The influence of curing conditions on the mechanical properties and leaching of inorganic polymers made of fayalitic slag

This study reports on the impact of the curing conditions on the mechanical properties and leaching of inorganic polymer （IP） mortars made from a water quenched fayalitic slag. Three similar IP mortars were produced by mixing together slag, aggregate and activating solution, and cured in three different environments for 28 d： a） at 20℃ and relative humidity （RH） - 50% （T20RH50）, b） at 20℃and RH≥90% （T20RH90） and c） at 60℃ and RH - 20% （T60RH20）. Compressive strength （EN 196-1） varied between 19 MPa （T20RH50） and 31 MPa （T20RH90）. This was found to be attributed to the cracks formed upon curing. Geochemical modelling and two leaching tests were performed, the EA NEN 7375 tank test, and the BS EN 12457-1 single batch test. Results show that Cu, Ni, Pb, Zn andAs leaching occurred even at high pH, which varied between 10 and 11 in the tank test＇s leachates and between 12 and 12.5 in the single batch＇s leachates. Leaching values obtained were below the requirements for non-shaped materials of Flemish legislation for As, Cu and Ni in the single batch test.

Ameliorating the interfacial issues of all-solid-state lithium metal batteries by constructing polymer/inorganic composite electrolyte

Lithium metal is one of the most promising anodes for next-generation batteries due to its high capacity and low reduction potential.However,the notorious Li dendrites can cause the short life span and safety issues,hindering the extensive application of lithium batteries.Herein,Li_(7)La_(3)Zr_(2)O_(12)(LLZO)ceramics are integrated into polyethylene oxide(PEO)to construct a facile polymer/inorganic composite solid-state electrolyte(CSSE)to inhibit the growth of Li dendrites and widen the electrochemical stability window.Given the feasibility of our strategy,the designed PEO-LLZO-LiTFSI composite solid-state electrolyte(PLLCSSE)exhibits an outstanding cycling property of 134.2 mAh g^(-1) after 500 cycles and the Coulombic efficiency of 99.1%after 1000 cycles at 1 C in LiFePO_(4)-Li cell.When cooperated with LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622)cathode,the PLL-CSSE renders a capacity retention of 82.4%after 200 cycles at 0.2 C.More importantly,the uniform dispersion of LLZO in PEO matrix is tentative tested via Raman and FT-IR spectra and should be responsible for the improved electrochemical performance.The same conclusion can be drawn from the interface investigation after cycling.This work presents an intriguing solid-state electrolyte with high electrochemical performance,which will boost the development of all-solid-state lithium batteries with high energy density.

Inorganic ionic polymerization:From biomineralization to materials manufacturing

Biomineralization process regulates the growth of inorganic minerals by complex molecules,proteins,and cells,endowing bio-materials with marvels structures and excellent properties.The intricate structures and compositions found in biominerals have inspired scientists to design and synthesize numerous artificial biomimetic materials.The methodology for controlling the formation of inorganics plays a pivotal role in achieving biomimetic structures and compositions.However,the current approach predominantly relies on the classical nucleation theory,which hinders the precise preparation of inorganic materials by replicating the biomineralization strategy.Recently,the development of“inorganic ionic polymerization”strategy has enabled us to regulate the arrangement of inorganic ions from solution to solid phase,which establishes an artificial way to produce inorganic materials analogous to the biomineralization process.Based on inorganic ionic polymerization,a series of achievements have been realized for the biomimetic preparation,including moldable construction of inorganic materials,hard tissue regeneration,and high-performance biomimetic materials.Moreover,the utilization of inorganic ionic polymerization has also facilitated the production of numerous advanced materials,including novel structures that exceed the current knowledge of materials science.The inorganic ionic polymerization system provides new artificial strategies and methodologies for the controllable synthesis of inorganics,which mimics the biomineralization process,paving the way for the future development of more high-performance materials.

Factors affecting the shrinkage of fly ash geopolymers

The shrinkage of fly ash geopolymers was studied in the present study.Fly ash was used as the source material for making the geopolymers.The effects of the concentration of NaOH,sodium silicate-to-NaOH ratio,liquid-to-ash ratio,curing temperature,and curing time on shrinkage were investigated.The geopolymers were cured at 25,40,and 60℃,respectively.The results indicate that the shrinkage of geopolymers is strongly dependent on curing temperature and liquid-to-ash ratio.The increase in shrinkage is associated with the low strength development of geopolymers.It is also found that NaOH concentration and sodium silicate-to-NaOH ratio also affect the shrinkage of geopolymers but to a lesser extent.

Electrical conductivity and dielectric property of fly ash geopolymer pastes

The electrical conductivity and dielectric property of fly ash geopolymer pastes in a frequency range of 100 Hz-10 MHz were studied.The effects of the liquid alkali solution to ash ratios（L/A） were analyzed.The mineralogical compositions and microstructures of fly ash geopolymer materials were also investigated using X-ray diffraction（XRD） and scanning electron microscopy（SEM）.The 10 mol sodium hydroxide solution and sodium silicate solution at a sodium silicate-to-sodium hydroxide ratio of 1.0 were used in making geopolymer pastes.The pastes were cured at 40℃.It is found that the electrical conductivity and dielectric constant are dependent on the frequency range and L/A ratios.The conductivity increases but the dielectric constant decreases with increasing frequency.

Moisture-proof and Enhanced Effect of Inorganic Coating on Porous Si_3N_4 Ceramic

Inorganic coating was fabricated on the surface of the porous Si3N4 ceramic by polymer derived（PD） and spraying technology, via using vinyl-polysilazane（PSN-1） as a preceramic polymer and Si3N4 and lithium aluminosilicate（LAS） powders as fillers. The phase and microstructure of the coatings were analyzed by X-ray diffraction（XRD） analysis and scanning electron microscopy（SEM）, respectively. The effect of the coatings on mechanical property and humidity resistance of the porous Si3N4 ceramic was investigated. The experimental results showed that we successfully fabricated the uniform and dense coating which preferably combined with the substrate upon the addition of fillers. The bending strength of the porous Si3N4 ceramic sprayed the coating increased by more than 18%, and the surface hardness increased by 1.7 times. The apparent porosity of the materials reduced by an average of 97.7%, and water absorption was below 0.5%. Therefore, the prepared coating with preferable density had an obviously moisture-proof and enhanced effect on the porous Si3N4 ceramic.

Tunable wavelength filters using polymer long-period waveguide gratings based on metal-cladding directly defined technique

In this work, long-period waveguide grating-based tunable wavelength filters using organic–inorganic grafting poly（methyl methacrylate）（PMMA） materials are designed and fabricated by metal-cladding directly defined technique.The thermal stabilities and optical properties of the organic–inorganic grafting PMMA core materials are analyzed. Structures and performance parameters of the waveguide gratings and self-electrode heaters are designed and simulated. The contrast of the filter is about 15 d B and the resonant wavelength can be tuned by different electric powers applied to the metal-cladding self-electrode heaters. The temperature sensitivity is 3.5 nm/℃ and the switching time is about 1 ms. The technique is very suitable for realizing the optoelectronic integrated wavelength-division-multiplexing systems.

Anchoring polysulfide with artificial solid electrolyte interphase for dendrite-free and low N/P ratio Li-S batteries

Lithium sulfur batteries are regarded as a promising candidate for high-energy-density energy storage devices.However,the lithium metal anode in lithium-sulfur batteries encounters the problem of lithium dendrites and lithium metal consumption caused by polysulfide corrosion.Herein we design a dualfunction PMMA/PPC/LiNO3composite as an artificial solid electrolyte interphase(PMCN-SEI)to protect Li metal anode.This SEI offers multiple sites of C=O for polysulfide anchoring to constrain corrosion of Li metal anode.The lithiated polymer group and Li3N in PMCN-SEI can homogenize lithium-ion deposition behavior to achieve a dendrite-free anode.As a result,the PMCN-SEI protected Li metal anode enables the Li||Li symmetric batteries to maintain over 300 cycles(1300 h)at a capacity of 5 m Ah cm^(-2),corresponding to a cumulative capacity of 3.25 Ah cm^(-2).Moreover,Li-S batteries assembled with 20μm of Li metal anode(N/P=1.67)still deliver an initial capacity of 1166 m A h g-1at 0.5C.Hence,introducing polycarbonate polymer/inorganic composite SEI on Li provides a new solution for achieving the high energy density of Li-S batteries.

Properties of polyferric-silicate-sulfate(PFSS) coagulant

Polyferric\|silicate\|sulfate(PFSS),as a new type of coagulant,was prepared by using sodium silicate, sulfuric acid and ferric sulfate as materials.The zeta potential of hydrolyzate of PFSS under different pH values was investigated.The effects of Fe/SiO\-2 molar ratio and dosage of PFSS on turbidity removal were studied. The relation between the optimum coagulation pH range and Fe/SiO\-2 molar ratio was found and the coagulation mechanism of PFSS was discussed.The experimental results showed that Fe/SiO\-2 molar ratio has an effect on the zeta potential of hydrolyzate, the coagulation performance and the optimum coagulation pH range of PFSS and that PFSS gives the best turbidity removal effect when its Fe/SiO\-2 molar ratio was 1.5.

Luminescence of Terbium Complexes Incorporated into Silica Matrix

Binary and ternary terbium complexes were synthesized: Tb(N PA) 3·4H 2O and Tb(N PA) 3(phen·2H 2O (N HPA = N phenyl 2 aminobenzoic acid and phen = 1,10 phenanthroline). These complexes were introduced into inorganic polymeric porous silica matrix by the sol gel method. The luminescence behavior of the complexes in silica gels was compared with the corresponding solid state complexes by means of emission, excitation spectra and luminescence lifetimes. The result indicates that the terbium ions show fewer emission lines and lower emission intensities in the silica gel than those in pure terbium complexes. The lifetimes of terbium ions in silica gel doped with terbium complexes become longer than those of terbium complexes.

First principles insights into oxide/polymer composites: SrTiO_(3) /polyaniline/graphene

A detailed computational investigation,based on density functional theory,of the interaction of polyani-line(PANI)and graphene nanoribbons(GNRs)with SrTiO_(3) is presented.The adsorption of PANI in var-ious oxidation states and co-adsorption with GNRs is found to be thermodynamically favourable.Ad-sorbed PANI introduces N and C 2p states into the SrTiO_(3) bandgap,while co-adsorption of PANI and GNRs leads to a bridging of the gap and semi-metallic behaviour,thus rendering the electrical properties highly sensitive to the loading of the GNRs/PANI in the composites.Modelling the lattice dynamics of the composites predicts a 68-88%reduction in the lattice thermal conductivity due to reduced phonon group velocities.Taken together,these findings provide insight into the growing number of experimental studies highlighting the enhanced thermoelectric performance of oxide-polymer composites and indicate co-adsorption with graphene as a facile direction for future research.

SYNTHESIS OF CdS/SiO_2/POLYMER TRI-LAYER FLUORESCENT NANOSPHERES WITH FUNCTIONAL POLYMER SHELLS

Tri-layer CdS/SiOz/polymer hybrid nanospheres were synthesized by distillation precipitation polymerization of either ethyleneglycol dimethacrylate （EGDMA） or EGDMA together with comortomers havirLg different functional groups, such as methacrylic acid, 4-vinylpyridine and 2-hydroxyethylmethacrylate, in the presence of 3-（methacryloxy）propyl trimethoxysilane （MPS）-modified CdS/SiO2 nanoparticles as seeds in acetonitrile with 2,2＇-azobisisobutyronitrile （AIBN） as initiator. In this approach, MPS-modified inorganic seeds were prepared by the modification of CdS/SiO2 nanoparticles via the self-condensation reaction between the hydroxyl groups of sinaols, in which the CdS/SiO2 nanoparticles were afforded by a reverse microemulsion technique for the synthesis of CdS core nanoparticles with the subsequent coating of silica layer. The polymer shell-layers encapsulated over the MPS-modified CdS/SiO2 inorganic seeds via the efficient capture of the monomers and oligomers from the solution with the aid of the vinyl groups incorporated by the MPS modification, in which the polymer shell-thickness and functional groups including carboxyl, pyridyl and hydroxyl, were facilely controlled by the feed of EGDMA as well as the types of comonomers used for the polymerization. These nanospheres were characterized by transmission electron microscopy （TEM）, Fourier-transform infrared spectroscopy （FT-IR）, thermogravimetric analysis （TGA）, fluorescence spectroscopy and zeta potential.

Speciation characterization and coagulation of poly-silica-ferric-chloride:The role of hydrolyzed Fe(Ⅲ) and silica interaction

The highly efficient inorganic polymer flocculants （IPFs） of the ferric-silica system is a new and promising coagulant. Interactions between ferric species and silica play a large part in the coagulation of suspensions. These effects are quite distinct from those associated with polymeric or colloid silica. However, although these species are key to coagulation efficiency, they have not been comprehensively discussed. A new type of coagulant, poly-silica-ferric-chloride （PFSC）, was synthesized by co-polymerization and characterized by time complexation spectroscopy and photon correlation spectroscopy. Compared with traditional ferric salt, the results indicated that PFSC had a higher molecular weight, lesser positive charge, lower Feb and higher Fec. The higher the Si/Fe ratio, the higher the silica and lower the silicac found. The PFSC with appropriate polysilica acid not only obtained better coagulation/flocculation efficiency in turbidity removal, enhanced the flocculation index （FI） and provided less residual ferric, it also lowered water treatment costs compared to traditional ferric salt. Results showed that PFSC could remove colloid particles in water by charge neutralization and sweeping, adsorption bridging mechanism.

Hydrolyzed Al(Ⅲ) clusters:Speciation stability of nano-Al_(13)

Pure nano-All3 and aggregates at various concentrations were prepared to examine the particle size effect of coagulation with inorganic polymer flocculant. The property and stability of various species formed were characterized using Infrared, 27Al-NMR, photo correlation spectroscopy （PCS）, and Ferron assay. Results showed that concentration and temperature exhibited different roles on the stability of Al13. The quantity of Alb species analyzed by ferron assay in the initial aging period corresponded well with that of Al13, which has been confirmed in a dimension range of 1-2 nm by PCS. Al13 solutions at high concentrations （0.5-2.11 tool/L） were observed to undergo further aggregation with aging. The aggregates with a wide particle size distribution would contribute to the disappeared/decreased Al13 basis on the eTA1-NMR spectrum, whereas a part of Al13 would still remain as Alb. At low concentrations, All3 solution was quite stable at normal temperature, but lost its stability quickly when heating to 90~C.