Melt-quenching Process Research Articles

Efficient fabrication of PLA/PHB composites with enhanced mechanical properties, excellent thermal stability, fast crystallization ability, and degradation rate via the synergistic of weak shear field and melt quenching technique

Melt blending is an attractive strategy for the industrial fabrication of high-performance Polylactic acid (PLA), nevertheless, the damage of traditionally strong shear-based melt plasticization process on PLA molecular chains reduces its comprehensive mechanical properties, thereby revealing defects such as low modulus, low heat deflection temperature, slow crystallization rate, and narrow thermal processing window. In this work, a synergistic strategy involving a weak shear of elongational rheology technique and a melt quenching process was utilized to fabricate high-performance PLA/Polyhydroxybutyrate (PHB) composites. While the weak shear force minimizes the molecular weight (Mw) destruction during the thermal processing and the PHB in-situ fibrillates promote the interfacial bonding, thus maintaining a high Mw, favorable thermal stability, and optimal mechanical properties. In addition, the melt quenching process enabled not only the original fibrillation structure of PHB to be well-reserved, but also significantly enlarged the crystallization rate of the PLA phase, resulting in high-crystallinity PLA/PHB. Encouragingly, the superior fabrication process achieved a considerable enhancement in the PLA degradation rate, yielding a 90.9 % weight loss over 10 days of degradation in an alkaline solution. As expected, high-performance PLA composites are acquired by weak shear melt-plasticization and melt-quenching processes. The proposed method demonstrates promising applications in biomedical, agricultural engineering, and food packaging fields.

Nb5+-doped SrTiO3-based glass-ceramics: Insight into crystallisation kinetics, microstructure, and dielectric properties

Nb5+-doped SrTiO3-based glass-ceramics composed of SrO–B2O3–SiO2–TiO2 were modified by Nb2O5 doping and prepared via a melt-quenching process accompanied by controlled crystallisation. The effect of the Nb2O5 concentration on the crystallisation, microstructure, and dielectric properties of the glass-ceramics was investigated. Surface analysis conducted by XPS revealed that with the addition of Nb2O5, the number of non-bridging oxygens (NBO) decreased while the number of bridging oxygens (BO) increased, increasing the interconnection of the structural units. The crystallisation activation energies of the samples tended to decrease from 376.06 kJ/mol to 271.50 kJ/mol (Kissinger model), and the crystal growth modes changed from two-dimensional to three-dimensional (Avrami indexes n: 2.38–4.23) with increasing Nb2O5 concentration. The XRD, SEM, and EDS analyses showed that the addition of Nb5+ promoted the growth of crystals (0.44–1.35 μm). The dielectric properties show that an appropriate amount of Nb2O5 greatly improves the dielectric constant of the glass-ceramics. The dielectric constant of the glass-ceramic doped with 1.5 mol% Nb2O5 is 178.1 (300 K, 1 MHz), which is approximately 6.7 times higher than that of the undoped Nb2O5-doped glass-ceramics (26.5). The introduction of Nb2O5 reduced the activation energy of glass devitrification, promoted crystal development, and improved the dielectric properties of the glass-ceramics.

Utilizing Fe2O3 in phosphate-based glasses to enhance biocompatibility and gamma-ray absorption characteristics: A step towards understanding of Na2O/Fe2O3 translocation in P2O5–CaO–Na2O glass system

In recent years, bioactive glasses have been used in several different contexts, from dental applications to FDA-approved bone augmentation treatments. We report the incorporation consequences of Fe2O3 into P2O5–CaO–Na2O glasses to enhance the biocompatibility and gamma-ray absorption characteristics for potential medical and dental application. Phosphate-based glasses with a composition of 50P2O5·30CaO·(20-x)Na2O.(x)Fe2O3 were prepared using the melt-quenching process; x varies from 0 to 5 mol% with 1 mol% incremental increase. The fundamental biological and physical properties such as cell viability, attachment, and gamma-ray absorption of these glasses were investigated. The number and spreading of human dental pulp stem cells and human fetal osteoblasts, indicated by the density of actin-stained cytoplasm, increased on glasses with more Fe2O3 content particularly for those with 4 and 5 mol%. Incorporation of Fe2O3 into the glass system provided a significant improvement in hDPSCs and hFOBs viability. The improved cell attachment and viability with increasing the Fe2O3 content could be attributed to the enhanced durability of glasses with the formation of more hydration resistant P–O–Fe bonds. The mass attenuation coefficient values of the 50P2O5·30CaO·15Na2O·5Fe2O3 glass with a 5% Fe2O3 contribution are found to be the highest over the whole investigated energy range. The half value layer values of the 50P2O5·30CaO·15Na2O·5Fe2O3 glass are the lowest and hence more favorable. It can be concluded that increasing the Fe2O3 mol% in the P2O5–CaO–Na2O glass system is a useful method for increasing the biocompatibility and gamma-ray attenuation characteristics of P2O5–CaO–Na2O bioactive glasses for medical and dental applications.

Effect of BaO/TeO2 oxide ratio in TiO2.B2O3.Fe2O3 glasses: Physical, thermal and optical absorption studies

Glasses of the composition xBaO-(30-x)TeO2-10TiO2-59.5B2O3-0.5Fe2O3 were synthesized using the melt-quenching process and investigated using differential scanning calorimeter (DSC), optical characterization techniques. The DSC spectra of the prepared glass samples attest to their glassy nature. Archimedes' principle was used to determine the density (ρ) of the glass samples. The progressive replacement of BaO with TeO2 leads to the structural compactness of the vitreous network and improves the glass stability. Optical absorption spectra have also been employed to examine the optical transitions and electronic band structure. From the edges of UV absorption, the Eopt and Urbach energies have been determined. All the glasses' physical properties have been examined in relation to BaO mol%.

Effect of Ni-Co transition metal ratios on structure-function of Lithium Aluminium Borate Glasses for battery electrode

The Lithium Aluminum Borate Glasses (Li2O-Al2O3-B2O3) doped with various concentrations of xNi: Co (where x = 1, 2, 3, and 4) effectively synthesized by melt-quench process. Glasses made of nickel-lithium borate have undergone rigorous study to determine the impact of nickel-cobalt content on the operation of electrochemical characteristics and battery performance. The phase structure of all samples was confirmed using TEM diffraction XRD patterns. Intriguingly, at a scan rate of 5 mV/s, the 1Ni: Co glass electrode displayed the highest specific capacitance of 76.6 F/g. By adjusting the Ni:Co ratio in the glass structure, produced (Li2O-Al2O3-B2O3) glasses exhibit improved electrochemical characteristics.

Influence of sintering temperature on structure, physical, and optical properties of wollastonite based glass-ceramic derived from waste eggshells and waste soda-lime-silica glasses

Calcium oxide from discarded eggshells and waste soda-lime-silica were utilized in this study to make wollastonite (CaSiO3) based glass-ceramics. The calcium oxide and silica were made using the melt-quenching process and sintered for 2 hours at 700 to 1000?C. The XRD data verified that the wollastonite crystalline peak appeared at high sintering temperatures, with crystalline phase values of 39.74%, 47.37%, and 48.91% as the sintering temperature increased at 800-1000?C, respectively. Additionally, crystalline size and phase have no obvious change at 800-1000?C, where the intensity has increased by the sintering temperature. The FTIR spectra revealed the wollastonite phase vibration at the wavelength of 501 cm-1, 650cm-1, 715cm-1, 808cm-1, 931cm-1, 2129 cm-1. Additionally, the FTIR spectral confirm the Si-O-Ca vibration band at the wavelength of 650 cm-1. For the optical sample, the value of indirect allowed transition with n=2 is the ideal value of the optical band gap based on a band gap rise from 3.89 to 4.23 eV with increasing sintering temperature. The value n=2 which is the indirect allowed transition is the optimal value of the optical band gap based on the value increase from 3.89-4.23 eV as the temperature increase. The synthesis approach introduced the low-cost method, recycle approach, simple and yet uses cheap starting materials for fabrication of wollastonite glass-ceramics product.

Near-infrared-shielding energy-saving borosilicate glass-ceramic window materials based on doping of defective tantalum tungsten oxide (Ta0.3W0.7O2.85) nanocrystals

NIR-shielding window materials were fabricated by direct embedding of Ta 0.3 W 0.7 O 2.85 nanocrystals in bulk borosilicate glass-ceramics during a facile melt-quenching process. Optical and thermal performance of the prepared windows can be adjusted by varying the concentration of H 2 WO 4 and Ta 2 O 5 in the starting materials. The optimized window fabricated from raw materials containing 4.5 mol% H 2 WO 4 and 0.3 mol% Ta 2 O 5 exhibited high visible light transmittance 74.4% and strong NIR-shielding ability ΔT = 68.9%. Its thermal insulation performance is much better than soda lime glass or ITO glass, and its visible light transmission is higher than cesium-tungsten-bronze-based film coated glass. The distribution of Ta 0.3 W 0.7 O 2.85 functional nanocrystals in the glass matrix was confirmed by sample characterization using XRD, Raman, XPS, HRTEM and EDS. The NIR-shielding property has been attributed to local surface plasmon resonance due to oxygen vacancies in the Ta 0.3 W 0.7 O 2.85 nanocrystals. This study sheds a light on fabricating energy-saving windows with a tunable NIR-shielding performance.

Controllable synthesis of SrO-B2O3-SiO2-TiO2 glass-ceramics: Insight into the crystallization kinetics and dielectric properties

SrO-B2O3-SiO2-TiO2 (SBST) glass and glass-ceramics were prepared using the melt-quenching process with controlled crystallization kinetics. The influence of the Sr/Ti ratio on the structure, crystallization kinetics, and dielectric characteristics of SBST glass and glass-ceramics was investigated in detail. The samples were characterized using Raman spectroscopy, XPS spectroscopy, differential thermal analysis (DTA), X-ray diffraction (XRD), and scanning electron microscope (SEM). The results indicate that a defined glass transition peak and two crystallization peaks were observed in the DTA curves of the SBST glass. The crystallization mechanisms of the two peaks were nucleation occurred on both the surface and inner phase. Most importantly, the SBST glass-ceramics showed excellent frequency and temperature stability, and especially SBST-1.10 glass-ceramics samples had dielectric losses as low as 1.07 × 10−3 (100 kHz, room temperature) and had excellent temperature stability (Δεr/εr298K < 10%) in the 298–500 K temperature range.

Radiation shielding performance of a newly synthesized bismuth borate glass system

The melt-quenching process was used to produce 9Na2O–5BaO–Fe2O3–25Bi2O3-(20–0.5x)SiO2-(40–0.5x)B2O3- x ZrO2 glasses, where 0 ≤ x ≤ 12 mol. %. The lead-free glasses were mechanically investigated in terms of hardness and fracture toughness via the indentation method. The hardness of glasses was meaningfully increased from 4.28 to 5.0 GPa, 17% while the fracture toughness of glasses was slightly reduced from 1.66 to 1.26 MPa m1/2, 24%.. The phase formation of the lead-free glass was studied using the X-ray diffraction peaks in the range of 20⁰-60⁰. The chemical bonds and bonding mechanisms in the prepared glasses were examined through Fourier transform infrared (FT-IR) spectra. The gamma mass attenuation coefficient μ/ρ of the glasses was determined for a 15 keV‒15 MeV energy spectrum by XCOM computation and FLUKA simulation data. The μ/ρ estimated through FLUKA simulations and XCOM agreed well. The photon shielding related parameters showed that the radiation absorption competence of the glasses decreased as Zr content increased for energies below 500 keV. The variation in the chemical structure of the glasses did not significantly affect the photon attenuation competence at energies beyond 500 keV. The absence of Pb makes the present glasses more attractive for shielding applications from health and environmental perspectives.

Temperature-dependent effect of cooling rate on the melt-quenching process of metallic glasses

The cooling rate during the melt-quenching process is a crucial factor in the formation of metallic glasses. This study reveals the temperature- and thermal-history-dependent effects of cooling rate on the relaxation state of metallic glasses prepared by the rapid quenching of a liquid alloy. Using molecular dynamics techniques, we conducted melt-quenching simulations in which the cooling rates were varied during the quenching process. Maps were constructed to demonstrate the effect of the cooling rate on the quenching process as a function of temperature. The critical temperature range varied depending on the thermal history of the cooling process. Analyses of the local atomic order and atomic dynamics revealed the atomistic origin of the temperature- and thermal-history-dependent effects of the cooling rate. This study also discusses the physical background of the upper and lower ends of the critical temperature range based on the potential energy landscape and atomic dynamics.

Study of concentration and temperature-dependent photoluminescence properties in DyF3-doped fluorophosphate glasses for thermal stable photonic device

The novel P2O5–ZnO–B2O3–Na2O–NaF multi-component fluorophosphate glasses doped with DyF3 were prepared via the conventional melt-quenching process. The effects of DyF3 concentration on the glass structure and photoluminescence properties were systematically discussed. The J-O analysis and radiative properties of Dy3+ ions in fluorophosphate glass were investigated. Upon the excitation of 349 nm, the fluorescence intensity of 4F9/2 → 6HJ/2 (J = 15, 13, 11, 9) transitions increase first and then decrease with the DyF3 concentration, and the optimum concentration was determined to be 1.5 mol%. The 1.5 mol% DyF3-doped glass exhibit a high photoluminescence quantum yield (54.65%) and great thermal stability. Finally, the temperature-dependent emission spectra contour map reveals that the fluorescence emission of the fluorophosphate glass with 1.5 mol% DyF3 demonstrates a downtrend with the temperature, and the fluorescence intensity of the yellow emission transition (4F9/2 → 6H13/2) at 473 K can still maintain 70% of that at the initial condition (298 K). These results suggest that these DyF3-doped fluorophosphate glasses may be applied for thermal stable photonic devices.

Transparent zinc silicate/ zinc oxide crystallized glass-ceramics for water remediation application under visible light

The present study focuses on taking advantage of both Zinc Silicate (Zn2SiO4) and Zinc Oxide (ZnO) crystals in the glass matrix for enhancing photocatalytic activity. The fabricated samples were used as a photocatalyst for degrading ∼ 5 mg/L concentrated “Methylene Blue” (MB) and “Rhodamine B” (RB) dye separately under visible light. For this, 44 SiO2:11 Al2O3:35 ZnO:10 K2O compositions were prepared via the traditional melt quench process followed by heat treating at a temperature of 750 °C at 2, 4, and 6 h. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) was employed to characterize the fabricated samples. The bandgap measured from Differential reflectance spectroscopy (DRS) was found to decrease with an increase in the heat treatment duration. 44 SiO2:11 Al2O3:35 ZnO:10 K2O composition heat-treated at 750 °C for 2 h degraded ∼59% and ∼71% of Rhodamine B (RB) dye and Methylene Blue (MB) dye under visible light in 4 h.

Enhanced Er3+ photoluminescence in sodium borate glasses containing silver nanoparticles for photonic functionalities

Herein, the titled glass routed with silver nanoparticles (achieved using thermal–reducing agent) containing trivalent erbium ions was synthesized via the melt–quench process. The electronic microscopic and linear absorption outcomes of glasses confirmed the formation of Ag0 nanoparticles. The prepared glass specimen was annealed at 400, 450 and 500 °C, it was identified that the photoluminescence properties were highest at 450 °C. Therefore, we considered this 450 °C as optimized temperature, since further annealing at this temperature for different durations causes significant improvement in photoluminescence properties compared to the properties obtained at other temperatures. The annealing at 450 °C for was performed for 0, 5, 10, 15 and 25 h to understand the influence of annealing duration on the optical absorption, visible and infrared photoluminescence properties of the prepared glass system. The photoluminescence intensity and related parameters such as bandwidth, gain bandwidth and quantum efficiency and also lifetime values of excited state for infrared emission transition were improved monotonously with annealing duration. The augmentation in the investigated properties was ascribed to the local field–produced by silver nanoparticles and the energy transfer from silver nanoparticles to erbium ions. The outcomes instantiate that the titled glass embedded with silver nanoparticles containing erbium ions annealed for 15 h at 450 °C could be useful for optoelectronic and photonic applications.

Investigation of optical, mechanical, and shielding properties of zirconia glass capsule

Five new developed ZrO2 doped borotellurite glass with nominal composition of 60B2O3 -10Na2O-(10-x) CaO–20TeO2 -xZrO2 (x = 0, 0.5, 1.0, 2.0, and 3.0 mol.%), were prepared by melt-quenching process. Their amorphous nature, surface properties, and element distribution were investigated. Optical measurements from ultraviolet–visible (UV–Vis/NIR) spectrophotometer reveal that increasing the ZrO2 content leads to a decrease in both the indirect optical bandgap and Urbach energy, and to an increase in the indirect refractive index. Makishima_Mackenzie's approach was employed to calculate theoretical elastic moduli where Vickers microhardness was measured experimentally. It was shown that increasing the content of ZrO2 enhanced the microhardness and elastic characteristics. Gamma shielding characteristics were estimated using Phy-X/PSD software. Regarding radiation shielding performance, samples with higher zirconia content have higher radiation absorption ability. These results suggest that doping borotellurite glass with ZrO2 would improve glass properties to be a good candidate for optoelectronic applications, fiber optics, and/or gamma radiation shielding capsule.

Radiation shielding properties of Cd-Bi-Pb-Zn-borate glasses: influence of Bi2O3 activation

We report the detail characterizations and γ-radiation protecting characteristics of some new types of cadmium (Cd)-bismuth (Bi)-lead (Pb)-zinc (Zn)-borate glasses of the form (70-x)B2O3-10ZnO-10PbO-10CdO-xBi2O3 (with x = 0 to 20 mol%) synthesized via melt-quenching process. The influence of various Bi2O3 contents on the γ-radiation shielding traits of the obtained glass samples was evaluated by exposing them at different γ-ray energies (0.356, 0.662, 1.173, and 1.33 MeV) which were recorded by the NaI detector. XRD analyses of the as-quenched specimens showed their glassy phase. A comparison between theoretically computed (Phy-X and XCOM software) and experimentally measured various shielding parameters of the glass samples were performed. Irrespective of the Bi2O3 contents, the values of the mass attenuation coefficient, effective atomic number and effective electron density of the prepared glass samples were reduced with the increase of γ-ray energies. Furthermore, the theoretically calculated values of all the shielding parameters were agreed well with the measured ones. Regardless of the γ-ray energy exposures, the shielding capacity of the studied glasses was improved with the increase of Bi2O3 doping contents. The proposed glass compositions were asserted to be useful for the γ-ray absorber applications.

Exploration of concentration-reliant optical and luminescence aspects of Sm3+: B2O3-Gd2O3-Li2O-Na2O-LiF glasses for color displays and visible lasers utilization

In this work, for seven compositions of 0.1–2.0 mol% Sm3+-doped transparent borate-rich glasses (prepared utilizing a quick and facile melt-quenching process), optical and visible fluorescence traits combined with luminescence decay patterns have been inspected and analyzed thoroughly. By X-ray diffraction, the amorphous phase has been clarified. Absorption spectra displayed distinctive peaks of Sm3+ ion in ultraviolet, visible, and infrared spectral regions. Relying on absorption and fluorescence spectra, for all Sm3+: glasses, J-O (Judd-Ofelt) analysis has been conducted to compute J-O parameters Ωλ (λ = 2, 4, 6) from experimental oscillator strengths, and using such parameters, radiative aspects like transition probabilities, branching ratios, and radiative decay times of 4G5/2 metastable state to 6H11/2, 6H9/2, 6H7/2, and 6H5/2 levels have been estimated. Ω2 reduced continually as Sm2O3 content increased from 0.1–2.0 mol%, hinting at improved symmetry and ionicity between Sm3+ ions and related ligands. Four luminescence bands centered at 565 nm, 602 nm, 648 nm, and 710 nm ascribed to transitions from 4G5/2 →6H5/2, 6H7/2, 6H9/2, and 6H11/2 levels sequentially are obtained under intense λexci. = 401 nm. In all emission peaks, the reddish-orange one (602 nm) is identified to be very intense in all glasses. All fluorescence bands’ intensity increased up to 0.5 mol% Sm3+ doping level and above 0.5 mol% doping content, intensity reduced regularly owing to the concentration quenching effect caused by the ET (energy transfer) via CR (cross-relaxation) channels among Sm3+ ions. CIE (Commission Internationale de l′éclairage) coordinates, CCT (correlated color temperature), dominant wavelength, and color purity have been derived from emission spectra of all investigated samples, and derived CIE (x, y) and CCT values are located in the CIE plot’s reddish-orange light region, signifying such glasses potential for color displays and orange light-emitting diodes. As CCT< 3200 K, all samples could be categorized as “warm” light sources. Further, 4G5/2 level decay profiles exhibited single and double exponential characters at lower (0.1 and 0. 25 mol% Sm3+) and higher (˃ 0.25 mol% Sm3+) doping contents accordingly for deducing τexp (experimental decay time). Here τexp of 4G5/2 state (λexci. = 401 nm, λemi. = 602 nm) gradually decreased with an increase in Sm3+ content from 0.1 m to 2.0 mol%. Non-exponential decay curves are well fitted to the Inokuti–Hirayama model for S = 6, implying that the ET process is of dipole-dipole nature for Sm-Sm ions. Later, effective bandwidth, stimulated emission cross-section, gain bandwidth, and optical gain have been calculated for all Sm3+ ion fluorescence transitions in studied glasses. In all samples, possessing lesser CR rates and higher quantum efficiency, 0.1 mol% Sm3+: glass could be opted for producing effective visible lasing action upon violet excitation.

Bi2O3–PbO–CdO–B2O3 glasses: competent candidates for radiation shielding

Abstract The Bi2O3–PbO–CdO–B2O3 glasses were shaped via the melt-quenching process. The XRD spectra reveal that the glasses are composed of amorphous material. Four distinct bands may be seen in the FTIR spectra at wavelengths between 400 and 600, 600–800, 800–1200, and 1200–1500 cm−1 range. This is due to a variety of bond stretching and vibration modes present in the system. A Monte Carlo simulation was used to verify the radiation shielding capabilities. The µ values grow as the amount of Bi2O3 in the manufactured glasses increases. The rise in µ values was coupled with a drop in the Δ0.5 values when the Bi2O3 concentration was increased. Additionally, the TF and RPE values were influenced by the enhancement in the µ values, with the RPE increasing from 34.61 to 44.42 percent and the TF values decreasing from 65.39 to 55.58 percent at 0.662 MeV when the Bi2O3 concentration was increased. The study showed that raising the Bi2O3 content improves the shielding capabilities. Thus, the produced glass samples, particularly BPCB25, exhibit excellent shielding capabilities, making them suitable for use in radiation shielding fields.

Investigation of color tunability of Dy3+& Eu3+ Co-doped bismuth borate glasses for lighting applications

This study concentrates on energy transfer between rare-earth ions in bismuth borate glasses. The LiBBiEu3+, LiBBi:Dy3+, and co-doped LiBBiDy15Eu20 glasses were synthesized by melt-quenching process and carried out their structural, physical, optical, and luminescence investigations. The photoluminescence (PL)-emission spectra of LiBBi:Eu3+ glass show intense red emission while those of LiBBi:Dy3+ exhibit blue (4F9/2 → 6H15/2) and yellow (4F9/2 → 6H13/2) emission under different excitation wavelengths. The co-doped LiBBiDy15Eu20 host glass shows improved red emission, indicating transfer of energy from Dy3+ to Eu3+ ions. The efficiency of energy transfer from Dy3+ to Eu3+ in host glass was determined from PL-emission intensities. The lifetime measurement was employed for single and co-doped glasses under different excitation and emission wavelengths. The lifetime of co-doped sample measured under different excitation and emission wavelengths, confirms energy transformation from Dy3+ to Eu3+ ions. The CIE coordinates indicate that the prepared glass can be employed as red and orange-red light-emitting diodes (LEDs) in lighting application.

Photoluminescence and optical transition properties of Sm3+ activated lead-borate glasses

The Sm2O3-doped B2O3- K2O-PbF2 host glasses were synthesized by melt-quenching process. to comprehend visible luminescence and lasing potentiality, optical absorption, excitation, emission and decay measurement of developed glasses were studied. The experimental oscillator strength were calculated from absorption spectra of BKPFSm0.5 (optimized) glass sample. The decline in decay time as the proportion of samarium ions in the host glass increase indicates energy transfer between samarium ions. To establish potentiality of these glasses as visible lasers, the radiative properties of fluorescent transition acquired from photoluminescence emission spectra were determined. The quantum efficiency acquired from experimental and theoretical lifetimes was found to be 74% for the BKPFSm0.5 glass. The high quantum efficiency (η), large stimulated emission cross-section (σe = 6.49 × 10−22 cm2) and high branching ratios (βR = 59%) for 4G5/2 → 6H7/2 transition of the BKPFSm0.5 glass specify acceptability of this glass for improvement of lasing (orange) and the photonic devices emitting the in visible region.

A long-lasting TIF-4 MOF glass membrane for selective CO2 separation

Membrane technology with environmentally friendly and cost-efficient features has been well acknowledged as a promising solution for effective CO2 separation. Metal organic framework (MOF) glasses are one of the most attractive membrane materials currently, because of their easy processability, absence of grain-boundary defects, and permanent porosity. In this study, a mixed linker tetrahedral imidazolate framework-4 (TIF-4) MOF with ultrahigh glass forming ability was selected for fabricating highly CO2 selective membranes. Through adjusting the molar ratio of the imidazole (Im) and 5-methylbenzimidazolate (5-mbIm) linkers in the TIF-4 framework, the melting temperatures as well as the CO2 adsorption property could be controlled systematically. After vitrification, TIF-4 glasses (agTIF-4) with varying 5-mbIm content were prepared, and all of them exhibit higher isosteric heat of CO2 adsorption than the corresponding TIF-4 crystals. Both CO2/CH4 and CO2/N2 uptake ratio (298 K, 1 bar) of agTIF-4 samples are more than twice as that of TIF-4 crystals, suggesting the great potential of agTIF-4 for CO2 separation. Further, agTIF-4 membranes were successfully prepared by the melt-quenching process from the polycrystalline membranes. agTIF-4 membranes are highly CO2 selective with CO2/N2 and CO2/CH4 separation factors of 27 and 30. More importantly, agTIF-4 membrane displays long-term stability up to 10 months, which is highly conductive to its industrial application for CO2 separation.