Water Resistance Test Research Articles

Synthesis and characterization of bioplastics based on silyated starch and acrylated epoxidized soybean oil

In the study, the bioplastics were prepared by coupling silylated starch with acrylated epoxidized soybean oil (AESO) at various curing temperatures. 3-aminopropyltriethoxy silane (APTES) was grafted onto starch by the condensation between Si-OH and C-OH. As demonstrated by FTIR and silica content analysis, starch was successfully modified by APTES. The compatibility between silylated starch and AESO was weak as observed by FESEM. The appearance of C-N bonds confirmed the reaction between AESO and silylated starch. An apparent increase of tensile strength from 8.03 MPa to 14.12 MPa was discovered when the bioplastics were cured from 80 °C to 120 °C. Opacity of the bioplastics was enhanced remarkably by AESO due to the incompatibility of silylated starch and AESO. Water resistance test showed that the bioplastics were less sensitive to water after the addition of AESO. The bioplastics maintained good biodegradability after the introduction of AESO. However, increasing the curing temperatures of the bioplastics yielded weak effects on the water resistance and enzymatic degradation of the bioplastics. The bioplastics with excellent mechanical and water-resistant properties were synthesized via the incorporation of AESO under high-temperature curing. The property changes are highly desirable for packaging applications.

A bioinspired hierarchical gradient structure to maximize resilience and enhanced cooling performance in polymeric radiative cooling coatings

Despite the extensive advancements in recent years, polymeric daytime radiative cooling (PDRC) coatings face certain challenges, encompassing restricted spectral performance, susceptibility to aging, poor mechanical strength, and so forth. Herein, we proposed a facile biomimetic 500 μm thick PDRC coating, featuring a gradient distribution of pore sizes throughout the cross-section. The proposed functional structure demonstrates spectral characteristics of a near-ideal broadband emitter by attaining over 0.95 emissivity in the main atmospheric window and 0.99 reflectance in the visible spectrum. During the outdoor experiment, it achieved an 8.5 °C subambient temperature drop along with a cooling power of ∼106 W/m2 at the solar irradiance of ∼800 W/m2 and ∼650 W/m2, respectively. Experimental findings highlight that the bioinspired design results in a tensile strength of ∼9 MPa along with a tensile strain of over 200%, which is more than twice that of non-gradient porous PDRC coatings. In addition, it offers tunable surface contact angle and manifests its resilience in anti-ultraviolet and water resistance tests. Furthermore, a building energy model reveals a decrease in cooling load of between 34 and 119 kWh/(m2.year), establishing its real-world application under broader climatic regions.

New geopolymer preparation methods and its application by recycle of double-waste: ground granulated blast furnace slag and fly ash

ABSTRACT This article mainly studies new geopolymer preparation methods by recycle of double waste:ground granulated blast furnace slag (GGBFS) and fly ash as geopolymer precursor, through different mass ratio of GGBFS and fly ash, to prepare geopolymers by alkali activation, the samples is cured at ambient temperature and the mechanical test is carried out together with the analysis of XRD, SEM and EDS to research the mechanism of strengthening and geopolymerisation. After analysis we find that the sample prepared by 30% mass ratio of GGBFS have good initial strength and short setting time, as well as best mechanical performance, which is attributed to moderate Ca2+ introduction accelerates the speed of geopolymerisation and the reactants of N-A-S-H gel, C-A-S-H gel and hydrated C-S-H help to bridge the gaps between the different hydrated phases, unreacted particles and matrix, result in a homogeneous and compacted geopolymeric sample. When GGBFS mass ratio above 50%, the mechanical of samples is deteriorated due to too much hydrated calcium containing compounds are formed and covered on the unreacted GGBFS particles surface to block further geopolymerisation. The acid attack test and water resistance test are carried out to analysis the durability between 30% GGBFS introduced geopolymer and ordinary Portland cement (OPC). In additional, a field application in case of 30% GGBFS introduced geopolymer grouting repair material indicated desirable construction based on visual observation and ground-penetration radar scanning.

Carbon nitride/polyaniline/metal oxide composite system endows epoxy resin with reinforcements in the fire safety, thermal stability, and water resistance

AbstractReducing the fire risk of epoxy coatings has been a significant focus in the research of thermosetting resin materials. Various carbon nitride/polyaniline/metal oxide hybrids (CNPMOs) were synthesized using in‐situ oxidative polymerization and modified adsorption methods. Combustion analysis results indicated that CNPMOs effectively reduced the heat release of epoxy coatings during combustion. The epoxy coatings containing various CNPMOs (EFe, EY, and ETi) exhibited excellent smoke suppression and toxicity reduction properties. Furthermore, in comparison to the pure sample (E0) and reference sample (E1), the epoxy coatings EFe, EY, and ETi demonstrated improved thermal stability. In water resistance tests, the water absorption rates of EFe, EY, and ETi were significantly lower than that of E0. The CNPMOs enhanced the hydrophobicity of the epoxy coating to better protect the substrate in humid environments.

Regulation of oxygen vacancies in MnCO3-based catalysts by thermally inducing for efficiently catalytic benzene combustion

Tuning oxygen vacancies through carbon pyrolysis is an effective strategy for fabricating high-performance catalysts to oxidize volatile organic compounds (VOCs). Herein, a series of MnCO3-based catalysts were synthesized by pyrolyzing MnCO3 precursors with different morphologies including dumbbell-like (D), bayberry-like (B) and cubic (C) structures for the benzene oxidation. The catalyst (D-300) derived from dumbbell-like MnCO3 exhibited superior catalytic performance for the benzene oxidation with a T90 of 176 °C and remarkable stability in long-term, cycling and water-resistance tests. Abundant oxygen vacancies in D-300 improved lattice oxygen mobility and redox ability, resulting in superior oxygen uptake and release capabilities. Moreover, oxygen vacancies greatly facilitated the activation and replenishment of gaseous oxygens to generate active oxygen species, thereby dramatically accelerating the cleavage of benzene rings and deep mineralization. In situ DRIFTS analysis demonstrated that benzene preferentially adsorbed onto D-300 due to its abundant acidic sites, and the oxidation of phenolate species was a rate-determining step. H2O may hinder the activation of gaseous oxygen, suppressing the activity of the catalyst.

Effects of silica aerogel particles on performance of the coatings for new energy vehicle battery packs

In order to reach the fire protection standard for new energy vehicle battery packs, the incorporation of SiO2 aerogel particles as a functional filler in the nitrogen and phosphorus fire-retardant system is necessary due to the inadequate mechanical properties. The effects of SiO2 aerogel on the properties of the coatings for the electric car battery pack were investigated by fire protection test, thermogravimetric analysis, limited oxygen index, UL-94 vertical test, combustion test, mechanical properties test, and weathering resistance test. The backside temperature fireproof coatings containing 1.5% SiO2 aerogel was effectively reduced to 250.2 ± 0.1 °C and the residual weight of the coating reached 32.61 ± 0.01%. The composition and structure of the carbon layer were analyzed further. Especially, the weight loss percentage of the fireproof coating is only 5.87 ± 0.02% in the water resistance test. However, excessive SiO2 aerogel decreased the performances of fireproof coatings.

Oxygen vacancy-mediated Mn2O3 catalyst with high efficiency and stability for toluene oxidation

Oxygen vacancy engineering in transition metal oxides is an effective strategy for improving catalytic performance. Herein, defect-enriched Mn2O3 catalysts were constructed by controlling the calcination temperature. The high content of oxygen vacancies and accompanying Mn4+ ions were generated in Mn2O3 catalysts calcined at low temperature, which could greatly improve the low-temperature reducibility and migration of surface oxygen species. DFT theoretical calculations further confirmed that molecular oxygen and toluene were easily adsorbed over defective α-Mn2O3 (222) facets with an energy of −0.29 and −0.48 eV, respectively, and corresponding OO bond length is stretched to 1.43 Å, resulting in the highly reactive oxygen species. Mn2O3-300 catalyst with abundant oxygen vacancies exhibited the highest specific reaction rate and lowest activation energy. Furthermore, the optimized catalyst possessed the outstanding stability, water tolerance and CO2 yield. In comparison with the fresh Mn2O3-300 catalyst, the physical structure and surface property of the used catalyst remained almost unchanged regardless of whether undergoing the stability test at consecutive catalytic runs as well as high temperature, and water resistance test. In situ DRIFTS spectra further elucidated that introducing the water vapor had little effect on the reaction intermediates, indicating the excellent durability of the defect-enriched catalyst.

Effectiveness of Mangifera Indica, Carica Papaya, and Citrus Limon Peels as Bio-Floor Wax for Classroom Use in the Philippines

The Philippines has a tradition of using floor wax to enhance the shine and durability of floors. However, commercial floor wax often contains harmful chemical substances that pose significant health risks. The study evaluated the potential of Mangifera indica, Carica papaya, and Citrus limon as bio-floor wax. Using a quantitative research approach, the research examined the odor, shininess, friction, and water resistance properties of these fruit peels. An antimicrobial sensitivity test was also conducted, and the mango extract had the highest average inhibition zone, while the combined extract had the lowest. The results showed that lemon peels have the highest friction on ceramic tiles, while papaya peels performed best on wood flooring. Mango peels showed the highest shininess on scarlet oak surfaces. The water resistance test showed no significant differences across different tiles. The results showed that the fruit peels could be a viable option for bio-floor wax in Philippine classrooms. Further research is recommended to develop formulations suitable for broader applications and to validate the product’s performance under different environmental conditions.

Effectiveness of using hydrophobic silica aerogel and grape seed extract in creating a sunscreen formula

Abstract Wearing sunscreen products protects human skin from the damaging effects of ultraviolet radiation from the sun. An experimental study was conducted to evaluate the effectiveness of utilizing hydrophobic silica aerogel and grape seed extract as additional raw materials in creating a sunscreen formula. This study aims to evaluate the acceptability of the sunscreen formulation in terms of determining its sun protection factor using UV-vis spectrophotometry, ability to remain on the surface using water resistance testing, and shelf life using a stability chamber. The methodology begins with obtaining a modified hydrophobic silica aerogel classified as cosmetic grade. The sunscreen formulation has a combination of 2 wt. % of hydrophobic silica aerogel, 3 wt.% of grape seed oil, and other ingredients using thermal procedures. The results demonstrated that the addition of hydrophobic silica aerogel and grape seed extract in sunscreen formulation exhibits satisfactory UV protection attaining an SPF value of 28.17073 which indicates a medium sun protection factor according to the standardized category of SPF values. On the contrary, the sunscreen without the active ingredients has an SPF value of 4.762. Additionally, both sunscreen’s water resistance was assessed by testing a total of 60 minutes in both tap water and salt water. The findings showed that both samples of sunscreens in tap water were more resistant compared to saltwater. Furthermore, the sunscreen with hydrophobic silica aerogel and grape seed extract stayed intact and did not dissolve in tap water after a 40-minute exposure time, but it did gradually disintegrate after 20 minutes in salt water since salt water has a higher density than tap water. In stability testing of both sunscreen formulations, the results revealed that the moisture content of the sunscreen formulation with hydrophobic silica aerogel and grape seed extract does not exceed 10% which indicates a low presence of oil. Hence, it proves its stability under the controlled conditions of 40°C and 75% relative humidity examined over one (1) month since it had a high moisture content of 78.98% obtained using the gravimetric method. For the sunscreen without these ingredients, the total moisture content under the same conditions and method is 29.07%. Thus, it indicates a high presence of oil and does not attain the standard moisture content for sunscreens. Overall, the evaluated performance of adding the hydrophobic silica aerogel and grape seed extract to the sunscreen formulation ensures its efficacy regarding its SPF, water resistance, and shelf life.

Mixture composition design of magnesium oxychloride cement-stabilized crushed stone materials applied as a pavement base

Conventional binding materials, such as silicate cement and lime, present high energy consumption, pollution, and carbon emissions. Therefore, we utilize crushed stone as a stabilization material. Magnesium oxychloride cement (MOC) is modified and used as an inorganic admixture owing to its eco-friendly nature and low carbon content. We analysed the control indicators of an integrated design of MOC-stabilized crushed stone by conducting unconfined compressive strength and water-resistance tests. The optimum mixing composition of the MOC-stabilized crushed stone was determined through the response surface methodology. We determined the best approach and dosage for improving the water resistance of MOC-stabilized crushed stone by comparing the effects of four modification methods: fly ash, citric acid + silica fume, phosphoric acid + waterborne polyurethane, and dihydrogen phosphate potassium salt. We also perform a comparison with 5% ordinary silicate cement-stabilized crushed stone. The results indicate that the MOC-stabilized crushed stone exhibits a rapid increase in strength in the early stage, but this rate reduces after 28 days. The mixing design employs the 4-day unconfined compressive strength and 1-day water resistance coefficient as the technical indicators. The best mixing composition includes a 4.27% MOC dosage and a molar ratio of MgO/MgCl2 of 5.85. We use 1% citric acid + 10% silica fume in equal amounts to replace the MOC dopant method for composite modification of the MOC stabilized crushed stone. Consequently, the 1-day water resistance coefficient before water immersion is significantly increased from 0.78 to 0.91 and its 4-day unconfined compressive strength is only reduced by 0.10 MPa. This significantly improves the water resistance of the MOC-stabilized crushed stone and ensures that its strength remains unaffected, which is the optimal modification method. However, this method must ensure that a small amount of citric acid and silica fume are uniformly distributed in the MOC-stabilized crushed stone, which increases the construction difficulty of the road base.

A novel poly(2-hydroxyethyl acrylamide) copolymer for the fabrication of transparent antifogging coatings on polycarbonate substrates

Although polycarbonate (PC) is widely used in various applications, its inherent hydrophobicity limits its potential in applications that require high light transmittance due to surface fog caused by changes in temperature or humidity in the environment. This work presents a facile method to fabricate transparent antifogging coatings on PC substrates based on poly(2-hydroxyethyl acrylamide-co-2-aminoethyl methacrylate) (P(HEAA-co-AEMA)), in which the AEMA segments have an amino functional group that can react with the ester group on the surface of the PC substrate to form covalent urethane bonds during the heat curing process, avoiding the problems of coating susceptibility to mechanical damage, ease of peeling, etc. Moreover, HEAA units are employed as hydrophilic groups, providing antifogging performance. These antifogging coatings can be easily obtained by coating P(HEAA-co-AEMA) copolymers on PC substrates at room temperature and then curing them by thermal treatment. These transparent coatings exhibited excellent antifogging and self-cleaning performance. Furthermore, the coatings exhibited good adhesion in the cross-cut test and thermal stability in the hot water resistance test. Therefore, the present P(HEAA-co-AEMA) copolymer coatings are promising for practical antifogging applications.

Preparation of a Consolidation Material of Organosilica-Modified Acrylate Emulsion for Earthen Sites and the Evaluation of Its Effectiveness

In this paper, a new consolidation material for earthen sites with silicone-modified acrylic emulsion was synthesized and applied to the consolidation test of soil samples of the site. The effectiveness was tested through the properties of soil samples on the changes in weight, color, permeability test, air permeability, hydrolysis resistance, water resistance, and salt resistance. The results show that the samples treated with the new material have an outstanding effect on hydrolysis resistance, water resistance, and salt resistance without the change in color and gas permeability. After being soaked in Na2SO4 and sodium chloride solution for half a month, the reinforced soil sample did not crack, and it could undergo 15 days of water resistance test and five cycles of sodium sulfate resistance.

Effects of biomaterial on the properties of waterborne intumescent fireproof coatings

AbstractSilk fibroin was used to enhance the properties of the fireproof coating, ensuring the safe evacuation of occupants in a fire accident. The effects of biomaterial on the properties of the coatings were investigated by fire protection test, thermogravimetric analysis, limited oxygen index, vertical flame test, water resistance test, and mechanical properties test. The carbon layers were characterized after the fire protection test by scanning electron microscopy, energy dispersive spectroscopy, X‐ray diffraction, and Fourier transform infrared spectroscopy to analyze the microstructure and chemical composition. The results show that the coating with 6% SF demonstrated the best fire protection, thermal stability, and water resistance. The temperature on the backside is only 255.9°C, and the residual weight is 37.52%. However, the coating with 4% SF exhibits good mechanical properties.

Hydrophobic Coating of Vegetable-Tanned Leather with Dodecylamine

Vegetable-tanned leather exhibits a hydrophilic character due to the abundance of hydroxyl groups (-OH). In this study, the surface of vegetable-tanned leather was modified to become hydrophobic. The leather was coated using dodecylamine (DDA) through the padding method in the finishing process. The concentration of DDA varied from 1%, 2%, 3%, and 4% to identify the optimum concentration. The coating process was assisted by an activator, either acid or base, to improve the adhesion of DDA to leather. Uncoated vegetable-tanned leather was used as a control. The success of coating was identified using FT-IR and SEM-EDX analysis. The hydrophobicity of leather was conducted through a water resistance test. The success of coating is shown by the increase in their weight and thickness. Absorption bands of alkyl and amino groups of DDA are observed in FT-IR spectra around 1450 cm-1 and 3400 cm-1, respectively. SEM micrographs show that coated leathers have flatter surfaces as a consequence of DDA attachment on the leather surface. The water resistance test proves that the use of DDA can improve the leather hydrophobicity and enhance the water absorption time by up to 4 times. The optimum water absorption time is obtained when using 2% DDA.

Experimental investigation and evaluation of the compactness and moisture damage of asphalt mixes incorporating dune and river sand

Road construction is mainly based on the use of raw materials that must be in compliance with the standards, thus ensuring the quality and durability of the road. The use of dune sand and river sand in road geotechnics is an interesting subject. Both types of sand can be used in road construction and maintenance for a variety of applications. Dune sand is often appreciated for its uniform grain size and drainage capacity, while river sand can offer good mechanical strength. The majority of common bituminous mixes contain fillers made of quarry sand, whose amounts are difficult to regulate because of the variety of rock deposits and the conditions under which they are manufactured. In this paper, the compactness and moisture damage of asphalt mixes with two sand types, River sand (RS) with (0/4) size was sourced from the valley in the province of Medea (Algeria) and Dune Sand (DS) with a particle size of (0/0.5) was obtained from a dune in the Algerian province of Djelfa, were examined. Furthermore, a 100% replacement rate by weight of Crushed Sand (CS) with (0/3) mm size was used (quarry sand). The investigation employed a comprehensive approach, utilizing Marshall and gyratory shear compaction tests to assess compactness, while moisture damage was evaluated through rigorous water resistance testing and compressive strength methodology. The results of the study reveal a notable disparity in the mechanical performance of asphalt mixtures containing dune and river sand, showcasing diminished compactness and heightened susceptibility to moisture-induced damage when compared to alternative mix formulations. These findings underscore the critical role of sand type selection in asphalt mix design, emphasizing the need for careful consideration to optimize performance and durability.

Effect of incorporation of calcined sediments and perlite as partial cement replacement on mortars behavior

The accumulation of sediments in varied dams built in Algeria denotes a vital problem that requires immediate attention and action from the authorities and managers of the National Agency for Dams and Transfers (ANBT). More than that, various research studies on sediments have revealed that subjecting them to heat treatment can exploit these sediments as a viable substitute for some of the cement used to produce cementitious materials. Combining the different types and quantities of natural Perlite pozzolan can achieve many benefits, including reduced consumption, minimized heat generation, improved workability, reduced permeability, and increased strength. This study aims to explore the potential of using dredged sediments from Chorfa II dams and perlite from Hammam Boughrara (located in western Algeria) as substitutes for cement in mortar analysis. A thorough examination of calcined sediments and perlite revealed the feasibility of partial cement replacement. Research has mainly focused on evaluating the properties of mortars in fresh and hardened states.

Preparation and properties of phosphogypsum based plastering mortar

In order to reduce the negative impact of phosphogypsum accumulation on the environment, this paper uses phosphogypsum, magnesium slag, potassium dihydrogen phosphate, fly ash and calcium carbide slag to prepare gypsum based plaster mortar as a cementing material, and explores the optimal ratio of the composite cementing material through orthogonal experimental design. The mechanical properties of the test block were analyzed by the flexural and compressive strength of the test block, and the slurry properties were evaluated by the initial and final setting time, stability measurement, fluidity test and water resistance test. The experimental results show that when phosphogypsum: potassium magnesium phosphate: fly ash: When titanium gypsum =50:25:20:20, the strength of the composite system can reach 2.98Mpa in 60 days, and the initial setting time is 118min and the final setting time is 223min, which meets the requirements of GB/T25181-2019 building gypsum plaster mortar that the initial and final setting time is greater than 60min and less than 480min. Its fluidity is 237mm, which meets the requirement that the fluidity of GB/T25181-2019 building gypsum plaster mortar is greater than 100mm.

Imidazolium‐based ionic thermoplastic polyurethane with low surface energy and antibacterial activities

AbstractA series of novel thermoplastic polyurethane elastomers with both low surface energy and antibacterial activity were synthesized in this paper. Firstly, four imidazole salt diols with different alkyl chain lengths at the N‐position of imidazolium cation ([CnIm+][Cl−]) were prepared. Then, imidazolium‐based ionic thermoplastic polyurethane elastomers (Si‐ITPUs) were formulated by incorporating polydimethylsiloxane and polytetramethylene glycol as a mixed soft segment, 1,4‐butanediol and [CnIm+][Cl−] as a chain extender, and 4,4′‐dicyclohexylmethane diisocyanate. The structure, thermal stability, mechanical properties, physical crosslinking density, and the anti‐graffiti properties of Si‐ITPUs were evaluated. The surface energy and water absorption were evaluated through static contact angle and water resistance tests, respectively. Furthermore, the antibacterial activities against both Staphylococcus.aureus and Escherichia coli were characterized by the plate colony counting method. The results demonstrated that Si‐ITPUs possessed surface energy of approximately 23 mN/m, which conferred excellent anti‐graffiti and self‐cleaning performance. Furthermore, the increase of the alkyl chain length of substitutions resulted in a decrease in the tensile strength but an increase in the elongation at break. Si‐ITPU‐C4 exhibited optimized antibacterial activities with an antibacterial rate of more than 99.9% against both S. aureus and E. coli. This novel polyurethane is anticipated to find applications in the medical device industry and food processing sector.

Novel four-in-one intumescent flame retardants for polypropylene: Synthesis, characterization and properties

To address the shortcomings of traditional intumescent flame retardants (IFRs), a novel four-in-one IFR (M [APP/NiCo2O4]) was constructed for the first time. It integrates acid source, gas source, carbon source (crosslinking β-CD), and synergistic agent (NiCo2O4 nanoparticles) into a single entity by a co-encapsulation technology. Under the loading of 20 wt%, its flame retardant performance was significantly better than that of simple mixed flame retardants, and it could increase the limiting oxygen index of polypropylene (PP) from 18 to 30.2 and pass the UL-94 V-0 rating. At the same time, it could reduce the peak of heat release rate, total heat release, and peak of CO production of PP by 77%, 22%, and 80%, respectively, showing excellent flame retardant performance. The excellent flame retardant performance is mainly because the synergist NiCo2O4 nanoparticles in the four-in-one flame retardant can easily combine and efficiently interact with the acid source, carbon source, and gas source in the intumescent flame retardant to form a more stable protective char residue. In addition, the crosslinking β-CD shell enhances both the water resistance and initial thermal decomposition temperature of PP containing the four-in-one IFR compared to PP with simple mixed control samples. After 72 h of water resistance test, it can still maintain the UL-94 V-0 rating. The presence of the crosslinking β-CD shell also improves the compatibility of the four-in-one flame retardant in PP, and its adverse effects on the mechanical properties of PP are also significantly smaller than those of the mixed control sample.

Effect of Adhesion and Corrosion Performance of Geomet Basecoat (321)- Topcoat (ML Black) Applications on Cataphoretic Coating

This study aimed to improve corrosion resistance and adhesion of metallic materials typically used in automotive application. A combination of cataphoretic and Geomet coatings has been used to improve corrosion resistance. Firstly, cataphoretic coating was applied and then the coating process was completed with Geomet 321 and ML Black respectively. The results of the corrosion tests were classified into different categories such as adhesion, water resistance, moisture resistance, salt resistance and cyclic tests. The corrosion properties of the two- and three-layer coatings were found to improve as a function of both the sandblast pre-treatment and the post-cataphoresis curing temperature. The findings show that the adhesion strength and corrosion properties of Geomet 321 increases with curing temperature and sandblasting. This study will be a contribution to the future of protective coatings in the automotive industry by describing the process steps necessary to achieve optimum results.