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The goal of this research was to understand how firefighter protective suits perform in different operational environments. This study used a sweating guarded hotplate to examine the effect of environmental temperature (20–45°C) and relative humidity (25–85% RH) on evaporative heat loss through firefighter turnout materials. Four firefighter turnout composites containing three different bi-component (semi-permeable) and one microporous moisture barriers were selected. The results showed that the evaporative resistance of microporous moisture barrier systems was independent of environmental testing conditions. However, absorbed moisture strongly affected evaporative heat loss through semi-permeable moisture barriers coated with a layer of nonporous hydrophilic polymer. Moisture absorption in mild environment (20–25°C) tests, or when testing at high humidity (>85% RH), significantly increased water vapor transmission in semi-permeable turnout systems. It was also found that environmental conditions used in the total heat loss (THL) test (25°C and 65% RH) produced moisture condensation in bi-component barrier systems, making them appear more breathable than could be expected when worn in hotter environments. Regression models successfully qualified the relationships between moisture uptake levels in semi-permeable barrier systems and evaporative resistance and THL. These findings reveal the limitations in relying on THL, the heat strain index currently called for by the NFPA 1971 Standard for Structural Firefighter personal protective equipment, and supports the need to measure turnout evaporative resistance at 35°C (Ret), in addition to THL at 25°C.

We describe here the fabrication, characterization, and properties of tough bioplastics made of a babassu oil-based acrylic polymer (PBBM), hemicellulose xylan grafted with PBBM chains, and carnauba wax (CW). The plastic was primarily designed to obtain bioderived materials that can replace low-density polyethylene (LDPE) in certain food packaging applications. To obtain plastic, the radical polymerization of an original babassu oil-based acrylic monomer (BBM) in the presence of xylan macromolecules modified with maleic anhydride (X-MA) was conducted. The polymerization resulted in a material (PBBM-X) mostly consisting of highly branched PBBM/X-MA macromolecules. PBBM-X has a glass transition of 42 °C, a storage modulus of 130 MPa (at 25 °C, RT), and a Young’s modulus of 30 MPa at RT. To increase the moduli, we blended PBBM-X with carnauba wax, a natural material with a high modulus and a melting temperature of ~80 °C. It was found that PBBM-X is compatible with the wax, as evidenced by the alternation of the material’s thermal transitions and the co-crystallization of BBM side alkyl fragments with CW. As a result, the PBBM-X/CW blend containing 40% of the wax had a storage modulus of 475 MPa (RT) and a Young’s modulus of 248 MPa (RT), which is close to that of LDPE. As polyethylene, the PBBM-X and PBBM-X/CW bioplastics have the typical stress-strain behavior demonstrated by ductile (tough) plastics. However, the bioplastic’s yield strength and elongation-at-yield are considerably lower than those of LDPE. We evaluated the moisture barrier properties of the PBBM-X/(40%)CW material and found that the bioplastic’s water vapor permeability (WVP) is quite close to that of LDPE. Our bioderived material demonstrates a WVP that is comparable to polyethylene terephthalate and lower than the WVP of nylon and polystyrene. Taking into account the obtained results, the fabricated materials can be considered as polyethylene alternatives to provide sustainability in plastics production in the packaging areas where LDPE currently dominates.

The impact of preparation conditions including heating temperature (from 60 °C to 90 °C) and drying temperatures (from 25 °C to 90 °C) on the properties of pure curdlan film and konjac glucomannan (KGM) and curdlan blend films were analyzed. Microstructure analysis indicated the KGM addition could significantly improve the relatively poor film-forming property of curdlan. FTIR and X-ray analysis showed that at high heating temperature 90 °C, molecular interaction might be enhanced in the films due to the stretched structure of curdlan and dissociation of curdlan bundles or triple-helix structure. This was supported by the changes in the mechanical property, surface hydrophobicity, moisture barrier, and moisture tolerance property. The impacts of drying temperature were some different for the curdlan film and KGM/curdlan blend film, and were explained from the molecular hydrophilicity-hydrophobicity, compactness of the films, curdlan conformation, and molecular interaction. This work guided biodegradable film production especially with curdlan added.

Summary With amazing progress in the state-of-the-art perovskite solar cells (PSCs) fabricated by laboratory-scale spin-coating methods, upscaling the PSCs via printing friendly techniques is becoming more and more important toward the future deployment of large-scale and stable perovskite modules. Here, we demonstrate the room-temperature meniscus coating of high-quality perovskite films incorporated with a multifunctional sulfobetaine-based zwitterionic surfactant. Systematic in situ studies uncover the perovskite crystallization pathway and emphasize the surfactant’s synergistic role in film construction, crystallization kinetics modulation, defect passivation, and moisture barrier protection. This strategy is applicable across perovskite compositions and device architectures with the enhanced power conversion efficiencies up to 22%. Upscaling the device area to 0.8 cm2 has negligible deterioration in the performance. This represents one of the highest records for the upscaling coated PSCs, not limited in room-temperature coated PSCs. In addition, this approach significantly improves the stability of perovskite films and devices under different aging conditions.

A polyorganosiloxane thin film was deposited on an optically transparent poly(ethylene 2,6-naphthalate) (PEN) film using plasma-enhanced chemical vapor deposition (PECVD) at room temperature to imp...

This paper presents the effect of process parameters of twin screw extruder and addition of Cloisite-15A on mechanical, thermal and moisture barrier properties of epoxy/Cloisite-15A nanocomposites. Four lobed kneading blocks were used the in shearing zone of the extruder, based on their effectiveness in dispersing nanofillers in epoxy. Screw speeds from 100 min−1 to 400 min−1, number of passes up to 15, temperature from 5°C to 80°C and Cloisite-15A contents from 1 wt.% to 2.5 wt.% were considered for designing the L12 Orthogonal Array. Improvements in tensile strength, compression strength, flexural strength, impact strength, hardness and moisture diffusivity in the nanocomposites were 11.89%, 20.06%, 27.73%, 37.26%, 25.48% and 56.22% respectively, when compared to neat epoxy. The improvements were achieved for screw speed of 400 min–1, 5 passes through the extruder, processing temperature of 5°C and 2 wt.% of Cloisite-15A. Dispersion of Cloisite-15A in epoxy was studied by XRD, SEM and TEM. Thermal stability and moisture barrier properties were superior in the nanocomposites.

Interactions between midlatitude westerlies and the Pamir–Tian Shan mountains significantly impact hydroclimate patterns in Central Asia today, and they played an important role in driving Asian aridification during the Cenozoic. We show that distinct west-east hydroclimate differences were established over Central Asia during the late Oligocene (ca. 25 Ma), as recorded by stable oxygen isotopic values of soil carbonates. Our climate simulations show that these differences are present when relief of the Pamir–Tian Shan is higher than 75% of modern elevation (∼3000 m). Integrated with geological evidence, we suggest that a significant portion of the Pamir–Tian Shan orogen had reached elevations of ∼3 km and acted as a moisture barrier for the westerlies since ca. 25 Ma.

Barrier film coating is the most appropriate and widely used approach to protect solid dosages from moisture, particularly for water-sensitive drugs including herbal medicines. This study aims to produce the barrier film of a typical herbal medicine by applying an electrostatic deposition process with ultrafine powders of hydroxypropyl cellulose so as to achieve the functionality of moisture protection. The flowability of the ultrafine powders was significantly improved by adding suitable nano additives. The applied plasticizer in the coating formulation had a significant effect on the water vapor permeability of the film. Also, the electrostatic deposition efficiency were significantly affected by the charging voltage of the electrostatic gun and the plasticizer ratio. Curing time and temperature were identified as two critical parameters for barrier coating in terms of surface morphology and hygroscopicity. All the results suggested that the electrostatic deposition process is capable to produce efficient barrier film for herbal medicines.

Photonic films based on cellulose nanocrystals (CNCs) are sustainable candidates for sensors, structurally colored radiative cooling, and iridescent coatings. Such CNC-based films possess a helicoidal nanoarchitecture, which gives selective reflection with the polarization of the incident light. However, due to the hygroscopic nature of CNCs, the structural colored material changes and may be irreversibly damaged at high relative humidity. Thus, moisture protection is essential in such settings. In this work, hygroscopic CNC-based films are protected with a bioinspired synthetic plant cuticle; a strategy already adopted by real plants. The protective cuticle layers altered the reflected colors to some extent, but more importantly, they significantly reduced the water vapor permeance by more than two orders of magnitude, from 2.1 x 10(7) (pristine CNC/GLU film) to 12.3 x 10(4) g mu m m(-2) day(-1) atm(-1) (protected CNC/GLU film). This expands significantly the time window of operation for CNC/GLU films at high relative humidity. Funding Agencies|Olle Byggmaestare [194-0679]; Knut and Alice Wallenberg Foundation (WWSC); Linkoeping University; Wallenberg Wood Science Center; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoeping University [2009 00971]

Baked food products are considered to be one of the most popular processed foods in the world. Among all the bakery products, biscuits are the most frequently consumed snack food item. There is a vast and diverse market for biscuits as a leader in ready-to-eat baked goods. Biscuits have long shelf life than other bakery products when stored under proper conditions. But immediately after exposure to the air by opening or damaging the package, biscuits absorb moisture from the air and reduce its crispiness of the biscuits. According to the market survey results, the highest number of respondents (53.7 %) suggested developing an edible coating for biscuits to prevent the loss of crispiness in biscuits upon storage. As well as 98.5 % of respondents prefer edible coatings developed using natural sources. Polysaccharide-based edible coatings maintain the physicochemical, microbiological & sensorial properties of the food. Therefore, okra mucilage was used as the main ingredient for edible coating preparation for biscuits. The coating was applied on biscuits with different coating methods, different baking stages and stored in different environmental conditions to identify the efficiency of the coating. According to the results, a coating applied before the baking stage displayed better moisture barrier properties than that of the coating applied after baking in controlled, semi-controlled, and normal atmospheric environmental conditions. It's responsible for the reduction of moisture absorption of biscuits upon storage

As the demand for flexible, rollable, and foldable displays grows, various state-of-the-art component technologies, including thin-film transistors (TFTs), electrodes, thin-film encapsulations (TFEs), and touch screen panels, have been developed based on organic light-emitting diodes (OLEDs) with flexible organic layers. Developing highly reliable flexible OLEDs is essential to realize flexible displays, but the flexible encapsulation technology still has technical difficulties and issues to be addressed. This review covers the recent developments in encapsulation technologies, particularly their material and structural designs, for highly reliable, flexible OLEDs. The solution concepts for the existing technical hurdles in flexible encapsulations are addressed. Among the various advanced flexible encapsulation technologies developed so far, neutral-axis engineering with a thin metal layer and a crack arrester is introduced.

Municipal firefighters count on their protective garments to avoid skin burns caused by thermal and flame exposures. Typical firefighting garment consists of three layers of different fire-resistant fabrics named as outer shell, moisture barrier and thermal liner. This paper employed a numerical heat transfer model for firefighters’ garments, which paid more attention to modeling air gaps bounded between garment’s layers. The paper explored and compared the influences of air gaps bounded between garment’s layers on its protective performance. Specifically, the paper investigated the effect of a variation in the air gaps between the garment layers from 1 mm to 6 mm, a variation in the backside emissivity of the outer shell and moisture barrier layers from 0.9 to 0.1 and a variation in their typical thicknesses from 50% to 200% on the protective performance of garment. The results showed that increasing the width of the gap between the moisture barrier and the thermal liner, reducing the outer shell backside emissivity and increasing the moisture barrier thickness improves the protective performance of firefighters’ garments more than does increasing the width of the gap between the moisture barrier and outer shell, reducing the moisture barrier backside emissivity and increasing the outer shell thickness, respectively.

The use of clay filler materials in dispersion coatings is a well-established method to provide improved barrier properties to the coated paper substrate, in particular lowering the water vapour transmission rate (WVTR) through the coating. In this paper we demonstrate the use of small spherical silica particles (∼100–220 nm) as an additive to a clay-latex coating formulation is able to provide further improvements to the barrier properties, when compared to the equivalent silica-free coatings. A significant decrease in both the water vapour transmission rate and the direct water uptake of water ( Cobb 120 {\text{Cobb}_{120}} wettability test) is observed for coatings containing as little as 1 % silica additive.

In this study, we developed the universal encapsulation method using poly(vinyl alcohol-co-ethylene) (EVOH) to improve the water stability of perovskite solar cells. In order to enhance the moisture barrier property, we utilized SiO2 and graphene oxide (GO) fillers in the EVOH matrix. First, UV-treated SiO2 increased the dispersibility in the EVOH matrix and made the penetrating path more complicated, which led to a better moisture barrier property. The water vapor transmission ratio (WVTR) is enhanced from 4.72 × 10-2 (EVOH only) to 1.55 × 10-2 (EVOH with SiO2 filler) g/m2 day. Second, we found that GO reduce the unreacted hydroxyl groups that could attract water molecules at the surface of EVOH. The addition of GO increased the WVTR up to 3.34 × 10-3 g/m2 day. Finally, our EVOH-based film successfully encapsulated without the efficiency drop. The encapsulated devices surprisingly maintained 86% of their performance even under direct contact with water for 5 h.

This review article critically presents a comprehensive overview of the current advances in the research and development of proteins derived bionanocomposites used in food packaging applications. The recent interest in protein-based biomaterials is due to sustainability, renewability, biodegradability and low carbon footprint. The inherent drawbacks of proteins-based materials for food packaging applications are their low mechanical strength, poor thermal, barrier and inferior physicochemical properties. The nanoreinforced bio-based polymers called bionanocomposites provide an opportunity to overcome these issues and have ability to supersede non-biodegradable food packaging plastics produced from petroleum resources. So far, most studied protein derived bionanocomposites suitable for food packaging are soy protein isolates (SPI) and gelatin proteins. Layered silicates are the most promising nanofillers used to increase strength, improve heat resistance and enhance barrier properties of proteins derived materials while montmorillonites (MMT) is the most commonly used silicate nanofiller. This review emphases on the processing strategies used for proteins-based biomaterials, their mechanical and moisture barrier properties for food packaging applications. Different proteins and nanofillers that have been studied to date in proteins derived food packaging applications are also discussed in detail.

Thin film encapsulation (TFE) is one of the key problems that hinders the lifetime and widespread commercialization of flexible organic light-emitting diodes (OLEDs). In this work, TFE of OLEDs with Al2O3/alucone laminates grown by atomic layer deposition (ALD) and molecular layer deposition (MLD) as moisture barriers were demonstrated. The barrier performances of Al2O3/alucone laminates with respect to the individual layer thickness and the number of dyads were investigated. It was found that alucone with suitable layer thickness could reduce the permeation to the defect zones of the inorganic layer by prolonging the permeation pathway, sequentially improving the moisture barrier performance. The water vapor transmission rate (WVTR) could be further lowered with increasing the number of dyads of the laminates, the WVTR value reached 1.44 × 10−4 g per m2 per day for laminates with 5.5 dyads. These laminates were incorporated in OLEDs with pixel define layer (PDL), and were found to be able to evidently prolong the lifetime of the OLED.

We report the development of a class-II-type hybrid coating (NS-EP hybrid) composed of surface-modified nanosilica (NS) as the filler and a thermo-curable epoxy polymer (EP) as the matrix. NS is synthesized using a hydrolytic sol-gel process; its hydroxyl surface is rendered cross-linkable using glycidyl ligands to ensure homogeneous dispersion and optimal hybridization with the EP matrix. The NS-EP hybrid shows high optical transparency, enhanced mechanical properties, and improved moisture barrier performance. Further, we discuss the physical properties of the hybrid with respect to the NS content. To study the applicability of the hybrid as a high-performance barrier material in practical applications, an actual OLED device is encapsulated using the hybrid.

In this work, we employ atomic layer deposition (ALD) to form Al2O3 layer as an encapsulant for perovskite solar cells (PSCs). Al2O3 layer deposited at temperature as low as 95 °C achieves water vapor transmission rate (WVTR) of 1.84 × 10−2 g m−2 d−1 at 45 °C–100%RH when thermal ALD is used. In order to test the moisture barrier capability of Al2O3 layer for PSCs, mesoporous perovskite devices, with spiro-OMeTAD or PTAA as hole transport layer (HTM) encapsulated by 50 nm Al2O3 film, are exposed to 65 °C–85%RH for 350 h and their stabilities are monitored. We find that the color of perovskite does not change after 350 h of exposure regardless of the type of HTM used. With regards to Th-ALD encapsulated devices, PTAA based PSCs experienced a smaller power conversion efficiency (PCE) drop than spiro-OMeTAD based PSCs after thermal stress at 65 °C. This is due to the presence of pinholes within spiro-OMeTAD layer after thermal stress which are not observed in PTAA. Finally, we successfully achieve excellent durability test results for mesoporous (HC(NH2)2PbI3)0.85(CH3NH3PbBr3)0.15/PTAA devices encapsulated by 50 nm Al2O3 with less than 4% drop in PCE after 7500 h (> 10 months) of exposure to 50%RH under room temperature.

Geosynthetics materials are having wide application in Geotechnical Engineering field. It is available in different forms and can be applied as per the different functions like separator, lining, barrier, filter, reinforcement, etc., in various application area of Geotechnical Engineering field. One of the application of Geosynthetics material in pavement construction as a separator and/or moisture barrier enhances the performance of pavement. In this study the strength parameter of woven coir mat, Jute mat, and geomembrane was analyzed through CBR (California Bearing Ratio) test. In this study, soil aggregate system was used in the CBR mold with and without the geosynthetics material. The soaked and unsoaked CBR value of geotextile and geomembrane was determined and found that their application in the pavement construction can be very effective.

Background Rapid dissolution in digestive tract and moisture sorption during ambient storage are the two challenges of dry probiotic preparations. To solve these problems, microcapsules with shellac (LAC) addition containing Limosilactobacillus reuteri TMW 1.656 were designed in this work to provide a good moisture barrier and to provide controlled release in digestive tract, based on the hydrophobicity and acid-resistance of LAC. Four microcapsules were prepared using the method of emulsification/external gelation based on the crosslinking reaction between alginate or LAC with calcium ion, including alginate/sucrose (ALG), alginate/shellac/sucrose (ALG/LAC), alginate/whey protein isolate/sucrose (ALG/WPI) and alginate/whey protein isolate/shellac/sucrose (ALG/WPI/LAC). Results Measurements of physical properties showed that microcapsules with LAC addition (ALG/WPI/LAC and ALG/LAC) had larger particle size, much denser structure, lower hygroscopicity and slower solubilization in water, which agreed with the primary microcapsule design. Probiotic survivals in digestive juices followed the order of ALG/WPI/LAC ≥ ALG/WPI ≥ ALG/LAC > ALG. Probiotic stability after heating and ambient storage both exhibited the order of ALG/WPI/LAC > ALG/LAC ≈ ALG/WPI > ALG, which can be explained by the decreased hygroscopicity with adding LAC. Conclusion LAC addition contributed to better probiotic survivals after freeze drying, simulated digestion, heating and ambient storage, and whey protein isolate (WPI) addition had a synergistic effect. Microcapsule hygroscopicity was closely related with probiotic survivals after heating and ambient storage, while microcapsule solubilization was closely related with probiotic survivals in simulated juices. Within our knowledge, this is the first report to improve probiotic stability during ambient storage based on LAC hydrophobicity. © 2020 Society of Chemical Industry.

Violin varnishes are known to affect both moisture absorption and vibrational properties of violin wood. However, traditional multi-layered varnish systems suffer from substantial wear as a result of intensive use, which calls for deeper understanding of the specific impact of individual layers. Using sophisticated in-situ neutron imaging and vibrational modal analysis, we show how wood sorption and vibrational behavior of tonewood depend on the build-up of the varnish system. The results demonstrate the protective effect of complete coatings and emphasize that strongly worn regions cannot accomplish the function as an effective moisture barrier, which might pose a risk for frequently played or aged string instruments. Furthermore, the build-up of the varnish system affects the vibrational properties of the tonewood, influencing its final sound quality. This delicate interplay should be considered both for the handling of antique and aged violins and for the production of modern high-quality instruments., Scientific Reports, 9, ISSN:2045-2322

This paper proposes a new method to determine the baking time for moisture-sensitive packages prior to dry pack. The concept is based on consideration of the continuous drying process for a package within moisture barrier bags (MBB), which contain a desiccant. If the moisture is not completely dried out during bake (usually at 125°C), the residual moisture will continue to diffuse out of the package body during storage and shipment in the MBB. In this paper, a 2.5D package is used for a worst-case scenario simulation through finite element modeling. It shows that after a 24hr bake at 125°C, the residual moisture weight gain remains 13% of the total saturated weight gain, and the maximum moisture concentration remains as high as 40% of the saturated moisture concentration; however, after 4 weeks of storage at 30°C in the MBB the residual moisture weight decreases to less than 1%, and the maximum saturated moisture concentration decreases to less than 5% of the saturated moisture concentration. Depending upon package construction, storage conditions and storage time before customer opening of MBB, the modeling results show that consideration of moisture diffusion in the MBB may permit the bake schedule to be shortened.

Purpose The purpose of this study is to review the recent approaches in food packaging trends to address the preferences of the modern world. Design/methodology/approach Recent studies in all the emerging food packaging technologies have been discussed with the examples of commercially available products. Findings Advanced food packaging solutions have acquired much appreciation from food industries to address the preferences of the modern world. This paper attempts to describe the current practices in food packaging with examples of commercially available products. Significant emphasis has been given on the technical aspects of the intelligent packaging components, namely, barcodes, radio frequency identification, sensors and indicators. Another distinctive area of packaging focused in this review is the importance of bioplastics due to non-degradable nature of synthetic polymers. Three major categories of biodegradable polymers, namely, polysaccharide-based materials, protein-based materials and lipid-based materials, have been discussed along with an insight about sustainable packaging and edible films and coatings. Originality/value Changes in the industrial & retail matters and increasing demand for fresh, safe, nutritious food are the factors owing to the new innovations in the packaging sector. Imminent packaging technologies aim at value addition involving the extension of shelf life, prevention of microbial attack, proper moisture barrier, use of carbon dioxide scavengers/emitters, ethylene scavengers, flavor absorbers, freshness indicators, biosensors and release of bioactive compounds during storage.

We report the facile fabrication of transparent and high-performance moisture barrier material (SC nanocomposite) using surface-modified bentonite clay (SC) as nanofiller and glycidyl silane as a surface-modifier/binder via simple, cost-effective and mass-producible process. SC is synthesised using a base-catalysed sol-gel process; their hydroxyl surfaces are decorated with glycidyl ligands to endure the densely stacked structure and high clay content in the final nanocomposite. The SC nanocomposite barrier exhibits high optical transparency (>90), dense multi-stacked clay structure, and considerably enhanced moisture barrier performance. We discuss the fabrication and physical properties of the SC nanocomposite. To assess the applicability of the nanocomposite as a high-performance barrier material in practical applications, typical organic light-emitting devices are encapsulated, and their lifetime is evaluated.

Biodegradable food packaging is sustainable and has a great application prospect. PLA is a promising alternative for petroleum-derived polymers. However, PLA packaging suffers from poor barrier properties compared with petroleum-derived ones. To address this issue, we designed bilayer films based on PLA and Pickering emulsions. The formed bilayer films were compact and uniform and double layers were combined firmly. This strategy enhanced mechanical resistance, ductility and moisture barrier of Pickering emulsion films, and concomitantly enhanced the oxygen barrier for PLA films. Thymol loadings in Pickering emulsion layer endowed them with antimicrobial and antioxidant activity. The release profile of thymol was well fitted with Fick's second law. The antimicrobial activity of the films depended on film types, and Pickering emulsion layer presented larger inhibition zone than PLA layer, hinting that the films possessed directional releasing role. This study opens a promising route to fabricate bilayer architecture creating synergism of each layer.

Applications of cellulose nanomaterials (CNMs) have attracted increasing attention in recent years. One conceivable path lies in their commercial applications for packaging, in which their barrier properties will play an important role in determining their competiveness with conventional materials. This review critically analyzes the performance of CNMs acting as a barrier against moisture and oxygen permeation in CNM films, CNM-coated polymers and papers, and CNM-reinforced polymer composites, gives some insights into remaining challenges, and brings an overall perspective of compositing CNMs with other materials to achieve balanced properties adequate for barrier packaging. In general, CNMs are a poor moisture barrier but excellent oxygen barrier in the dry state and are still good below 65% relative humidity. The addition of CNMs can improve the oxygen barrier of the resulting polymer composites; however, neat CNM coatings and films can afford better oxygen barrier properties than dispersed CNMs in coa...

Biodegradable polymers have emerged as a subject of enormous scientific and industrial interest due to their environmentally friendly compostability. For the benefit of the market economy and reoccurring environmental hazards, biodegradable materials should play a more critical role in packaging materials, which currently accounts for 60% of plastic products. However, various challenges remain for biodegradable polymers towards practical packaging applications. Particularly pertaining to the poor gas/moisture barrier issues which greatly limit the food packaging application of current biodegradable polymers. The chain architecture tailoring, crystallinity, melt blending/multi-layer co-extrusion, nanotechnology and surface coating have been considered as effective strategies for overcoming the poor gas/moisture barrier facing biodegradable polymers, which have been extensively researched for decades. In this review, we provide an in-depth study on the oxygen/water vapor barrier of representative biodegradable polymers in mainstream research with an emphasis on theoretical models and experimental modifications to improve their barrier properties. The influence of various strategies on the barrier improvement, and the pros/cons of each method are summarized. The limitations of current methods are discussed, and potential methods to overcome these limitations are presented. Finally, we conclude this review by listing current challenges associated with the barrier properties, processing and scalability of biodegradable polymers in the food packaging market, and future perspectives for these biodegradable polymers in sustainable composites field.

Summary Biodegradable food packaging promises a more sustainable future. Poly(lactic acid) (PLA) is a promising alternative for petroleum-derived polymers. However, PLA films suffer from poor barrier properties compared with petroleum-derived ones. To address this issue, we designed bilayer and sandwich-architectured trilayer films based on PLA and gliadin. We reported firstly the direct formation of PLA–gliadin bilayer/trilayer films without surface modification on PLA film. The films were compact and uniform, and double/triple layers were combined firmly, preventing delamination. This strategy enhanced mechanical resistance, ductility and moisture barrier of gliadin films and concomitantly enhanced the oxygen barrier for PLA films. Thymol loadings endowed bilayer/trilayer films with antimicrobial activity and antioxidant activity. The antimicrobial activity of the films depended on film types, and gliadin layer presented larger inhibition zone than PLA layer, hinting that the films possessed directional releasing role. This study opens a promising route to fabricate bilayer/trilayer architecture helping to create synergism of the biopolymers.

Temperature and moisture measurements were made in a ventilated attic on a house with 200 mm mineral wool insulation. The measurements showed that 1) solar radiation had a great effect on the temperature in the attic; 2) moisture content reached a level below the risk of mold formation – no mold was seen. The measurements were compared with simulations for insulation thickness from 50 to 500 mm. The calculations indicated that the temperature was nearly the same when the attic was insulated with 200 to 500 mm; hence increased insulation was not a problem. The important assumption was that the roof was constructed with a moisture barrier.

Popping of starchy pellets in a domestic microwave oven has proven difficult compared to pellets expanded in frying oil, and even to microwave expanded popcorn. These pellets encounter problems like uneven popping, burning and the absence of an audible cue for the end of popping. The lack of a moisture barrier, like the pericarp of popcorn, leads to the development of an inverse temperature gradient in the pellets and a significant moisture loss before and after expansion. In this paper we review the hypotheses and solutions for the criticality of microwave popping of starchy pellets, as discussed in scientific and patent literature. We have found a large collection of critical factors and their associated hypotheses, which have been structured via linking them to specific steps in the physical expansion process. We conclude with a list of hypotheses that we view valuable for further investigation.

We fabricated inorganic/organic composite film as encapsulation for top-emitting OLEDs, where the inorganic layer was composed of an Al2O3/MgO laminated structure prepared by atomic layer deposition (ALD), while the solution-processed polymer (CYTOP, PDMS and SU-8) was fabricated as the organic protective layer. It was found that the optimized inorganic/organic bi-layer structure has better barrier performance, leading to a superior water vapor transmission rate (WVTR) as low as 1.05 × 10−6 g m−2 day−1 at 60 °C and 100% R.H., and the encapsulated OLEDs device produces no black spots under a harsh environment (85 °C & 85% R.H.) for 250 h. These improvements were attributed to the hydrophobic surface of the capping polymer lowering the adsorption of water vapor into the bulk material.

Coconut oil constitutes the most important source of dietary fat in many countries. But, of late the consumption of coconut oil has been linked with incidence of coronary heart diseases and sustained campaign against its use is going on. Normal coconut oil contains 92% of saturated fatty acids, most of them are medium chain fatty acids (MCFA). The monoglyceride monolaurium is the substance that keeps infants from getting viral or bacterial or protozoal infections. Coconut oil lowers cholesterol through stimulation of thyroid function. Also coconut oil has high resistance to oxidative rancidity, sharp melting behavior, effective heat transfer agent in frying, provides moisture barrier and in frying, loss to bakery items in spray oil use, carrier and protective agent for fat soluble vitamins, maximum glycerin content, easily saponifiable even in cold, germicidal and antimicrobial property, ready penetration into the skin and appreciable water absorbing property.

Structural fire-protective clothing must be effective at minimizing the thermal effects of fire. However, water remaining on the outer shell might play an important role in conducting heat transfer, which causes skin burns in a firefighter when he douses a fire with water through a hose. Therefore, this research demonstrated the difference in the heat transfer and humidity created by the remaining water or lack of water on the outer shell under a condition in which the temperature (45 ± 1℃) of the external environment was higher than that of the skin. Two types of multilayered systems, which simulated real fire-protective clothing (outer shell, moisture barrier, thermal liner) were tested by using a human–clothing–environment (HCE) simulator. The experimental results verified that water on the outer shell increased the microclimate temperature in the structural fire-protective clothing. In particular, we assume that air permeability in the outer shell can be an important factor to control heat and mass transfer within the microclimate.

Semi fabricates based on Cu(In,Ga)Se 2 solar cells with flexible metallic substrate packaged in innovative moisture barriers that demonstrated failure after damp heat exposure were analyzed using thermographic imaging, luminescence imaging and optical microscopy. This made it possible to visualize and identify the failure modes and find explanations for the causes of failure. The most important causes of failure were concluded to be 1) the relaxation of stresses induced during lamination, 2) moisture ingress from the sides of the samples and 3) moisture ingress at positions where the barrier had been damaged due to the topology of the sample.

Due to the interest in health and concern for the environment, this review work was concentrated on biodegradable and edible materials for the agricultural sector. Edible polymers are recognized as safe for human consumption. In agricultural industry, a film coating is required to prolong the shelf life of products, since moisture plays a critical role in their stabilities. Materials used in film coatings include proteins, polysaccharides and lipids. Shellac is a lipid polymer of interest due to an outstanding moisture barrier and an abundant natural resource of Thailand. However, the shellac film has some drawbacks due to the polymerization and strength of film. This book chapter will focus on the current work to solve the drawbacks of shellac. The application of shellac for film coating in agricultural products, as well as the use of surface free energy for the prediction of coating efficiency was also reviewed in this chapter.

The test house with special timber structure was built by the department of rural building of Estonian University of Life Sciences. The hygrothermal properties of sawdust and cellulose, used as insulation materials in building envelope, were investigated in long term. The test was carried out during four winters. The wind and moisture-vapor barriers were not applied in the first testing period. In the second testing period the wall was covered inside with the moisture barrier and outside with the wind barrier and the layer of OSB plates. In wintertime the test house was heated with electric batteries to keep the indoors temperature stable. The aim of this research was to measure and determine the thermal transmittance of differently insulated wall sections. To fulfil the task the devices to measure relative moisture and temperature were placed in five different positions (in three depths inside the insulation) and indoors and outdoors. The heat flux plates were applied on the inner surface of the wall. Data were recorded with 10 min interval. The analysis of these test periods was carried out and presented in this paper.

Perovskite based photovoltaic (PV) devices have gained enormous importance due to their high power conversion efficiencies and ease of fabrication (solution processing). Conventionally, flexible solar cells have been reported on substrates like PET and PEN. Corning® Willow® Glass, owing to its superior processability and oxygen and moisture barrier property, is a potential replacement for these substrates. In this work, devices fabricated on Willow Glass substrates have been subjected to bending and fatigue tests to assess their worthiness as substrates for flexible solar cells.

Nanocellulose (NC) films are considered as a prospective alternative to non-sustainable packaging materials, however, their higher embodied energy and limited moisture barrier properties are regarded as a huge constraint regarding their commercialization. This study aims to produce films with relatively low environmental impact and improved barrier performance. For this purpose, carboxymethyl cellulose (CMC) and NC were combined, and this resulted in multidimensional advantages. The mass production of films could be achieved in only 2 h (requiring at least 24 h under ambient conditions) when dried in an oven at 75 °C with enhanced mechanical properties and without compromising their dimensional stability. The moisture barrier properties of the NC/CMC films were improved up to 92 % compared with the NC films alone and the results achieved are comparable with packaging materials such as polyethylene terephthalate (PET), polycarbonates (PC) etc. Finally, the NC/CMC (1:1) films have low environmental impact compared with PET films.

Atomic layer deposited nanolaminates of alternating AlOx and TiOx thin-films are investigated as moisture barriers for organic electronic devices. Direct encapsulation on organic light emitting diodes (OLEDs) is tested in aging experiments and compared to calcium corrosion tests of equivalent barrier films. This allows for a direct assessment of moisture barrier performance in simple as well as more complex systems. Thickness variations are performed for the nanolaminate single and total layer thickness, with an optimum single layer thickness of 1–2 nm observed. This correlates to the maximum number of dyads once completely closed single layers are produced. For large single layer thickness and low dyad count, strong lateral diffusion from the edges occurs in the OLEDs, which likely correlates to poor mechanical stability. At optimum single layer thickness, barriers remain mechanically and chemically stable up to 100 nm total thickness. OLEDs encapsulated with such nanolaminate barriers show no significant degradation after 2500 h of continuous aging.

Protection from steam burns is beneficial to reduce the nonfatal injuries of firefighters in firefighting and rescue operations. A new multifunctional testing apparatus was employed to study heat and steam transfer in protective clothing under low-pressure steam and low-level thermal radiation. Single-, double-, and triple-layered fabric assemblies were selected in this experiment. It is indicated that the existence of hot steam weakens the positive influence of the fabric’s thickness, but increases the importance of the air permeability on the thermal protection. The fabric assemblies entrapping moisture barrier can better resist the penetration of steam through the fabric system, and significantly improve the thermal protection in low steam and thermal radiation exposure due to the low air permeability. Additionally, the total transmitted energy ( Qe) and dry thermal energy ( Qd) under low steam and thermal radiation are dramatically larger than that under thermal radiation ( p 0.05). The understanding of steam heat transfer helps to provide proper guidance to improve the thermal protection of the firefighter’s clothing and reduce steam burns.

Integrated standardised methodology for biopolymer derivatives (BPD) production from novel intact bitter cassava was demonstrated by desirability optimisation of simultaneous release, recovery, cyanogenesis (SRRC) process. BPD were evaluated for yield and colour using buffer (0, 2, 4% v/v), cassava waste solids (15, 23, 30% w/w), and extraction time (4, 7, 10 min). Nearly all the root was transformed into BPD, with higher yield and colour in comparison to starch extrinsically processed. Maximum global desirability, predicted efficient material balance, buffer 4.0% w/v, cassava waste solids 23% w/w and extraction time, 10 min, producing BPD yield, 38.8% wb Validation using buffer, 3.3% w/v, cassava waste solids, 30% w/w and extraction time, 10 min, produced 40.7% wb BPD. SEM, DSC, TGA, FTIR and moisture barrier analyses revealed a uniform microstructure and high thermal stability of BPD and film, thus demonstrating efficient performance of the standardised integrated methodology. Hence, processing intact cassava root as a standardised integrated methodology could be used to produce sustainable low cost BPD for a broad range of applications. Methodologies designed around standard integrated procedures, matching zero-based approach to contamination, are novel strategies, and if used effectively can eliminate cassava wastes and recover BPD resources as sustainable biomaterials.

Herein, a novel thin-film encapsulation for flexible organic light-emitting diodes (FOLEDs) is proposed, and its long-term reliability in tensile stress conditions was tested. The hybrid nano-stratified moisture barrier consists of 2.5 dyads of an Al 2 O 3 /ZnO nano-stratified structure and a S-H nanocomposite organic layer. The nano-stratified structure is prepared by low-temperature atomic layer deposition and the S-H nanocomposite by spin-coating at a thickness of 30 and 120 nm, respectively. An optical transmittance of 89.05% was measured with the 2.5-dyad hybrid nano-stratified moisture barrier with a total thickness of 330 nm. A low water vapor transmission rate (WVTR) of 1.91 × 10 −5 g/m 2 day was recorded based on an electrical Ca test at 30 °C and 90% R.H. without losing its properties after a bending test. With this highly reliable hybrid nano-stratified moisture barrier, FOLEDs were successfully encapsulated. After 30 days under conditions of 30 °C and 90% R.H. with tensile stress, the J-V-L performances of the FOLEDs were comparable to those of the initial state without dark spots. These results suggest that this hybrid nano-stratified moisture barrier is an excellent method for encapsulating FOLEDs.

Firefighters are required to carry out their responsibilities under a wide range of environmental conditions. For this reason, the physiological and psychological responses of firefighters while wearing their protective clothing should be analyzed to minimize their thermal or cold stress. Four environmental conditions were selected: hot and humid (HH, 34℃, 75% relative humidity (RH)), hot and dry (HD, 34℃, 30% RH), warm and dry (WD, 27℃, 30% RH), and slightly cold (SC, –3℃). Six professional firefighters served as subjects. The exercise was performed on a treadmill at the maximum speed of 8 km/h. The microclimate temperature and RH, skin temperature, heart rate, oxygen uptake, sweat loss, sweat evaporation, moisture accumulation within the outer shell, moisture barrier and thermal liner, and subjective sensations were measured. The microclimate wet-bulb globe temperatures (micro-WBGTs) were calculated. High microclimate measures, skin temperature, and heart rate, as well as low scored subjective sensations, were observed under the HH condition. A 45% difference in RH between HH and HD resulted in clearer differential responses compared with the 7℃ difference in air temperature between HD and WD. Under the SC condition, subjects had a cool to cold feeling. A quite different distribution of moisture accumulation in clothing layers was observed under the SC condition compared with other conditions. This moisture accumulation affected the comfort sensation. A linear relationship was found between the comfort sensation and the micro-WBGT. The micro-WBGT was a good indicator of the physiological status of the wearers. The microclimate, moisture accumulation and its distribution within firefighters’ protective clothing should be extensively studied in the future.