Initial Crystallization Temperature Research Articles

Study on water-salt phase transition of saline soils during freezing

As the temperature decreases, when the freezing temperature is reached, the solution in the pores of saline soil undergoes ice crystallization and salt crystallization phenomena. Theoretical and experimental studies have been carried out in order to investigate the behaviour of water-salt phase transitions within the pores of saline soils. Firstly, the theoretical expression for the initial crystallization radius is given from the thermodynamic theory by considering the interphase chemical potential equilibrium and the Young-Laplace equation, and the relationship between the initial crystallization radius and temperature as well as the initial salt content is analyzed. Then, a theoretical model to predict the pore solution content and crystal content was developed in conjunction with the Van Genuchten soil-water characteristic curve model, and the water-salt phase transition behaviour of saline soils was analyzed by numerical calculations. Finally, the validity of the theoretical model was verified by a saline soil freezing test. The results show that the water-salt phase transition behaviour of the solution within the pores of saline soils is affected by temperature and initial salt content, and the water-salt phase transition behaviour mainly occurs at the early stage of freezing. Salt lowers the freezing temperature of the soil; the higher the salt content, the lower the freezing temperature, and the presence of salt inhibits the growth of ice crystals. As the temperature decreases, the precipitation of ice salt crystals during the phase transition of the soil pore solution reduces the soil porosity and decreases the channels for ion migration, resulting in a gradual increase in the soil pore volume ratio.

Fabrication and Characterization of PLA/PBAT Blends, Blend-Based Nanocomposites, and Their Supercritical Carbon Dioxide-Induced Foams.

In this study, a twin-screw extruder was used to fabricate poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blends and blend-based nanocomposites with carbon nanotube (CNT) or nanocarbon black (CB) as nanofillers. The fabricated samples were subsequently treated with supercritical carbon dioxide (scCO2) to fabricate the corresponding foams. Bi-phasic morphology and selective distribution of CNTs or CBs in the PBAT phase were observed in the blends/composites through scanning electron microscopy. After the scCO2 treatment, the selective foaming of the PBAT phase in the prepared blends/composites was confirmed. The cellular structure of PBAT phase in scCO2-treated blends is similar to the size/shape of PBAT domains in untreated blends or treated neat PBAT foam. The addition of CNTs or CBs in the blends led to a slight reduction in cell size of the foamed PBAT phase, demonstrating CNT/CB-induced cell nucleation. Differential scanning calorimetry (DSC) results showed that CNTs and CBs played as nucleating agents and increased the initial crystallization temperature up to 14 °C compared with neat PBAT for PBAT in different composites during cooling. The scCO2 treatment induced the bimodal stability of PBAT crystals in different samples, which melted mainly in two temperature regions in DSC studies. Thermogravimetric analyses revealed that compared with parent blends, the addition of CNTs or CBs increased the temperature at 80 wt.% loss (degradation of PBAT portion) up to 6 °C. The electrical resistivity decreased by more than six orders of magnitude for certain CNT- or CB-added composites compared with the parent blends. The hardness of the blends slightly increased after forming the corresponding composites and then declined after the scCO2 treatment.

Correlations between selecting crystallization temperature and modulating α-Fe/amorphous complex phase structure in extending frequency characteristic of the Fe-Si-B-Nb-Cu ultra-thin ribbons

Fe-Si-B-Nb-Cu nanocrystalline ribbons, with thicknesses exceeding 20 μm, have been extensively utilized in designing magnetoelectric devices. Recent advancements in automotive electronics and 5 G technology have shifted the focus to higher working frequencies reached to MHz, making ultra-thin ribbons (below 20 μm) more desirable. However, its fully amorphous structure often complicate the adjustment of the α-Fe/amorphous complex phase structure (α-Fe/amor CPS), subsequently affecting frequency characteristics. The study investigated the controllability of α-Fe crystallization behaviors and focused on the relationship between the initial crystallization temperature (Ta2) and the initial crystallization volume fraction (vi). The findings suggest that selecting ultra-thin ribbons and controlling Ta2 to maintain vi below 4 % is effective in adjusting α-Fe crystallization behaviors, achieving a uniform α-Fe/amor CPS with substantial vα-Fe, enhancing the frequency characteristics by technology magnetization process. In a notable example, ribbons with a thickness of 15 ± 1 μm, crystallized at Ta2 = 490 ℃ with a vi of approximately 0.94 %, achieved a uniform α-Fe/amorphous CPS with nano-sized α-Fe grains (average diameter of Dα-Fe = 13.4 nm) and a high grain number density (Nd, α-Fe) of about 3.0 × 1023m−3 and a high volume fraction (vα-Fe) 37.78 %. This resulted in a magnetized permeability (μi) of 5800 at 1 MHz and an impedance (Z) peak of approximately 126 Ω at 40 MHz.

Enhanced thermal stability of amorphous Al-Fe alloys by addition of Ce and Mn

The thermal stability of mechanically alloyed amorphous Al-Fe-based alloy powders, with nominal compositions Al82Fe16Ce2 and Al82Fe14Mn2Ce2, was investigated using differential scanning calorimetry (DSC), x-ray diffraction (XRD), and scanning electron microscopy (SEM) complemented by energy-dispersive x-ray spectroscopy (EDX). Analysis through DSC indicated that both Al82Fe16Ce2 and Al82Fe14Mn2Ce2 alloys undergo a two-stage crystallization process. Notably, the initial crystallization temperatures for the Al82Fe16Ce2 and Al82Fe14Mn2Ce2 alloys were determined to be approximately 525 °C and 550 °C, respectively. This high thermal stability is attributed to the delayed nucleation process induced by the presence of Ce and Mn within the Al-Fe matrix. During polymorphic crystallization, distinct phases such as β-AlFe, Al13Fe4 for Al82Fe16Ce2, and β-Al(Fe, Mn), Al13Fe4, Al10CeMn2 for Al82Fe14Mn2Ce2 were identified. Furthermore, post-annealing of these amorphous alloy powders at elevated temperatures of 600, 700, and 800 °C led to distinct morphological characteristics based on the alloy composition. For Al82Fe16Ce2, the particles preserved a nearly spherical morphology, with size distributions ranging from 1 to 5 μm. In contrast, for Al82Fe14Mn2Ce2, the particles exhibited an irregular shape with a broader size range of 1 to 15 μm.

Influence of TiO2/SiO2 and BaO/CaO ratios on viscosity, crystallization and structure of high-TiO2 mold slags for casting of high-Ti steel

In the current study, the influence of TiO2/SiO2 and BaO/CaO ratios on viscosity, crystallization and structure of high-TiO2 mold slags was discussed through the measurement of viscosity-temperature relationship, melting temperature, crystallization temperature, crystallization rate and phases, and Raman spectrum. With the substitution of SiO2 by TiO2 in slags from 0 % to 12 %, the viscosity at 1300 °C, the melting temperature and break temperature decreased and then increased, while those of slags with the substitution of CaO by BaO from 4 % to 16 % decreased. With the substitution of SiO2 by TiO2 from 0 % to 10 %, crystallization phases gradually changed from cuspidine (Ca4Si2F2O7) to perovskite (CaTiO3), the initial and complete crystallization temperatures had the tendency to increase from 918 °C to 1260 °C and from 857 °C to 1139 °C, respectively, and the overall crystallization ability of slags increased. With the substitution of CaO by BaO from 4 % to 16 %, the initial and complete crystallization temperature of these slags decreased, and the overall crystalline ability decreased. With the substitution of SiO2 by TiO2 from 0 % to 10 %, structural units changed from the simple units to complex units, but the transition was opposite with the substitution from 10 % to 12 %, which was related to the transition of TiO2 from basic oxide to amphoteric oxide. With the substitution of CaO by BaO from 4 % to 16 %, the degree of polymerization and the viscosity of theses slags decreased, which was related to the supplement of more active O2− ion from BaO. Hence, the excessive substitution of SiO2 by TiO2 under the steel-slag reaction would cause the increase of the slag viscosity and crystallization ability, while the substitution of CaO by BaO could weaken the variation of slag viscosity and crystallization ability.

High stability and high corrosion resistance of a class of Co–Cr–Mo–Nb–B high-entropy metallic glasses

In this study, we have developed a class of new Co–Cr–Mo–Nb–B high-entropy metallic glass alloys with high stability and high corrosion resistance. It was found that for Co26Cr26Mo26Nb7B15 metallic glass, the glass transition temperature reached to 1058 K, and the initial crystallization temperature of Co24.5Cr26.5Mo26.5Nb7.5B15 metallic glass was as high as 1132 K. There is a large hardness of 18.1 GPa and Young's modulus of 267 GPa of Co27.5Cr27.5Mo26.5Nb3.5B15 metallic glass. The excellent thermodynamic property and mechanical properties were proved to be related to the covalence bond and hybridization of metal-metalloid bonds. The Co–Cr–Mo–Nb–B metallic glasses exhibited a lower self-corrosion current density and higher self-corrosion voltage compared with 316 in 1 M hydrochloric acid solution, and the high corrosion resistance could be attributed to passive films enriched with Cr3+ and Mo4+. These findings provide a new and effective way to design high-entropy metallic glasses with excellent comprehensive properties and suitable for high stability applications.

A method for fabricating polyvinylidene fluoride/poly methyl methacrylate/graphite nanoplates nanocomposites foams with high strength, large expansion ratio and outstanding heat insulation properties

Developing lightweight and high-performance polymer foams for heat insulation is of utmost significance for energy conservation, emission reduction, and improving energy efficiency. Introducing carbon fillers such as graphite nanoplates (GNPs) can effectively reduce heat radiation in foams and greatly enhance their mechanical and flame-retardant properties. However, there are technical challenges in achieving eco-friendly and scalable production of lightweight polymer/GNP nanocomposite foams, including poor dispersion of GNPs and lower foaming ratios. In this work, a method for fabricating lightweight nanocomposite foams through melt blending combined with a carbon dioxide molten-foaming process was proposed. By using this method, the ultralight, high-strength, and hydrophobic polyvinylidene fluoride (PVDF)/poly (methyl methacrylate) (PMMA)/GNP nanocomposite foams with excellent heat insulation and flame-retardant properties were successfully prepared. It was found that the addition of GNP improves the melt viscoelasticity and increases the initial crystallization temperature of PVDF. Furthermore, GNPs can also expand the foaming temperature window, refine the cell size, and induce open-cell structures in the foams. The nanocomposite foams fabricated using this method have a foaming temperature window of over 20 °C, a foaming ratio exceeding 40, and a density below 0.04 g/cm3. Thanks to the higher foaming ratio, well-developed open-cell structures, and the heat radiation attenuation effect of GNPs, the nanocomposite foam exhibits a remarkably low thermal conductivity of 30.14 mW⋅m−1⋅K−1. Additionally, the foams display favorable compressive mechanical properties, hydrophobicity, and flame retardancy.

The Structure and Properties of Medical Disposable Protective Clothing Materials with Different Packaging and Models under γ Irradiation

AbstractThis study investigated the radiation effects of commercially available medical disposable protective clothing materials under γ irradiation. FT‐IR, contact angle, DSC, OIT, and mechanical properties were used to examine the radiation effects of medical disposable protective clothing materials. The results showed when the radiation dose was less than or equal to 50 kGy, the FT‐IR spectra did not show any changes. However, when the radiation dose reached 70 kGy, new absorption peaks appeared in the infrared spectra of the TS−A and TS−B medical disposable protective clothing materials, indicating chemical changes. Contact angle analysis showed that medical disposable protective clothing materials were hydrophobic and had higher hydrophobicity on the inside than the outside under different packaging and irradiation conditions. Rheological analysis showed that the shear thinning phenomenon of medical disposable protective clothing materials increased significantly with the increase of radiation dose, and good rheological behavior was observed under vacuum packaging conditions when the radiation dose was 30 kGy. The crystallinity and initial crystallization temperature showed the order of vacuum, nitrogen, and air. The oxidation induction time trend was vacuum>nitrogen>air, while the fracture strength trend was nitrogen>vacuum>air. The mechanical properties met the national standard.

Thermal stability and crystallization kinetic of Se-Te-Ag glassy alloys and thick films for electronic devices

The present work has examined the thermal features of glassy chacogenide materials Se0.75-xTe0.25Agx (x = 0, 2, 4, 6, 8, 10 at %). The thermal stability of these compositions has been assessed under non-isothermal conditions using Differential Scanning Calorimetry (DSC), which has been used to find the glass transition temperature (Tg), the initial crystallization temperature (Tin), the temperature corresponding to the top of the crystallization rate (Tp), and the melting temperature (Tm). In addition, the kinetic parameter Kr(T) was given as an additional sign of thermal stability. Among these compositions, it was discovered that Se0.71Te0.25Ag0.04 had the best glass-forming ability and glass-thermal stability. The average coordination numbers of the considered samples have been discussed in relation to these results. Additionally, we measured the sheet resistivity, ρ, whose thickness is equivalent to 1000 nm at heating rate 5 K/min, in this work to study the crystallization kinetics of thick films of Se0.75-xTe0.25Agx (x = 0, 2, 4, 6, 8, 10 at %) in the temperature range of 300 to 625 K. This range was sufficient to draw attention to two substantial areas in the resistivity versus temperature curve, and the derivation of resistivity as a function of temperature established that the films under study only had one crystallization region.

Investigation of the effect of P2O5 and CaF2 on the crystallization behavior of La2O3-bearing calcium–silicate–aluminum slags using the single hot thermocouple technique

The effects of P2O5 and CaF2 components of rare earth (RE)-bearing slags on their crystallization behavior were investigated using single hot-thermocouple technique (SHTT). The time temperature transformation (TTT) diagram exhibited single-nose curves within the examined slag composition range, in agreement with the individual CaLa4(SiO4)3O-type phase detected by an isothermal crystallization experiment in a furnace. Additionally, an increase in the P2O5 content shortened the incubation time and increased the nucleation rate of the columnar CaLa4(SiO4)3O-type phase in the 1350–1150 °C temperature range, while an increase in the CaF2 content had the opposite effects on the incubation time and nucleation rate. The sizes of the CaLa4(SiO4)3O-type phases in the slags with CaF2 were larger than those in the slags with P2O5, as verified by both in situ SHTT images and the crystallization experiment. The continuous cooling transformation (CCT) diagram suggested that an increase in the P2O5 content increased the initial crystallization temperature, whereas an increase in the CaF2 content decreased it. An analysis of the isothermal crystallization kinetics revealed that the columnar CaLa4(SiO4)3O-type phase exhibited phase diffusion-controlled growth. An increase in the P2O5 content tended to decrease the crystallization activation energy, while an increase in the CaF2 content increased the activation energy.

High Seebeck Coefficient Inorganic Ge15Ga10Te75 Core/Polymer Cladding Fibers for Respiration and Body Temperature Monitoring.

Wearable thermal sensors based on thermoelectric (TE) materials with high sensitivity and temperature resolution are extensively used in medical diagnosis, human-machine interfaces, and advanced artificial intelligence. However, their development is greatly limited by the lack of materials with both a high Seebeck coefficient and superior anticrystallization ability. Here, a new inorganic amorphous TE material, Ge15Ga10Te75, with a high Seebeck coefficient of 1109 μV/K is reported. Owing to the large difference between the glass-transition temperature and initial crystallization temperature, Ge15Ga10Te75 strongly inhibits crystallization during fiber fabrication by thermally codrawing a precast rod comprising a Ge15Ga10Te75 core and PP polymer cladding. The temperature difference can be effectively transduced into electrical signals to achieve TE fiber thermal sensing with an accurate temperature resolution of 0.03 K and a fast response time of 4 s. It is important to note that after the 1.5 and 5.5 K temperatures changed repeatedly, the TE properties of the fiber demonstrated high stability. Based on the Seebeck effect and superior flexibility of the fibers, they can be integrated into a mask and wearable fabric for human respiration and body temperature monitoring. The superior thermal sensing performance of the TE fibers together with their natural flexibility and scalable fabrication endow them with promising applications in health-monitoring and intelligent medical systems.

Effect of BaO/Al2O3 ratio and Li2O content on viscosity and crystallization of BaO–Al2O3–TiO2-based mold slags

In the current study, the influence of different BaO/Al2O3 ratios and Li2O contents on the viscosity, melting temperature, crystallization behavior and structure of BaO–Al2O3–TiO2-based mold slags was investigated through the measurement of the viscosity-temperature relationship, hemisphere point method, crystallization process and crystallization temperature, and the calculation of NBO/T and optical basicity. With the increase of the BaO/Al2O3 ratio from 0.60 to 1.67, the viscosity at 1573 K and the melting temperature of mold slags decreased from 0.3 to 0.05 Pa s, and 1261 K–1217 K, respectively, while those also slightly decreased from 0.15 Pa s to 0.11 Pa s, and 1244 K–1213 K with the Li2O content from 4 % to 6 %, respectively, which was related to the increase of fluxing reagent or oxygen ions released by basic oxide in slags. In current slags, precipitated phases mainly existed as LiTiO2 and BaTiO3, and the difference of the BaO/Al2O3 ratio and Li2O content resulted in the competitive precipitation of these phases. With the increase of BaO/Al2O3 ratio from 0.60 to 1.67, precipitated phases gradually changed from LiTiO2 to BaTiO3, and the initial crystallization temperature had the tendency to decrease and increase. On the contrary, the precipitated phase gradually changed from BaTiO3 to LiTiO2, and the initial crystallization temperature as well as the break temperature decreased with the Li2O from 4 % to 8 %. The parameter NBO/T and optical basicity of molten slags increased with the increase of BaO/Al2O3 and Li2O content, and the polymerization degree of the melt decreased, resulting in the decrease of the activation energy of viscous flow and the viscosity. Hence, the increase of the BaO/Al2O3 ratio and Li2O content within limits could lower the viscosity, melting temperature, break temperature and crystallization ability of mold slags, and then improve the lubrication of the slag on solidified shell.

Mineral chemistry of the Água Limpa suite: Insights into petrological constraints and magma ascent rate of Mesoarchean sanukitoids from the Sapucaia terrane (Carajás Province, southeastern Amazonian Craton, Brazil)

The Água Limpa suite is comprised of two E‒W elongated sanukitoid-affinity plutons named the Água Azul and Água Limpa, exposed along with other intrusive granitic bodies and typifying Mesoarchean granitic activity in the Sapucaia terrane (Carajás Province). In the present study, the T-P-fO2-H2Omelt conditions, viscosity of magma and upward magma transport rate were retrieved on the basis of mineral chemistry and partial dissolution of magmatic epidote. The mafic mineral assemblage is dominated by amphibole (magnesio-hornblende, tremolite, pargasite and magnesiohastingsite compositions), in addition to magmatic epidote (Ps of 25–32%) and magnesio-biotite. Titanite, apatite, zircon, magnetite, ilmenite and chalcopyrite are the main accessory phases. The apatite saturation thermometer indicates at least initial crystallization temperatures between 903 and 850 °C. The Al-in-amphibole geobarometer provided temperatures varying from 1039 to 718 °C and 984 to 707 °C for the Água Limpa and Água Azul plutons, respectively. A variation in pressure from 625 to ∼100 MPa was obtained for both plutons, related to the deep crustal level of formation and shallow depths of emplacement. Experimental studies carried out on similar magma compositions indicate the parental Água Limpa suite magmas were water-rich (> 6 wt% dissolved H2O) and crystallized under high oxygen fugacity conditions (0.3 ≤ NNO ≤ 2.5). Partial corrosion of the magmatic epidote in these two plutons occurred within a timeframe of no more than 1–9 years, corresponding to upward magma transport rates of 1481–13,333 m/year. A structurally controlled network of conduits associated at the mesoscale pervasive migration developed during the active deformation stage (faults and shear zones), and small-scale diking probably acted as pathways for magma transfer through distinct pulses that underwent subsequent crystallization before reaching the hot continental crust at peak metamorphism, and permitted survival of the epidote that was out of equilibrium at the low pressure of final emplacement. The Água Limpa suite reveals strong mineralogical and geochemical affinities with the sanukitoids from the Rio Maria suite and the Ourilândia complex of the Carajás Province and differs from the sanukitoids from other cratons in terms of age and geological setting.

Investigation of the glass forming regularity and thermal behavior of lead-free V2O5-TeO2-RO (R = Ca, Sr, Ba) low temperature sealing glass for electronics packaging

Lead-free V2O5-TeO2 glass systems are promising new sealant materials for electronics vacuum packaging, with low-melting temperature and unique light absorption. The glass forming regularity, structure and corresponding properties of the V2O5-TeO2-RO (R=Ca, Sr, Ba) glass system are systematically studied and analyzed in this paper. The results show that there is a wide glass forming region for the V2O5-TeO2-RO glass system, and with the increase of TeO2/V2O5 molar ratio, the thermal stability of V2O5-TeO2-SrO glass with the RO content of 20 mol% increases and the coefficient of thermal expansion increase from 11.2 to 15.86 × 10–6/°C due to transformation process of glass network structure from the [VO4] to transition state [TeO3 + 1] and [TeO3] group. The higher initial crystallization temperature of 40 mol%V2O5-40 mol%TeO2-20 mol%SrO glass is conducive to the flow of the glass slurry during the sealing process, obtaining a sealing device with good airtightness at extremely low temperatures of 350 °C.

Crystal violet adsorption onto modified biosorbent prepared from agricultural waste: kinetics, isotherm and thermodynamic studies

The present study investigated crystal violet removal by modifying the chestnut shell with a chemical activation method. For this purpose, H2SO4 and NaOH pretreatments were applied to the chestnut shell and the pretreatment method that gave the best performance under the same conditions was determined. The best adsorption efficiency was achieved with the NaOH pretreatment (99.06%) and the crystal violet adsorption reached equilibrium within 60 min. After selecting the best chemical activation method, the modified chestnut shell was characterized before and after adsorption (FTIR and SEM). Furthermore, the effects of parameters such as pH, initial crystal violet concentration, adsorbent dosage, temperature, and contact time were observed. Moreover, isotherm, kinetics and thermodynamics of the adsorption process were researched in detail. The best results were obtained with the Langmuir isotherm model (R2=0.99) and the pseudo-second-order kinetic model (R2=0.99). Thermodynamic parameters showed that the adsorption process is spontaneous, endothermic and feasible.

Tunable magnetic properties and magnetic domain structure of nanocomposite permanent materials via Ti addition into Nd-Fe-Co-B alloys

In this work, the effect of tunable Ti content on the microstructure, magnetic domain structure, and magnetic properties of as-spun and annealed Nd9.5Fe79-xCo5TixB6.5(x = 0,1,2,3,4) alloys at the quench speed of 18 m/s were investigated. For the as-spun alloy, augmenting the Ti content enhanced the initial crystallization temperature and the stability of the amorphous phase. Simultaneously, the incorporation of Ti led to augmentation in the quantity of nanocrystals within the amorphous matrix, thereby facilitating the formation of vortex-like magnetic domains with large size but reduced the saturation magnetization Ms. For the annealed alloy, the incorporation of Ti inhibited the precipitation of α-Fe phase, refined the grain, enhanced the exchange coupling between the soft and hard magnetic phase and facilitated the formation of smaller, more uniform vortex-like magnetic domains, These alterations were beneficial to improve the comprehensive magnetic properties. Furthermore, the addition of tunable Ti resulted in a remarkable impact on coercivity enhancement. The coercivity value exhibited a significant increase of 54.30%, surging from 374.24 kA/m to 577.51 kA/m. Upon a thorough analysis of the magnetic domains and coercive force mechanisms, it was ascertained that the introduction of Ti substantially augmented the creation of vortex-like domains. These domains effectively impede domain motion, consequently elevating the material's coercivity.

Exploring influence of MgO/SiO2 on viscosity-temperature property of coal ash slags under entrained flow gasification condition

To realize smooth slag discharge of Zhundong coals in entrained-flow-bed gasifier, the viscosity-temperature characteristics of slags with different MgO/SiO2 ratios were studied. The results show that low MgO/SiO2 ratio causes high BO content in liquid slag, resulting in excessive polymerization degree and viscosity. As the MgO/SiO2 increases, the activation energy of liquid slag increases, occurrence form of oxygen transforms from BO to NBO, more structural depolymerization reactions occur, and [SiO4] tetrahedra obtains more O2− and show more NBO. NBO is more likely to react with Mg2+, Ca2+, Al3+, and Fe2+ to form crystals, thus increasing the crystallization reaction activity of slag and cause the initial crystallization temperature and crystal content increasing. An increasing MgO/SiO2 causes a characteristic transition of slag from weak crystallinity and high polymerization degree to strong crystallinity and low polymerization degree, meanwhile, the poor viscosity-temperature characteristics with high viscosity of liquid slag is first improved, and then the problem of strong crystallinity leading to poor viscosity-temperature characteristics with high Tcv occurs. Therefore, the viscosity-temperature characteristics first improve and then deteriorate. The crystal size increases as MgO/SiO2 increases, which also cause Tcv increasing. Large ΔT and low Tp25 make 0.28MS become the most suitable for slag discharge.

Straightforward Strategy Toward In Situ Water-Phase Exfoliation and Improved Interfacial Adhesion to Fabricate High-Performance Polypropylene/Graphene Nanocomposites.

Graphene is a potential candidate for achieving high-performance and multifunctional polypropylene (PP) composites. However, the complex manufacturing process and low dispersibility of graphene, as well as poor interfacial adhesion between graphene and polypropylene chains, stifle progress on large-scale production and applications of graphene/polypropylene composites. Here, we develop a strategy of maleic anhydride grafted polypropylene (MAPP) latex-assisted graphene exfoliation and melt blending to address the key challenges facing in industrial production. The surface property of the graphitic precursor is well-designed to achieve a high graphene exfoliation yield of ∼100% and induce abundant hydrogen bonding between the obtained mild-oxidized graphene (MOG) sheets and MAPP chains. Therefore, the MAPP-modified MOG can homogeneously disperse in the PP matrix and exhibits an excellent interfacial compatibility with the polymer. The addition of 5 wt % MOG results in simultaneous increase in the initial decomposition temperature, crystallization temperature, tensile strength, and Young's modulus by 43.2, 11.4 °C, 21.5, and 50.7%, respectively, and the electrical conductivity increases to 0.02 S·m-1. This work illustrates a practical solution to low-cost, eco-friendly, and feasible industrial production of graphene/PP composites through synchronous exfoliation and interfacial modification of graphene.

Composition design of high Bs Fe-based amorphous powders with good sphericity

Fe83SixByC(17-x-y) has good glass forming ability (GFA), and high saturation magnetic induction (Bs), and spherical amorphous powder can be prepared using a gas–water coupling atomization (GWC) device. Herein, the effects of metalloid elements (B, C, Si and P) on the thermal parameters and magnetic properties of the Fe83SixByC(17-x-y) powder are discussed. The research conclusion shows that the Fe83Si2.5B11.5C3 amorphous powder exhibits the best comprehensive performance. Through the Lorentz microscope pattern of Fe83Si2.5B11.5C3 amorphous powder, magnetic domains walls are observed to gather and interlace in the outer region of the particle. The Fe83Si2.5B11.5C3 amorphous powder exhibits a high initial crystallization temperature (Tx1), followed by a ΔTx of 27 ℃, and then crystallization completion at 561.1 ℃. Some clusters or primary crystals are produced in the amorphous matrix after annealing at 520 ℃ (below Tx1 534 ℃) for 1 h. A further increase in the annealing temperature to 570 ℃ (beyond Te1 561.1 ℃) causes the precipitation of a large amount of crystalline phase α- Fe (Si) and hard magnetic phase Fe2B, thereby resulting in the rapid deterioration of the magnetic properties of the amorphous powder.

Crystallization, rheological behavior and mechanical properties of carbon nanotube/metallocene polypropylene composites

In this paper, metallocene polypropylene (mPP) composites filled with carbon nanotubes (CNTs) were prepared using twin-screw extruder. The crystallization behavior, mechanical properties and rheological behavior were characterized by a differential scanning calorimetry (DSC), universal material testing machine and rotational rheometer. The results of DSC indicated that the effect of CNTs on heterogeneous nucleation of mPP was very obvious and the crystallizability of the resin matrix was improved after adding CNTs, especially the initial crystallization temperature (T 0), crystallization temperature (T c) increased by 9.63 °C and 8.28 °C when the CNTs content was 1.25 wt%. The yield stress and elastic modulus increased to 33.98 MPa and 1605.6 MPa as the CNTs concentration increased to 1.0 wt% in contrast to that of the neat mPP. The results of SEM images showed that the better dispersion and adhesion of CNTs into polymer matrix. The results of rotational rheometer proved that interactions increased between CNTs and mPP as the content of CNTs increasing.