Melt Polymerization Research Articles

Structure and Density of H2O‐Rich Mg2SiO4 Melts at High Pressure From Ab Initio Simulations

AbstractWater has a strong effect on silicate melt properties, yet its dissolution mechanism in depolymerized melts, typical for mantle composition, remains poorly understood. Here we report results of first‐principles molecular dynamics simulations for hydrous Mg2SiO4 melts with 6, 16, and 27 wt% H2O at pressure and temperature conditions relevant to the upper mantle and mantle transition zone. The results show that hydrogen bonds not only to the network‐forming cation Si but also to Mg which—nevertheless—remains the most important network modifier. There is no evidence to support the hypothesis based on experimental data that water may cause an increase in melt polymerization for ultramafic magmas; the ratio of non‐bridging oxygen per Si increases with the addition of the oxygen from H2O. The partial molar volume of water is independent on concentration in our simulations which allows us to examine the density of hydrous melt systematically. The critical water content—at which melts are neutrally buoyant compared to the surrounding mantle—is ~4 wt% H2O for a pyrolite composition, much lower than the high water content (>10 wt%) observed in petrological experiments and estimated thermodynamically for low‐degree partial melts formed in the vicinity of the mantle transition zone.

A new class of poly(ether‐block‐amide)s based on semi‐aromatic polyamide: synthesis, characterization and structure–property relations

AbstractA new type of poly(ether‐amide) thermoplastic elastomer (TPAE) was synthesized using poly(decamethylene terephthalamide (10T)/decamethylene isophthalamide) as hard segment and poly(ethylene glycol) as soft segment via an efficient, accessible and low‐pollution melt polymerization method. Thermoplastic elastomer was synthesized based on semi‐aromatic polyamide for the first time. The effects of various compositions of hard segments on the thermal and mechanical properties were investigated. The results show that TPAE synthesized from semi‐aromatic polyamide has excellent thermal stability, the initial decomposition temperature of all samples being between 370 and 378 °C. With an increase of 10T content, crystallization ability of the hard segment increased. As 10T content increased, TPAE changed from amorphous to crystalline, and the melting temperature ranged from 175 to 236 °C. Tensile testing revealed that TPAE had excellent and adjustable mechanical properties, and that tensile strength, elongation at break and elasticity modulus were in the ranges 7–40 MPa, 468–835% and 0.036–1.80 MPa. Furthermore, high‐temperature tensile test results showed that TPAE‐4 still maintained considerable mechanical properties, and had better mechanical properties compared with Pebax® 5533. In particular, TPAE‐4 had higher performance decay point for which elasticity modulus and stress at ε = 500% decreased rapidly when the temperature was higher than 80 °C, this point for Pebax® 5533 appearing at 50 °C. Such outstanding performance indicated that this new class of elastomer has the potential to be used in high‐temperature conditions. © 2020 Society of Industrial Chemistry

Effect of Ti4+ on the structure of nepheline (NaAlSiO4) glass

In this study, the effect of Ti4+ on the structure of nepheline glass (NaAlSiO4) is investigated as SiO2 is systematically replaced with TiO2. Traditionally, TiO2 is considered to be a nucleating agent for silicate crystallization but can also be incorporated into the glass network in relatively large amounts as either a network former or modifier depending on its coordination with oxygen. To determine the effect of Ti4+ on the structure of nepheline glass, X-ray and neutron pair distribution function (PDF) analysis paired with Empirical Potential Structure Refinement (EPSR) were conducted and are supplemented with Raman spectroscopy, electron probe microanalysis, and X-ray absorption spectroscopy (including Extended X-ray Absorption Fine Structure, EXAFS). Through these methods, it has been found that up to 15 mol% (16 wt%) TiO2 can incorporate into the glass network as a four-fold coordinated species, with a minor contribution of higher coordinated Ti. Between NaAlTi0.1Si0.9O4 and NaAlTi0.2Si0.8O4, EXAFS suggests a local structure change in the second coordination sphere of Ti, which changes from Ti-Ti to Ti-Al. Raman spectroscopy also suggests that as Ti content increases, the Na environment becomes more ordered. These results suggest that the Ti activity coefficient and its isotopic fractionation for magnetite and other Ti-bearing minerals should be fairly constant in polymerized melts, such as metaluminous and peraluminous rhyolites.

Temperature-pressure-composition model for melt viscosity in the Di-An-Ab system

A model for the viscosity (η) of melts in the system CaMgSi2O6-CaAl2Si2O8-NaAlSi3O8 (Di-An-Ab) based on data compiled from the literature is presented. The model is calibrated on 560 measurements of melt viscosity at 1 atm pressure on 40 individual melt compositions and 303 measurements obtained at high pressure on 18 melt compositions. The model is continuous and accounts for variations in melt composition (X), temperature (T) and pressure (P). At ambient pressure, the model spans 15 orders of magnitude of η, a T range of 933–2450 K, and reproduces the dataset well (RMSE = 0.26 log units). The high-P model is calibrated over a T range of 970–2470 K and pressures of 50 MPa to 13 GPa for viscosities of 10−1 to 1014.5 Pa s and reproduces the high-pressure dataset to within (larger) experimental uncertainties (RMSE = 0.35 log units). Used in conjunction with chemical proxies for melt structural organization (i.e. SM and NBO/T), the model illustrates the strong coupling between viscosity and changes in melt polymerization as a function of X and P. Di-An-Ab melts with SM values >25.34 have positive pressure coefficients and show a minimal to strong increase in viscosity with pressure. Model values of glass transition temperatures (Tg) (i.e. η ~ 1012 Pa s) range between 930 K and 1130 K at 1 atm; Tg values for highly polymerized melts are depressed by as much as 150 K at 5 GPa at elevated pressures but are higher for more depolymerized melts and higher P. Melt fragility (m) is only weakly affected by increased P as expressed by a slight decrease in m for the most fragile melts versus a slight increase for the least fragile melts. Activation energies (Ea) increase with rising P for depolymerized melts and decrease with rising P for polymerized melts with the crossover at SM = 25.34. Ea values increase at low T for all P conditions and the effects of P are most pronounced at lower T. Lastly, a comparison of the liquidus surface topology for the ternary system to the corresponding isokoms of viscosity shows the relative effects of composition and temperature on melt viscosity at liquidus conditions to be highly varied.

Effect of alkalis on water diffusion in silicate melts based on new experimental data for a shoshonitic melt

Water diffusion is an important mechanism affecting magmatic water content, vapor bubble growth, and the dynamics of volcanic eruptions. Water diffusivity in silicate melts is dependent on temperature, pressure, H2O content and speciation, and melt composition. While a general model has recently been developed for water diffusivity in calc-alkaline (subalkaline) melts as a function of silica content, the effect of alkalis on water diffusion is less clear due to the lack of experimental data for alkali-rich melts and a systematic evaluation. Here, water diffusion in shoshonitic melt with up to 1.6 wt% H2O was investigated at 1654–1926 K and 1 GPa in a piston cylinder apparatus using both hydration and diffusion couple methods. Diffusion profiles measured by FTIR microspectroscopy are in accordance with a modified speciation-based diffusion model which takes into account different mobility of hydroxyl (OH) and molecular H2O (H2Om). The diffusivity ratio DOH/DH2Om in shoshonitic melt increases with increasing temperature and falls into the range of 0.24–0.55, greater than the values for all of the melts previously investigated. The remarkable contribution of OH to water diffusion in shoshonitic melt is attributed to a substantial presence of free OH species (OH bonding with network-modifying cations but here especially with K or Na). The total H2O diffusivity in shoshonitic melt can be expressed as:DH2Ot=e-12.11-16765T1+Ce-11.14+17381-262.6CT,where D is in m2/s, T is temperature in K, and C is H2Ot content in wt% (DH2Ot reduced to DOH at C = 0). The above equation replicates the experimental data within 0.1 natural log unit. The total H2O diffusivities at 1 wt% H2Ot in three alkali-rich melts, including shoshonite, trachyte and phonolite, appear to fall onto a single Arrhenian trend line over a broad temperature range of 1100–1900 K. Compared to the general water diffusivity model for calc-alkaline melts, water diffusivities in alkali-rich silicate melts are generally higher and roughly twofold at the same P-T-H2Ot-XSi conditions, with XSi being the mole fraction of Si among all cations. Excess alkalis decrease degree of melt polymerization and promote formation of mobile K-OH and Na-OH species, thereby having a positive influence on water diffusion and vapor bubble growth in magma.

Water speciation in oxide glasses and melts

Silicic melts in magma chambers below active volcanoes typically contain several wt% H2O. The dissolved water has drastic effects on the chemical and physical properties of the melts and, hence on processes like magma differentiation, ascent and degassing. But interaction of water with glasses and melts is also of great importance for the production and application of glasses. The effect of water is closely related to its speciation. OH groups bond to tetrahedral cations and H2O molecules are predominant species in polymerized melts. In strongly depolymerized melts “free” OH groups may also be present.In this paper we review the data on water speciation in oxide melts, considering new data for hydrous silica and basaltic melts. SiO2 glasses containing up to 4 wt% H2O were produced at temperatures of 1573–1673 K and pressures of 100–200 MPa in an internally heated gas pressure vessel. Water speciation in the quenched glasses was determined by near-infrared spectroscopy. The set of samples used for the calibration of the absorption coefficients for the combination bands of OH and H2O also included a natural hyalite and water-poor commercial silica glasses. Fictive temperatures of the glasses were estimated based on viscosity and cooling rate. The derived K values (=[OH]2/([O]∙[H2O]),) indicate, at given melt temperature, higher abundance of molecular H2O for hydrous silica melts than for other oxide melts. For tholeiitic basalt melts, water speciation was inferred using speciation data for glasses from Shishkina et al. (2010), and Tf was estimated using the viscosity model of Giordano et al. (2008).Some general trends can be derived by considering literature data for water speciation in oxide melts. At constant p,T, little variation of K values is observed for melts of the pseudo join from rhyolite to basalt, implying that composition has minor effect for most natural aluminosilicate melts. However, this applies only to melts with Al/Si ≪ 1. The network can be hydrolyzed much more easily if alternating Al-O-Si bonds are present, i.e. when Al/Si approaches 1. K values are higher for silicate melts than for aluminosilicate melts, implying that non-bridging oxygen support the dissociation of H2O. The type of network former also has a strong influence on the dissociation of H2O in the melt as well. Replacement of Al by B favors the formation of OH groups, and OH contents are particularly high in borate and phosphate melts. This can be explained by easy hydrolysis of PO and BO bonds.

An experimental system for time-resolved x-ray diffraction of deforming silicate melt at high temperature.

Rheological behavior of silicate melts controls the dynamics of volcanic eruptions. Previous experimental studies have investigated melt viscosity and found non-Newtonian behavior of the melt under a high shear rate. However, the relationship between macroscopic rheology and atomic-scale behavior under shear remains unclear. We developed an experimental system for time-resolved x-ray diffraction (XRD) at high temperature to investigate the atomic-scale structural change in melts under shear. The manufactured deformation apparatus and heating furnace were set on the synchrotron radiation x-ray beamline (BL20XU) of SPring-8; the XRD pattern of the melt at high temperature could be observed using this system because the furnace mainly consists of a boron nitride cylinder with high x-ray transmittance. Here, we report results of fiber elongation experiments for a soda-lime melt. Melt fibers with ∼0.7 mm in diameter and ∼27 mm long were elongated at 100 µm sec-1 at temperatures of 595 °C and 620 °C, and the XRD pattern was obtained every 100 msec. Brittle failure of the melt occurred at 595 °C, whereas the melt viscously elongated at 620 °C. The XRD patterns obtained during elongation did not indicate any clear change immediately before brittle failure. The intensity of the XRD pattern decreased with the elongation at 620 °C, although there was no clear variation in its shape. These results indicate that the atomic-scale structure observed by XRD may not change during the elastic and viscous elongation of the soda-lime melt. This experimental system will be further developed and applied to more polymerized and natural silicate melts.

Synthesis and Nonisothermal Crystallization Kinetics of Poly(Butylene Terephthalate-co-Tetramethylene Ether Glycol) Copolyesters.

Poly(butylene terephthalate-co-tetramethylene ether glycol) (PBT-co-PTMEG) copolymers with PTMEG ranging from 0 to 40 wt% were synthesized through melt polymerization. The structure and composition were supported by Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (1H NMR). All samples had excellent thermal stability at a Td−5% around 370 °C. Crystallization temperature (Tc) and enthalpy of crystallization (ΔHc) were detected by differential scanning calorimetry (DSC), revealing a decrement from 182.3 to 135.1 °C and 47.0 to 22.1 J g−1, respectively, with the increase in PTMEG concentration from 0 to 40 wt%. Moreover, nonisothermal crystallization was carried out to explore the crystallization behavior of copolymers; the crystallization rate of PBT reduced gradually when PTMEG content increased. Hence, a decrement in the spherulite growth rate was detected in polarizing light microscope (PLM) observation, observing that the PTMEG could enhance the hindrance in the molecular chain to lower the crystallinity of PBT-co-PTMEG copolyester. Moreover, thermal properties and the crystallization rate of PBT-co-PTMEG copolymers can be amended via the regulation of PTMEG contents.

Detailed analysis on thermal, microstructural, mechanical, and morphological features of side chain liquid crystalline polymer/isotactic polypropylene graft copolymers: Effect of grafted and ungrafted polymer units

AbstractThe main scope of this comprehensive study is to investigate the effects of poly(p‐benzophenoneoxycarbonylphenyl acrylate), poly(BPOCPA), which presenting as only graft units or both graft and ungrafted units in the matrix, on the fundamental features of isotactic polypropylene (IPP). The graft copolymerization of BPOCPA onto IPP was performed with the aid of bulk melt polymerization at varying monomer content levels ranging from 5% to 40%. The thermal behavior, crystal quality, mechanical performance, and surface morphology of the samples were investigated by means of differential scanning calorimeter, X‐ray diffractometer (XRD), universal mechanical test, and scanning electron microscope (SEM) techniques. Thermal analyses depicted that there existed the noteworthy enhancements in both crystalline melting temperatures and percent crystallinities of matrix polymers. Furthermore, according to XRD results, a and b parameters increased significantly at low percentages of the graft units, while the parameter c decreased in all products in consistence with the content. As for the mechanical characterization, the grafting led to remarkable improvements in modulus, tensile and impact strength of the products. SEM micrographs indicated that the samples were completely homogeneous without any phase separation and the products exhibited brittle nature with some ductility.

Blast Furnace Ironmaking Process with Super High TiO2 in the Slag: High-Temperature Structure of the Slag

To increase the utilization fraction of V-Ti-Magnetite ore in the burden of the blast furnace over 80 pct, the technology of “replacing CaO with MgO” was discussed. The high content of TiO2-bearing raw materials leads to a super high TiO2 content in the blast furnace slag, which affects the normal operation of the blast furnace ironmaking process. The physicochemical properties of TiO2-bearing blast furnace slag such as viscosity are fundamentally determined by the high temperature and structure of the slag. In this study, Raman spectroscopy focusing on the effect of TiO2 and MgO/CaO ratio on the structure of super high TiO2-bearing blast furnace slag was performed. The results indicate that most of the Ti4+ ions are in the tetrahedron unit, and a few of Ti4+ ions are in the octahedron unit with a coordination number of six; this is confirmed by the presence an emission spectrum related to Ti-O stretching vibrations at wavenumbers less than 700 cm−1. The mole fraction of the band below 700 cm−1, which is related to the coupling of Al-O stretch vibration and the Ti-O stretch vibrations of Ti4+ in sixfold coordination, increased from 0.14 to 0.19 as the TiO2 content in CaO-SiO2-TiO2-MgO-Al2O3 slag increased from 20 to 34 mass pct. The (Q3)2/(Q2) ratio that is proposed as an index for the degree of polymerization (DOP) of melts decreased from 5.72 × 10−3 to 1.0 × 10−3 as the TiO2 content increased. Increasing the MgO/CaO ratio caused a slight decrease in the fraction of the bands below 700 cm−1 and resulted in the decrease of the (Q3)2/(Q2) ratio; thus, the DOP of the melts increased with increasing MgO/CaO ratio. The quantitative relationship, ln(η) = 0.91 + 0.11·ln((Q3)2/(Q2)), between the high-temperature structure information and the viscosity of TiO2-bearing blast furnace slag was established.

Degradability and biocompatibility of bioglass/poly(amino acid) composites with different surface bioactivity as bone repair materials

AbstractBioglass (BG) possesses excellent bioactivity and has been widely used in the manufacture of biomaterials. In this study, a composite with different surface bioactivity was fabricated via in situ melting polymerization by incorporating BG and poly(amino acid) (PAA) at a suitable ratio. The structure of the composite was characterized by Fourier transform infrared spectroscopy and XRD. The compressive strength of the BG/PAA composites was 139 MPa (BG:PAA = 30:70). The BG/PAA composites were degradable, and higher BG in composite showed higher weight loss after 4 weeks of incubation in simulated body fluid. In addition, the BG/PAA composite maintained adequate residual compressive strength during the degradation period. The SEM results showed the differences in surface bioactivities of the composites directly, and 30BG/PAA composite showed thicker apatite layer and higher Ca/p than 15BG/PAA. in vitro MG‐63 cell culture experiments showed that the composite was noncytotoxic and thus allows cells to adhere, proliferate, and differentiate. This indicates that the composite has good biocompatibility. The implantations in the bone defects of rabbits for 4 and 12 weeks were studied. The composites had good biocompatibility and were capable of guiding new bone formation without causing any inflammation. The composite may be successfully used in the development of bone implants.

Synthesis and properties of wholly aromatic phosphorus-containing thermotropic liquid crystal copolyesters with excellent fibre formation ability

ABSTRACT In this study, wholly aromatic phosphorus-containing thermotropic liquid crystal polymers (TLCP) derived from 6-hydroxy-2-naphthenic acid (HNA), terephthalic acid (TA) and 10-(2,5-Dihydroxypheny)-10 h-9-oxa-10-phospha-phenanthrene-10-oxide (DOPO-HQ) are successfully synthesised via one pot melt polymerisation method. Although, the resulted copolyesters are amorphous, high glass transition temperature (182–196 °C) is observed due to the existence of kinked DOPO-HQ unit and crankshaft HNA monomer. The nematic liquid crystal behaviour is found for all of the copolyesters under POM at relatively low temperature (190–207 °C). The copolyesters show good thermal stability and high char yield under both nitrogen and air atmosphere, which of the initial degradation temperature (T5%) and char yield are above 450 °C and 50%, 439 °C and 29%, respectively. Dynamic rheology results show that viscous modulus of the obtained copolyesters are much more prominent under both frequency and temperature sweeping mode, indicating have excellent processing ability. The fibres can be easily drawn from the melt, and exhibit well oriented fibrillated structure. The convenient polymerisation method, excellent thermal stability and fibre formation ability of the phosphorus-containing TLCP endow them much potential use in the safety protection field.

Activated carbonates: Enabling the synthesis of differentiated polymers via solution carbonation

Activated carbonates facilitate the preparation of polycarbonates based on monomers that are unsuitable for traditional melt polymerization at high temperatures. Here, we demonstrate the successful solution polymerization of bis(methyl salicyl)carbonate (BMSC) with a range of different diols, including bisphenol-A. It was shown that the use of BMSC in solution leads to a reduction in the (already low) amounts of by-products when compared to the use of BMSC in melt polymerization. Furthermore, the benefits of the lower temperature solution carbonation were demonstrated by the successful synthesis of segmented block copolycarbonates, without suffering from the scrambling caused by trans reactions. Finally, the use of solution polymerization for thermally unstable monomers was demonstrated by preparing a polycarbonate ionomer.

Oxygen fugacity and melt composition controls on nitrogen solubility in silicate melts

Knowledge of N solubility in silicate melts is key for understanding the origin of terrestrial N and the distribution and exchanges of N between the atmosphere, the silicate magma ocean, and the core forming metal. To place constraints on the incorporation mechanism(s) of N in silicate melts, we investigated the effect of the oxygen fugacity (fO2) and melt composition on the N solubility through N equilibration experiments at atmospheric pressure and high temperature (1425 °C). Oxygen fugacity (expressed in log units relative to the iron-wüstite buffer, IW) was varied from IW –8 to IW +4.1, and melt compositions covered a wide range of polymerization degrees, defined by the NBO/T ratio (the number of non-bridging oxygen atoms per tetrahedrally coordinated cations). The N contents of the quenched run products (silicate glasses) were analyzed by in-situ secondary ion mass spectrometry and bulk CO2 laser extraction static mass spectrometry, yielding results that are in excellent agreement even for N concentrations at the (sub-)ppm level. The data obtained here highlight the fundamental control of fO2 and the degree of polymerization of the silicate melt on N solubility. Under highly reduced conditions (fO2 = IW –8), the N solubility increased with increasing NBO/T from 17.4 ± 0.4 ppm·atm−1/2 in highly polymerized melts (NBO/T = 0) to 6710 ± 102 ppm·atm−1/2 in depolymerized melts (NBO/T ∼ 2.0). In contrast, under less reducing conditions (fO2 > IW –3.4), N solubility is very low (≤2 ppm·atm−1/2), irrespective of the NBO/T value. Our results provide constraints on N solubility in enstatite chondrite melts and in the shallow part of a planetary magma ocean. The nitrogen storage capacity of an enstatite chondrite melt, which may approximate that of planetesimals that accreted and melted early in the inner Solar System, varies between ∼60 and ∼6000 ppm at IW –5.1 and IW –8, respectively. In contrast, a mafic to ultra-mafic magma ocean could have incorporated ∼0.3 ppm to ∼35 ppm N under the fO2 conditions inferred for the young Earth (i.e., IW –5 to IW). The N storage capacity of a reduced magma ocean (i.e., IW –3.4 to IW) in equilibrium with a N-rich atmosphere is ≤1 ppm, comparable to the N content of the present-day mantle. However under more reducing conditions (i.e., IW –5 to IW –4), the N storage capacity is significantly higher (∼35 ppm); in this case, Earth would have lost N to the atmosphere and/or N would have been transported into and stored within its deep interior (i.e., deep mantle, core).

Cost-Effective Synthesis of High Molecular Weight Biobased Polycarbonate via Melt Polymerization of Isosorbide and Dimethyl Carbonate

Green synthesis of poly(isosorbide carbonate) (PIC) with remarkable properties is a huge challenge in industrial applications due to low molecular weight and harsh reaction conditions. We reported ...

Bio-Based Polyesters with High Glass-Transition Temperatures and Gas Barrier Properties Derived from Renewable Rigid Tricyclic Diacid or Tetracyclic Anhydride

Novel tricyclic diacid (TCDA) and tetracyclic anhydride (TCAH) were synthesized from renewable furan to generate a series of bio-based polyesters via melt polymerization (MP) of TCDA with seven lin...

Ge coordination inNaAlGe3O8glass upon compression to 131 GPa

Structural transformations at high pressure in NaAlGe3O8 glass were investigated by means of x-ray absorption spectroscopy at the Ge K edge in combination with a diamond anvil cell. The obtained results provide a detailed picture of the local structural behavior of Ge in a chemically complex glass under compression. First and second shell bond distances (RGe-O and RGe...Ge) were extracted assuming contributions of two scattering paths (Ge-O and Ge…Ge). We observed a significant extension of the Ge-O distance from 1.73 to 1.82 A between 3 and ∼26GPa, accompanied by an increase of the fitted number of nearest neighbors from ∼4 to ∼6. These observations can be attributed to the change from tetrahedral to octahedral Ge coordination. Second shell bond distances Ge…Ge are also consistent with this structural transformation. Between 34 and 131 GPa, the evolution of the fitted Ge-O distance implies a gradual volume reduction of the Ge octahedra. At the highest probed pressure of 131 GPa a Ge-O distance of 1.73 A was found, which is similar to the one obtained at ambient conditions for Ge in fourfold coordination. The compressibility of the Ge-O octahedron in NaAlGe3O8 beyond 34 GPa is considerably higher than the one reported for amorphous GeO2 from x-ray diffraction analysis but it is similar to the one reported for the Ge octahedron in crystalline rutile-type GeO2. We attribute the high compressibility of the Ge-O bond in NaAlGe3O8 glass to the presence of Al and Na that increase the system's complexity and therefore its degrees of freedom. Beyond 110 GPa the data on NaAlGe3O8 glass indicate the onset of polyhedral distortion. The performed study provides insights into the structural changes of complex and polymerized germanate glasses or melts at extreme pressure conditions.

Bifunctional iron-phtalocyanine metal–organic framework catalyst for ORR, OER and rechargeable zinc–air battery

Exploring non-noble metal and high-activity electrocatalysts through a simple and controllable protocol remains a great challenge for oxygen reduction reaction (ORR) and zinc–air batteries. Herein, we developed a melt polymerization strategy to synthesize iron-polyphthalocyanine (FePPc) metallic–organic frameworks (MOFs) over the carbon black matrix (FePPc@CB). Through non-covalent $$\uppi$$ – $$\uppi$$ interactions, FePPc molecules can anchor on carbon matrix, thus facilitating the electron transfer process and stabilizing the systems. Owing to abundant free electrons and atomically MN4 catalytic sites in the macrocycle structure, FePPc@CB exhibits excellent oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) electrocatalytic activity. The FePPc@CB also delivers excellent performances for liquid and flexible all-solid-state batteries compared to that of commercial Pt/C, making it a promising ORR/OER electrocatalyst.

Reply on the comment by X. Xue on «Towards the reconciliation of viscosity change and CO2-induced polymerization in silicate melt» by Yann Morizet, Michael Paris, David Sifré, Ida Di Carlo, Sandra Ory, and Fabrice Gaillard [chemical Geology 458, 38-47

Reply on the comment by X. Xue on «Towards the reconciliation of viscosity change and CO2-induced polymerization in silicate melt» by Yann Morizet, Michael Paris, David Sifré, Ida Di Carlo, Sandra Ory, and Fabrice Gaillard [chemical Geology 458, 38-47

Effect of 1,2,4,5-Benzenetetracarboxylic Acid on Unsaturated Poly(butylene adipate-co-butylene itaconate) Copolyesters: Synthesis, Non-Isothermal Crystallization Kinetics, Thermal and Mechanical Properties.

Unsaturated poly (butylene adipate-co-butylene itaconate) (PBABI) copolyesters were synthesized through melt polymerization composed of 1,4-butanediol (BDO), adipic acid (AA), itaconic acid (IA) and 1,2,4,5-benzenetetracarboxylic acid (BTCA) as a cross-linking modifier. The melting point, crystallization and glass transition temperature of the PBABI copolyesters were detected around 29.8–49 °C, 7.2–29 °C and −51.1 and −58.1 °C, respectively. Young’s modulus can be modified via partial cross-linking by BTCA in the presence of IA, ranging between 32.19–168.45 MPa. Non-isothermal crystallization kinetics were carried out to explore the crystallization behavior, revealing the highest crystallization rate was placed in the BA/BI = 90/10 at a given molecular weight. Furthermore, the thermal, mechanical properties, and crystallization rate of PBABI copolyesters can be tuned through the adjustment of BTCA and IA concentrations.