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Liner materials have extensive applications in automobile industry, packaging, and aeronautics. One of the specific uses of such materials is in thermal barrier, coating rockets, missile, and other systems used in space and defense. Each liner material exhibits different properties according to their chemical structure and composition. In this study, accelerated thermal aging of the liner material, silicone‐hollow glass microsphere composite (SHGC) has been studied along with the determination of its life span. The effect of such aging on the thermal properties of SHGC has been studied using thermogravimetry. Activation energy of the process has been determined to be in the range of 45–55 KJmol−1. The results have been compared with already reported silicon polymers. Shelf‐life of SHGC composite has also been determined using Arrhenius model. Stochastic model has been applied to determine the lower and upper limits of shelf‐life. Shelf‐life of SHGC is found to be 24 years with 28 and 18 years of upper and lower error limits. [ABSTRACT FROM AUTHOR]

Dithienylethene photoswitches with an aromatic π‐linker as the bridge between the two thiophene units are attractive starting materials for developing molecular solar thermal energy (MOST) storage systems, partly because the aromaticity of their ring‐open forms is a favorable feature with regard to the energy‐storage densities of their ring‐closed forms produced by photoinduced electrocyclization (photocyclization) reactions. At the same time, this typically leads to small barriers for their thermal cycloreversion reactions, which are not desirable in this context. Here, we use computational methods to show that this problem can be circumvented with polycyclic heteroaromatic π‐linkers. Specifically, through the tuning of the aromatic character of the individual rings of such a π‐linker (like indole or isoindole), it is shown to be possible to strike a delicate balance between the seemingly contrasting requirements of simultaneously achieving both a high energy‐storage density and a large cycloreversion barrier. Furthermore, this design is also found to provide for a quick and efficient photocyclization reaction, owing to the onset of excited‐state antiaromaticity in the π‐linker upon light absorption of the ring‐open form. Altogether, dithienylethenes with polycyclic heteroaromatic π‐linkers appear to have both thermal and photochemical properties suitable for further development into future MOST systems. [ABSTRACT FROM AUTHOR]

In recent years, there has been a growing concern to counter environmental pollution, and as a result the development of biodegradable materials in various applications has become a major focus. This study aimed to fabricate a biodegradable composite by utilizing discarded hair keratin from beamhouse processing in leather production along with incorporating graphene oxide (GO) to reduce pollution. The composite was prepared using a simple solution mixing method, where the amino functional group of keratin and the carboxyl group of GO were covalently bonded under a redox system. Various analyses, including UV–visible spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, SEM, biodegradability and oxygen gas transmittance rate, were carried out to evaluate the composite's structure and performance. The results demonstrated that GO was successfully integrated into the keratin matrix, with uniform dispersion of GO observed instead of agglomeration. The composite with the optimum ratio exhibited a 173.98% increase in tensile strength and a 33.52% decrease in elongation as well as improved thermal and biodegradation properties compared to pure keratin. Furthermore, the composite displayed significantly better gas barrier properties (39%) than pure keratin, which can be attributed to the reduction of intermolecular gaps through the composite's strong bonding. Hence, the keratin‐GO composite is a cost‐effective and biodegradable solution to waste materials, with potential use as a packaging material. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Poly(3‐hydroxybutyrate) (P3HB), a biologically produced, biodegradable natural polyester, exhibits excellent thermal and barrier properties but suffers from mechanical brittleness, largely limiting its applications. Here we report a mono‐material product design strategy to toughen stereoperfect, brittle bio or synthetic P3HB by blending it with stereomicrostructurally engineered P3HB. Through tacticity ([mm] from 0 to 100 %) and molecular weight (Mn to 788 kDa) tuning, high‐performance synthetic P3HB materials with tensile strength to ≈30 MPa, fracture strain to ≈800 %, and toughness to 126 MJ m−3 (>110× tougher than bio‐P3HB) have been produced. Physical blending of the brittle P3HB with such P3HB in 10 to 90 wt % dramatically enhances its ductility from ≈5 % to 95–450 % and optical clarity from 19 % to 85 % visible light transmittance while maintaining desirably high elastic modulus (>1 GPa), tensile strength (>35 MPa), and melting temperature (160–170 °C). This P3HB‐toughening‐P3HB methodology departs from the traditional approach of incorporating chemically distinct components to toughen P3HB, which hinders chemical or mechanical recycling, highlighting the potential of the mono‐material product design solely based on biodegradable P3HB to deliver P3HB materials with diverse performance properties. [ABSTRACT FROM AUTHOR]

The industry desires to create robust, resilient, thermally stable, and environmentally friendly composites. In this study, we created a poly (lactic acid) (PLA) composite via a straightforward method. The Ti3C2TX was surface‐coated with polydopamine (PDA) via a bioinspired approach and was then reinforced in the PLA using melt blending. The PDA layer adorned on the Ti3C2TX provided several functional groups for the MXene nanosheets and strengthened the PLA‐MXene interaction by hydrogen bonding. The well‐dispersed PDA@Ti3C2TX in the PLA improved mechanical, thermal, and tribological properties. For PLA/PDA@Ti3C2TX‐1, the tensile strength and elongation at the break of the nano‐composite were 9.03% and 25.5% higher than pure PLA, respectively. The flexural strength and modulus were increased by 49.5% over pure PLA, reaching 148.8 and 6702 MPa, respectively. The nanocomposite toughness increased by up to 53.3%. The nanocomposites had 3.8% and 49.08% lower friction coefficient and specific wear rate, respectively, than pure PLA. The addition of Ti3C2TX and PDA@Ti3C2TX increased the thermal stability of PLA at lower temperatures and promoted carbonization. PLA/PDA@Ti3C2TX‐1 showed the maximum char yield of 10 wt.% at 800°C, proving the highest thermal barrier effect due to MXene exfoliation during PDA and increased PLA dispersion state. [ABSTRACT FROM AUTHOR]

This article investigates the impact of gamma irradiation on the thermal properties of porous silicon with varying levels of porosity. Porous silicon is a crucial nanomaterial in modern materials science, widely utilized in electronics, optoelectronics, and various applications. Understanding how its thermal transport properties change under gamma irradiation is of importance for various industries, including military, space, and nuclear technologies, where materials may be exposed to ionizing radiation. For this purpose, we employed the non-destructive photoacoustic method with gas-microphone registration. We assessed thermal conductivity as a function of porosity and irradiation time by simulating the experimental amplitude-frequency dependencies using an appropriate model. Our findings reveal that prolonged gamma irradiation of samples using Iridium-192 with an activity of 50 Curie for up to 20 minutes leads to a decrease in thermal conductivity in porous silicon. This is due to the emergence of defects in the crystalline structure of porous silicon and even its possible amorphization. These defects and alterations in the material's structure restrict the movement of heat carriers, thereby reducing its thermal conductivity. It is worth noting that the most significant change observed in this study is a two-fold reduction in thermal conductivity, particularly evident in samples with the highest level of porosity (60 %). Samples with higher porosity exhibit a stronger response to gamma irradiation because they contain less material within their volume that can conduct heat. The constraints within the crystalline structure of samples with greater porosity create additional barriers to heat transfer, leading to increased vulnerability of the material to radiation and a decrease in its thermal conductivity [ABSTRACT FROM AUTHOR]

Aliphatic polycarbonates (APCs) have become an essential packaging material because of their renewability, biodegradability, and biocompatibility. In this study, a series of high molecular weights APCs have been successfully synthesized using dimethyl carbonate (DMC) and different lengths of aliphatic diols with even carbon (n-CH2 = 4–12) via melt polymerization. Thermal properties, isothermal crystallization behavior, crystal structure, and scale of microstructure of APCs indicated that the flexibility and crystallization of molecular chains gradually increased with the increasing number of methylene groups of repeating units. However, due to the rigidity of ester group was higher than methylene group, and crystallization could increase the rigidity of chain segments, yielding strength and Young's modulus of APCs decreased first and then gradually increased with the increasing number of methylene groups in the repeating units. Furthermore, the scale of microstructure indicated that Brill transition increased the distance between intermolecular chains. Therefore, although the trans-gauche coexistence chain conformation simultaneously decreased the rigidity and crystallization of chain segments, barrier property of poly(octamethylene carbonate) with Brill transition was similar to long-chain APCs because of the lengthened diffusion path. The analytical mechanism of structure-performance relationship from the viewpoint of molecular interactions and chain structure will provide an entirely new thought for developing new barrier materials. [ABSTRACT FROM AUTHOR]

With the increasing number of electric vehicles (EVs) rises the need to recycle their used lithium-ion batteries (LIBs). During the mechanical process of the recycling of the LIB cells, a fine fraction, the so-called black mass, is created. This black mass consists mostly of the coatings originating from the cells' electrodes and residues from the electrolyte, together with a low amount of Al and Cu from the crushed current collector foils. The amount of black mass as well as its composition is influenced by the chosen grid size at the crusher discharge. To reduce solvent emissions during the recycling process, a thermal pre-treatment can be added before crushing, which also influences the black mass and its properties due to changes in the adhesion between electrode foils and coating. This study investigates the influence of the crusher settings as well as the pre-treatment temperatures to find an optimum between the recovery of the coating and conductive salt, while limiting the amount of Al and Cu in the black mass. [ABSTRACT FROM AUTHOR]

Mechanical, barrier, and thermal properties of films based on blends of corn starch and chitosan plasticized with ethylene glycol, glycerol, and sorbitol were investigated. Starch amylopectin variation was explored, and contents of 100% and 73% were employed to blend with chitosan and polyols. The findings showed that high amylopectin content has a significant effect (p < 0.05), resulting in films with lower tensile strength (TS) and reduced water vapor permeability (WVP). On the other hand, the incorporation of polyols showed a significantly high (p < 0.05) elongation at break (EB) for films plasticized with glycerol and sorbitol at high amylopectin content. For chitosan/73% amylopectin film, the addition of plasticizers exhibited no significant difference (p < 0.05) among the samples for TS and WVP results. The amylopectin content played no influence in the degradation stability of the films measured by thermogravimetry (TGA). However, amylopectin content influences the endothermic peak temperature observed by differential scanning calorimetry (DSC) analysis. A reduction of about 15 °C was noticed for the film prepared with high amylopectin content, a behavior correlated to its amorphous structure, capable of retaining more water than a crystalline region. [ABSTRACT FROM AUTHOR]

In this work, the effects of different ZnO-decorated graphene (Graphene-ZnO) proportions on the comprehensive properties of Poly(butylene succinate) (PBS) nanocomposites were investigated. The results show that the nanocomposites have stronger mechanical properties, higher thermal stability, greater crystallinity, better barrier ability, and excellent antibacterial property due to the influence of Graphene-ZnO. The tensile strength, crystallinity, melting temperature, thermal stability and barrier performance of the nanocomposites reached the maximum when Graphene-ZnO with a content of 0.2 phr was added. Compared with pure PBS, when Graphene-ZnO was added to PBS at 0.2 phr, the tensile strength, yield strength, elongation at break and moisture barrier performance of PBS were significantly increased by 22.5%, 31.34% ,62.84% and 42.57% respectively. This improvement in barrier performance might be attributed to the presence of Graphene-ZnO extended the penetration path of molecules and the coordination from PBS and Graphene-ZnO, so as to narrow the H2O transmission path. The results of the buried soil test show that the weight loss rate of the nanocomposite increased with increase Graphene-ZnO content, which may be caused by boundary defects between nanofiller and matrix, and poor compatibility at high content of Graphene-ZnO. [ABSTRACT FROM AUTHOR]

Pullulan-based smart packaging films were prepared by mixing cooked amaranth juice and bergamot essential oil. The impact of cooked amaranth juice and bergamot essential oil on the color-changeability, structural characterization, and barrier, antioxidant, mechanical and thermal properties of pullulan-based films was determined. Results showed the cooked amaranth juice contained pH-response color-changing betacyanins. The pullulan films containing cooked amaranth juice were color-changeable in pH 9–12 buffers and in ammonia vapor. The color-changeable property of betacyanins in cooked amaranth juice was unaffected by bergamot essential oils. The inner structure of pullulan films was greatly affected by cooked amaranth juice, forming big and ordered humps in film cross-sections. The crystallinity of pullulan films was improved by the combined addition of cooked amaranth juice and bergamot essential oil. Among the films, the pullulan film containing cooked amaranth juice and 6% bergamot essential oil showed the highest UV-vis light barrier property, antioxidant activity, and tensile strength; while the pullulan film containing cooked amaranth juice and 4% bergamot essential oil showed the highest oxygen barrier property and thermal stability. Moreover, the pullulan films containing cooked amaranth juice were able to monitor the freshness of shrimp by presenting color changes from reddish purple to dark red. [ABSTRACT FROM AUTHOR]

Utilizing 3D-printing techniques to fabricate novel composites with multifunctional properties is a real challenge. This study deals with the synthesis of graphitic carbon nitride (g-C3N4) using melamine and reinforcing it with Poly (lactic acid) (PLA) to achieve enhanced mechanical and thermal properties. g-C3N4 is a silane surface modified to increase the bonding strength between filler and matrix. PLA/ g-C3N4 composite filament is extruded using a controlled speed of 30 rpm and a temperature of 170 °C, and samples are 3D-printed. To improve mechanical and thermal properties, varying weight percentages (0, 0.5, 1, 3, 5) of g-C3N4 are reinforced into the PLA matrix. The PLA composite (3% filler) exhibited a tensile strength of 62 MPa. The flexural and impact strengths of the composite containing 3% g-C3N4 were 63 MPa and 6.5 KJ/m2, respectively. Mechanical properties of 3D printed PLA/g-C3N4 composites were enhanced due to dispersed g-C3N4 filler particles, which shared the stress produced in the polymer and the g-C3N4 entrapped the polymer matrix molecular chain. Compared to PLA composite (5% filler) and pure PLA, the initial and final degradation temperatures were increased by about 4.15% and 4.38%, respectively. The thermal properties improved owing to the g-C3N4 particles acting as a thermal barrier in the PLA matrix. Additionally, silane-treated g-C3N4 particles meet the PLA matrix, and the organo-functional group of the silane interacts with the PLA matrix, thus enhancing the interfacial bonding, which restricts the motion of polymer chains at elevated temperatures. The 3D printing process could make them more competitive in the market by making commercial PLA parts that are better for the environment and have better mechanical and thermal properties. [ABSTRACT FROM AUTHOR]

Nanocomposites are heterogeneous media with two or more micro‐structural levels. For instance, a nano‐level is characterized by isolated nano‐inclusions, and a micro‐level is represented by the clusters resulting from aggregation processes. Based on the reiterated homogenization method, we present a procedure to study the influence of this aggregation process and interfacial thermal resistance on the effective thermal conductivity for 2‐D square arrays of circular cylinders. First, an effective intermediate thermal property is obtained by taking into account only the influence of the individual nano‐inclusions in the matrix. Second, the final effective thermal coefficient (k^RH$$ {\hat{k}}_{RH} $$) is calculated considering the clusters immersed in the intermediate effective medium derived in the first step. The conductivity gain (kgain$$ {k}_{gain} $$) is defined as the quotient (k^RH/k^CH$$ {\hat{k}}_{RH}/{\hat{k}}_{CH} $$) where k^CH$$ {\hat{k}}_{CH} $$ is the effective thermal coefficient computed considering only one microstructural level with the same volumetric fraction of inclusions. We apply the theory of complex variable functions deriving in an infinite system of equations solvable by truncation method. The analytical formulas of the effective coefficient used in the calculations generalize other well‐known formulas reported in the literature. We also provide formulas for several truncation orders. The main novel contribution is in the reiterative application of the obtained formulas to illustrate the gain effect in nanocomposites, expressed as a function of the Biot number, thermal conductivities, volumetric fibers fraction, and an aggregation parameter. Furthermore, this result can be used to assess numerical computations and for nano‐reinforced fibers and nanofluids applications. An appendix is included showing similarities and differences with a three‐phase model. [ABSTRACT FROM AUTHOR]

This study investigated the impact of a Ge2Sb2Te5 (GST) thermal barrier on the performance of NbO2-based selector devices. Our findings showed that the GST barrier could significantly decrease the off-state leakage current from 3 μA to 300 nA without increasing the threshold switching voltage owing to its insulation properties and high thermal resistance. We also found that the GST barrier can effectively contain the Joule heat within the NbO2 switching region, as confirmed through a cryogenic analysis of the thermal resistance of GST. The results showed that the GST/NbO2 device had a thermal resistance 3.48 times higher than that of a single-layer NbO2 device. Our results provide design guidelines for utilizing a barrier layer to reduce the leakage current in low-power threshold switching devices. [ABSTRACT FROM AUTHOR]

Polymer nanoclay composites have received significant attention due to their substantially enhanced mechanical, thermal and barrier properties. However, the effect of these nanoclays on the dynamic fracture resistance of a polymer matrix during fast fracture events has not been documented. In this study, the effect of nanoclay addition on the rapid crack propagation (RCP) resistance of high-density polyethylene (HDPE) was investigated through the high-speed double torsion test. Results showed that the addition of 1, 3, and 5% of nanoclays improved the dynamic fracture resistance under the plane strain conditions ( G d 1 ) of HDPE up to 65%. An increase in the storage and loss modulus, and a decrease in crystallinity and melt flow index with nanoclay content was also found. Although the presence of agglomerates can hinder the enhancement of G d 1 as it promotes agglomerate fracture and debonding, the increase in energy consumption through fibrillation and crazing promoted by the nanoclay prevails, suggesting that the nanoclay's toughening effect that has been extensively reported under quasi-static and impact tests, is also present under RCP conditions, and that the HDPE nanocomposites could be used in applications in which RCP must be prevented. [ABSTRACT FROM AUTHOR]

The bioeconomy aims to discover new sources for producing energy and materials and to valorize byproducts that otherwise would get wasted. In this work, we investigate the possibility of producing novel bioplastics, made up of argan seed proteins (APs), extracted from argan oilcake, and amylose (AM), obtained from barley plants through an RNA interference technique. Argan, Argania spinosa, is a plant widespread in arid regions of Northern Africa, where it plays a fundamental socio-ecological role. Argan seeds are used to obtain a biologically active and edible oil, producing a byproduct, the oilcake, that is rich in proteins, fibers, and fats, and is generally used as animal food. Recently, argan oilcakes have been attracting attention as a waste to be recovered to obtain high-added-value products. Here, APs were chosen to test the performance of blended bioplastics with AM, because they have the potential to improve the properties of the final product. High-AM-starches present attractive features for use as bioplastics, including a higher gel-forming capacity, a higher thermal stability, and reduced swelling compared to normal starch. It has already been demonstrated that pure AM-based films provide more suitable properties than normal starch-based films. Here, we report on the performance of these novel blended bioplastics in terms of their mechanical, barrier, and thermal properties; and the effect of the enzyme microbial transglutaminase (mTGase) as a reticulating agent for AP's components was also studied. These results contribute to the development of novel sustainable bioplastics with improved properties and confirm the possibility of valorizing the byproduct, APs, using them as a new raw material. [ABSTRACT FROM AUTHOR]

The solution precursor plasma spray (SPPS) process involves injecting atomized droplets of a precursor solution into the plasma plume. In this study, two different solution precursors were used in the SPPS process including zirconium oxynitrate and zirconium acetate to make thermal barrier coatings (TBC). The effect of these solutions on microstructure and high-temperature properties of thermal barrier coating made by SPPS has been studied. The results showed that the use of zirconium acetate as a precursor compared to zirconium oxynitrate led to the formation of more vertical cracks with an average spacing of 150-200 μm in the microstructure of coatings. This was due to the presence of more un-pyrolysis or semi-pyrolysis materials in the coating structure and their shrinkage stresses during the deposition that was dependent on the solution chemistry in the plasma plume. The oxidation test at 1000 °C for various times of 12, 50, 120, and 250 h showed similar behavior for both coatings. In addition, the coating obtained from zirconium acetate precursor exhibited an average life of 648 cycles in a 1-h 1000 °C thermal cycling test, which was more than about 1.5 times that of SPPS-TBC coating made of zirconium oxynitrate precursor (431 cycles) due to the presence of much more vertical cracks in its structure. [ABSTRACT FROM AUTHOR]

The high-entropy ceramic materials (Zr 0.25 Ce 0.25 Hf 0.25 Y 0.25)O 1.875 (H-0) and (Zr 0.2 Ce 0.2 Hf 0.2 Y 0.2 RE 0.2)O 1.8 (H-RE) (RE = La, Nd and Sm) with fluorite structure and homogeneous element distribution were prepared. With fluorite structure, fine grain size and high density, the H-0 and H-RE ceramics displayed low thermal conductivity, suitable thermal expansion coefficient, high hardness and fracture toughness. The effect of La, Nd and Sm on the mechanical, heat conductivity and heat expansion properties of high entropy ceramics were discussed. The single-phase high-entropy ceramic materials in this work are very suitable for application as thermal barrier materials. [ABSTRACT FROM AUTHOR]

In this paper, a series of poly(ethylene terephthalate‐co‐2,6‐naphthalate) (PETN) (co)polyesters with different naphthalene ring contents were synthesized via a two‐step transesterification and polycondensation. The effects of the monomer compositions on the sequence distribution, crystallization, mechanical, thermal, and barrier properties of the (co)polymers were investigated systematically. The results showed that the introduction of naphthalene ring units (NDC) changed the sequence length of the PETN and disrupted the orderly arrangement of the PETN molecular chains, thus affecting the aggregated structure and properties of the copolymer. When the NDC content was less than 30%, the PETN copolymers displayed good ductility and higher yield strength comparable to PET, and the heat distortion temperature (HDT), thermal stability properties, and barrier properties of the copolymer were also improved. In addition, the diffusion kinetics of water and oxygen molecules in the (co)polymer were investigated by the MS program simulation software. The differences in gas barrier properties of the different PETN (co)polymers were explained at the molecular level. This study provides a systematic theoretical basis and comprehensive practical guidance for the preparation of high‐performance copolyester materials. [ABSTRACT FROM AUTHOR]

Polyurethane (PU) and zinc ionomer (ZnI)-based polymer composites films were developed by melt extrusion method. The structure, phase morphology, rheology, and mechanical properties of the PU/ZnI blends were studied. The X-ray diffraction analysis displaced that there is no major effect on the crystallinity of PU phase by the addition of ZnI. Scanning electron microscopic images confirmed the partial miscibility of PU and ZnI, which greatly influenced on the tensile and elongation at break (EB) properties of the composite films at a high ratio. Dynamic mechanical analysis indicated that with increasing the ZnI content, the storage modulus of the blends decreased and exhibited two T g temperature peaks. Tensile strength of the PU/ZnI composites decreased drastically and EB increased significantly by the addition of ZnI, however a degree of interaction has been found. PU/ZnI composite films improved surface hydrophobic with excellent water barrier properties. The ultraviolet transmittance of the PU increased with increasing the content of ZnI. [ABSTRACT FROM AUTHOR]

Titanium dioxide hollow microspheres (HMS-TiO 2) were successfully synthesized through a sol-gel and subsequent high-temperature calcination method using a hard template. These microspheres exhibit an average particle size of about 13.66 μm and a shell layer thickness approximately 1.18 μm. Furthermore, the thermal insulation effect is evident in cementitious materials coated with an HMS-TiO 2 -based composite film. The maximum average near infrared (NIR) reflectance and thermal insulation temperature difference of these coated materials are 46.81 % and 9.3 ℃, respectively. Notably, the modified composite film displays excellent mechanical and impermeable properties when applied to the surface of cement mortar samples. These comprehensive results indicate that introducing HMS-TiO 2 with the synergy of structure and composition significantly enhances the thermal, mechanical, and durability properties of modified waterborne coatings on cement-based materials. This augmentation makes them well-suited for thermal insulation and heat preservation applications in building structures. • Micro-scale hollow TiO 2 was synthesized using a hard template method. • The synergy of structure and composition is crucial for cement coatings. • Hollow TiO 2 -based coatings show excellent thermal insulation properties on buildings. [ABSTRACT FROM AUTHOR]

The mechanical properties especially the compression performance are very important for thermal interface materials (TIMs) to mitigate warpage failure caused by stress concentration and reduce contact resistance in practical applications. However, high thermal conductivity and excellent mechanical properties are generally incompatible in traditional TIMs. Herein, we fabricate a high-performance carbon fiber-based TIM by using an extrusion method based on the flow shearing effect. The vertically oriented composite shows a through-plane thermal conductivity up to 18.5 W·m−1·K−1 at 20 wt% carbon fiber content, which is 92.7 times that of pure matrix and 6.3 times that of the random structure. Moreover, the as-prepared material exhibits low hardness of 56 (Shore 00) and outstanding elastic compression performance of 51.4% compression under a pressure of 45 psi. These excellent properties are primarily attributed to the high orientation of the carbon fibers (CFs), thereby establishing a direct and effective thermal conductivity path in the vertical direction. In addition, the synergistic effect of carbon fibers and alumina particles is also beneficial for building thermal conduction pathways. Our work provides an insight to further research in fabricating high-performance flexible TIMs as a promising candidate for applying in advanced thermal management fields. • The composite achieves a thermal conductivity of 18.54 W·m−1·K−1. • The composites exhibit good elastic compliance under high through-plane thermal conductivity. • The synergistic effect of carbon fibers and alumina promotes the enhancement of thermal conductivity [ABSTRACT FROM AUTHOR]

• Thermal transport through SEI of Li-ion batteries was studied using MD simulations. • Three representative inorganic components of SEI were considered. • Impact of structural properties and temperatures were investigated. • Thermal conductivity of amorphous compounds is closely related to the components. • Results provide valuable insights for the design of electrolytes and SEI. The thermal behavior during operation of Lithium-ion batteries (LIBs) is widely concerned with respect to their electrochemical performance and safety. The solid electrolyte interphase (SEI) is a critical layer formed during electrochemical reactions in LIBs. A thorough understanding of SEI's thermal transport properties is essential to identify limitations within the internal heat transfer of LIBs. In this work, a computational study of the thermal transport through SEI was performed based on classical molecular dynamics (MD) simulations. Three representative inorganic components of SEI, namely Li 2 CO 3 , Li 2 O and LiF, were explored. First, the force fields were evaluated for accurate MD simulations. Subsequently, the impact of structural properties and temperatures on the thermal conductivities of SEI were investigated, followed by discussion on radial distribution functions and vibrational density of states. It was found that the comparison of thermal conductivity of the ordered crystals is Li 2 O > LiF > Li 2 CO 3. As temperature increases, the thermal conductivity of inorganic components decreases significantly. Additionally, it was discovered that the thermal conductivity of amorphous compounds is notably lower than that of ideal crystals and is closely related to the molar ratio of inorganic components. The results of this work can help understand the thermal transport properties of SEI and offer valuable insights for the design of electrolytes and SEI toward improving the thermal safety performance of LIBs. [ABSTRACT FROM AUTHOR]

Carboxymethyl starch (CST) was introduced to improve gelatin films and its practical application as edible high-performance films for food packaging and cooking was also investigated. The gelatin films modified by carboxymethyl starch exhibited the transparent appearance, tensile strength, barrier properties (oxygen, water vapor and UV light), and thermal performance (TGA, thermal shrinkage and heat-sealing strength). Resulting from the effect of electrostatic interaction modes on the properties of films, electrostatic repulsion could surpass electrostatic attraction in improving the tensile strength, oxygen barrier property and thermal stability of the films probably due to extensive physical entanglement without aggregation. Analysis of FTIR, zeta potential, interfacial dilatational rheology, shear rheological properties, XRD, Raman, SEM and AFM suggested that hydrogen bonding and electrostatic repulsion contributed to the excellent performance. The packaged food could also be cooked with the prepared film for porridge; and the film slightly influenced the shear rheological properties of porridge and imposed little effect on the odors (Electronic-Nose) of porridge. Hence, the gelatin films modified by carboxymethyl starch could potentially work as the edible inner packaging or the edible quantitative packaging for food, offer convenience for consumers, reduce the packaging waste and avoid an extra burden on environment. • CST improved mechanical and barrier properties (O 2 , moisture and UV light) of films. • CST enhanced the thermal stability, thermal shrinkage and sealing strength of films. • Hydrogen bonds and electrostatic repulsion improved compact matrix and performance. • Excessive CST granules caused the weak interactions and the property deterioration. • The packaged food could cook porridge and slightly affect the rheology and odors. [ABSTRACT FROM AUTHOR]

The effects of substituting the B cation in A3BO7 ceramics on their thermal physical properties were investigated by applying a large mass difference. Y3(Nb1‐xTax)O7 (x = 0, 0.1, 0.2, 0.3, 0.4, and 0.5) ceramics were synthesized, and their structural characteristics were determined. All the fabricated Y3(Nb1‐xTax)O7 ceramics showed defective fluorite structures and glass‐like low thermal conductivity (1.18−2.04 W/m∙K at 25°C) because of the highly distorted crystal structure and significant mass difference. Substitution with Ta5+ enhanced the sintering resistance, leading to superior thermal‐insulating performance via grain boundary scattering. Furthermore, the ceramics exhibited excellent coefficients of thermal expansion, implying the promising applicability of Y3(Nb1‐xTax)O7 as new thermal barrier materials. The effect of mass difference on the thermomechanical properties of the ceramics was examined, suggesting a simple strategy for engineering the chemical composition of new thermal barrier materials. [ABSTRACT FROM AUTHOR]

In the present study, the effect of nanoclay and nanomica on the structural, thermal and barrier properties of poly (ethylene terephthalate) was investigated. The morphology of the papered nanocomposites (Clay and Mica) was illustrated by X-Ray Diffraction (XRD), Transmission electron microscopy (TEM) and Atomic force microscopy (AFM). According to Dynamic Mechanical Thermal Analyzer (DMTA) results, the samples' tanδ values ranged from 0.4 to 0.6. The results of Differential scanning calorimetry (DSC) revealed that the incorporation of nanoparticles increased both the crystallization temperature (Tc) and the degree of crystallization (Xc). Then, the higher aspect ratio of nanomica compared to nanoclay led to higher levels of Xc. A significant water vapor permeability decrease (maximum reduction at 1% loading level of nanomica) of nanocomposites was attributed to an increase in the tortuosity of water vapor molecules path diffusing into the nanocomposites. PET/mica nanocomposites presented larger tortuosity factors compared to PET/clay. As a result, improved barrier properties of nanocomposites were obtained in the case of food packaging. [ABSTRACT FROM AUTHOR]

In this study, a high-entropy approach was employed to design a new single-phase A 2 B 2 O 7 oxide for thermal insulation applications. Multicomponent high-entropy oxides, containing up to seven different cations, were successfully synthesized in a single defective fluorite structure. We observed that the incorporation of the functional cation, Zn2+, effectively blocked the heat radiation phenomenon by reducing the photon mean free path, and further reduced the high-temperature thermal conductivity owing to the larger free carrier concentration originated from the large number of oxygen vacancies. Although a large concentration of Zn2+ caused a slight reduction in thermal expansion, this study suggests that functional cations can be easily incorporated; thus, expanding the material diversity beyond the typical doping levels to develop new thermal barrier materials. [ABSTRACT FROM AUTHOR]

Because the CMAS corrosion and phase transformation at elevated temperatures above 1250 °C have limited the applications of traditional YSZ, the design of novel thermal barrier materials is a hotspot. GdTaO 4 is considered as a type of potential novel thermal barrier material owing to its low thermal conductivity. In this study, the mechanical and thermal properties, CMAS corrosion resistance, and the wettability of the GdTaO 4 were studied and compared with that of YSZ. The results show that the coefficient of thermal expansion and hardness of GdTaO 4 are 14.1 × 10−6 K−1 (1350 °C) and 534.2 Hv 0.3 respectively. The thickness of CMAS reaction layer of GdTaO 4 is ~30.8 μm after 24 h reaction at 1350 °C, which is thinner than that of YSZ. After corrosion reaction, the CMAS glass aggregated instead of completely disappearing or continuously extending over the surface of GdTaO 4. The main reaction product is Ca 2 Ta 2 O 7 , and the anorthite phase may not be detected, which is similar to YTaO 4. By comparison, the dense substrate of YSZ became porous and CMAS glass has disappeared after 10 h. CMAS corrosion at 1350 °C. The on-line contact angle results show that the wettability of CMAS on GdTaO 4 is worse than that on YSZ at 1350 °C, while the opposite of the work of adhesion, which indicates that GdTaO 4 can remove liquid CMAS more easily than YSZ TBCs during the service. Furthermore, the corrosion depth and areas of GdTaO 4 are smaller than those of YSZ in the same situation. These findings suggest that GdTaO 4 possesses better high-temperature properties and CMAS corrosion resistance than YSZ as a kind of potential of thermal barrier material. [ABSTRACT FROM AUTHOR]

Amine‐functionalized MIL‐101(Cr)‐NH2 metal–organic frameworks (MOF‐N)/epoxy nanocomposites with Excellent cure label and high thermal stability were developed. Structure–property relationship was discussed by comparison of the cure state, thermal and viscoelastic behavior of epoxy nanocomposites containing pristine MOF or MOF‐N applying differential scanning calorimetry (DSC), thermogravimetric analysis, and dynamic mechanical analysis. Epoxy containing 0.3 wt% MOF‐N exhibited high glass transition temperature (Tg) of 96°C compared with 85°C observed for epoxy/MOF system. Thus, MOF‐N played the role of catalyst in epoxy/amine curing reaction. Correspondingly, a lower activation energy was obtained based on cure kinetics modeling based on DSC measurements. Besides, incorporation of low amount (0.5 wt%) MOF‐N induced an early‐state resistance against decomposition, featured by 11°C rise in decomposition temperature at 5% weight loss. This was ascribed to the formation of porous metallic oxides during thermal decomposition of MOF‐N in the epoxy system acting as a heat barrier, which increased the activation energy of decomposition. Amine‐functionalization considerably prevented from further oxidation of the inner part of the matrix. [ABSTRACT FROM AUTHOR]

Biodegradable starch material is considered one of the best alternatives to traditional petroleum-based synthetic plastics. The effects of ultrasound (40 kHz) and ozone (20 g/h) modifications on corn starch were investigated using ultraviolet absorption, titration, Fourier transform, differential scanning calorimetry, and X-ray diffraction. As well as the effects of the dual modification on biodegradable films' morphology, thickness, water content, water solubility, moisture absorption, water vapor permeation, opacity, water contact angle, and mechanical and thermal properties were evaluated. For dual modification, the ultrasonic modification was carried out first, followed by oxidation under the same conditions as an individual modification. After ultrasonic and ozone modification, the crystallinity of starch decreased, and the solubility increased to some extent. Starch's swelling power and solubility increased by 4.90% and 159%, respectively, after 10 min of ozone treatment. The tensile strength of the films modified by ozone for 10 min increased by 276%, the elongation at break increased by 72.5%, the water contact angle of the films modified by ozone increased by 154%, and the water vapor permeability decreased by 34.7%. Compared with the natural and single-modified starch films, the dual-modified ones had lower water vapor transmittance, moisture absorption rate, and higher transparency. The water vapor permeability decreased by 32.2%, and the transparency increased by 73.7%. The modification in this study had little effect on the solubility of the films. [Display omitted] • The combination of ultrasonic and ozone was an innovation in the corn starch film. • Ultrasonic and ozonation dual-modification had positive effects on starch films. • The TS, WVP, and WCA of the O10 starch film were significantly improved. • The high MA of the oxidized starch film was reduced by ultrasonic treatment. [ABSTRACT FROM AUTHOR]

The demand for biopolymer-based green packaging has attracted growing attention because of its outstanding properties and consistency with clean environmental principle, unfortunately, its slow crystallization rate and narrow processing window are challenging. Inspired by combined functions in nanocellulose-based conductive hybrids, this work developed high-performance polylactic acid (PLA) composites using conductive cellulose nanofiber (CNFene). Interestingly, CNFene has multiple functions as highly graphitized carbon and abundant hydroxyl groups, delivering stimulating properties to PLA composites. As nucleating agents, 3 wt% CNFene has a carbon layer on the surface combined with a hydrogen bonding network synergistically enhancing the tensile and crystallization properties of PLA-C3, with a tensile strength of ∼ 53.7 MPa, crystallinity of ∼ 33.9 %, and 6.6 °C decrease in the cold crystallization temperature. Additionally, the compatibility between CNFene and PLA can form a multi-level "reinforcement" network structure, further improving thermal stability and barrier properties. The resultant PLA-C3 showed higher thermal decomposition onset temperature (T 0), wider melt-processing window (197.6 °C) and extremely lower overall migration levels in ethanol (68.6 μg/kg) and isooctane (16.3 μg/kg), due to that improved interaction between CNFene and PLA positively affects crystallization ability and kinetic/mechanism of PLA to meet the requirements of industrial and green biopackaging applications. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Bio-based copolyesters involving 2,6-pyridine structure with isosorbide as a second diol were synthesized. • Incorporation of isosorbide enhanced thermal properties of the pyridine-based polyesters. • Isosorbide significantly improved the mechanical properties of the pyridine-based polyesters. • The copolyesters showed high gas barrier properties. Driven by sustainable development and low-carbon policies, many high-performance bio-based polyesters are produced. Our previous work uncovered the high barrier but low thermal and mechanical properties of a renewable 2,6-pyridinedicarboxylic-based polyester. In this article, the copolymerization with isosorbide as a second diol is considered to ameliorate these properties. The chemical structures of copolyesters and the successful introduction of isosorbide were confirmed by FT-IR and 1H NMR. The 1H NMR spectra also allowed the calculation of isosorbide ratio in polymers. GPC revealed a decrease in molar masses with the increase of isosorbide ratio. Contact angle and water/gas permeation measurements disclosed an increase in hydrophilicity and water/gas permeability with the introduction of isosorbide. TGA and DSC analyses demonstrated an enhancement in thermal stability: 8 mol% of isosorbide to the total diol ratio increased the 5 % weight loss temperature (T 5%) by 9 °C, the maximum weight loss temperature (T max) by 8 °C and the glass transition temperature (T g) by 6 °C. DSC investigation showed that the incorporation of isosorbide significantly influenced the crystallization properties, particularly from the melt, by decreasing the crystallinity. XRD patterns indicated the presence of similar crystallization units in these polyesters. Tensile test revealed that incorporating 8 mol% of isosorbide greatly improved the mechanical properties by doubling Young's modulus and tripling the strength at break. Such enhancement in thermal and mechanical properties is important for high gas barrier food packaging applications of these polyesters. [ABSTRACT FROM AUTHOR]

Packaging materials based on lightweight and flexible thermoplastic/graphene composite films are gaining popularity in both the academic and industrial sectors. In this research work, graphene nanoplatelet (GNP) of 1–5 wt% was integrated into linear low density polyethylene (LLDPE) by employing melt compounding technique at 160 °C to produce flexible composite films. The LLDPE/GNP nanocomposite films were irradiated with doses up to 50 kGy using a 2.5 MeV electron beam accelerator in air at ambient temperature. The uniform distribution of GNP in the thermoplastic matrix obtained from FESEM analysis improved the samples' mechanical characteristics. As the GNP concentration in the LLDPE matrix increases, both the thermal stability and impermeability qualities (oxygen and water vapor) get significantly improved. Electron beam irradiation of film samples further enhances the physico-mechanical, thermal and gas barrier properties compared to non-irradiated composite films and neat LLDPE film. The tighter connections between graphene and LLDPE chains as well as the development of cross-linked networks by E-beam irradiation are responsible for the improved performance properties. Therefore, GNP incorporation as well as electron beam irradiation of thermoplastic nanocomposite films could be a viable alternative for producing high-performance and high-barrier flexible LLDPE/GNP composite films for packaging applications. • Combine effects of GNP addition and electron beam irradiation on properties of LLDPE composite films. • The fabricated flexible composite films irradiated up to the dose of 50 kGy. • The E-beam irradiated samples improved mechanical, thermal and barrier properties. • These irradiated, and high-barrier composite films for flexible packaging materials. [ABSTRACT FROM AUTHOR]

AZ91 Mg alloy has a wide range of applications in the automotive industry, although its use is restricted to powertrain applications due to its low creep resistance. In this study, the effect of the micro arc oxidation (MAO) coating on the creep resistance of an AZ91 Mg alloy was investigated to take advantage of the coating layer with high thermal insulation properties. In this context, the MAO process was applied to AZ91 Mg alloy using a bipolar pulsed DC power supply. The creep tests were conducted at different temperatures (150–200 °C) and stresses (25–90 MPa) for the bare and coated samples, and the minimum creep rates were determined. It has been shown that the MAO coating reduces the creep rate of the bare alloy by 35%–84% depending on the temperature and the stress due to the stress-reducing effect and thermal barrier properties of the MAO coating. Based on the calculated creep activation energy and stress exponents, creep mechanisms were proposed for the bare and coated alloys. Effective activation energy was also calculated and lattice diffusion-controlled dislocation climb was determined to be the effective creep mechanism for both samples at lower stresses, while pipe diffusion-controlled dislocation climb was effective at higher stresses. • Creep resistance of AZ91 alloy increased with the MAO coatings. • The minimum creep rates of the bare alloy were reduced by 35%–84% when MAO coating was applied. • MAO coatings decreased stress on AZ91 substrate by 28%. • Lattice and pipe diffusion controlled dislocation climb are the main mechanisms for low and high stresses, respectively. • MAO coatings remained intact after the creep tests owing to the thermal shock resistance of the coatings. [ABSTRACT FROM AUTHOR]

Researchers at the University of Amsterdam have developed a simple synthesis strategy to overcome the low reactivity of isosorbide, a glucose-derived secondary diol monomer. By incorporating an aryl alcohol in the polymerization process, the researchers were able to enhance the reactivity of isosorbide and produce high-molecular-weight poly(isosorbide succinate) (PIsSu) with high fractions of the bio-based secondary diol. The resulting plastics outperform existing materials in terms of heat resistance, barrier properties, and mechanical strength. The research was funded by the Dutch Research Council and supported by industry partners including The LEGO Group and Avantium Chemicals. [Extracted from the article]

• The pores act as a "thermal barrier wall" on the heat transfer path in the MPL. • The fractal characteristics of the MPL inhibit heat transfer. • The structural parameters of the MPL is correlated with the thermal properties. Heat transfer in the fuel cells is generally limited by the effective thermal conductivity of the microporous layer (MPL). Due to the complexity of the microstructure and the difficulty of the test conditions, studies on the key parameters that affect the thermal conductivity of MPL is lacking. In this paper, we develop an analytical fractal model for the effective thermal conductivity of the MPL based on a lumped parametric model of the cube and a fractal particle chain model, and provide the contact ratio of the agglomerates using a 3D FIB-SEM reconstruction. The results indicate that the main factors affecting the thermal conductivity of MPL include the structural parameters, fractal dimension, and the thermal conductivity of the carbon particles and pores. The fractal characteristics of the MPL inhibit heat transfer rate and the pores act as a "thermal barrier wall" on the heat transfer path in the MPL. When the volume fraction of the MPL is 40 percent, the contact area ratio and fractal factor of the agglomerates are 0.351 and 0.84, respectively. In addition, this research will help to develop novel MPL structures with high thermal conductivity and improve simulation results for fuel cell temperatures. [ABSTRACT FROM AUTHOR]

Known as one of the super adiabatic materials today, vacuum insulation panels (VIPs) is wildly applied in building industry. It has the double advantage of saving energy and improving space utilization. However, its expensive cost is the application obstacle. A new type of VIPs with recycled and economical cotton fiber core was prepared and innovated in this study. The micromorphology of the recycled cotton core material, as well as the barrier and thermal conductivity of the prepared VIPs, was experimentally and mathematically investigated. A designed vacuum measurement device was introduced to analyze the variation of thermal conductivity versus gas pressure. Three types of laminated films were prepared to investigate VIPs' adiabatic properties. Three typical barriers, respectively AF, MF-Ⅰ, MF-Ⅱ, were involved to investigate the impact of sustainability. The final results showed that AF as the barrier layer for VIPs with performed better than other VIPs considering thermal conductivity. The effective thermal conductivity (ETC) of the VIPs is sensitive to inner pressure and the optimum gas pressure is less than 0.1Pa. The drying process for porous cotton fibers is a continuous heating at a temperature of 120 °C for 30–40 min. The ETC of the VIPs prepared using AF barrier envelopes was about 3.17 mWm−1K−1. The VIPs with cotton fiber core material has good thermal properties and also has the dual characteristics of low price and environmental protection. As a potential candidate for the VIPs core material, the recycled wasted cotton fiber core material is a new development direction. [ABSTRACT FROM AUTHOR]

• Long-term heat exposure above critical temperature can induce continuous degeneration of thermal insulation property for Fe-based amorphous coating, revealing an importance of kinetic effect. • The coupling effect of microstructure transformation and structural sintering is disclosed, leading to a particular insight into the degeneration mechanism. • The low atomic diffusivity of amorphous phase retards the progress including crystallization transition, grain growth and pore healing, resulting in a sluggish degeneration of thermal insulation property. Fe-based amorphous coatings have been proposed to perform a promising thermal barrier application, however, the uncertain degeneration of properties induced by thermal stimulation is significantly concerned owing to their metastable nature. Herein, Fe 57 Cr 15 Nb 4 B 20 Si 4 amorphous coating with a low thermal conductivity was employed to investigate the degeneration of thermal insulation property and related mechanisms during long-term heat exposure. Excellent stability can be defined for the amorphous coating when annealed below glass transition temperature, despite a slight increase of thermal conductivity induced by structural relaxation. Extraordinary increase of thermal conductivity is found when prolonged annealing time at a critical temperature of 600 °C. The sluggish structural sintering dominates thermal conductivity to increase, whereas the effect of precipitated ultrafine nanocrystals is little. The cooperation of grain coarsening and structural sintering leads to a dramatical increase of thermal conductivity at the initial stage of 850 °C annealing, while the relatively low increase of thermal conductivity with prolonged duration is ascribed to the further grain growth. The obtained results demonstrate a comprehensive understanding on the thermal evolution of Fe-based amorphous coatings and form a basis for future works aiming to shed further light on the degeneration of related metallic coatings at high temperatures. [ABSTRACT FROM AUTHOR]

In the present work, faba bean protein (FBP) films plasticized with glycerol and reinforced with different amounts (2.5, 5.0, 7.5 and 10% by weight of FBP) of lignin extracted from pine cones (PL) have been obtained by solution casting. The results obtained showed an elongation at break of 111.7% with the addition of 5% PL to the FBP film, which represents an increase of 107% compared to the FBP control film. On the other hand, it was observed by thermogravimetric analysis (TGA) that the incorporation of lignin improved the thermal stability of the FBP film, leading to an increase in the protein degradation temperature, being this increase higher in the sample film reinforced with 10% PL. The barrier properties of the FBP films were also affected by the presence of lignin, leading to a decrease in water vapor permeability (WVP) in comparison to the unreinforced film. The results show that the sample reinforced with 2.5% PL had the lowest WVP value, with a reduction of 25% compared to the control film. Chemical analysis by Fourier transform infrared spectroscopy (FTIR) confirmed the formation of intramolecular interactions between lignin and proteins which, together with the inherent hydrophobicity of lignin, resulted in a decrease of the moisture content in the films reinforced with PL. This research work has allowed the development of biobased and biodegradable films with attractive properties that could be of potential use in sectors such as packaging. • Addition of 5% pine cone lignin in FBP films increased its elongation by 107%. • Addition of lignin to FBP films increases their tensile strength and stiffness. • Addition of 10% lignin delayed the degradation temperature of FBP films around 14 °C. • Low contents of pine cone lignin improve the water vapor permeability of FBP film. • Intramolecular interactions between lignin and proteins decrease the moisture content of films. [ABSTRACT FROM AUTHOR]

This study gives an overview of the most relevant processing and performance properties of a wide selection of biobased and biodegradable plastic materials that are currently commercially available. It provides the most extensive and up-to-date scientific overview of critical properties of biobased and biodegradable plastics. Materials that are tested include fully biobased polymers (polylactic acid, polyethylene, polyamide 10,10 and a range of polyhydroxy alkanoates), partially biobased polymers (polybutylene succinate, polybutylene succinate adipate, cellulose acetate, cellulose acetate propionate, polyethylene terephthalate, polytrimethylene terephthalate, an isosorbide based polycarbonate, a thermoplastic urethane and a starch based blend) and a number of fossil-based materials (polycaprolactone, polybutylene adipate terephthalate, polyglycolic acid and polypropylene). The mechanical (tensile, flexural, impact resistance and hardness), thermal (glass transition temperature, melting temperature, melt-flow index and haul-off force) and barrier (oxygen transmission rate, water vapour transmission rate) properties of all these materials were measured and are presented in a comprehensive overview. This overview shows that the majority of functionalities that are currently being offered by fossil based polymers can be met by biobased alternatives and by biodegradable materials if this is considered to be favourable at end-of-life. • The most extensive and up-to-date scientific overview of critical properties of biobased and/or biodegradable plastics. • Mechanical properties characterized; tensile, flexural, impact resistance and hardness. • Thermal properties characterized; glass transition temperature, melting temperature, melt-flow index and haul-off force. • Barrier properties characterized; oxygen transmission rate, water vapour transmission rate. [ABSTRACT FROM AUTHOR]

Infectious diseases are considered as a significant threat to human health as well as environment. Due to the increasing microbial diseases, researchers are trying to find out new materials with superior antimicrobial properties. Insertion of various nanofillers into rubber matrices will result in the production of advanced rubber nanocomposites with improved mechanical, electrical, thermal and barrier properties. However, improvement in antimicrobial properties of rubber nanocomposites is still remaining as an unexplored area. But the existing studies show that, the addition of antimicrobial nanofillers can introduce antimicrobial properties into the final rubber nanocomposites and thus can be used in various biomedical applications. Thus the present review tries to bring together all the available antimicrobial works in the area of rubber nanocompositses. • This review brings light into the antimicrobial studies in rubber nanocomposite. • Various antimicrobial nanofillers are discussed in a comprehensive way. • Antimicrobial studies in rubber nanocomposites are summarized. [ABSTRACT FROM AUTHOR]

Nonwoven aramid fabric is widely used as thermal barrier of fireproofing clothing due to its inherent flame retardancy and light weight. In fire or high temperature scenario, radiative heat transfer becomes the predominant heat transfer mode inside firefighters' clothing. In this work, Fourier transform infrared spectroscopy (FTIR) was adopted to measure the spectral transmittance and spectral extinction coefficients of four aramid fabrics with different porosity in infrared wavelength range between 2.5 and 25 μm. It was found that the radiative properties of fibrous aramid fabric are strongly dependent on its bulk density or porosity. The spectral extinction coefficient decreases with increasing porosity or decreasing bulk density. The infrared optical properties combined with infrared imaging measurements demonstrate that aramid fabric may be used as infrared semi-transparent textile. A predicted model, combined the effects of conduction-radiation heat transfer, has been developed to calculate the effective thermal conductivity of aramid fiber materials. The model implemented the Rosseland diffusion approximation to evaluate radiative thermal conductivity, and the Parallel-Series structural model to evaluate tortuosity-weighted phonic thermal conductivity. The predicted results were also compared with experimental data obtained from TPS method. This work provides useful information for future studies of heat transfer mathematical modeling of firefighters' clothing. [ABSTRACT FROM AUTHOR]

Chitosan/lignin-containing cellulose nanofibrils (CS/LCNF) biocomposites were prepared by a facile and green method that combined hydrothermal pretreatment, mechanical fibrillation, and dry casting. LCNFs were isolated from switchgrass with various lignin contents, and their effects on the transparency, micromorphology, mechanical properties, interfacial compatibility, thermal stability, surface wettability, and barrier properties of the CS/LCNF biocomposites were comprehensively investigated. Their transparency was affected by changing the lignin and cellulose contents, as well as the order degree of cellulose. The hydrophobic micro/nano- lignin particles with the optimum contents (33.8%) coated on CNFs or embedded their networks prompt the dispersion of LCNF in CS matrices and enhance interfacial interaction of CS and LCNF. This synergistically improved the mechanical properties and thermal stability of CS/LCNF biocomposites. CS/LCNF8 maintained a ductility of 503% and showed a tensile strength that was 46.7% higher than that of CS/CNF, as well as a T max and WCA that were 2.6 °C and 11.06° higher, respectively. Furthermore, CS/LCNF8 displayed a more competitive OTR (0.20 cc/(m2 day)) than those of pure chitosan, mechanically-fibrillated CNFs, carboxymethylated CNFs, and TEMPO-oxidized CNF/CS films at the same ratio. This study provides promising environmentally-friendly biocomposite films with outstanding comprehensive performance for green food packaging. [Display omitted] • Flexible and transparent CS/LCNF biocomposites were prepared by a facile and green way. • CS/LCNF biocomposites are promising candidates for green food packaging. • Lignin and compatibility synergistically affect mechanical, thermal and barrier properties. • CS/LCNF display a competitive OTR and hydrophobicity than those of previous reports. • CS/LCNF8 maintained a ductility of 503% and showed a 46.7% higher tensile strength. [ABSTRACT FROM AUTHOR]

Red pomelo peel pectin, casein and egg albumin were mixed at various proportions to form edible composite films using casting method. The effect of addition of pectin at different concentration on the mechanical, structural, morphological and thermal properties were investigated. The composite films developed by mixing red pomelo peel pectin, casein and egg albumin at ratio of 50:50:0 (F4) and 50:25:25 (F7) possessed lower water vapour permeability and higher tensile strength in comparison to other films. The diffractograms obtained from XRD analysis revealed the amorphous structure of pectin film and pectin blended composite films. The FT-IR analysis revealed that with the addition of pectin, intermolecular interaction increased resulting in the compactness of film matrix. Pectin incorporated composite films were smooth in structure with no cracks and cavities indicating proper homogenization with no phase separation as well as indicated decrease in the degree of disorder in composite films. Thermal properties of composite films indicated that pectin incorporation into films resulted in increase in thermal stability of films. [Display omitted] • Pectin was extracted from red pomelo peel pectin using ultrasonication technique. • The composite films were developed from pectin, casein and egg albumin at various ratios using casting method. • The analysis of physiochemical, structural, morphological and thermal properties of films was done. • Pectin addition led to enhancement in physiochemical, structural, barrier and thermal properties of films. • Structural and morphological analysis reported compactness in structure of film matrix with pectin addition. [ABSTRACT FROM AUTHOR]

In this study, the mechanical resistance and the thermal insulation potential of novel thermal barrier coatings (TBCs) made of a foam of hollow alumina particles are assessed through scratch testing, micro-indentation and thermal diffusivity measurements using laser-flash. The thermal diffusivity of the foam coatings ranges between 0.6 × 10−7 and 5 × 10−7 m2·s−1 and is thus comparable with the thermal insulation potential of the standard plasma-sprayed (PS) and electron beam–physical vapour-deposited (EB-PVD) TBCs made of yttria-stabilised zirconia (YSZ). The coatings annealed in more oxidative atmospheres exhibit greater mechanical resistance due to the thickening of the alumina shells and the increased sintering of the foam. However, when the oxidation is poorly tailored, the adhesion of the foam to the substrate decreases due to the presence of unwanted oxide that grows at the substrate/coating interface. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel high-entropy oxide (YYHEO) was engineered with significant mass disorder. • YYHEO exhibited glass-like low thermal conductivity (1.27 W/m∙K). • YYHEO exceeded typical substitutional solid solubility limit even with a significant atomic size difference (>50%). • YYHEO shows thermal stability even at elevated temperature (1500 ° C) without any phase degradation. • Thermophysical properties were compatible with YSZ (CTE: 10.08 × 10−6 K−1, E : 218.21 ± 3.64 GPa and H : 14.42 ± 0.5 GPa). An entropy-stabilization strategy was applied to engineer a novel thermal insulating material by establishing a single-phase solid solution with the formula of (Y 1/2 Yb 1/2) 2 (Ti 1/3 Zr 1/3 Hf 1/3) 2 O 7 (YYHEO). Structural analysis revealed that this material exceeded the typical substitutional solubility limit, even with a significant atomic size difference, where the conventional determination rule was defied. YYHEO exhibited a lower glass-like thermal conductivity due to its highly disordered crystal structure and the specific design strategy. The coefficient of thermal expansion and mechanical properties (e.g. elastic modulus and hardness) were comparable to conventional materials, suggesting that YYHEO is a promising candidate for application as a new thermal insulating material. [ABSTRACT FROM AUTHOR]

Schematic of lignin content on the compatibility of LCNF and PLA. [Display omitted] • PLA/LCNF composites with both high strength and great ductility were prepared. • Lignin particles improved the interfacial interaction and compatibility between LCNF and PLA. • UV-shielding, water vapor barrier performance, and good thermal stability were integrated in the PLA composites film. • A fully biodegraded composites using the green LCNF and biodegradable PLA were produced. Currently, it is challenging to produce biodegradable polylactic acid (PLA) composite with both high strength and great ductility. In this work, lignin-containing cellulose nanofibrils (LCNF) derived from old newspaper were amalgamated with a biodegradable PLA matrix to prepare multifunctional composites with integrated strength and ductility. Owing to the lignin content of LCNF, the interfacial interaction and compatibility between LCNF and PLA matrix were improved by hydrogen bonding and van der Waals interactions, thereby the mechanical properties of PLA/LCNF composite films were successfully enhanced. After blending LCNF with PLA, the prepared PLA/LCNF composite films exhibited excellent UV-shielding, water vapor barrier performance, and good thermal stability. This study reveals a feasible strategy to design full biodegradable multifunctional composite using the green LCNF and biodegradable PLA. [ABSTRACT FROM AUTHOR]

[Display omitted] • High yield extraction of hydroxy-fatty acids from agro-industrial byproducts. • Bioinspired polyesters are formed by co-polymerization of fatty acid and glycerol. • Tuning the level of esterified glycerol modifies the polymer's structure. • Resulting in modified elastomer's mechanical properties (up to 200 % elongation). • With significant impact on O 2 permeability and anti-biofouling properties. By mimicking the cutin natural polyester networks of plant cuticles, we produced hydrophobic elastomers by a sustainable process, i.e., using a catalyst- and solvent-free polycondensation of glycerol and hydroxy fatty acids, two by-products of the agro-food industry. The hydroxy fatty acid fraction was obtained by ethanolic alkaline hydrolysis of cuticle from industrial tomato. This industrial-like fatty acid fraction contained more than 90 wt%. of 9(10),16 dihydroxyhexadecanoic acid (diOHC16). The co-polyesters were designed by increasing the ratio of esterified glycerol/diOHC16 in a range observed in plant cutins (up to 6 wt%). Their structure and functional properties (thermal, mechanical, gas permeability, interaction with bacterial cells) were characterized. Increasing the glycerol contents induced a significant decrease in the crosslink density of the polyesters and the formation of crystalline domains with a hexagonal organization. These structural modifications were related to a marked increase of elastomeric extensibility (up to 217 %). While water vapor permeability was not impacted, the increase of glycerol content induced a significant decrease in oxygen permeability. None of the polyesters displayed biocide activity, but an increase of glycerol content significantly reduced the adhesion of bacterial cells, potentially giving rise to antifouling applications. [ABSTRACT FROM AUTHOR]

This article aimed to study the effects of chitosan fiber and a newly modifying agent, based on organosolv lignin, on mechanical and thermal performances and the enzymatic degradation of PLA/chitosan biocomposites. A newly modifying agent based on polyacrylic acid-grafted organosolv lignin (PAA-g-OSL) was synthesized via free radical copolymerization using t-butyl peroxide as the initiator. The biocomposites were prepared using an internal mixer and the hot-pressed method at various fiber loadings. The results demonstrate that the addition of chitosan fiber into PLA biocomposites remarkably decreases tensile strength and elongation at break. However, it improves the Young's modulus. The modified biocomposites clearly demonstrat an improvement in tensile strength by approximately 20%, with respect to the unmodified ones, upon the presence of PAA-g-OSL. Moreover, the thermal stability of the modified biocomposites was enhanced significantly, indicating the effectiveness of the thermal protective barrier of the lignin's aromatic structure belonging to the modifying agent during pyrolysis. In addition, a slower biodegradation rate was exhibited by the modified biocomposites, relative to the unmodified ones, that confirms the positive effects of their improved interfacial interaction, resulting in a decreased area that was degraded through enzyme hydrolysis. [ABSTRACT FROM AUTHOR]