Thermal Water Vapor Research Articles

Sustained-release composite films incorporated with cinnamon essential oil: Characterization, release kinetics and application for cherry tomato preservation

Food spoilage waste accelerated the development of bio-based active food packaging. Sustained-release composite films based on oxidized corn starch/ pullulan were prepared by incorporating cinnamon essential oil (CEO) nanoemulsion. The SEM, ATR-FTIR and XRD results showed that CEO was successfully encapsulated in film matrixes. The composite films exhibited the increase of thermal stability, UV-shielding, flexibility and water vapor resistance properties. The films containing CEO nanoemulsion (≥10%) showed excellent antimicrobial activities against S. aureus, E. coli and B. cinerea (the maximum inhibition zones achieving 27.23 ± 2.31 mm). The release kinetics results showed sustained release of CEO from the films with high content of CEO nanoemulsion, and the dominant release mechanism was Fickian diffusion. The composite films effectively maintained cell structure, weight, firmness and total soluble solids content of fruits during storage. Therefore, the sustained-release composite films could be a prospective packaging material for fruits preservation.

Efficient Bio-Based Insulation Panels Produced from Eucalyptus Bark Waste

Traditional thermal insulation panels consume large amounts of energy during production and emits pollutants into the environment. To mitigate this impact, the development of bio-based materials is an attractive alternative. In this context, the characteristics of the Eucalyptus fiber bark (EGFB) make it a candidate for insulation applications. However, more knowledge about the manufacturing process and in-service performance is needed. The present study characterized the properties that determine the in-service behavior of the EGFB insulation panel. The assessment involved two different manufacturing processes. The results indicated that the hot plates and the saturated steam injection manufacturing system can produce panels with similar target and bulk density. The thermal conductivity fluctuated between 0.064 and 0.077 W/m·K, which indicated good insulation, and the values obtained for thermal diffusivity (0.10–0.37 m mm2/s) and water vapor permeability (0.032–0.055 m kg/GN s) are comparable with other commercially available panels. To guarantee a good in-service performance, the panels need to be treated with flame retardant and antifungal additive. The good performance of the panel is relevant because bio-based Eucalyptus bark panels generate less CO2 eq and require less energy consumption compared to traditional alternatives, contributing to the sustainability of the forestry and the construction industry.

Development of Prefabricated Additional Insulation Elements for the Renovation of High-Rise Apartment Buildings

Prefabricated additional insulation elements have demonstrated success in renovating up to 5-storey apartment buildings. However, the unique challenges posed by high-rise buildings necessitate a closer examination of installation and long-term performance. In this study, we developed an additional insulation element specifically tailored for renovating high-rise apartment buildings and analysed its hygrothermal performance. To test the performance of the insulation elements, we installed a prototype and measured its performance at critical points along the external envelope. We calibrated a calculation model and applied building performance simulation software to explore various combinations of prefabricated elements. Our goal was to compare the associated risks and the key hygrothermal properties of these different material combinations within the insulation element. Critical points between the insulation layer and the wind barrier, as well as between the surface of the existing concrete panel wall and the vapour control layer of the additionally insulated exterior wall were analysed. The study's results indicate that the thermal resistance and water vapour permeability of the wind barrier layer, and the presence of an appropriate vapour control layer primarily influence the performance and moisture dry-out of a structure. Additionally, the study results indicate that the weather component has a higher impact than in lower buildings as the wind-driven rain loads are considerably higher in the upper parts of the high-rise buildings. The initial moisture (w = 110 kg/m3 at the height of the 9th storey and w = 117 kg/m3 at the height of the 16th storey) dry-out can last more than 3 years depending on the building type and materials used. This study underscores the importance of tailored solutions and vigilant moisture safety management in high-rise apartment building renovations, particularly when utilizing prefabricated additional insulation elements.

Design and analysis of biodegradable and potentially biobased multiphase systems from starch and co-polyesters

To develop tailored and performing biodegradable multilayer systems with polyester as cap layers and thermoplastic starch (TPS)/polyester blends in the core, several TPS-based blends, with varying formulations and several biodegradable and potentially biobased polyesters, were first elaborated. Poly(butylene adipate-co-terephthalate) (PBAT), poly(butylene succinate) (PBS) and poly(butylene succinate-co-adipate) (PBSA) were tested. The TPS-based blends for the core layer were compatibilized with a multifunctional epoxide styrene-acrylic reactive chain extender. As evidenced by tensile tests, the compatibilization was more effective with blends based on PBAT, probably due to its higher number of reactive chain ends. Multilayer films comprising neat PBAT cap layers and a TPS/PBAT blend, compatibilized or not, as a core layer were then elaborated by coextrusion. Thanks to the PBAT cap layers, the multilayer films had improved thermal stability and water vapor barrier properties, while TPS in the core layer added oxygen barrier properties to the global systems. In connection with the applications, the biocompatibility was also demonstrated through cell growth tests. The suitability of such multilayer films for biodegradable packaging linked to biomedical applications was thereby confirmed.

An innovative approach to develop plant-derived and CO2-based active biocomposite films towards antioxidant activity

In this study, novel biocomposites composed of CO2-derived poly(propylene) carbonate and plant-based cellulose were developed employing solvent casting technique. An innovative and rapid strategy was employed, whereby pre-dissolving cellulose improves dramatically the compatibility of poly(propylene) carbonate with cellulose whilst pristine cellulose powder displays inhomogeneous distributions of cellulose within the biocomposite. Resulting biocomposites produce flat homogeneous surfaces with low cellulose content, whilst rougher surfaces and thicker cross sections were observed in films with higher cellulose content. Developed biocomposites outperformed biocomposites produced from pristine cellulose powder in terms of homogeneity, thermal stability, antioxidant activity and biocompatibility. Higher cellulose content samples show the formation of a new hydrogen bonding network between PPC and cellulose polymer chains and this contributes to improved thermal stability. TGA results reveal improved thermal stability for high cellulose content films and show enhanced water vapor permeability. A cell viability study shows that the developed materials are biocompatible. Curcumin, a natural antioxidant, was incorporated into optimized biocomposites to produce active biocomposites with antioxidant features to accelerate wound healing. Curcumin is shown to display a sustained release profile over a time period of 3 days, and this is ideal for would healing. The curcumin-functionalized biocomposites also contributed to enhanced thermal stability and water vapor permeability. Thus, these biocomposite films show promise as active biocomposites which can be used for biomedical applications such as wound healing.

Anomalous Characteristics of Water Vapor Budget on the Tibetan Plateau under the Influence of Tropical Cyclones over the Bay of Bengal during Early Summer

Abstract Early summer is a peak time for tropical cyclone (TC) activities over the Bay of Bengal (BoB) and a period of South Asian monsoon onset, and the TCs during this time have a significant impact on the water vapor transport associated with monsoons. This study investigates the anomalous characteristics of the dynamic–thermal atmospheric circulation structure and water vapor budget over the Tibetan Plateau (TP) under the influence of BoB TCs generated in May from 1979 to 2020 with JTWC best track data and ERA5 data. Results reveal that a significant southerly water vapor channel forms from the BoB to the southeastern TP with a water vapor convergence near the Yarlung Zangbo Grand Canyon. A part of the water vapor is transported directly to the TP by deep southerly jet, while the other part is lifted by TCs and then climbs upward to the TP by two uplift processes occurring on the southern slope of the TP and over the TP respectively, which makes the whole troposphere over the southeastern TP warmer and wetter. It is found that anomalous southeasterly airflow in the northeast of TC circulation turns to anomalous southwesterly airflow forming an abnormal anticyclonic circulation over the southern TP in the middle and upper troposphere due to the diabatic heating effect. In this process, the TP acts as an anomalous water vapor sink with remarkable water vapor inflow through its southern boundary, with the main water vapor outflow through the eastern boundary, but a weak easterly water vapor backflow to the eastern TP in the lower troposphere. Significance Statement This study attempts to investigate the anomalous features of the water vapor budget over the Tibetan Plateau (TP) under the influence of the Bay of Bengal (BoB) tropical cyclones (TCs) during early summer. Results show that a significant southerly water vapor channel forms from the BoB to the southeastern TP with a water vapor convergence near the Yarlung Zangbo Grand Canyon. The TP acts as an anomalous water vapor sink with more and higher water vapor inflows through the southern boundary of the TP. A positive temperature and humidity anomaly can be found over the southeastern TP extending upward into the middle and upper troposphere. The results are helpful to understand how the BoB TCs affect the weather process over the TP.

Developing a novel, low-cost, antimicrobial, and biodegradable pectin/HEC/ZnO biofilm for edible food packaging applications

AbstractThe purpose of this study was to investigate the potential of pectin extracted from orange waste by acid hydrolysis and prepared Pectin/ hydroxyethyl cellulose (HEC)/ZnO nanoparticles (ZnO-NPs) biofilm for food packaging applications. The pectin/HEC/ZnO biofilms were prepared in an aqueous solution at room temperature using solvent casting method and characterized by different techniques such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscope (SEM). Also, thermal gravimetric analysis (TGA), mechanical properties, and water vapor permeability-WVP were evaluated. Moreover, its antimicrobial activity against Gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Salmonella enterica Typhimiurium) and two Gram positive bacteria (Listeria monocytogenes and Staphylococcus aureus), and also has antifungal activity against Candida albicans was assessed. The obtained results display that the water vapor permeability (WVP) indicated a reduction in permeability with increased ZnO concentration, with WVPs ranging from 2.55 × 10−12 to 4.28 × 10−12 gm/pas.m2, which indicates that our pectin/HEC/ZnO bionanocomposite biofilm could efficiently decrease moisture transfer, thereby potentially extending the shelf-life of packaged food products. Furthermore, the results showed enhanced tensile strength and flexibility in the biofilms with the addition of 1% ZnO nanoparticles from 1.2 to 2.6 MPa and 4.5 to 13 MPa respectively. The WVP indicated a reduction in permeability with increased ZnO concentration, with WVPs ranging from 2.55 × 10−12 to 4.28 × 10−12 gm/pas.m2. The antimicrobial activity against pathogens such as Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica Typhimurium, Listeria monocytogenes, Staphylococcus aureus, and Candida albicans was significant, with a 99.96% reduction in E. coli counts at a biofilm concentration of 200 mg/mL. Furthermore, the current study revealed that the synthesized bionanocomposite biofilms had excellent qualities such as transparency, flexibility, low cost, and being environmentally friendly. The pectin/HEC/ZnO bionanocomposite was found to be an ideal biofilm for food packaging due to its safety and affordability, which is able to prolong food shelf-life.

(Invited) Ion Transport in Solid-State Electrolytes Based on TTF - TCNQ Charge-Transfer Complexes

Current research on solid-state organic electrolytes mainly focuses on polymer electrolytes where ion transport is facilitated by chain segmental motion. The ionic conductivity of these polymer electrolytes at room temperature in too low for many practical applications. A limited number of prior reports suggest that solid-state electrolytes including organic crystalline charge-transfer complexes can have surprisingly high ionic conductivity. We report1 that processing and environmental conditions drastically impact electron and ion charge transport properties of charge-transfer complex electrolytes based on tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) mixed with lithium bis(trifluoromethylsulfonylimide) (LiTFSI). Thermal annealing and water vapor treatment decrease electronic conductivity and increase ionic conductivity. The electrolyte with 1-1-2-0.45 molar ratio of TTF-TCNQ-LiTFSI-H2O has an ionic conductivity of 2 × 10-3 S/cm at 25 °C with electronic conductivity of order 10-7 S/cm. Thermal annealing helps reduce connectivity of the charge-transfer complexes and expose more surfaces to interact with LiTFSI, thereby decreasing electronic conductivity. Exposure of the sample to water vapor then causes a substantial increase in ionic conductivity, even when the material remains in the solid state. In this presentation, we will also report on additional experimental studies of solid-state electrolytes incorporating TTF-TCNQ.Reference 1. L. Yang and J. L. Schaefer, “Water-Assisted Ion Conduction in Solid-State Charge-Transfer Complex Electrolytes for Lithium Batteries,” ChemRxiv, 2023. https://doi.org/10.26434/chemrxiv-2023-9k024

Preparation and characterization of electrospun cellulose nanocrystals-reinforced trans-1,4-polyisoprene nanocomposite elastomeric fiber membranes

To overcome the limitations of low strength of conventional electrostatic spinning trans-1,4-polyisoprene (TPI) fiber membranes, cellulose nanocrystals (CNC) were added into the TPI spinning solution as a backbone material, and CNC/TPI nanocomposite elastomeric fiber membranes were prepared using electrostatic spinning. This study examined the effect of CNC content on the morphology, mechanical properties, and hydrophilicity of the electrostatically spun CNC/TPI nanocomposite elastomeric fiber membranes. The prepared CNC/TPI nanocomposite elastomeric fiber membranes were characterized using 3D measurement laser microscopy, tensile testing, Fourier-infrared spectrometry, thermogravimetric analysis, differential scanning calorimetry, and water contact angle. With increase in CNC content, the tensile strength of the nanocomposite elastomeric fiber membrane increased from 1.79 MPa (without CNC) to 10.28 MPa (with 1 wt% CNC), the average diameter first decreased and then increased, the thermal stability and water vapor transmission rate decreased, and the water contact angle gradually increased. The maximum water contact angle was 124.27° and the minimum water vapor transmission rate was 851.41 g/m2·24 h. The proposed high-strength hydrophobic breathable fiber membrane preparation method can be used in various fields such as high-strength waterproof/breathable protective clothing and wearable electronic devices.

Extended hygrothermal characterization of unstabilized rammed earth for modern construction

Although hygrothermal properties of rammed earth represent great potential for improving thermal comfort during hot summers, still little knowledge is available about this topic. The literature lacks complete sets of hygrothermal characteristics of rammed earth, although they are fundamental for heat and moisture transfer modeling necessary to predict earthen building performances. The present work reports the results of a large collaboration between four academic laboratories in order to obtain an extended hygrothermal characterization of rammed earth, focusing on the material used in a modern construction in Lyon, France. The aim of the article is to provide for the same kind of soil an extend characterization on a large span of relative humidity to provide complete set of material properties for heat and moisture transfer simulation. The hygrothermal measurements cover adsorption and desorption isotherm, intermediate isotherm loop, specific heat capacity, dry thermal conductivity, moisture-dependent thermal conductivity and water vapor resistance factor for a large span of relative humidity. In addition, the capillary rise test was performed to estimate the liquid transport coefficient for suction and redistribution. The results show that variations in the density of the samples have a low impact on sorption isotherm, while they have a non-negligible impact on thermal conductivity and water vapor permeability. Surprisingly, variations in the grain size distribution do not produce a significant modification in the sorption isotherm, while hysteresis slightly reduces when bigger grains are added to the soil composition. Approximation of empirical model coefficients for the determination of moisture-dependent thermal conductivity is proposed for rammed earth materials.

Impact of North Indian Atmospheric Diabatic Heating on Summer Precipitation in Central Asia

Abstract The impact of North Indian atmospheric diabatic heating variation on summer rainfall over Central Asia (CA) at an interannual scale during 1960–2019 was investigated from thermal adaptation and water vapor transportation perspective. The results showed that more precipitation in southeastern CA is associated with the southward subtropical westerly jet (SWJ), caused by the ascending motion and weakened water vapor output on the south side. When the SWJ moves southward, the high-level water vapor transportation on the south side changes from outward (−1.9 × 106 kg s−1) to inward (0.6 × 106 kg s−1), and the positive anomalous relative vorticity advections by the basic westerly winds produce ascending anomalies over southeastern CA. The position change in the SWJ was mainly related to atmospheric diabatic heating over northern India (NI). The thermal vorticity adaptation caused by a weakened heating rate over NI leads to an anomalous upper-level cyclone over southeastern CA, and the associated cold temperature advection eventually cools the upper troposphere of southeastern CA and reduces the temperature gradient at mid-to-high latitudes, leading to the southward SWJ. Thermal adaptation of the circulation and temperature anomaly over southeastern CA to the NI thermal forcing were also verified by numerical experiments. Both the abnormal ascending motions and the weakened outward water vapor associated with the southward SWJ, caused by the weakened heating rate over NI, lead to more summer rainfall in southeastern CA. The changes in diabatic heating over NI are closely related to Indian Ocean SST. When the Indian Ocean SST is warmer, the south Asian summer monsoon weakens, causing less precipitation and, thus, a weakened heating rate over NI. Significance Statement This study established that the northern Indian atmospheric diabatic heating anomalies associated with Indian Ocean SST variation play an important role in influencing precipitation in central Asia (CA). The weakening of the atmospheric diabatic heating over the NI would not only cause an abnormal cyclone and cooling over southern CA through thermal adaptation but also lead to southward subtropical westerly jet (SWJ), ascending motions, and decreased outward water vapor on the south side in southeastern CA, eventually resulting in more precipitation in southeastern CA. The results emphasize the influence of tropical SST and atmospheric heat sources on midlatitude climate and are important for understanding summer precipitation change in southeastern CA.

Thermochemical Stability of Yb2Si2O7 Environmental Barrier Coatings During Thermal Cycling and Water Vapor Corrosion at 1350 °C

Thermochemical Stability of Yb2Si2O7 Environmental Barrier Coatings During Thermal Cycling and Water Vapor Corrosion at 1350 °C

Water-Assisted Ion Conduction in Solid-State Charge-Transfer Complex Electrolytes for Lithium Batteries

Current research on solid-state organic electrolytes mainly focuses on polymer electrolytes where ion transport is facilitated by chain segmental motion. A limited number of prior reports suggest that solid-state electrolytes based on organic charge-transfer (CT) complexes can have surprisingly high ionic conductivity. Here, we report that processing and environmental conditions drastically impact charge transport properties of CT complex electrolytes based on tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) mixed with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). Thermal annealing and water vapor treatment decreases electronic conductivity and increases ionic conductivity. The electrolyte with a 1-1-2-0.45 molar ratio of TTF-TCNQ-LiTFSI-H2O has an ionic conductivity of 2 × 10–3 S/cm at 25 °C with order 104 times lower electronic conductivity. In this system where ion conduction is decoupled from the mobility of the organic phase, thermal annealing helps reduce CT connectivity and expose more surfaces to interact with LiTFSI, and water promotes the dissociation of LiTFSI.

Thermal plasma potential to remediate soil contaminated with diesel

Petroleum hydrocarbons (PHCs) are recognized as one of the major soil contaminants causing negative environmental impact. Thereby, PHCs remediation from the soil is essential. Hence, this experimental study aimed to assess the potential of thermal water vapor and air plasmas to remediate soil contaminated with habitually used PHCs – diesel. The impact of contaminant content in the soil on the remediation process also was estimated. The results of this research demonstrated that 99.9% contaminant removal efficiency was received proceeding diesel contaminated soil remediation in the environment of the thermal plasma in defiance of whether water vapor or air was employed as a plasma-forming gas. Moreover, the soil's contaminant content (80–160 g/kg) did not influence its' removal efficiency. The soil de-pollution process also caused the decomposition of the soils' natural carbon reserves since carbon content decreased from an initial 9.8 wt% in the clean soil to 3–6 wt% in the remediated soil. Furthermore, PHCs – diesel was decomposed into producer gas mainly consisting of H2, CO (also known as synthesis gas) and CO2. Thus, the thermal plasma offers a way not only to de-pollute the soil but also to reuse the PHCs present in the soil by breaking it down into gaseous products that can further be used to meet human needs.

Characterization and sustained release study of starch-based films loaded with carvacrol: A promising UV-shielding and bioactive nanocomposite film

Present study was aimed to develop sustainable active films with starch/carvacrol for potential food packaging. The physicochemical, antioxidant, antibacterial and release kinetics were analyzed. The results demonstrated that carvacrol nanoemulsion (CNE) was uniformly dispersed in the film matrix and interacted with hydrogen bonds. The addition of carvacrol improved the thermal stability, UV shielding, water solubility and water vapor permeability of the films, but reduced their mechanical properties. Films prepared with CNE (≥10%) exhibited high antioxidant activity (>60%), and inhibition zones of the best antimicrobial activities achieved 28.6 ± 1.4 and 57.2 ± 3.7 (mm) against E. coli and S. aureus. The release kinetics of carvacrol from the nanocomposite films exhibited a higher carvacrol release in the acidic simulant than in the aqueous simulant at equilibrium. The dominant mechanism of carvacrol release was Fickian diffusion and showed minimal erosion. Overall, the sustainable composite films exhibited desirable physical properties and bioactivity, and could be used as edible materials for food preservation, especially for extending the shelf life of acidic foods.

Cellulose/Grape-Seed-Extract Composite Films with High Transparency and Ultraviolet Shielding Performance Fabricated from Old Cotton Textiles

Plastics displaying many merits have been indispensable in daily life and they still maintain the strong momentum of development. Nevertheless, petroleum-based plastics possess a stable polymer structure and most of them are incinerated or accumulated in the environment, leading to devastating impacts on our ecology system. Thus, exploiting renewable and biodegradable materials to substitute or replace these traditional petroleum-derived plastics is an urgent and important task. In this work, renewable and biodegradable all-biomass cellulose/grape-seed-extract (GSEs) composite films with high transparency and anti-ultraviolet performance were fabricated successfully from pretreated old cotton textiles (P-OCTs) using a relatively simple, green, yet cost-effective, approach. It is proved that the obtained cellulose/GSEs composite films exhibit good ultraviolet shielding performance without sacrificing their transparency, and their UV-A and UV-B blocking values can reach as high as nearly 100%, indicating the good UV-blocking performance of GSEs. Meanwhile, the cellulose/GSEs film show higher thermal stability and water vapor transmission rate (WVTR) than most common plastics. Moreover, the mechanical property of the cellulose/GSEs film can be adjusted by the addition of a plasticizer. Briefly, the transparent all-biomass cellulose/grape-seed-extracts composite films with high anti-ultraviolet capacity were manufactured successfully and they can be used as potential materials in the packaging field.

Mitigation Effect of Dense “Water Network” on Heavy PM2.5 Pollution: A Case Model of the Twain-Hu Basin, Central China

The influence of the underlying surface on the atmospheric environment over rivers and lakes is not fully understood. To improve our understanding, this study targeted the Twain-Hu Basin (THB) in central China, with a unique underlying surface comprising a dense "water network" over rivers and lakes. In this study, the Weather Research and Forecasting Model with Chemistry (WRF-Chem) was used to simulate the impact of this dense "water network" on a wintertime heavy PM2.5 pollution event in the THB. On this basis, the regulating effects of density and area of the lake groups, with centralized big lakes (CBLs) and discrete small lakes (DSLs), on PM2.5 concentrations over the underlying surface of the dense "water network" in the THB were clarified, and the relative contributions of thermal factors and water vapor factors in the atmospheric boundary layer to the variation of PM2.5 concentrations were evaluated. The results show that the underlying surface of dense "water networks" in the THB generally decreases the PM2.5 concentrations, but the influences of different lake-group types are not uniform in spatial distribution. The CBLs can reduce the PM2.5 concentrations over the lake and its surroundings by 4.90-17.68% during the day and night. The ability of DSLs in reducing PM2.5 pollution is relatively weak, with the reversed contribution between -5.63% and 1.56%. Thermal factors and water vapor-related factors are the key meteorological drivers affecting the variation of PM2.5 concentrations over the underlying surface of dense "water networks". The warming and humidification effects of such underlying surfaces contribute positively and negatively to the "purification" of air pollution, respectively. The relative contributions of thermal factors and water vapor-related factors are 52.48% and 43.91% for CBLs and 65.96% and 27.31% for DSLs, respectively. The "purification" effect of the underlying surface with a dense "water network" in the THB on regional air pollution highlights the importance of environmental protection of inland rivers and lakes in regional environmental governance. In further studies on the atmospheric environment, long-term studies are necessary, including fine measurements in terms of meteorology and the environment and more comprehensive simulations under different scenarios.

Sonochemical Approach of Highly Thermal, Mechanical, and Corrosion Inhibition Performance of Metal–Organic Framework (ZIF‐8)‐Decorated Waterborne Polyurethane Nanocomposite

Herein, highly porous metal–organic framework (ZIF‐8)‐decorated environmental friendly waterborne polyurethane (WPU) (ZIF‐8@WPU) nanocomposites via facile sonochemical technique are synthesized. The ZIF‐8@WPU shows threefold excellent mechanical performance (tensile strength ≈23 MPa and elongation 670%) at a very low 2.5 wt% filler loading compared to pristine WPU. In addition, the synthesized ZIF‐8@WPU exhibits high thermal stability and water vapor permeability properties with increasing nanofiller concentration. Interestingly, the incorporation of ZIF‐8 into WPU potentially improves the corrosion inhibition performance with a superior corrosion rate (υcorr) 1.7 × 10−2 mm year−1 and ≈94% protection efficiency (PE) at lower filler (2.5 wt%) loading, attributing to the facile synthesis methods, internal structural arrangement, well interaction of filler and matrix, high surface area, and tuneable pore size of filler material. The crystallinity of ZIF‐8 and ZIF‐8@WPU is analyzed by powder X‐ray diffraction, morphology by scanning electron microscopy, thermal properties by thermogravimetric analysis, and mechanical properties by the universal testing machine. This new insight has potential toward the green approach for synthesizing and structural engineering high‐performance advanced nanocomposites in the coating, breathable devices, and food packaging industrial utilization.

A sustainable approach on the potential use of kale puree in edible wraps

Edible films can be used to prevent food spoilage, and investigations in this regard are paramount. When prepared alongside biopolymers, these materials become totally biodegradable in a short period of time, decreasing the amount of solid residues discarded into the environment. The ingestion of fruits and vegetables has increased in the last decades due to significant health benefits, and their durability comprises an important parameter for their marketing and use. Vegetables come in a variety of colors, sizes and shapes, comprising relevant features for their commercialization and packaging and for final consumers. In this regard, kale leaves are highly consumed in Brazil and new alternatives to improve their physical and organoleptic characteristics for novel applications, such as food wraps and in the replacement of high perishability leaves, are of interest in this scenario. Thus, the aim of the present study was to develop kale puree and sodium alginate films and evaluate their solubility, mechanical and thermal properties and water vapor permeability, focusing on improving their physical and organoleptic properties. The films were prepared by casting sodium alginate solutions with the addition of kale puree employing a film generator. Puree incorporation reduced film water vapor permeability and solubility. Pure alginate films presented a contact angle of 50 ± 1°, increasing to 62 ± 2° with the addition of kale puree. The same was noted for the alginate film that, when cross-linked with kale puree displayed an angle increase of 72 ± 5° This behavior may be due to interactions between these components and the hydrophobic phases. Calcium chloride was added for film crosslinking, contributing to biopolymer chain separation and mobility. This study highlights important issues concerning the use of vegetables in the production of edible films, especially biodegradable films, and emphasizes the importance of their development, due to reduced environmental impacts, low costs and the fact that they comprise a renewable resource.

Asymmetric Thermal and Water Vapor Transport of Polyester Spacer and Cotton Nonwoven Fabric Assembly

ABSTRACT Spacer fabric is often used in cushions, footwear, filter material, and other products because of its high air permeability and three-dimensional (3D) structure. However, for practical applications, it is typically combined with other materials. We investigated the thermal properties and water vapor permeability of assembly-combined thicker spacer (16 mm) and various cotton nonwoven fabrics. The assembly-combined lightest nonwoven (30 g/m2) and spacer fabric exhibited the highest thermal resistance, increasing by 66.62% compared with the bare spacer fabric; however, no significant difference was observed when combined with the heaviest woven fabric (60 g/m2). Furthermore, the fabric arrangement during assembly could affect the heat and moisture-transfer efficiencies. The assembly-combined lightest nonwoven (30 g/m2) and spacer fabric under the upward test condition exhibited the highest thermal resistance, highest Clo, lowest heat transfer coefficient, highest insulation ratio, and lowest evaporation resistance among all assemblies. Higher thermal resistance and lower evaporative resistance could benefit physiological comfort. However, the assembly-combined heaviest nonwoven and spacer fabric under the downward test condition exhibited similar thermal resistance to the spacer fabric and the highest evaporation resistance. The asymmetric heat- and moisture-transfer properties of a porous assembly can contribute toward developing new materials for applications in other engineering fields.