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In this work, epoxy (EP) resin composites with multi-scale reinforcements were prepared by hand lay-up and hot-pressing. The epoxy was reinforced with basalt fibers (BF) modified with a silane coupling agent (KH560). Carboxylated multi-walled carbon nanotubes (CNTs) were also grafted onto the surface of the modified BF using an impregnation method to achieve BF/CNTs multi-scale reinforcement. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) showed that KH560 was successfully grafted onto the BF surface. Scanning electron microscopy (SEM), indicated a better resin adhesion on the BF and thus a stronger interfacial interaction in the BF/CNTs-reinforced composite. It was observed that the mass fraction of KH560 was a significant parameter in achieving desirable CNT immobilization and mechanical properties of the composites. At an optimal mass fraction of KH560 (5%), the tensile, flexural, and interlaminar shear strength (ILSS) of the modified composite (BF-5%KH560-CNT/EP) increased by 12.5%, 20.9%, and 25.5% respectively compared with the BF-washed/EP composite due to more efficient load transfer. In addition, compared with BF-washed/EP, the decomposition onset temperature of BF-5%KH560-CNT/EP increased from 387°C to 396°C, the maximum decomposition rate temperature increased from 400°C to 408°C, and the residual weight increased by 5.8%. [ABSTRACT FROM AUTHOR]

This study reports how hybrid nano‐filler can enhance the tensile strength, electrical properties and thermal stabilization of PAN (polyacrylonitrile) nanocomposite films. The nano‐fillers used are graphene oxide (GO), single‐wall carbon nanotubes (SWCNT), and a hybrid of both. The combination of both nano‐fillers was made by dispersing GO in DMAc (dimethyl acetamide) and then adding SWCNT to the solution. The solution was mixed well using ultrasonication and high‐speed stirring. 1 wt% amount of nano‐filler solutions was added to PAN liquid to make PAN nanocomposite films. The films were tested for mechanical properties, electrical resistivity, thermoxidative stabilization, and thermal stability. The results showed that adding nano‐fillers to PAN significantly improved its tensile strength. GO increased the tensile strength by 42.9% (38.3 MPa), while SWCNT increased it by 57.3% (42.15 MPa). The combination of both (0.5 wt% SWCNT + 0.5 wt% GO) had a remarkable effect, increasing the tensile strength by 96% (52.53 MPa). This was because the combination of both prevented SWCNT from agglomerating together and made it interact better with the PAN, forming a complete network. The combination of both also made the PAN oxidize and stabilize early and efficiently during heating, which made its residual weight increase by ~5.5% more than pristine PAN in TGA. The electrical resistivity and SEM micrograph data correlate with the thermal analysis data, showing that PCG (1 wt% combination) reached the percolation threshold because of the benefits of both GO and SWCNT. The combination of both also showed 95.6% synergy in tensile strength compared to individual nano‐fillers, indicating its potential for efficient reinforcement. Highlights: Hybrid filler boosts PAN strength from 26.8 to 52.53 MPa, surpassing PC, PG.TGA: ~5.5 wt% increased residual weight in 1 wt% hybrid‐reinforced PCG composites.Hybrid undergoes GO decomposition, early oxidation and improved stabilization.PCG composite: Enhanced oxidation, improved stabilization via SWCNT network.PC & PCG composites show low volumetric resistivity due to SWCNT network. [ABSTRACT FROM AUTHOR]

Blending with ductile polycaprolactone (PCL) is one of the common toughening methods for polylactic acid (PLA). However, it seems inevitable to experience a trade‐off in mechanical strength and thermal stability of PLA. Therefore, this study aimed to improve the mechanical and thermal properties of PLA/PCL blends by adding different contents of talc (0–10 wt%) and conducting annealing treatments. Interestingly, the maximum tensile strength (52.04 MPa), elongation at break (83.51%), and impact strength (6.05 kJ/m2) were achieved by incorporating 2.5 wt% talc into the blends without annealing. Meanwhile, the addition of just 1 wt% talc shortened the semi‐crystallization time of PLA to one‐third of the neat PLA at 100°C. Particularly, after annealing treatment, the crystallinity of PLA increased to 32.1%, and the Vicat softening temperature reached as high as 133.3°C with 2.5 wt% talc. Importantly, the increase in crystallinity did not compromise the toughness of PLA composites but significantly enhanced the impact strength to 8.91 kJ/m2. This study provides an updated understanding of the relationship between toughness and crystallinity in PLA composites. Highlights: Thermo‐resistance of polylactic acid (PLA) composite increases to 133.3°C.Talc aids nucleation and promotes PLA crystallization.Increased crystallinity and high toughness are simultaneously realized.Adding 1 wt% talc reduced PLA semi‐crystallization time by one‐third.Crystal transformation and sea‐islands structure are vital for reinforcements. [ABSTRACT FROM AUTHOR]

By using the aerodynamic levitation and laser melting technique to well extend the glass‐forming region into the Mg‐rich and peraluminous regime, a series of magnesium aluminosilicate glasses were prepared to investigate the Mg and Al mixed effects on thermal properties, including glass transition temperature (Tg), crystallization behavior, and thermal stability. With the gradual substitution of Mg by Al, Tg exhibits two types of near‐linear rises with different slopes in two compositional regions separated by r = 0.57, where r is equal to the molar ratio of [Al2O3]/([Al2O3] + [MgO]). Moreover, when it comes to other properties, that is, crystallization behavior and thermal stability, this critical point precisely appears at the same r = 0.57. Compared to the slower increase of Tg in Mg‐rich region, the steeper rise of Tg in the peraluminous region is mainly ascribed to the step‐by‐step formation of oxygen triclusters driven by Pauling's second rule. Moreover, the occurrence of the critical point for Tg rise at r = 0.57 rather than the theoretical 0.5 can be seen as a proof of the role of Mg cations partly as a network former. [ABSTRACT FROM AUTHOR]

Silicone foam (SF) is a porous silicone rubber with a lower density, higher elasticity, and good thermal stability. In this work, we selected aluminum spheres and carbon fiber (CF) as thermally conductive fillers to prepare hybrid SF. After optimization, we found that Al and CF hybrid SF (Al-CF-SF) has a higher thermal conductivity (1.37 W·m-1·K-1) than the single-filler filled SF (CF-SF, 1.2 W·m-1·K-1 or Al-SF, 0.52 W·m-1·K-1) under the same filling amount of 60 wt%. The finite element simulation was used further to explore the thermal conductive mechanism of the hybrid SF. Meanwhile, the compressive and tensile modulus of the material (CF-SF) was increased to 10.8 and 3.3 MPa compared with pure SF, respectively, and the mechanical properties were improved. In addition, infrared thermography further demonstrated that Al-CF-SF has a faster heat transfer rate under relaxation and applied pressure. [ABSTRACT FROM AUTHOR]

Vanadium-doped quaternary bioactive glass systems 46 SiO2, (24–x/2) Na2O, (24–x/2) CaO, 6P2O5, xV, where x = 0, 0.5, 2.5, 2.8, and 5 mass% of vanadium through the use of V2O5 oxide, were successfully synthesized by the melt-quenching technique. Several physicochemical methods were employed to study the effects of vanadium on the physical, structural, and thermal properties of all doped bioactive glasses 46S6-xV. Density (ρg), molar volume (Vm), oxygen molar volume (VO), and oxygen packing density (OPD) variations were correlated with the decrease in compactness of the vitreous network upon the introduction of 2.8 mass% vanadium. Investigations revealed that the bioactive glass network is less polymerized with an increase in vanadium content up to 2.8 mass%. The thermal characteristics and excess entropy ΔSex of doped bioactive glasses were determined. Calculated thermal stability factors show the high forming ability of elaborated bioactive glass. The obtained results show that the introduction of 2.8 mass% of vanadium on the glass matrix induces a significant decrease in ∆Tg (49 K) and ∆Tf (250 K). Increases in excess entropy confirm that the presence of vanadium leads to a more disordered 46S6 glass matrix. The studied 46S6 glass exhibits better thermal properties when vanadium is incorporated, making it more useful for various industrial and technological applications. [ABSTRACT FROM AUTHOR]

The thermoelectric materials community has made significant progress on nanostructured and processable materials to improve efficiency and flexibility, reducing manufacturing costs. Selenide compounds, such as Ag2Se and Cu2Se, have received a lot of attention because of their promising capabilities in thermoelectric applications. Additionally, Se is significantly more abundant than Te, with approximately ten times higher availability. High-energy ball milling (HEBM) process is a powerful solid-state synthesis/powder mechanical alloying method. The objective of this work is to form selenide compounds at different milling times (1–20 h) by HEBM process. The structural characterization of the compounds was studied by X-ray Diffraction and X-ray Photoelectron Spectroscopy, while the thermal stability of the prepared samples was examined by Thermogravimetric Analysis. The experimental results show that the Ag2Se sample synthesized at 20 h presents lower thermal stability because of the higher specific surface area and the increased porosity as a result of the hardening effect. Additionally, Cu2Se presents Cu2O(SeO3) as the main phase at low temperatures, while at higher temperatures, CuO is the dominant phase. Therefore, as the heating temperature increases, there is a complete evaporation of Se and a conversion of the remaining copper into copper oxide. The present study demonstrates a simple method for the synthesis of Ag2Se and Cu2Se thermoelectric materials with high oxidation resistance. [ABSTRACT FROM AUTHOR]

Crystal structure, thermal stability, and the process of scandium tris-methylcyclopentadienyl Sc(MeCp)3 evaporation are studied. It is shown by XRD that crystals of this compound with the C2/c space group and the following parameters at 150 K are formed from the gas phase and from the solution: a = 7.9568(4) Å, b = 13.7620(6) Å, c = 28.239(2) Å, β = 107.4860(10)°, V = 2949.3(3) Å3, Z = 8, Dcalc = 1.217 g/cm3. The violation of the crystal packing order is manifested as diffuse scattering accompanied by single-crystal Bragg diffraction. The obtained data suggest that the complex has the Sc(η5-MeCp)2(η1-MeCp) structure with Sc–Z distances equal to 2.26-2.37 Å, where Z is the center of the η5-MeCp species or the C atom (for η1-MeCp). The NMR data obtained for the Sc(MeCp)3 samples, which were kept for 7 days at 423 K, 453 K, and 483 K, indicate that the substance undergoes noticeable decomposition only at the highest temperature. Temperature dependences of the saturated vapor pressure of the complex are measured independently by the flow method (transpiration) (392-469 K) and by the static method (441-514 K). As a result of joint processing of the tensimetry data, the following thermodynamic parameters of Sc(MeCp)3 evaporation are determined: ΔevH0(458.5) = 82.5±1.1 kJ/mol, ΔevS0(458.5) = 135±2 J/(mol·K). [ABSTRACT FROM AUTHOR]

Sealants are easily subjected to microbial attachment, colonization, and deterioration in humid environment. Developing antimicrobial sealants have become an extremely imperative strategy to solve this problem. A kind of antimicrobial sealant was prepared with silane-modified polyether (SMPE) as a matrix and 3-(trimethoxysilyl) propyldimethyloctadecylammoniumchloride (TPOAC) as an antimicrobial agent in a room-temperature curing system. The tack-free time testing indicated that the introduction of TPOAC can significantly accelerate the curing rate of sealants. The effects of TPOAC on the mechanical, bonding, and thermal properties and surface wettability of the antimicrobial SMPE sealants were investigated through mechanical testing, thermogravimetric analysis (TGA), and water contact angle measurement. The mechanical properties of sealants were improved with an appropriate content of TPOAC, and the sealant exhibits optimal mechanical properties with the TPOAC content of 1.5%. Furthermore, TGA results indicated that the thermal behavior of SMPE sealants displayed a one-step weight loss process by heating in a nitrogen atmosphere and the introduction of TPOAC has little effect on the thermal stability of SMPE sealants in a nitrogen atmosphere. Moreover, the sealants exhibit more and more hydrophobic with the amount of TPOAC increased. The findings of this investigation indicated that using TPOAC as an antimicrobial agent is a practical way to obtain antimicrobial SMPE sealants with favorable properties. [ABSTRACT FROM AUTHOR]

The matrix's dielectric constant can be reduced with little quantity of POSS because of its unique cage skeleton structure and remained air in the caves. After epoxied, epoxy polyhedral oligomeric silsesquioxane (EPPOSS) promoted its compatibility with bisphenol A cyanate ester (BADCy) and bisphenol A benzoxazine (BA-a) by a curing processing between BADCy and EPPOSS and further copolymerizing with ring opened BA-a. Consequently, two Tgs were observed in the integrated nanocomposite, attributing to the BADCy homopolymer and the BADCy and BA-a copolymer. The more quantity of EPPOSS, the lower dielectric constants of nanocomposites achieved, as well as the initial storage modulus and Tgs due to the flexible ether bonds generated by EPPOSS. With up to 15 wt.% EPPOSS, the dielectric constant decreased to 2.72 at 1 MHz. The toughness and thermal stability of the nanocomposites also enhanced through increased the crosslinking density and inorganic Si–O–Si framework of EPPOSS. [ABSTRACT FROM AUTHOR]

Herein, the rational design and facile synthesis of high‐refractive‐index copolymers with good optical transparency and tunable thermal stability using aromatic heterocycle‐based vinyl sulfides via conventional radical copolymerization is presented. 2‐Thiazolylvinylsulfide (2TVS), 1,3,4‐thiadiazolylvinylsulfide (1,3,4‐TVS), 3‐methylimidazolylvinylsulfide (3MIVS), and 5‐methlthio‐1,3,4‐thiadiazolylvinylsulfide (MeSTVS) are selected to enhance the refractive index, and N‐vinylphthalimide (NVPI) and N‐phenylmaleimide (NPMI) are chosen as comonomers to achieve improved transparency and thermal stability while maintaining the refractive index. The sulfur, ─C═N─, and imide contents in the copolymers are varied by adjusting the monomer structures and their compositions, and their effects on the refractive index, Abbe number, and optical and thermal properties are investigated. The MeTVS monomer in poly(MeSTVS) and poly(MeSTVS‐co‐NVPI) contained three sulfur atoms and two ─C═N─ units; consequently, these polymers exhibit excellent refractive indices in the 1.7139–1.6567 range at 589 nm, Abbe numbers between 19.1–29.1, good transparency (>90% at 400 nm), and tunable thermal properties (Tg = 49–138 °C, Td10 = 244–268 °C). Optically transparent poly(1,3,4‐TVS‐co‐NVPI) films (>95% at 400 nm) with improved thermal stability (Tg = 89–175 °C, Td10 = 251–301 °C) are obtained while maintaining a relatively high refractive index (1.6662–1.6752). [ABSTRACT FROM AUTHOR]

In this paper, polystyrene (PS)-based reduced graphene oxide (rGO) composites were prepared by mixing PS latex particles with graphene oxide (GO) and the following in-situ reduction. The structure and morphology of PS/rGO composites were characterized, and the effects of rGO content on the dielectric properties as well as thermal stability of PS/rGO composites were investigated. Results showed that rGO sheets armoured on the surface of PS particles and exhibited well dispersion in the PS matrix after hot compression. The introduction of rGO improved the dielectric properties of the composites remarkably. When rGO content was 0.12 vol%, the dielectric permittivity and breakdown strength of PS/rGO arrived at 6.3 at102 Hz and 107 kV/mm, with 50% and 35.4% enhancement compared to the pristine PS. Furthermore, PS/rGO presented better thermal stability than the pristine PS, but the overlapping of rGO sheets in PS matrix induced the instability of dielectric loss with frequency. [ABSTRACT FROM AUTHOR]

Lead-free piezoceramics with superior piezoelectric properties don't meet the requirements of practical applications due to their lower phase transition temperature and poor thermal stability. In the present work, we report a new insight into the effect of glass phase on the piezoelectric, Curie temperature and thermal stability of (Ba 0.85 Ca 0.15)(Ti 0.9 Zr 0.1)O 3 (BCZT) ceramic. Unlike traditional glass materials with more than 80% of B 2 O 3 and SiO 2 as glass formers, our approach is to fabricate a glass phase (Ba 0.85 Ca 0.15)(Ti 0.9 Zr 0.1)O 3 -0.05B 2 O 3 (abbreviate BBCZT) with the same elements and concentrations as the ceramic phase. The ceramics-doped glass samples with the composition [(1-x)BCZT-xBBCZT], where x=(0.0, 0.025, 0.05, 0.075 and 0.1 wt%), were sintered according to the glass phase content. The effect of BBCZT glass composition on the crystal structure, dielectric, ferroelectric and piezoelectric properties of BCZT was investigated in detail. X-ray diffraction revealed that the addition of glass phase causes a defect engineering of the tricritical triple point of BCZT ceramic, where the tetragonal (T) and rhombohedral (R) phases were suppressed by the addition of glass phase and the T-phase has completely vanished at x = 0.05. The maximum value of permittivity (ε = 4102) and converse piezoelectric coefficient (d* 33 = 1150 Pm/V) were achieved for the 0.975BCZT-0.025BBCZT sample at ambient temperature. Furthermore, the diffusion coefficient (γ) and Curie temperature (T c) were observed to increase beyond x = 0.025, indicating enhanced thermal stability of BCZT at high glass content. These results qualify that the addition of (BBCZT) can enhance piezoelectric properties, phase transition temperature and thermal stability of BCZT ceramic which can meet wide requirements of practical applications. [ABSTRACT FROM AUTHOR]

The Li-Mn-O system is a crucial constituent of cathode materials used in lithium-ion batteries (LIBs). Numerous research teams have focused on enhancing its electrochemical properties and thermal stability at lower temperatures to develop high-performance cathode materials. However, in the recycling of LIBs in pyrometallurgical processing, the high temperature phase behavior of the Li-Mn-O system is important. Today, there is still a lack of systematic understanding regarding the high-temperature phase behavior of the Li-Mn-O system under well-defined atmospheric conditions, which is highly sought after in the pyrometallurgical process route to increase the recycling efficiency of lithium from spent LIBs. In this study, we investigate the high temperature phase behavior of the pseudo binary system Li2O-MnO under inert atmosphere. Thermal and caloric properties are measured as well as the contact angle at high temperatures to identify the solid-liquid transition. Based on the obtained phase behavior, thermodynamic database of Li2O-MnO within the Calphad framework is developed, where the liquid phase is modelled by the Modified Quasichemical Model (MQM). [ABSTRACT FROM AUTHOR]

In order to improve the thermal stability of 2,6-diamino-3,5-dinitropyridine-1-oxide (ANPyO), polydopamine was coated on the surface of ANPyO crystal by in situ polymerization, based on the principle of dopamine oxidation self-polymerization. ANPyO@PDA core-shell composite materials with different coating rates were prepared by adjusting the reaction time. The morphology, crystal structure, molecular structure, and element content of ANPyO@PDA composites were characterized by scanning electron microscopy (SEM), X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FT-IR) and X-ray photoelectron spectroscopy (XPS). The thermal decomposition performance of the ANPyO@PDA composites was also tested by thermogravimetry-differential scanning calorimetry (TG-DSC). The results show that PDA formed uniform and compact coating on the surface of the ANPyO, and the crystal and molecular structures of the ANPyO remained unchanged after the PDA coating. Additionally, the coating rate gradually increased with the growth of coating time. The thermal decomposition peak temperatures of the ANPyO were increased by 1.97 and 1.95 °C, respectively, as well as the apparent activation energy increased by 25.04 and 139.33 kJ/mol, and the critical temperatures of the thermal explosion were increased by 23.12 and 20.04 t after PDA coating for 3 and 9 h, respectively. The thermal stability and thermal safety of the ANPyO@PDA composites are higher than that of the ANPyO. [ABSTRACT FROM AUTHOR]

In our investigation of poly(vinylidene fluoride) (PVDF) films embedded with Au-BaTiO3 (AuBT) nanoparticles, we noted a synergistic improvement in both thermal stability and dielectric properties. PVDF films with varying concentrations of AuBT were expertly fabricated. Remarkably, the films retained their flexibility even at a high volume fraction of filler (fAuBT = 0.5). The predominant phases of PVDF (α, β, and γ) were observed. An increase in fAuBT resulted in a modest decrease in the melting temperature, while simultaneously causing a significant 40% increase in thermal conductivity compared to pure PVDF. The dielectric permittivity reached ∼160 at 1 kHz, while maintaining a loss tangent of ∼0.05. These improvements were attributed to discrete Au growth on BT particles, hindering conduction in PVDF. The rise in dielectric response resulted from interfacial polarization and inherent high dielectric permittivity of BT. [ABSTRACT FROM AUTHOR]

Polymer nanocomposites have been of great interest to packaging, energy, molding, and transportation industries due to several favorable properties including a higher resistance to stress and cracking even under flexed conditions, and also a chemical resistance to water, acids, and alkalis. The current work disseminates the studies on the mechanical and thermal properties of the polypropylene HHR102 polymer reinforced with nano dispersoids of silicon dioxide at varied weight fractions. The nanocomposites, fabricated via melt processing followed by injection molding, were tested for tensile strength, % elongation, tensile modulus, and impact toughness. Further, the samples were also subjected to dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) to determine the dynamic storage modulus and thermal stability. The addition of nano-silica in polypropylene HHR102 resulted in enhanced ductility and well-balanced tensile modulus; however, the tensile strength and impact toughness were found to be decreased. On the other hand, the storage modulus was significantly increased for all nano-silica (NS)-containing polypropylene HHR102 matrices. With the increased nano-silica content, the storage modulus was optimal. Further, with the lower weight loss of 30% and 50%, the thermal stability of the increased silica content PP nanocomposites was much affected. However, it improved at a weight loss of 30% for the lower silica content PP nanocomposite (PP-1%NS). The imbibition was found to increase with the increase in NS. The increase in imbibition is attributed to the micro-voids generated during ageing. These micro-voids act as channels for water absorption. Further, the degree of crystallinity of the nanocomposites was decreased as a result of inhibition by the nano-particles on the regular packing of polymer molecules. The structure–property correlations were explicated based on the achieved mechanical properties. [ABSTRACT FROM AUTHOR]

A novel phthalazine‐based phthalonitrile resin was prepared by two different curing procedures. The phthalonitrile monomer, namely, 4,4′‐(((phthalazine‐1,4‐diylbis(oxy))bis(3,1‐phenylene))bis(oxy))diphthalonitrile (PDOP), was synthesized from the reaction of 1, 4‐dichloropthalazine, resorcinol, and 4‐nitrophthalonitrile. Its curing behavior and curing kinetics with 4‐(4‐aminophenoxy)phthalonitrile (APPH) were investigated by Differential Scanning Calorimetric (DSC). Isoconversional method based on Starink was applied to analyze the curing process of PDOP/APPH. The PDOP monomer exhibits a low melting point (89 °C) and a wide processing window (146 °C). The PDOP polymer mainly forms triazine, isoindoline, and phthalocyanine structure, as revealed by Fourier Transform Infrared (FTIR) spectroscopy, and its properties improved with the increase of post‐curing temperature and curing time. After post‐curing at 350 °C, the polymer has high storage modulus (3313 MPa), high glass‐transition temperature (380 °C), and outstanding thermal stability and thermal oxidation stability. [ABSTRACT FROM AUTHOR]

ZIF-L, a metal-organic framework (MOF) material, has a two-dimensional (2D) foliation, a large specific surface area, excellent thermal stability and CO 2 adsorption performance, respectively. In this work, in order to further improve the thermal insulation performance of SiO 2 aerogel composite fabrics, ZIF-L powder was first prepared as a reinforcing particle, and then added to silica aerogel. Finally, SiO 2 /AF/ZIF-L composites were obtained by solution impregnation method. The influence of different ZIF-L concentrations on the insulation performance of composites and their influencing factors were studied. Furthermore, these composites were fully characterized using BET measurement, Instron 5967, precision transient thermal performance tester, infrared thermal imager, insulation performance test, thermogravimetric analyzer, and dynamic thermomechanical analyzer. The results showed that 0.12% SiO 2 /AF/ZIF-L composites had excellent thermal insulation performance, with a thermal conductivity as low as 0.029 W/(m·K). In addition, SiO 2 /AF/ZIF-L composites fabricated by atmospheric drying method had the best thermal insulation performance under the conditions of gel time of 24 h, hydrolysis time of 5 h, and polycondensation pH value of 5–6. [ABSTRACT FROM AUTHOR]

In this study, two types of ortho-oxazine functionalized bismaleimides with exceptional thermal properties and solubility were synthesized. The excellent solubility in many solvents is attributed to the stable twisted structure of the monomer. The monomer containing the cyano group showed enhanced solubility. It was found that the curing mode of ortho-oxazine functionalized bismaleimide was autocatalytically cured. In situ FT-IR spectroscopic studies indicated that the structure of bismaleimide resin undergoes a structural transformation at higher temperatures to form benzoxazole resin with enhanced thermal stability. The carbon residue rates of bismaleimide and benzoxazole resins at 800°C were 69% and 77%, respectively. The new bismaleimide and benzoxazole resins were analyzed using Microscale Combustion Calorimeter (MCC), and it was found that they also possess excellent flame-retardant properties, specifically benzoxazole resin. [ABSTRACT FROM AUTHOR]

Semi‐crystalline poly (arylene ether nitrile) (PEN) with outstanding thermal stability and mechanical properties are expected to be used in structural materials. Increasing the crystallinity of PEN helps improve the processability of the materials as well as the thermal and mechanical properties of the products. In present work, the comprehensive properties of PEN composites are improved by the introduction of aramid staple fiber combined with hot stretching method. The effects of aramid fiber content and hot stretch multiplicity on the properties of the composite were investigated. The result shows that when the mass fraction of aramid fiber (AF) powder is 0.3% (PEN/AF3), the composites have the best overall performance, including thermal and mechanical properties. In addition, when the tensile ratio was 300% (PEN/AF3‐300), the properties of the samples are greatly improved, with the crystallinity increasing to 36.1%, the thermal decomposition temperature of 5% (Td5%) increasing by 10°C, and the tensile strength increasing to 195.40 MPa, which is 87.34% higher than that of the non‐thermal tensile composites. Therefore, this work provides a technical route for the preparation of high performance semi‐crystalline PEN composites, which is beneficial for the development of PEN applications. [ABSTRACT FROM AUTHOR]

Chalcogenide glasses are unquestionably one of the most popular materials known for their phase change property. Phase change materials (PCM) have a key role in the field of photonics, memory devices, imaging, etc. With an aim to study the worth of ternary Sb10Se90-xGex (x = 0, 19, 21, 23, 25, 27) and quaternary Sb10Se65Ge25-yIny (y = 0, 3, 6, 9, 12, 15) chalcogenide systems as PCM, the composition variation and effect of dopants on the thermal properties of two systems has been probed. The thermal stability of two glass systems has been investigated using criteria such as the S parameter, fragility index, and rate constants at glass transition and crystallization temperatures. The mechanism of the phase change phenomenon occurring in the glasses has been studied using the Avrami index. [ABSTRACT FROM AUTHOR]

The polydimethylsiloxane/nano-graphite (PDMS-NG) nanocomposites were prepared via a two rolled mixing mill and subjected to characterization using techniques such as Transmission Electron Microscopy (TEM), stress-strain analysis during elongation, as well as thermal properties including Thermo-Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The transition temperature was observed to be below -70°C for PDMS nanocomposites reinforced with Nano-Graphite (NG). The thermogram from the thermo-gravimetric analysis indicated that at 10%, 20%, 30%, and 50% weight loss, the temperatures for PDMS nanocomposites were higher compared to unfilled PDMS. These findings suggest a substantial improvement in the thermal stability of PDMS-NG nanocomposites. [ABSTRACT FROM AUTHOR]

Novel phenolic resin/silicone aerogels (PR-Si) were prepared through a facile sol-gel polymerization and ambient pressure drying process without solvent exchange. Without the addition of an additional catalyst, the hydroxyl condensation reaction between the siloxane oligomer and the phenolic resin resulted in the silicon being incorporated into the PR. The obtained aerogels exhibited high compressive strength (0.84–21.11 MPa) and low thermal conductivities [0.046–0.077 W/(m·K)]. The introduction of a Si–O network structure in the PR effectively improved the mechanical properties and thermal stability of aerogels. It is clear from the TGA plot that the mass loss temperature of the PR-Si aerogel was increased by 73 and 79 °C for the weight loss temperatures of 5 and 10% compared to cured pure PR. [ABSTRACT FROM AUTHOR]

The influences of ethylene-based elastomer (EE) and the compatibilizer agent ethylene-butyl acrylate-glycidyl methacrylate (EBAGMA) on the thermal degradation of PLA/EE blends were evaluated by the thermal degradation kinetics and thermodynamic parameters using thermogravimetry. The presence of EE and EBAGMA synergistically improved the PLA thermal stability. The temperature of 10% of mass loss (T10%) of PLA was around 365 °C, while in the compatibilized PLA/EE blend, this property increased to 370 °C. The PLA average activation energy ( E a ¯ ) reduced in the PLA/EE blend (from 96 kJ/mol to 78 kJ/mol), while the presence of EBAGMA in the PLA/EE blend increased the E a ¯ due to a better blend compatibilization. The solid-state thermal degradation of the PLA and PLA/EE blends was classified as a D-type degradation mechanism. In general, the addition of EE increased the thermodynamic parameters when compared to PLA and the compatibilized blend due to the increase in the collision rate between the components over the thermal decomposition. [ABSTRACT FROM AUTHOR]

Some photosensitive resins have poor mechanical properties after 3D printing. To overcome these limitations, a polyurethane acrylate oligomer (PUA) microsphere was prepared using the Pickering emulsion template method and ultraviolet (UV) curing technology in this paper. The prepared PUA microspheres were added to PUA-1,6-hexanediol diacrylate (HDDA) photosensitive resin system for digital light processing (DLP) 3D printing technology. The preparation process of PUA microspheres was discussed based on micromorphology, and it was found that the oil-water ratio of the Pickering emulsion and the emulsification speed had a certain effect on the microsphere size. As the oil-water ratio and the emulsification speed increased, the microsphere particle size decreased to a certain extent. Adding a suitable proportion of PUA microspheres to the photosensitive resin can improve the mechanical properties and thermal stability. When the modified photosensitive resin microsphere content was 0.5%, the tensile strength, elongation at break, bending strength, and initial thermal decomposition temperature were increased by 79.14%, 47.26%, 26.69%, and 10.65%, respectively, compared with the unmodified photosensitive resin. This study provides a new way to improve the mechanical properties of photosensitive resin 3D printing. The resin materials studied in this work have potential application value in the fields of ceramic 3D printing and dental temporary replacement materials. [ABSTRACT FROM AUTHOR]

Outstanding high-temperature resistance, thermal stability, and dielectric properties are fundamental for dielectric materials used in harsh environments. Herein, TiO2 nanoparticles are decorated on the surface of BN nanosheets by internal crosslinking between polydopamine (PDA) and polyethyleneimine (PEI), forming three-dimensional novel nanohybrids with a rough surface. Then, an ether nitrile (PEN) matrix is introduced into the polyarylene to form polymer-based nanocomposite dielectric films. Meanwhile, the structure and micromorphology of the newly prepared nanohybrids, as well as the dielectric and thermal properties of PEN nanocomposites, are investigated in detail. The results indicate that TiO2 nanoparticles tightly attach to the surface of BN, creating a new nanohybrid that significantly enhances the comprehensive performance of PEN nanocomposites. Specifically, compared to pure PEN, the nanocomposite film with a nanofiller content of 40 wt% exhibited an 8 °C improvement in the glass transition temperature (Tg) and a 162% enhancement in the dielectric constant at 1 kHz. Moreover, the dielectric constant–temperature coefficient of the nanocomposite films remained below 5.1 × 10−4 °C−1 within the temperature range of 25–160 °C, demonstrating excellent thermal resistance. This work offers a method for preparing highly thermal-resistant dielectric nanocomposites suitable for application in elevated temperature environments. [ABSTRACT FROM AUTHOR]

In this paper, a novel hydrogen-bonded liquid crystalline binary complex system was synthesized from pure mesogenic 4-(octyloxy)benzoic acid (8OBA) and non-mesogenic n-aminobenzoic acid (nABA, n = 3, 4) chemicals. Differential scanning calorimeter (DSC) experiments were performed to investigate the thermal properties of the synthesized samples, and polarized optical microscopy (POM) experiments were performed to investigate the mesogenic phase textures. The DSC and POM results showed that the phase sequence was Cr ↔ SmA ↔ SmC ↔ N ↔ I during continuous heating and cooling cycle. In addition, the thermal stability factor, phase transition entropy, and phase transition activation energy were calculated using DSC data. According to the calculated values, it was concluded that the mesogenic phases of the synthesized complexes occur regularly and the most stable phase is the SmC phase. Moreover, the optical tilt angle value for the SmC phase was measured and it was seen that the value increased up to 29° and 30° for 8OBA/4ABA and 8OBA/3ABA complexes, respectively. The formation of hydrogen bonds between the mesogenic and non-mesogenic molecules in the synthesized mesogenic structure was confirmed by Fourier-transformed infrared spectroscopy (FTIR). Furthermore, XRD results showed that the molecular ordering of the synthesized hydrogen-bonded 8OBA/4ABA and 8OBA/3ABA binary complexes occur in a monoclinic structure in the solid phase. [ABSTRACT FROM AUTHOR]

In this study thermal and structural properties characterization were performed for prepared ultra-high molecular weight polyethylene/carbon nanotube (UHMWPE/CNT) nanocomposite sheets by using a melt compounding method. The sheets were prepared by using six types of CNTs; pristine single walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs), oxidized- SWCNT and MWCNT, and amide- SWCNT and MWCNT. Thermogravimetric analysis results revealed that the addition of CNTs increased the nanocomposites thermal stability (17 °C) being produced by P-MWCNT. Differential scanning calorimetry and x-ray diffraction (XRD) results show no significant crystalline structure changes compared with the pure polymer, and increase in crystallinity (4%) for O-SWCNTs additions (4%). Scanning electron microscope images showed improved bridging in the polymer matrix by using oxidized and functionalized CNTs compared with pristine CNTs. These findings suggest that the durability of UHMWPE is enhanced by this nano-modification method, improving its suitability for many lightweight, high strength material applications. [ABSTRACT FROM AUTHOR]

Developing of high-performance thermosets with outstanding thermal properties has attracted increasing attention. Herein, a combined strategy, acetylene modification and copolymerization with bismaleimide, has been utilized for a novel bio-based tri-functional benzoxazine monomer. The monomer (RES-pa) was successfully synthesized using biomass resources, resveratrol, as raw material. Three systems with different ratios (RES-pa: bismaleimide = 1:0, 1:1, 1:2) were designed. The thermal derived polymerization of three systems was monitored by DSC and in situ FT-IR. Thermal stability of derived thermosets was systemically investigated in detail by dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). Specially, poly(RES-pa-co-DDM-BMI-1/1) is found to show a high Tg value of 374 °C and Td10 of 387 °C. Promisingly, the combined strategy used in the work may grant efficient way for design and preparation of high-performance thermosets. [ABSTRACT FROM AUTHOR]

Biodegradable films are extremely important for food packaging applications since they minimize environmental effects. However, their application areas are limited due to insufficient characteristics required for particular applications. The objective of the present research was to improve the properties of sago‐based biodegradable films embedded with nano‐ and micro‐ZnO (zinc oxide). Nano and micro‐ZnO were incorporated in the films at different percentages (1%, 3%, and 5%) in that the films were formed using the solvent casting method. The physicochemical, barrier, thermal, optical, morphology, and mechanical properties of sago‐based films were investigated. Adding 5% of micro‐ and nano‐ZnO significantly improved film thickness (0.162 and 0.150 mm, respectively) and WVP (4.40 and 5.64 (kg/s)/(m.Pa), respectively) while the optical properties and thermal stability exhibited superior performance. Micro‐ZnO particles improved the mechanical properties of sago‐based biodegradable films with the tensile strength reaching 6.173 MPa. Moreover, sago‐based nano‐ZnO films showed excellent UV‐shielding performance and relatively good visible‐light transmittance. This study suggested that sago biodegradable film incorporated with micro‐ZnO could be an excellent alternative to petroleum‐based plastic packaging. [ABSTRACT FROM AUTHOR]

Copyright of Polimery is the property of Industrial Chemistry Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Polimery is the property of Industrial Chemistry Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study explores the effect of alkali treatment at ambient (25 °C) and elevated temperatures (100 °C) on the physicochemical, structural, morphological, and thermal properties of Calamus tenuis cane fibers (CTCFs) for the first time. Our purpose is to investigate their potential use as reinforcement in polymer composites, since cane fibers are generally known for their accurate and consistent geometrical orientation. Treatment with 8% (w/v) sodium hydroxide (NaOH) is carried out at ambient temperature and at 100 °C for 4 h. Chemical analysis and Fourier transform IR spectroscopy (FTIR) indicate some removal of non-cellulosic elements from CTCFs during alkali treatment, resulting in increased surface roughness, as confirmed by using SEM micrographs. This removal of non-cellulosic elements leads to an enhancement in the density of the treated CTCFs. Untreated and treated fibers are analyzed for maximum degradation temperature, thermal stability, and kinetic activation energy (Ea) using thermogravimetric analysis (TGA). In particular, Ea was considerably diminished with treatment and temperature. X-ray diffraction (XRD) results show an improved crystallinity index (37.38% to 44.02%) and crystallite size (2.73 nm to 2.98 nm) for fibers treated with 8% NaOH at ambient temperature. In conclusion, a general benefit was achieved by treating CTCFs, though the influence of increasing temperature treatment appears controversial. [ABSTRACT FROM AUTHOR]

The main objective of this work is to evaluate the mechanical and thermal strength of a recently developed composite made of Cissus quadrangularis fiber coupled with Polylacticacid (PLA) in comparison to other natural fibers. This study investigated three different fiber and PLA compositions—20%, 30%, and 40%, respectively used to produce a composite. In contrast, another composite with the same volume percentage was created using calcium hydroxide Ca(OH)2 to coat the fibers in order to alter their microcrystalline structure and enhance their mechanical properties. The composite was created using an injection molding procedure. Tests were performed to assess the improved properties. According to a preliminary study, the mechanical characteristics of PLA combined with treated Cissus quadrangularis fiber are increased when compared to PLA coupled with untreated Cissus quadrangularis fiber and neat PLA. Calcium hydroxide acted as a binding agent in fiber to enhance stress transmission in the matrix, increasing tensile and flexural modulus as well as toughness elongation. Further DSC analysis showed that the inclusion of the preceding components increased the glass transition temperature and melting temperature. The temperature at the beginning of deflection has risen as a result of showing how increasing HDT, fiber–matrix adhesion, and fiber content are related. The morphological analysis was performed on both untreated and chemical-treated fiber composites by using an optical microscope to see the interaction with the fiber matrix. [ABSTRACT FROM AUTHOR]

Herein, a direct comparison of the thermal conductivity and stability of different silica‐fiber‐reinforced silica aerogels is presented. The thermal performance under high‐temperature exposure within an arc‐heated facility is evaluated by means of thermal propagation and stability. All aerogel materials, tested within this study, outperform the high‐temperature fiber‐based insulation mat in terms of thermal protection. Modification of the aerogels in the composition and opacification leads to an improvement of thermal insulation properties as well as of thermal stability against the high temperature. All materials are prepared in the form of cylindrical disks of 100 mm diameter having a thickness of 20 mm. Based on classic silica aerogel, an opacified silica aerogel and an aerogel in mullite composition, inorganic fiber‐reinforce composites have been prepared and tested, and their performance is discussed comparatively. The specimens with mullite composition are intended to form mullite in situ during application to avoid energy‐costly pretreatment. [ABSTRACT FROM AUTHOR]

The failure of mineral oils to work in machinery and engines under intense pressure, heat, and corrosion has prompted researchers to consider the development of synthetic lubricating oils that are appropriate for these demanding conditions. This research was conducted to synthesize new esters by reaction of citric acids (CA) with mono-alcohols (hexanol, octanol, decanol and 2-ethylhexanol), then the products were reacted with propanoic acid, valeric acid, and octanoic acid separately using 1:1 molar ratio. The resulting esters were characterized using nuclear magnetic resonance spectroscopy (NMR), Fourier-transform infrared spectroscopy (FTIR), and thermal gravimetric analysis (TGA). The rheological properties were studied, and it was found that the prepared esters have high thermal stabilities as the degradation takes place in the range of 175 °C - 425 °C. The prepared esters show Newtonian behaviors as their viscosities do not change by changing shear rate. The physicochemical characteristic of prepared esters were also determined which showed improved low temperature properties (PP) -36 °C for ester (2R)-1,2-bis(2-ethylhexyl) 3-nonyl 2-(pentanoyloxy)propane-1,2,3-tricarboxylate (COEV) and viscosity index (VI) at 195 for ester (2R)-1-decyl 3-(2-ethylhexyl) 2-heptan-3-yl 2-(propionyloxy)propane-1,2,3-tricarboxylate (CDEP). The stabilities of the prepared esters were confirmed via the computational analysis and their stabilities were ranked as CDEP>COEP>COEO>COEV. [ABSTRACT FROM AUTHOR]

Rheological and thermal properties are important parameters to understand the role of the numerous variables involved in manufacturing and to achieve a high‐quality final product. The composites were prepared by compounding polypropylene (PP) with treated (alkaline and silane) oil‐palm empty fruit bunch (EFB) fiber using a twin screw extruder. Generally, regardless of fiber loading, the thermal stability of EFBPP composites was increased after using alkaline and silane‐treated EFB fibers as reinforcement. DSC analysis shows that there is a change in the melting temperature (Tm) and the degree of crystallinity (Xc) values of the EFB composites. The melt flow rate (MFR) of the composites decreased while viscosity increased with an increase in fiber loading. Rheological analysis reveals the composites to have a viscoelastic solid behavior where storage modulus (G') is greater than loss modulus (G"). The composites exhibit predominantly viscous behaviour (G" > G') at lower frequencies, whereas at higher frequencies the composites exhibit elastic behavior (G' > G"). The decrement of complex viscosity (η*) with an increasing angular frequency (ω) shows the materials exhibit shear thinning behavior. The composites also show the ability for regeneration when analyzed using time‐dependent behavior. [ABSTRACT FROM AUTHOR]

Synthesis and properties of cerium aluminate catalyst were investigated. The catalyst was prepared via combustion synthesis involving aluminum and cerium nitrates and glycine in the presence of palladium chloride. The obtained material was investigated using X-ray diffraction, Fourier transformed infra-red spectroscopy, differential thermal and thermo-gravimetric analysis, N2 adsorption, Raman spectroscopy, scanning electron microscopy, energy dispersion X-ray spectroscopy and X-ray photoelectron spectroscopy. Catalytic activity was tested for the toluene oxidation process. The direct product of combustion synthesis was CeAlO3 which remained stable even after thermal treatment at 400 °C for 2 h in static air, while temperature treatment at 800 °C for 2 h resulted in the decomposition of CeAlO3 into CeO2 and γ-Al2O3. Both thermal treatment products had sponge-like microstructure, but relatively small specific surface areas. Nevertheless, CeO2 prepared at 800 °C was nanocrystalline. Palladium was present as oxide homogeneously dispersed throughout the catalyst. The prepared catalyst proved to be highly active for the toluene oxidation process. [ABSTRACT FROM AUTHOR]

Herein, novel photoresponsive spiropyran (SP)‐based P(DEGMA‐co‐SpMA) copolymers with variable percentages of SP fractions are synthesized. The SP group present in these polymers exhibited the abilities of reversible photoisomerism. Their photoresponsive, structural, and thermal properties have been investigated and compared using various characterization techniques. These light‐responsive copolymers are found to exhibit photoswitchable glass transition temperature (Tg), high thermal stability (Td > 250°C), instant photochromism as well as fluorescence upon exposure to UV light. It is demonstrated that the Tg of these synthesized polymers increased when irradiated with UV light (λ = 365 nm), as a consequence of the photoisomerization of incorporated SP groups into their merocyanine form. This increase in Tg is attributed to an increase in polarity and a decrease in the overall entropy of the polymeric system when it switches from the ring‐closed SP form (less‐ordered state) to the ring‐opened merocyanine form (more‐ordered state). Therefore, such polymers with a unique feature of phototunable glass transition temperatures provide the possibility to be integrated into functional materials for various photoresponsive applications. [ABSTRACT FROM AUTHOR]

A method was proposed for the synthesis of Eu(III) compounds with para-methoxycinnamic acid anions and neutral ligands, starting from the sodium salt of para-methoxycinnamic acid. Using the methods of chemical elemental and thermal analyses and IR spectroscopy, the composition of the complexes and the coordination mode of carboxylate anions were determined. It was found that europium(III) methoxycinnamate with hexamethylphosphotriamide has the highest luminescence intensity. Luminescent polymer materials with synthesized europium(III) methoxycinnamates were obtained. [ABSTRACT FROM AUTHOR]

Simple Summary: Bacteriophage endolysins are specialized enzymes that act like natural antibiotics, breaking down the outer layer of harmful bacteria. One specific endolysin, PlyC, has shown promising abilities in effectively combating streptococcal bacteria. However, before considering PlyC as a long-term treatment option, we must comprehend its behavior under various conditions. This study investigated PlyC's stability under different temperatures to assess its potential as a therapeutic option. The findings revealed that when exposed to 46 °C, PlyC's structure starts to unfold, rendering it inactive. Particularly, the PlyCA region containing two enzymatic domains is highly sensitive to temperature changes, leading to PlyC's overall inactivity. In contrast, PlyCB, the part responsible for binding to bacterial surfaces, can endure higher temperatures: up to about 75 °C. Understanding the behavior of PlyC, along with its PlyCA and PlyCB domains, is crucial for its future development as a highly effective treatment against bacterial infections. Bacteriophage endolysins degrade the bacterial peptidoglycan and are considered enzymatic alternatives to small-molecule antibiotics. In particular, the multimeric streptococcal endolysin PlyC has appealing antibacterial properties. However, a comprehensive thermal analysis of PlyC is lacking, which is necessary for evaluating its long-term stability and downstream therapeutic potential. Biochemical and kinetic-based methods were used in combination with differential scanning calorimetry to investigate the structural, kinetic, and thermodynamic stability of PlyC and its various subunits and domains. The PlyC holoenzyme structure is irreversibly compromised due to partial unfolding and aggregation at 46 °C. Unfolding of the catalytic subunit, PlyCA, instigates this event, resulting in the kinetic inactivation of the endolysin. In contrast to PlyCA, the PlyCB octamer (the cell wall-binding domain) is thermostable, denaturing at ~75 °C. The isolation of PlyCA or PlyCB alone altered their thermal properties. Contrary to the holoenzyme, PlyCA alone unfolds uncooperatively and is thermodynamically destabilized, whereas the PlyCB octamer reversibly dissociates into monomers and forms an intermediate state at 74 °C in phosphate-buffered saline with each subunit subsequently denaturing at 92 °C. Adding folded PlyCA to an intermediate state PlyCB, followed by cooling, allowed for in vitro reconstitution of the active holoenzyme. [ABSTRACT FROM AUTHOR]

Inorganic aerogels have exhibited many superior characteristics with extensive applications, but are still plagued by a nearly century-old tradeoff between their mechanical and thermal properties. When reducing thermal conductivity by ultralow density, inorganic aerogels generally suffer from large fragility due to their brittle nature or weak joint crosslinking, while enhancing the mechanical robustness by material design and structural engineering, they easily sacrifice thermal insulation and stability. Here, we report a chemically bonded multi-nanolayer design and synthesis of a graphene/amorphous boron nitride aerogel to address this typical tradeoff to further enhance mechanical and thermal properties. Attributed to the chemically bonded interface and coupled toughening effect, our aerogels display a low density of 0.8 mg cm−3 with ultrahigh flexibility (elastic compressive strain up to 99% and bending strain up to 90%), and exceptional thermostability (strength degradation <3% after sharp thermal shocks), as well as the lowest thermal conductivities in a vacuum (only 1.57 mW m−1 K−1 at room temperature and 10.39 mW m−1 K−1 at 500°C) among solid materials to date. This unique combination of mechanical and thermal properties offers an attractive material system for thermal superinsulation at extreme conditions. [ABSTRACT FROM AUTHOR]

Environment friendly polymer composites made of plant based natural fibers such as bamboo fiber, roselle fiber (RF), aloe vera fiber (AF) oil, or kenaf fiber are cardinal of the current world toward sustainability. They offer lower carbon footprint, higher biodegradability, higher specific strength, higher thermal, and acoustic characteristics. On the other hand, properties of synthetic glass fibers (GFs) such as high specific strength to weight ratio, great resistance during impact, and high durability extend their application perspective for various engineering materials. As such, in the present study, mechanical properties and thermal stability of hybrid laminate comprising of natural fiber (i.e., AF and RF) and synthetic fiber (i.e., GF) fabricated using hand layup process were investigated. Experimental findings reveal that sequencing of the fibers significantly affects properties of the composite. Introducing a layer of AF between RF increased the tensile strength by 30.2% respectively while hybrid laminates composed of three successive layers of RF exhibited 12.6% higher impact strength compared to hybrid laminate composed of AF. Besides, the thermal stability of hybrid laminates was higher (i.e., minimal weight loss of <6.1% when heated up to 800°) compared to neat polymer or laminates with single reinforcement. The enhanced thermal stability, mechanical properties, and tribological properties of the "greener" hybrid laminates can be employed in various structural or lightweight industrial applications. Highlights: Hybridization using natural fibers and synthetic fibers are attempted and investigated.Fiber sequencing significantly affects mechanical properties of the composite.Higher thermal stability of hybrid laminates, that is, minimal weight loss of <6.1% when heated up to 800°.Laminated composed of AF in between RF exhibited lowest frictional coefficient."Green" hybrid polymer laminate suitable for various structural and lightweight industrial applications is identified. [ABSTRACT FROM AUTHOR]

In the global pursuit of using sustainable constituents for developing composite materials, the current investigation has paid particular attention to the most promising biopolymers, such as poly(lactic acid) (PLA) and bio-based poly(butylene succinate) (bio PBS). The research endeavor emphasizes a comparative assessment of short sisal fiber (SF) reinforced (10, 20, and 30 wt%) PLA and bio PBS biocomposites. The analysis and discussion have been reported for the thermal, mechanical, crystallinity, and dynamic mechanical behavior of developed composite materials. Based on mechanical properties, the optimal fiber loading for SF/PLA and SF/bio PBS biocomposites was 20 and 30 wt%, respectively. The developed composites have shown a considerable improvement in crystallinity of 17.88 and 41.13% at 20 and 30 wt% of fiber loading in SF/PLA and SF/bio PBS, respectively. The maximum storage modulus values of 14.23 GPa (20SF/PLA) and 11.74 GPa (30SF/bio PBS) were observed. The loss modulus of the SF/PLA and SF/bio PBS composites was around 74 and 89% higher than the loss modulus of the PLA and the bio PBS matrix, respectively. Overall, composites fabricated with bio PBS (SF/bio PBS) have shown better crystallinity, thermal stability, and ease of processing than SF/PLA composites. [ABSTRACT FROM AUTHOR]

BACKGROUND: Chestnut has recently attracted attention because of its exceptional functional properties, which are mainly influenced by the structural properties of chestnut starch (CS). In this study, ten varieties of chestnut from the northern, southern, eastern, and western regions of China were selected, and their functional properties, including thermal properties, pasting properties, in vitro digestibility, and multi‐scale structural characteristics were characterized. The relationship between structure and functional properties was clarified. RESULTS: In the varieties that were studied, the pasting temperature of CS was in the range of 67.2–75.2 °C and the pastes displayed diverse viscosity characteristics. Slowly digestible starch (SDS), and resistant starch (RS) of CS were in the range of 17.17–28.78% and 61.19–76.10%, respectively. Chestnut starch from north‐eastern China exhibited the highest RS content of 74.43–76.10%. Structural correlation analysis revealed that smaller size distribution, fewer B2 chains, and thinner lamellae thickness contributed to higher RS content. Meanwhile, CS with smaller granules, more B2 chains, and thicker amorphous lamellae displayed lower peak viscosities, stronger resistance to shear, and higher thermal stability. CONCLUSION: Overall, this study clarified the relationship between the functional properties and the multi‐scale structure of CS, revealing the structural contributions to its high RS content. These findings provide significant information and basic data for use in the creation of nutritional chestnut food. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The use of phase change materials (PCMs) for thermal storage, thermal management, and thermal insulation has been widespread for many years. Thermal storage systems (TES) based on PCMs can be improved and optimized by adding nanoparticles (NPs) to them. Throughout this study, PCM nanocomposites (NCs) based on paraffin wax (PW) loaded by anatase titania (TiO2) NPs were fabricated and characterized to examine their thermal performance as phase change materials. The as-synthesized TiO2 NPs were obtained by hydrolysis technique and showed a well-defined spherical shape with a diameter in the nanoscale range and a crystallite size ~ 22.75 nm. Throughout the used concentrations of TiO2 NPs, 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, and 0.5%, the morphological feature for the PW/TiO2 NCs revealed a good dispersion of NPs in PW. The non-isothermal differential scanning calorimetry (DSC) measurements at a constant heating rate of 10 °C min−1 were used in order to get the melting point (Tm), latent heat of fusion (LH), and latent heat rate (LHR) as a function of TiO2 NP concentrations for the investigated PW/TiO2 NCs. Both LH and LHR values for PW/TiO2 NCs are higher than those obtained for a pure PW sample. The significant enhancement in LH and LHR values for PW/TiO2 NCs was found to be 21.2% and 134.3% in comparison with the pure PW sample, respectively. The thermal stability of the investigated PW/TiO2 NCs was examined using thermal gravimetric (TG) scans. It is found that the thermal stability varies with TiO2 NP concentrations with a non-monotonic trend. At concentrations up to 0.25 mass%, the thermal stability improved. For concentrations over 0.25 mass%, the degradation process became rapid. [ABSTRACT FROM AUTHOR]

This paper focuses on the use of castor oil plant (Ricinus communis) as filler in rotomolded parts using polyethylene (PE) and polylactic acid (PLA) as polymer matrixes. The vegetable shredded material was used in 5 and 10% weight following a dry blending procedure and then rotomolded to obtain cube test parts. This material was characterized to determine its chemical composition, thermal stability, and structure. The NaOH-treated material shows reduced hemicellulose content and higher thermal stability. Obtained composite materials were characterized in terms of mechanical (tensile, flexural, and impact) and thermal properties, morphology, and bio-disintegration behavior. The use of Ricinus as filler in rotomolded PE composite decreases, in general terms, mechanical properties of neat PE, while no significant changes in thermal or bio-disintegration properties are found. On the contrary, PLA composites show higher tensile strength and similar Young's modulus than the matrix, although with reduced flexural and impact properties. Alkali-treated Ricinus material produces parts with higher porosity and thus, lower mechanical properties than composites with untreated material. Finally, the incorporation of this vegetal material modifies to a great extent the thermal properties of the PLA matrix. The bio-disintegration rate increases due to the use of fibers, probably because of the higher moisture absorption of composites. [ABSTRACT FROM AUTHOR]

Herein, Nd 2 O 3 -doped 0.11PIN-0.89PHT (PIN-PHT) single-phase tetragonal piezoelectric ceramics are prepared by traditional solid-phase method. In addition, impacts of Nd-doping on crystal structure and electrical performance for 0.11PIN-0.89PHT ceramics are systematically investigated. Based on Landau theory, we propose a novel strategy for obtaining high-performance ceramics by combining tetragonal phase and relaxor ferroelectrics. Results reveal that the introduction of polar nano-regions in tetragonal phase ceramics by doping with rare-earth ions to convert normal ferroelectrics into relaxed ferroelectrics is responsible for excellent properties of 0.11PIN-0.89PHT- x Nd ceramics. The optimized comprehensive performance is obtained at x = 0.9 mol%, where d 33 = 670 pC/N, S max = 0.29% (45 kV/cm), strain hysteresis = 8.68% (45 kV/cm), d 33 * = 736 p.m./V (30 kV/cm), T C = 312.6 °C, ε r = 3234, k p = 0.62, tan δ = 0.014, and excellent high-temperature stability in temperature range of 20–240 °C. After 106 cycles, electrical properties and strain remain unchanged, showing excellent anti-fatigue behavior. This work provides a novel approach for the development of ceramics with outstanding piezoelectric response, high strain, low strain hysteresis, excellent anti-fatigue resistance and thermal stability, and is expected to realize practical applications of piezoelectric ceramics. [ABSTRACT FROM AUTHOR]

Layered materials exhibit competitively low thermal conductivity along the out-of-plane direction. The solution process is a promising method for preparing stacked structures. However, the thermal stability of the layered materials is poor after processing in solution, thus hindering their applications at high temperatures. One of the solutions to improve the thermal stability of layered structures is to expand the interlayer distance by inserting large-size metal ions. In this work, we studied the thermal properties of Cs+ intercalated layered niobate obtained by the ion-exchanged process. The layered structure of the Cs+ intercalated layered niobate survives after thermal treatment even at 1200 °C. The room temperature thermal conductivity of as prepared stacked Cs–HCa 2 Nb 3 O 10 is as low as 0.11 W m−1 k−1. Upon thermal annealing, the thermal conductivity increases. After annealing at 1200 °C, the value is 0.90 W m−1 k−1. The finding suggests Cs+ intercalated layered niobate is a promising material for high-temperature insulation applications. [ABSTRACT FROM AUTHOR]