрытий

To increase the reliability and durability of structures and equipment, various protection methods are used, the most common of which is the application of protective and decorative polymer coatings. The surface layers of the coatings are most sensitive to external factors. The processes occurring in these layers are one of the main reasons for the change in decorative properties, including color indicators. At the same time, high weather resistance of the outer layer provides enhanced protective properties of the entire paint system. The paper studies the persistence of color indicators of various polymer coatings in a subtropical climate, characterized by high aggressiveness of the factors. Using instrumental methods for field exposure of samples in an open atmospheric area for 2.5 years, the colorimetric indicators in the CIELAB system and their color difference between the initial state and after aging were determined. The test samples were exhibited on the coastal test site on the Black Sea coast in the Imereti Lowland at Cape Imeretinsky (43o23′ N, 39o59′ E) 40 meters from the water edge. The tests were carried out on open atmospheric stands at an angle of 45o to the horizon with the control of the environmental parameters during the exposure of the samples. High color stability was shown by the coatings of the fluoroplastic group – enamel Viniftor and VE-46, while the worst performance was shown by perchlorovinyl enamel XV-518. The results of such studies under natural conditions are most valuable for a comparative assessment of the effectiveness of the protective and decorative properties of coatings.

Modeling of thermal conductivity of reed products

The present work researches processes of heat transfer by samples of mats manufactured from reed. Due to the unique properties of the reed, such as medium density, low thermal conductivity, relatively high weather resistance, high chemical resistance, possibility to produce parts on-site, cost-effectiveness and others, reed products are widely used in building construction despite the high rate of development of new technologies. The mechanisms of heat insulation in the result of energy transfer through the material are established, which makes it possible to influence this process. It is proven, that the mechanisms are conditioned upon the increased porosity of the material. Thus, decreasing volume weight results in decreasing thermal conductivity, and vice versa. The simulation of the heat transfer process with the flameproof coating is carried out, the dependencies of the thermophysical coefficients on the temperature are determined. Based on the obtained dependencies, the coefficient of thermal conductivity for the products made of dry pine wood is calculated and makes 0.056 W / (m · K). Features of slowing down the process of heat transfer to material made of wood wool and glue binding agent with the formation of pores were studied. This is explained by the fact that there is no movement of air in large pores, accompanied by heat transfer. Thus, there are grounds to argue for the possibility of directed regulation of the processes of the formation of thermal insulation products using the reeds characterized by voids in the stems.

Bright Yellowish-Red Pigment Based on Hematite/Alumina Composites with a Unique Porous Disk-like Structure.

Inspired by a bacteriogenic, iron-based oxide material and a traditional Japanese red pigment, a bright yellowish-red pigment was prepared by heating an Al-containing iron oxyhydroxide precursor. The obtained red pigment had a unique porous disk-like structure, comprising Al-substituted hematite particles and crystalline alumina nanoparticles. Although these disk-like structures loosely gathered to form an aggregate in powder, they can be easily dispersed into a single, disk-like structure by simple ultrasonic irradiation. The powder exhibited a bright yellowish-red color and high thermostability, making it attractive as a coloring material for various industrial products needing a bright-red color, high weather resistance, and durability. Quantitative color measurements revealed extremely high L*, a*, and b* values that are much greater than those of commercially available hematite. The thermostability test showed that even after exposure to high temperatures, the pigment retained the red color, indicating its high thermostability. The unique microstructure should be strongly related to the bright yellowish-red color and the high thermostability of the developed red pigment.

A review on weldability of additive manufactured titanium alloys

The Additive manufacturing technologies familiarize many innovative and monetary gains when compared to conservative subtractive manufacturing methods in rapid prototyping (RP) and small production capacity. In other exceedingly industrialized fields including aerospace, automobile, and bio-medical industries, additive manufacturing has turned out to be a subject of high interest. Nowadays, Additive manufacturing (AM) of Titanium alloys has grown into an imperative field of study. The foremost prominence of Titanium alloys is excellent strength to weight ratio, high weathering resistance, and admirable characteristics involving high tensile strength and toughness with comparatively low electrical and thermal conductivity. The manufacturing of Titanium through AM technology is marginally expensive and durable as it enables to create freedom in design community to fabricate user defined and complex structures which is hard to produce through other conventional manufacturing methods. The Ti-6Al-4V alloy is popularly known as the “work horse” of titanium is comprehensively used in aerospace and biomedical industries. At present, several studies have focused on hybrid manufacturing and enhancing the mechanical properties of Ti-6Al-4V with additive manufacturing techniques. In this research work, a short review on additive manufacturing of Ti-6Al-4V alloys has been investigated to define its mechanical and metallurgical properties in both as-built and heat treated conditions.

Preparation and Performance Optimization of Two-Component Waterborne Polyurethane Locomotive Coating

This paper reports the effects of different formulas on the performance of waterborne polyurethane (WPU), including two-component WPU and curing agent, wetting dispersant, defoaming agent, and wetting agent. The optimization of rheological additives selection, through the optimization of coating physical properties and chemical properties, can make the film show uniform color and appearance without pinholes, bubbles, or wrinkles, and have a long probation period. Through the analysis of performance after a 1000-h quick ultraviolet (QUV) aging test, the light reduction rate is 23.19%, and the color difference is 1.9. As can be seen from the scanning electron microscope (SEM) image and the three-dimensional stereomicroscope, the film shows relatively uniform dispersion, good compactness, and smooth surface. The two-component WPU topcoat is found to have high gloss 87.1 (60°) and high weather resistance, which provides a positive indication for the modulation and production of waterborne locomotive paint.

Preparation and Study of High Reflectance Color Solar Heat-reflective Insulation Coatings

Based on the existing preparation process of common thermal insulation coatings, a kind of high reflectance color solar heat-reflective insulation coatings was developed by improving the thermal insulation coatings. The effects of hollow glass beads, titanium dioxide and other factors on the properties of the coatings were discussed, and the thermal insulation properties of the coatings were characterized by solar reflectance ratio. The results show that the water-based color solar heat-reflective insulation coatings with high solar reflectance, high weathering resistance and high stain resistance can be prepared by using pure acrylic emulsion and silicone acrylic emulsion as the film-forming base material, using the rutile type titanium dioxide, calcined kaolin, precipitated barium sulphate and hollow glass beads as the insulated function pigments and fillers, and using the auxiliaries for coatings.

Performance of Retro-Reflective Building Envelope Materials with Fixed Glass Beads

Urban heat islands (UHI) are growing in size and intensity, which is partly attributable to the large amount of anthropogenic waste heat. Moreover, heat emitted from building exterior walls accounts for a large portion of the total anthropogenic waste heat. Thus, strategies and technologies for preventing the emission of heat from building exterior walls are being pursued by researchers worldwide. Amongst these technologies, the potential of use of retro-reflective (RR) materials instead of diffuse highly reflective (HR) materials applied to building envelopes for UHI mitigation is being studied widely. However, RR materials haven’t been applied to building envelopes in practice due to their unproven weather resistance. In order to develop RR materials with high weather resistance for application to building envelopes, two types of micro glass beads with different refractive indices (1.5, 1.9) and five different colors of base layers were evaluated in this study. Their RR performance was measured by optical experiment and compared to two types of RR sheets commercially available in Japan. The results showed that the glass bead RR samples with a refractive index of 1.9 had much higher retro-reflectivity (better RR capacity) compared to those with a refractive index of 1.5.

HIGH PROTECTION PERFORMANCE OF COATING SYSTEMS BASED ON ZINC RICH PRIMER AND FLUOROPOLYMER COATING

Coating systems based on zinc rich primer and fluoropolymer top coat were exposed for 8 years at different atmospheric stations in Vietnam: Hanoi, Ha Long and Nha Trang. For comparison the coating system with zinc rich primer and polyurethane topcoat was also tested. The degradations of coating systems were evaluated by gloss measurement and electrochemical impedance spectroscopy. The obtained results show that coating systems with zinc rich primer and top coatings based on fluoropolymer and polyurethane topcoats show very high weather resistance and corrosion protection performance, but the systems with fluoropolymer are better than coating system with polyurethane topcoat.