Glass Thermal Stability Research Articles

Synthesis and Evaluation of Polyurethane as Waterproof Adhesion Layer for Steel Bridge Deck

Service life of traditional steel bridge deck pavement is significantly shortened due to the failure of waterproof adhesion. To improve the interlayer bonding performance and extend its service life, polyurethane is proposed as a waterproof adhesion layer (WAL) for a steel bridge deck. This study aims to synthesize polyurethane WAL by free radical solution polymerization under different types and dosages of crosslinking agents as well as the mixing ratio of an acrylic co-blend. Tensile properties, water resistance, glass transition temperatures, thermal stability, and adhesive strength of the polyurethane binder are evaluated. The results demonstrate that polyurethane WAL yields desirable performance by using a hydroxyl molar ratio of 1/3 and an acrylic co-blend of 65%. Specifically, the tensile strength and breaking elongation of polyurethane WAL reach the maximum values of 6.466 MPa and 268.4%, respectively. The water absorption rate of polyurethane WAL is less than 4%. Glass transition temperatures of polyurethane WAL are between −80 °C and 60 °C, respectively. Polyurethane WAL features remarkable high- and low-temperature performance and thermal stability. Finally, adhesion strength between polyurethane WAL and the steel plate reaches up to 5.21 MPa. The outcome of this study facilitates the design and application of polyurethane waterproofing adhesion layers for steel bridge decks.

Preparation of Environmentally Friendly Anticorrosive Coatings with Aniline Trimer-Modified Waterborne Polyurethane

Eco-friendly waterborne coatings frequently exhibit poor corrosion resistance, high solvent content, and extended curing times, attributed to the excessive employment of hydrophilic groups and petroleum-derived polyols. In this work, aniline trimer (ACAT) and polyethylene glycol (PEG) were used as chain extenders. E-44 epoxy resin was subsequently utilized to modify the system and an aniline trimer-modified waterborne polyurethane (AT-WPU) dispersion was prepared and characterized. The chemical structure of the synthesized ACAT was characterized employing 1H NMR, ESI-MS, and FTIR spectroscopy. The structure and coating performance of the AT-WPU dispersion were investigated utilizing FTIR, particle size analysis, thermogravimetric analysis, DSC, TEM, SEM, and electrochemical corrosion testing. The results demonstrate that the aniline trimer-modified waterborne polyurethane dispersion was successfully synthesized. Additionally, the DSC analysis results and thermogravimetric graphs indicate that the glass transition temperature and thermal stability of the coatings increased with the addition of aniline trimer. As the aniline trimer content increased, the hardness and adhesion of the coatings were significantly enhanced. In the electrochemical corrosion assessment, the corrosion current density of AT-WPU-3 attained 7.245 × 10−9 A·cm−2, and the corrosion rate was as low as 0.08 μm·Y−1, indicating excellent corrosion resistance. The present study provides promising practical applications in the domain of metal material protection.

Influence of exfoliation method of graphene on physical properties of graphene/High Density Polyethylene nanocomposites: Semiconductor‐like electrical conductivity, glass transition, and melting temperature

AbstractDespite the wide range of applications of polyethylene (PE), many efforts are being made to improve its properties with carbon allotropes such as graphene. The addition of graphene can improve the electrical, thermal, and mechanical properties of this polymer. Through the present study, the effects of exfoliated graphene nanoplatelets (XGNPs) and few‐layer graphene (FLG) on the electrical conductivity and thermal properties of high‐density polyethylene (HDPE) were investigated. XGNPs were synthesized by ultrasonication of graphite nanoplatelets, and FLG was synthesized by shear exfoliation of flake graphite. Finally, HDPE powder particles were coated with dispersed XGNPs and FLG. Then XGNPs/HDPE nanocomposites and FLG/HDPE nanocomposites were fabricated by compression molding. The morphology, structural, electrical, and thermal properties of the graphite, graphene, PE, and nanocomposites were observed and comparatively studied by transmission electron microscopy, field emission scanning electron microscope, x‐ray diffraction (XRD), Raman spectroscopy, and conductivity measurements. The graphene's D, G, and 2D bands were revealed by Raman spectroscopy of nanocomposites and verified the existence of the graphene in the polymer matrix. XRD revealed that the graphene did not affect the original crystalline structure of the HDPE matrix, and the Fourier‐transform infrared spectroscopy revealed that the nanocomposite was obtained without the formation of any functional groups. The electrical properties of the nanocomposites were comparatively studied. After adding XGNPs (7 wt%), volumetric electrical conductivity in a sample reached from 10−16 to 10−3 S/m. The highest volumetric conductivity, 1.1 × 10−2 S/m, that is, semiconductor‐like conductivity, was achieved after adding 7 wt% of FLG. The glass transition temperatures (Tg), melting temperatures (Tm), and thermal stability were investigated by differential scanning calorimetry and TGA, respectively, and it was concluded that Tg and Tm increase by adding the graphene. This study shows that shear exfoliation of graphene is the best and the most facile method to prepare mass‐scale graphene for the production of graphene/polyolefin nanocomposites.Highlights Two types of graphene were produced by using sonication and shear‐exfoliation. HDPE powders were coated with two types of graphene and then hot pressed. The method of (G) preparation is crucialparameter on electrical conductivity. In the sample containing 7 wt% (XGNPs), the highest conductivity is 10−3 S/m. In the sample containing 7 wt% (FLG), the highest conductivity is 10−2 S/m.

Green synthesis of boehmite-reinforced cashew gum/polypyrrole biopolymer blend for advanced biomaterials

Electrically conducting biopolymer blend nanocomposites based on different contents of boehmite (BHM) reinforced cashew gum (CG) /polypyrrole (PPy) blend is synthesized by an in situ polymerization technique using water as a green solvent. The resulting bio-blend nanocomposites underwent comprehensive analysis concerning their structural, morphology, thermal, and electrical properties, such as dielectric constant, dielectric loss, electric modulus, and AC conductivity. The Fourier transform infrared spectroscopy (FTIR) spectra revealed the presence of metal oxide stretching in the blended nanocomposite at 512 cm−1. Field emission scanning electron microscopy (FE-SEM) confirmed the attachment and uniform dispersion of BHM within the CG/PPy blend at 7 wt% loading, and beyond this loading, the nanoparticles get agglomerated in the biopolymer blend. The glass transition temperature and thermal stability of all the blended nanocomposites are higher than that of the pure CG/PPy blend and these thermal properties increase with the loading of nanoparticles. Conductivity experiments demonstrated that as the nanofiller content increases up to 7 wt%, there is a concurrent rise observed in AC conductivity, dielectric loss, and dielectric constant. There is a substantial difference of 1.21 Scm−1 between the maximum and minimum AC electrical conductivity, at 102 Hz. However, a decrease in electrical properties is observed at the highest loadings of BHM due to the agglomeration of nanoparticles in the polymer blend matrix. The lowest activation energy value (0.049 × 10−4 eV) is also exhibited by 7 wt% BHM nanocomposites. Furthermore, the electrical properties of both CG/PPy and CG/PPy/BHM nanocomposites exhibited a temperature-dependent behavior, progressively increasing until reaching maximum values. This study suggests that such bio-based polymer dielectrics could be promising materials for various applications, offering enhanced thermal and electrical properties through careful control of nanofiller content and dispersion.

Diphenylphosphine oxide derivative with a symmetrical structure as an efficient flame retardant for application in epoxy resin

AbstractA fresh phosphorus‐containing fireproofing agent (oxybis(4,1‐phenylene))bis((2,5‐dihydroxyphenyl)(phenyl)phosphine oxide) (ODDPO‐HQ) was synthesized by a simple two‐step reaction. The effect of ODDPO‐HQ on the glass transition temperature (Tg), crosslinking density, thermal stability, fire resistance, dielectric performances, hydrophobicity, and water absorption of epoxy resin (EP) was studied. EP/ODDPO‐HQ containing 1.2 wt% phosphorus not only achieved the vertical burning V‐0 grade with a limited oxygen index of 28.9% but also maintained good thermal stability. Compared to unmodified EP, its Tg value has only decreased by 7.2°C. Detailed studies revealed that the excellent flame resistance of ODDPO‐HQ for epoxies was ascribed to the flame suppression both in the gaseous phase and condensed phase, especially the obvious barrier effect. Although the water uptake of the modified epoxies slightly rose with the content of ODDPO‐HQ caused by the reduction of the crosslinking density within the matrix, it did not adversely affect the properties of the polymer. The modified epoxies showed reduced dielectric constant and dielectric loss values, and the contact angle of EP/ODDPO‐HQ samples increased as the flame retardant content rose, which might be due to the symmetrical structure of ODDPO‐HQ reducing the polarity. Our study presents an easy approach for producing high‐performance epoxies.

Exploration of physical, structural, thermal, and optical properties of alkali zinc boro tellurite glasses doped with europium trioxide

In this present work we have studied the physical, structural, thermal, and optical properties of a new set of alkali zinc boro tellurite glasses doped europium trioxide prepared using the melt-quenching method. X-ray diffraction technique (XRD) and SEM were used to determine the non-crystalline property and microstructure property of the prepared samples. By using MAS-NMR spectroscopy and FTIR spectroscopy, the structural changes in the glasses were revealed. The physical properties were described by considering the densities of glass samples and hence molar volume, polaron radius, and oxygen packing density were measured. Thermal stability of glasses was perceived by performing DSC analysis and values ranges from 145 to 190 °C. Using UV–visible absorption spectra, it was possible to calculate the optical properties. The highest refractive index is found as 2.275 for glass AZBTE0 and the lowest is 2.241 for AZBTE5 glass. The ionic behaviour of the glasses was determined by electronegativity and values lie in the range of 1.51 to 1.688. The outcomes of the physical, thermal, and optical characteristics of glasses are intended for potential uses in optical switching and Europium doped fibre amplifier applications.

Facile Synthesis of Bis-Diphenylphosphine Oxide as a Flame Retardant for Epoxy Resins.

A phosphorus-containing compound, (oxybis(4,1-phenylene))bis(phenylphosphine oxide) (ODDPO), was successfully synthesized and used as a flame retardant for epoxy resin (EP). The results demonstrated that EP/ODDPO, containing 1.2 wt% phosphorus, achieved a vertical burning V-0 rating, with a limited oxygen index value of 29.2%, indicating excellent flame retardancy. Comprehensive evaluations revealed that ODDPO exhibited both gas-phase and condensed-phase flame-retardant effects on EP, with a particularly notable barrier effect. In addition, the incorporation of ODDPO had a minimal negative impact on the glass transition temperature (Tg) and thermal stability of the EP matrix. Compared to unmodified EP (EP-0), the Tg value and initial decomposition temperature of EP/ODDPO-1.2 decreased by only 7.6 °C and 10.0 °C, respectively. Moreover, the introduction of ODDPO significantly improved the hydrophobicity and water absorption resistance of epoxy materials, which is attributed to ODDPO's rigidity and symmetric structure, reducing water molecule permeation. Furthermore, the dielectric properties of ODDPO-modified EP samples were strengthened compared to EP-0, due to the ODDPO's symmetric structure reducing the polarity of the matrix. The above results indicated that ODDPO serves as an excellent flame retardant while enhancing other properties of the EP matrix, thereby contributing to the preparation and application of high-performance epoxy materials.

Enhancing the dyeability of polyurethane fibers by introducing protonated tertiary amine groups

Traditional polyurethane fibers (CPUF) are widely used in the preparation of blend clothing in order to improve the elasticity and comfort of fabrics. However, there has been a problem of low acid dye adsorption for CPUF, resulting in light hue of dyed CPUF. In this work, a poly (HMDI-BHOPA) was prepared with dicyclohexylmethane 4,4′-diisocyanate (HMDI) and 1,4-(2-hydroxyethyl) piperazine (BHOPA), and then added into the CPUF spinning solution for the preparation of modified polyurethane fibers (BPUFs) through dry-spinning technology. Tertiary amine groups were introduced after the addition of poly (HMDI-BHOPA), which could be protonated at acidic conditions to form binding sites for acid dyes, further enhancing the adsorption capacity of the fibers. Nuclear magnetic resonance spectroscopy (1H and 13C NMR) was used to confirm the structure of poly (HMDI-BHOPA). The results of differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA) demonstrated that the addition of poly (HMDI-BHOPA) had little effect on the glass transition temperature and thermal stability of BPUFs. The addition of poly (HMDI-BHOPA) affected the ordered arrangement of hard segments and reduced crystallization enthalpy of hard and soft segments in polyurethane. Hence, the elastic recovery of BPUFs showed little change, and the elongation at break and break strength decreased compared to CPUF. Zeta potential testing results showed that BPUFs was protonated under acidic conditions. Dyeing results proved the enhancement of dyeability of BPUFs. The dyeing kinetics and thermodynamics of acid dyes on BPUFs were studied to investigate the dyeing mechanism. From the dyeing kinetics results, both CPUF and BPUFs fitted Elovich model. From dyeing thermodynamics results, Langmuir model showed a better applicability for BPUFs at a low pH and temperature condition, while Freundlich model fitted better for CPUF.

Eco-friendly synthesis, characterization, and properties of copper oxide nanoparticles in cashew gum/polypyrrole blend for energy storage applications

Conducting biopolymer blend nanocomposites of cashew gum (CG) and polypyrrole (PPy), with varying concentrations of copper oxide (CuO) nanoparticles were synthesized through an in-situ polymerization method using water as a sustainable solvent. The formation of blend nanocomposites was characterized using UV–visible (UV–vis) spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). UV spectroscopy revealed a significant reduction in absorption intensity with the addition of CuO, indicating enhanced optical properties. FT-IR and XRD analysis confirmed the successful incorporation of CuO into the CG/PPy blend. FE-SEM images revealed the uniform distribution of nanoparticles throughout the biopolymer blend, particularly in the 7 wt% sample. TGA and DSC results demonstrated a significant enhancement in thermal stability, increasing from 352 °C to 412 °C and a rise in the glass transition temperature from 89 °C to 106 °C in the blend nanocomposites. The dielectric constant, dielectric loss, impedance, Nyquist plot, electrical conductivity, and electric modulus were extensively examined at different temperatures and frequencies. The dielectric constant of the CG/PPy blend increased from 2720 to 92,950 with the addition of 7 wt% CuO, measured at 100 Hz. The improved glass transition temperature, thermal stability, and superior electrical properties imply potential usage of the developed nanocomposite in nanoelectronics and energy storage applications.

Effect of hollow glass microspheres on transverse properties of carbon fiber reinforced epoxy composites

AbstractHollow glass microsphere (HGM)—based composites are gaining popularity in materials research due to their ability in altering material characteristics drastically. The current study investigates HGMs filled carbon fiber reinforced epoxy (CE) composites on transverse properties, aiming for aerospace and defense applications mainly in composite pressure vessels. Unidirectional laminates of Carbon/Epoxy with varying HGM percentages (0.2, 0.4, 0.6, 0.8, 1.0 wt. %) were wounded onto a flat‐plate mandrel using a 4‐axis filament winder, along with a baseline sample without HGM for comparison. The glass transition temperature (Tg) and thermal stability were analyzed by carrying out dynamic mechanical analysis and thermogravimetric analysis. The fracture mechanism of the samples loaded under tension was investigated using FESEM. Experimental results indicate reduction in density with increase in HGM content, up to 0.4% HGM there is increase in transverse tensile strength of 25% compared to baseline and further increase in HGM content, decrease trend is observed. 30% decrease in transverse compressive strength is observed compared from baseline to 1.0 wt. % of HGM. No significant change was noticed in the thermal stability and Tg on introduction of HGM. Microscopy images of fractured samples revealed effective physical interaction and dispersion of the HGM within the matrix.Highlights Transverse mechanical properties are tested to know the influence of HGM filler on filament wound composites. Density of the composite decreases with increase in HGM content. Thermal stability and Tg shows less change on introduction of HGM in composites.

3D printed polymer-matrix loaded with graphene oxide

This research deals with adding graphene oxide, resulting in a novel resin suitable for additive manufacturing technologies based on layer-by-layer photopolymerization. The mechanical and thermal properties demonstrate that the specimens manufactured with graphene oxide with low concentration achieve an excellent combination of strength and ductility. Graphene oxide highly influences the molecular dynamics of the polymeric matrix, modulating the glass transition and thermal stability so that it obtains a more elastic behavior or enhanced stiffness, depending on the concentration. The structural properties show that the structural disorders in the polymer matrix are due to variations in graphene oxide content, so graphene oxide embedded in the photopolymer resin did not produce relevant structural changes, form any covalent bond, or add new functional groups.

Room temperature catalytic upgrading of unpurified lignin depolymerization oil into bisphenols and butene-2

Lignin is the largest source of renewable aromatics on earth. Despite numerous techniques for lignin depolymerization into mixtures of valuable monomers, methods for their upgrading into final products are scarce. The state of the art upgrading methods generally rely on catalytic funneling, requiring high temperatures, catalyst loadings and hydrogen pressure, and lead to the loss of functionality and bio-based carbon content. Here an alternative approach is presented, whereby the target monomers are selectively converted in unpurified mixtures into easily separable final products under mild conditions. We use reductive catalytic fractionation of wood to convert lignin into iso-eugenol and propenyl syringol enriched oil followed by an olefin metathesis to yield bisphenols and butene-2, thus, valorizing all bio-based carbons. To further demonstrate the synthetic utility of the obtained bisphenols we converted them into polyesters with a high glass transition temperature (Tg = 140.3 °C) and thermal stability (Td50% = 330 °C).

BaTiO3-B2O3-MgO-Na2O-CaO glass series: Radiation shielding, thermal, and mechanical properties

The effect of BaTiO3 on the mechanical, thermal and radiation shielding properties of the borate glass with the composition of (60-x)B2O3 + 10MgO + 15Na2O + 15CaO+(x)BaTiO3 (x: 0,2.5,5,7.5 and 10 mol%) were synthesized by the melt quenching method. The physical, thermal, mechanical and radiation protection properties of the glasses produced with this designed composition were carefully investigated. As the BaTiO3 amount increased from 0 % to 10 %, the density of the glass increased from 2.571 to 2.870 g/cm3 and the glass thermal stability (ΔT) also enhanced from 51 to 63. The LAC value at 276 keV, 0.2831 cm−1 for 0 % BaTiO3 and enhanced linearly with increasing BaTiO3 concentration and reach to 0.3475 cm−1 at 10 % BaTiO3. The experimentally obtained MAC values are in agreement with the theoretically calculated MAC values with XCOM and MCNP6.2. It was concluded that the increase in the BaTiO3 value of the glass positively affects the radiation shielding properties of the glasses.

Green blend nanocomposites developed from waste sericin, polyvinyl alcohol and boehmite for flexible electronic devices

The present research article demonstrates the dispersion of boehmite (BHM) nanoparticles into sericin (SER) from silk industry waste with polyvinyl alcohol (PVA) to enhance the optical, mechanical, thermal and electrical characteristics of PVA/SER blend nanocomposites prepared by a simple green synthesis. Techniques such as Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), UV visible spectroscopy, field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were carried out for the characterization of the prepared composites. XRD revealed the increased crystallinity of the polymer blend by the reinforcement of BHM. The existence of intermolecular interactions in the blend composite was confirmed by FTIR and UV spectroscopy. The optical bandgap energy of the biopolymer blend decreases with the inclusion of BHM. The SEM and HR-TEM confirmed the homogeneous dispersion of BHM in the blend at 5 wt% loading. The glass transition temperature and thermal stability of the blend nanocomposites were significantly improved by the inclusion of BHM was deduced from DSC and TGA. The dielectric constant and AC conductivity were remarkably increased with the reinforcement of nanoparticles. The activation energy obtained from AC conductivity decreased with temperature. The mechanical properties of the blend nanocomposites (hardness, tensile strength and Young's modulus) were greatly increased in presence of BHM. The 5 wt% sample has the highest tensile strength, Young's modulus, dielectric constant, AC conductivity and optical properties, allowing it to be used to make optoelectronic devices with better charge-storing capacity and flexible-type electrochemical gadgets.

Photopolymerization-based 4D-printing of shape-memory materials containing high-performance polymers

High-performance aromatic heterochain polymers are engineering thermoplastics with exceptional mechanical and thermal properties that have attracted great interest in various areas ranging from aerospace to biomedicine. However, there have been a number of difficulties to 3D-print materials based on such polymers with new promising performance characteristics. Herein, a number of new photosensitive compositions (PSCs) based on high-performance polyetherimide (PEI) or polysulfone (PSU), reactive functional monomer (N,N-dimethylacrylamide) and oligomer (bisphenol A ethoxylate diacrylate) has been developed. It has been shown that the use of the developed PSCs allows the formation of 3D-structures with high printing resolution by LCD 3D-printing. Subsequent thermal post-curing of 3D-printed green-state samples at 250°С for 1 h led to the fabrication of materials with the highest tensile strength (up to 41.9 ± 3.1 MPa), glass transition temperature (141 °C) and thermal stability (above 350 °C). In addition, 3D-printed structures demonstrate high-temperature shape memory effect with shape fixity ratio > 99% and shape recovery ratio up to 97.1%.

Introducing rigid-flexible integrated structure and constructing sacrificial bonds to achieve mechanically robust and malleable epoxy resin

Epoxy resin (EP) is usually brittle because of highly cross-linked chemical structure, so it is necessary to carry out research on toughening of epoxy resin. Here, a modified epoxy resin with enhanced mechanical toughness and strength was prepared using a novel modifier (PEA-BA), synthesized from polyetheramine D-400 (PEA) and benzoic acid (BA). Polyether chains that represent flexible structures, and aromatic rings representing rigid structures, were integrated together into the modifier to achieve simultaneous enhancement of the toughness and strength of the resulting epoxy resin. Moreover, the aromatic rings in PEA-BA formed π-π interactions with the aromatic rings in the EP network, further increasing the ductility of the modified epoxy resin. Research results demonstrated that the modified epoxy resin exhibited significantly improved elongation at break (increasing from 6.7 % to 39.2 %), as well as higher tensile strength (from 61.9 MPa to 69.3 MPa) and impact strength (from 25.3 kJ·m−2 to 62.9 kJ·m−2). Importantly, the glass transition temperature and thermal stability of the modified epoxy resin were not markedly reduced. The above properties indicated that PEA-BA achieved a favorable combination of high strength and ductility of epoxy resin, providing a new idea for toughening epoxy resin.

Incorporation of canola meal as a sustainable natural filler in PLA foams

The canola oil industry generates significant waste as canola meal (CM) which has limited scope and applications. This study demonstrates the possibility of valorization of CM as a sustainable natural filler in a biodegradable polymer composite of Poly(lactic acid) (PLA). Generally, interfacial bonding between natural fibers and the polymer matrix in the composite is weak and non-uniform. One possible solution is to derivatize natural fibre to introduce interfacial bond strength and compatibility with the PLA polymer matrix. Here, CM was succinylated in a reactive extrusion process using succinic anhydride at 30 wt% to get 14% derivatization with 0.02 g of -COOH density per g of CM. The CM or succinylated CM at 5 and 15 wt% was co-extruded with amorphous PLA to get composite fibers. CM-PLA and succinylated CM-PLA biocomposites were foamed using a mild and green microcellular foaming process, with CO2 as an impregnating agent without any addition of organic solvents. The properties of the foams were analyzed using differential scanning calorimetry (DSC), Dynamic mechanical thermal analysis (DMTA), shrinkage, and imaging. The addition of CM or succinylated CM as a natural filler did not significantly change the glass transition temperature, melting point, percent crystallization, stiffness, and thermal stability of PLA foams. This suggests succinylation (modification) of CM is not a mandatory step for improving interphase compatibility with the amorphous PLA. The new PLA-CM foams can be a good alternative in the packaging industry replacing the existing petroleum-based polymer foams.Graphical

Fluorine-free waterborne polyurethanes modified with bis-amino silane coupling agent: Synthesis and properties

Series of anionic waterborne polyurethanes (WPU) were synthesized with isophorone diisocyanate (IPDI) and polycaprolactone diol (PCL). Silane coupling agent (KH-792) was introduced into waterborne polyurethane system as modifiers. The effect of KH-792 contents on the properties of waterborne polyurethane was investigated. The Si-O bonds in KH-792 would be hydrolyzed into Si-O-Si bonds in the WPU system, forming a cross-linked network and improving the hydrophobic properties of WPU. The experimental results showed that the introduction of KH-792 significantly improved the glass transition temperature, thermal stability and water resistance of films. When the content of KH-792 was 1.5%, the comprehensive property of film was the best: the tensile strength was 26.80 MPa, the elongation at break was 693.83%, the adhesion was 1.74 MPa, and the T-type peel strength was 13.95 MPa. This offered a research basis for developing a new type of waterborne polyurethane fabric coating with strong adhesion, high mechanical properties and good water resistance.

Correlations of structural, thermal and electrical properties of sodium doped complex borophosphosilicate glass

Borophosphosilicate glasses with varying sodium ion concentrations were investigated for their, structural, thermal, and electrical properties. All the obtained glasses were transparent except the glass with the highest sodium content, which exhibited translucency due to inhomogeneities. Increasing sodium content led to reduced boron and silicon content while maintaining a constant B/Si ratio, indicating progressive depolymerization of the glass network. Confocal microscopy, scanning electron microscopy, and atomic force microscopy showed homogeneous and granular structure for samples with lower sodium content, but higher sodium content resulted in visible agglomeration/nanocrystallization. X-ray diffractograms showed amorphous nature for most samples, with samples doped with the highest concentrations of Na2O showing several broad reflections suggesting nanoscale crystallinity. Fourier-transform infrared spectroscopy revealed shifts in dominant bands with increasing sodium content, indicating depolymerization of the borate network. An observed decrease in glass transition temperature and thermal stability with increasing sodium content was attributed to depolymerization and formation of non-bridging oxygens. Impedance spectroscopy revealed two relaxation processes associated with the transport of Na+ ions through two different regions. DC conductivity and activation energy predominantly increased with the sodium ion content at high temperatures.

KBiFe2O5 triggered-phase transition of Bi2Fe4O9 and Fe3O4 in tellurite glass with huge nonlinear and magnetic properties

In the quest for glass materials with high nonlinearity and strong magnetism to meet the demands of advancing technology, magnetic nanocrystal (NC) doping emerges as a promising approach. The paper investigates the phase transition from KBiFe2O5 to Bi2Fe4O9 and Fe3O4 NCs within a TeO2–Bi2O3–B2O3 glass matrix. The novelty of this study lies in leveraging the coexistence of multiple phases to amplify both the polarization and magnetic moment of glass. Various techniques, including X-ray diffraction, transition transmission electron microscopy, X-ray photoelectron spectroscopy, Mössbauer spectroscopy, and vibrational sample magnetometer were employed to analyze the impact of NCs content and heat treatment temperature on crystallization, structure modification, and properties. KBiFe2O5 NCs doping induces changes in crystal phases and modifies the glass network structure by forming multi-valence states and altering coordination numbers, such as FeO4→FeO6, TeO4→TeO3, and BO4→BO3. Concurrently, appropriate temperature conditions result in reduced NC size, preserving glass transparency and thermal stability. Spinel Fe3O4 NCs formation at higher temperatures enhances magnetic behavior. A glass sample containing 1 mol% KBiFe2O5 NCs, heat-treated at 410 °C, exhibits a narrow bandgap (Eg) of 1.82 eV, high nonlinear parameters (α3 = 3.98 × 10−10 m/W, χ(3) = 8.65 × 10−11 esu), and a low limiting threshold (1.01 × 1012 W/m2). Additionally, owing to the incorporation of high spin states and active magnetic exchange interactions, the same glass demonstrates robust ferromagnetic behavior (Ms = 2.3 emu/g and Hc = 850 G). The approach developed in this study has been demonstrated to be highly effective in producing transparent glass with promising nonlinearity and magnetic performance suitable for photonics applications.