In-situ copolymerization of aniline with alkyl amine by APS:Kinetics and application

The kinetic study of in-situ eopolymerization of aniline with o- and p-methylaniline by ammonium persulfate （APS） has been carried out. UV-vis spectroscopic method was used to investigate the course of copolymerization. Structural characterization was studied by PT-IR spectral analysis. The electronic spectra of the copolymers poly（aniline-co-p-toluidine） and poly（aniline-co-o- toluidine） show blue shift. The shift has been observed in the bands corresponding to π→π^＊ transition as well as in the exciton transition. The increase in absorbance recorded during the reaction for different concentration of aniline, o- and p-toluidine at various intervals of time of polymerization reaction indicates a growth in the polymer formation. The resulting first-order rate constant was used to calculate the rate of copolymer formation using the rate equation -d[A]/dt = kc^n.

Ethylene Copolymerization with Linear and End-Cyclized Olefins via a Metallocene Catalyst:Polymerization Behavior and Thermal Properties of Copolymers

Olefin solution polymerization can be used to obtain high-performance polyolefin materials that cannot be obtained via other polymerization processes.Polyolefin elastomers(POE)are a typical example.Due to cost,only a few linear a-olefins(e.g.,1-butene,1-hexene,and 1-octene)are used as comonomers in solution polymerization in industry.However,a-olefin comonomers with other structures may have different effects on polymerization in comparison with common linear ones.Moreover,the properties of the corresponding materials may differ significantly.In this work,copolymers of ethylene with linear and endcyclized a-olefins are synthesized using a metallocene catalyst.The copolymerization of ethylene with linear a-olefins results in a higher turn-over frequency(TOF)and lower incorporation than copolymerization with end-cyclized a-olefins,which may indicate that end-cyclized a-olefins have a higher coordination probability and lower insertion rate.In this reaction,the comonomer is distributed randomly in the polymer chain and efficiently destroys crystallization.End-cyclized a-olefins exhibit a much stronger crystallization destructive capacity(CDC)in the copolymer than linear a-olefins,possibly because linear a-olefins act mainly in the radial direction of the main chain of the polymer,while end-cyclized a-olefins act mainly in the axial direction of the main chain.

Assessing the conservation impact of Chinese indigenous chicken populations between ex-situ and in-situ using genome-wide SNPs

Conservation programs require rigorous evaluation to ensure the preservation of genetic diversity and viability of conservation populations. In this study, we conducted a comparative analysis of two indigenous Chinese chicken breeds, Gushi and Xichuan black-bone, using whole-genome SNPs to understand their genetic diversity, track changes over time and population structure. The breeds were divided into five conservation populations(GS1, 2010, ex-situ;GS2, 2019, ex-situ;GS3, 2019, in-situ;XB1, 2010, in-situ;and XB2, 2019, in-situ) based on conservation methods and generations. The genetic diversity indices of three conservation populations of Gushi chicken showed consistent trends, with the GS3 population under in-situ strategy having the highest diversity and GS2 under ex-situ strategy having the lowest. The degree of inbreeding of GS2 was higher than that of GS1 and GS3. Conserved populations of Xichuan black-bone chicken showed no obvious changes in genetic diversity between XB1 and XB2. In terms of population structure, the GS3 population were stratified relative to GS1 and GS2. According to the conservation priority, GS3 had the highest contribution to the total gene and allelic diversity in GS breed, whereas the contribution of XB1 and XB2 were similar. We also observed that the genetic diversity of GS2 was lower than GS3, which were from the same generation but under different conservation programs(in-situ and ex-situ). While XB1 and XB2 had similar levels of genetic diversity. Overall, our findings suggested that the conservation programs performed in ex-situ could slow down the occurrence of inbreeding events, but could not entirely prevent the loss of genetic diversity when the conserved population size was small, while in-situ conservation populations with large population size could maintain a relative high level of genetic diversity.

In-situ AFM and quasi-in-situ studies for localized corrosion in Mg-9Al-1Fe-(Gd) alloys under 3.5 wt.% NaCl environment

Revealing the localized corrosion process of Mg alloy is considered as one of the most significant ways for improving its corrosion resistance.The reliable monitor should be high distinguishability and real-time in liquid environment.Herein,Mg-9Al-1Fe and Mg-9Al-1Fe-1Gd alloys were designed to highlight the impact of intermetallic on the corrosion behaviour.In-situ AFM with a special electrolyte circulation system and quasi-in-situ SEM observation were used to monitor the corrosion process of the designed alloys.SEM-EDS and TEM-SAED were applied to identify the intermetallic in the designed alloys,and their volta potentials were measured by SKPFM.According to the real-time and real-space in-situ AFM monitor,the corrosion process consisted of dissolution of anodicα-Mg phase,accumulation of corrosion products around cathodic phase and shedding of some fine cathodic phase.Then,the localized corrosion process of Mg alloy was revealed combined with the results of the monitor of corrosion process and Volta potential difference.

An in-situ study of static recrystallization in Mg using high temperature EBSD

It has been a common method to improve the mechanical properties of metals by manipulating their microstructures via static recrystallization,i.e.,through heat treatment.Therefore,the knowledge of recrystallization and grain growth is critical to the success of the technique.In the present work,by using in-situ high temperature EBSD,the mechanisms that control recrystallization and grain growth of an extruded pure Mg were studied.The experimental results revealed that the grains of priority for dynamic recrystallization exhibit fading competitiveness under static recrystallization.It is also found that grain boundary movement or grain growth is likely to show an inverse energy gradient effect,i.e.,low energy grains tend to swallow or grow into high energy grains,and grain boundaries of close to 30°exhibit superior growth advantage to others.Another finding is that{10-12}tensile twin boundaries are sites of hardly observed for recrystallization,and are finally swallowed by adjacent recrystallized grains.The above findings may give comprehensive insights of static recrystallization and grain growth of Mg,and may guide the design of advanced materials processing in microstructural engineering.

An in-situ self-etching enabled high-power electrode for aqueous zinc-ion batteries

Sluggish storage kinetics is considered as the main bottleneck of cathode materials for fast-charging aqueous zinc-ion batteries(AZIBs).In this report,we propose a novel in-situ self-etching strategy to unlock the Palm tree-like vanadium oxide/carbon nanofiber membrane(P-VO/C)as a robust freestanding electrode.Comprehensive investigations including the finite element simulation,in-situ X-ray diffraction,and in-situ electrochemical impedance spectroscopy disclosed it an electrochemically induced phase transformation mechanism from VO to layered Zn_(x)V_(2)O_5·nH_(2)O,as well as superior storage kinetics with ultrahigh pseudocapacitive contribution.As demonstrated,such electrode can remain a specific capacity of 285 mA h g^(-1)after 100 cycles at 1 A g^(-1),144.4 mA h g^(-1)after 1500 cycles at 30 A g^(-1),and even 97 mA h g^(-1)after 3000 cycles at 60 A g^(-1),respectively.Unexpectedly,an impressive power density of 78.9 kW kg^(-1)at the super-high current density of 100 A g^(-1)also can be achieved.Such design concept of in-situ self-etching free-standing electrode can provide a brand-new insight into extending the pseudocapacitive storage limit,so as to promote the development of high-power energy storage devices including but not limited to AZIBs.

Microstructural characterization and mechanical properties of(TiC+TiB)/TA15 composites prepared by an in-situ synthesis method

Titanium matrix composites reinforced with ceramic particles are considered a promising engineering material due to their combination of high specific strength,low density,and high modulus.In this study,the TA15-based composites reinforced with a volume fraction of 10% to 25%(TiB+TiC)were prepared using powder metallurgy and casting technique.Microstructural characterization and phase constitution were examined using optical microscopy(OM),scanning electron microscopy(SEM),and X-ray diffraction(XRD).In addition,the microhardness,room temperature(RT)and high temperature(HT)tensile properties of the composites were evaluated.Results revealed that the reinforcements are distributed uniformly even in the composites with a high volume of TiB and TiC.However,as the volume fraction exceeds 15%,TiB and TiC particles become coarsening and exhibit rod-like and dendritic-like morphology.Microhardness increases gradually from 321.2 HV for the base alloy to a maximum of 473.3 HV as the reinforcement increases to 25vol.%.Tensile test results indicate that a reinforcement volume fraction above 20% is beneficial for enhancing tensile strength and yield strength at high temperatures,but it has an adverse effect on room temperature elongation.Conversely,if the reinforcement volume fraction is below 20%,it can improve high-temperature elongation when the temperature exceeds 600℃.

Investigation on chain structure of LLDPE obtained by ethylene in-situ copolymerization with DSC and XRD

Thermal segregations of LLDPE were treated with successive self-nucleation/annealing (SSA) on dif-ferential scanning calorimetry (DSC). Information on molecular heterogeneity of LLDPE was obtained. After SSA was treated, the multiple endothermic peaks were observed in the DSC thermograms during heating experiment. It is obtained that the thickness of different lamellas formed by segments of vari-ous lengths was 4―10 nm. X-ray diffraction (XRD) results showed that the crystallites dimensions of various reflections were about several dozens of nanometers. The ethylene/α-olefin copolymers and the copolymer via in-situ copolymerization were similar to each other for molecular heterogeneity and XRD characteristics, which revealed that it was possible to use the ethylene/α-olefin copolymers to simulate the copolymer via in-situ copolymerization of ethylene to simplify the complexity of the structure of the ethylene in-situ copolymer.

In-situ polymerized PEO-based solid electrolytes contribute better Li metal batteries:Challenges,strategies,and perspectives

Polyethylene oxide(PEO)-based solid polymer electrolytes(SPEs)with good electrochemical stability and excellent Li salt solubility are considered as one of the most promising SPEs for solid-state lithium metal batteries(SSLMBs).However,PEO-based SPEs suffer from low ionic conductivity at room temperature and high interfacial resistance with the electrodes due to poor interfacial contact,seriously hindering their practical applications.As an emerging technology,in-situ polymerization process has been widely used in PEO-based SPEs because it can effectively increase Li-ion transport at the interface and improve the interfacial contact between the electrolyte and electrodes.Herein,we review recent advances in design and fabrication of in-situ polymerized PEO-based SPEs to realize enhanced performance in LMBs.The merits and current challenges of various SPEs,as well as their stabilizing strategies are presented.Furthermore,various in-situ polymerization methods(such as free radical polymerization,cationic polymerization,anionic polymerization)for the preparation of PEO-based SPEs are summarized.In addition,the application of in-situ polymerization technology in PEO-based SPEs for adjustment of the functional units and addition of different functional filler materials was systematically discussed to explore the design concepts,methods and working mechanisms.Finally,the challenges and future prospects of in-situ polymerized PEO-based SPEs for SSLMBs are also proposed.

In-situ interfacial passivation and self-adaptability synergistically stabilizing all-solid-state lithium metal batteries

The function of solid electrolytes and the composition of solid electrolyte interphase(SEI)are highly significant for inhibiting the growth of Li dendrites.Herein,we report an in-situ interfacial passivation combined with self-adaptability strategy to reinforce Li_(0.33)La_(0.557)TiO_(3)(LLTO)-based solid-state batteries.Specifically,a functional SEI enriched with LiF/Li_(3)PO_(4) is formed by in-situ electrochemical conversion,which is greatly beneficial to improving interface compatibility and enhancing ion transport.While the polarized dielectric BaTiO_(3)-polyamic acid(BTO-PAA,BP)film greatly improves the Li-ion transport kinetics and homogenizes the Li deposition.As expected,the resulting electrolyte offers considerable ionic conductivity at room temperature(4.3 x 10~(-4)S cm^(-1))and appreciable electrochemical decomposition voltage(5.23 V)after electrochemical passivation.For Li-LiFePO_(4) batteries,it shows a high specific capacity of 153 mA h g^(-1)at 0.2C after 100 cycles and a long-term durability of 115 mA h g^(-1)at 1.0 C after 800 cycles.Additionally,a stable Li plating/stripping can be achieved for more than 900 h at 0.5 mA cm^(-2).The stabilization mechanisms are elucidated by ex-situ XRD,ex-situ XPS,and ex-situ FTIR techniques,and the corresponding results reveal that the interfacial passivation combined with polarization effect is an effective strategy for improving the electrochemical performance.The present study provides a deeper insight into the dynamic adjustment of electrode-electrolyte interfacial for solid-state lithium batteries.

Interplay of laser power and pore characteristics in selective laser melting of ZK60 magnesium alloys:A study based on in-situ monitoring and image analysis

This study offers significant insights into the multi-physics phenomena of the SLM process and the subsequent porosity characteristics of ZK60 Magnesium(Mg)alloys.High-speed in-situ monitoring was employed to visualise process signals in real-time,elucidating the dynamics of melt pools and vapour plumes under varying laser power conditions specifically between 40 W and 60 W.Detailed morphological analysis was performed using Scanning-Electron Microscopy(SEM),demonstrating a critical correlation between laser power and pore formation.Lower laser power led to increased pore coverage,whereas a denser structure was observed at higher laser power.This laser power influence on porosity was further confirmed via Optical Microscopy(OM)conducted on both top and cross-sectional surfaces of the samples.An increase in laser power resulted in a decrease in pore coverage and pore size,potentially leading to a denser printed part of Mg alloy.X-ray Computed Tomography(XCT)augmented these findings by providing a 3D volumetric representation of the sample internal structure,revealing an inverse relationship between laser power and overall pore volume.Lower laser power appeared to favour the formation of interconnected pores,while a reduction in interconnected pores and an increase in isolated pores were observed at higher power.The interplay between melt pool size,vapour plume effects,and laser power was found to significantly influence the resulting porosity,indicating a need for effective management of these factors to optimise the SLM process of Mg alloys.

Oxidation of emerging organic contaminants by in-situ H_(2)O_(2) fenton system

The existence and risk of emerging organic contaminants(EOCs)have been under consideration and paid much effort to degrade these pollutants.Fenton system is one of the most widely used technologies to solve this problem.The original Fenton system relies on the hydroxyl radicals produced by Fe(Ⅱ)/H_(2)O_(2) to oxidize the organic contaminants.However,the application of the Fenton system is limited by its low iron cycling efficiency and the high risks of hydrogen peroxide transportation and storage.The introduction of external energy(including light and electricity etc.)can effectively promote the Fe(Ⅲ)/Fe(Ⅱ)cycle and the reduction of oxygen to produce hydrogen peroxide in situ.This review introduces three in-situ Fenton systems,which are electro-Fenton,Photo-Fenton,and chemical reaction.The mechanism,influencing factors,and catalysts of these three in-situ Fenton systems in degrading EOCs are discussed systematically.This review strengthens the understanding of Fenton and in-situ Fenton systems in degradation,offering further insight into the real application of the in-situ Fenton system in the removal of EOCs.

In-situ coating and surface partial protonation co-promoting performance of single-crystal nickel-rich cathode in all-solid-state batteries

The poor electrochemical performance of all-solid-state batteries(ASSBs),which is assemblied by Ni-rich cathode and poly(ethylene oxide)(PEO)-based electrolytes,can be attributed to unstable cathodic interface and poor crystal structure stability of Ni-rich cathode.Several coating strategies are previously employed to enhance the stability of the cathodic interface and crystal structure for Ni-rich cathode.However,these methods can hardly achieve simplicity and high efficiency simultaneously.In this work,polyacrylic acid(PAA)replaced traditional PVDF as a binder for cathode,which can achieve a uniform PAA-Li(LixPAA(0<x≤1))coating layer on the surface of single-crystal LiNi_(0.83)Co_(0.12)Mn_(0.05)O_(2)(SC-NCM83)due to H^(+)/Li^(+)exchange reaction during the initial charging-discharging process.The formation of PAA-Li coating layer on cathode can promote interfacial Li^(+)transport and enhance the stability of the cathodic interface.Furthermore,the partially-protonated surface of SC-NCM83 casued by H^(+)/Li^(+)exchange reaction can restrict Ni ions transport to enhance the crystal structure stability.The proposed SC-NCM83-PAA exhibits superior cycling performance with a retention of 92%compared with that(57.3%)of SC-NCM83-polyvinylidene difluoride(PVDF)after 200 cycles.This work provides a practical strategy to construct high-performance cathodes for ASSBs.

Preparation and properties of RE^(3+) doped luminescent co-polymer by solution copolymerization

Bonded type RE3+ doped luminescent co-polymer was synthesized by solution free radical copolymerization. The influence of charge sequence, monomers and co-polymerized method on properties and structures of the co-polymers was studied. The emission intensity of the co-polymers at different RE3+ concentrations was tested. The results showed that the co-polymers of Eu-PSt and Eu-PMMA both had wide absorption peak at 200-400 nm and the strongest peak appeared at 235 nm. The fluorescent intensity of Eu3+ doped polystyrene co-polymer was stronger than that of Eu3+ doped PMMA copolymer. The characteristic emission of europium ions was observed in the co-polymers. The copolymer doped with rare earth elements showed the 'sensitization effect' for the central ions. The bonded-type rare earth copolymer not only enhanced the energy transfer efficiency, but also improved the fluorescence intensity by increasing the rigidity of main and side chain.

Monomer reactivity ratios for fluoroacrylate and butyl methacrylate in miniemulsion copolymerizations initiated by potassium persulphate

Miniemulsion copolymerization of butyl mathacrylate （BMA） with fluoroacrylate （HFMA, TFMA） was carried out at 70 ℃ by employing potassium persulphate （KPS） as initiator. Copolymer compositions at low conversion levels were determined by ^1H NMR spectra techniques. The reactivity ratios were evaluated by employing Kellen-Tudos （K-T） methods, which yields the apparent reactivity ratios, rBMA = 0.74, rHFMA = 0.87 and rBMA = 0.73, rTFMA = 0.75, respectively, and Q- and e-values of HFMA and TFMA were calculated by the Alfrey-Price method. The results show that HFMA and TFMA are more active than BMA, and the cross-propagation rate constant is greater than the self-propagation one in these two copolymerizations.

GRAFT COPOLYMERIZATION OF VINYL MONOMERS ONTO STARCH INITIATED BY TRANSITION METAL-THIOUREA REDOX SYSTEMS

In this paper, the capabilities of grafting acrylonitrile (AN) onto starch initiated by Fe(III)-TU, V(V)-TU, Cr(VI)-TU, Mn(VII)-TU redox systems were compared in the presence of sulfuric acid of different concentrations. It was shown that the grafting capability of Mn(VII)-TU is the highest in these initiating systems. Using Mn (VII-TU as initiator, the effects of various acids (HClO4, H2SO4, HNO3, HCl) on the graft copolymerization of acrylonitrile onto starch were discussed, and the capabilities of graft copolymerization of methyl methacrylate (MMA), acrylamide (AM), acrylic acid (AA) onto starch were investigated. The experimental results show that the order of the influences of different acids is HClO4 > H2SO4 > HNO3 > HCl, and the order of grafting capabilities of different monomers grafted onto starch is MMA > AN > AM > AA. The structure and morphology of graft, copolymers were studied with infrared spectroscopy and scanning electron microscopy. The size, shape and roughness of surface of the grafted starch granules are changed after grafting.

INFLUENCE OF DIALKYLZINC IN RARE-EARTH TERNARY CATALYST ONTHE COPOLYMERIZATION OF CARBON DIOXIDE AND PROPYLENE OXIDE

Rare-earth ternary catalysts Y（CCl3COO）3-ZnR2-glycerin were prepared for the copolymerization of carbon dioxide and propylene oxide （PO）, where dialkylzincs （ZnR2） were diethylzinc, di（n-propyl）zinc, di（n-butyl）zinc, di（i-propyl）zinc, di（i-butyl）zinc, di（s-butyl）zinc,respectively. The Y（CCl3COO）3-ZnR2-glycerin catalysts displayed the highest catalytic activity at the molar ratio of Y（CCl3COO）3：ZnR2：glycerin = 1：20：10. In the same copolymerization condition, catalysts containing dialkylzincs with branched alkyl group showed lower catalytic activity than that with primary alkyl group. For those catalysts including dialkylzincs with primary alkyl group, their catalytic activity decreases with increasing number of carbon atom in the alkyl group with the following sequence： Y（CCl3COO）3-ZnEt2-glycerin 〉 Y（CCl3COO）3-Zn（n- Pr）2-glycerin〉Y（CCl3COO）3-Zn（n-Bu）2-glycerin. However, the alkyl group in the dialkylzinc does not influence the insertion of PO into the propagation chain end.

CATALYTIC COPOLYMERIZATION OF STYRENE AND ETHYLENE BY NEUTRAL NICKEL(Ⅱ) COMPLEXES IN EMULSION

Emulsion copolymerization of styrene and ethylene catalyzed by a series of neutral nickel(Ⅱ) complexes was carried out in an aqueous system to give high-molecular-weight copolymers.The copolymers and emulsions were characterized by an array of techniques including NMR,GPC,TEM,WAXD and DSC.The results indicate that the copolymers obtained are mostly block copolymers of polyethylene with random insertion of styrene units,and their M_W is in the range of 10~5-10~6.By enhancing the electron withdrawing of the s...

Copolymerization of Styrene with N-phenylmaleimide by Rare Earth Coordination Catalysts

Copolymerization of styrene (St) with N-phenylmaleimide (NPMI) was studied with rare earth coordination catalyst Nd(naph)3-AlEt3 in toluene. Characterization of the copolymers showed that the copolymers possess an alternating structure.

Thermosensitive Particles with Unusual Morphology Prepared by Dispersion Copolymerization

The monodispersed polymeric particles with an unusual structure were prepared by the dispersion copolymerization of acrylonitrile/styrene（AN/St） in mixed solvents of ethanol/water by using the poly（N-isopropylacrylamide） （PNIPAAm） macromonomer as a reaction stabilizer. It was found that the AN monomer plays a key role in the formation of the particles with special morphology analyzed via scanning electron microscopy （SEM）. The reaction parameters have remarkable influences on the particle size and morphology. The particles possess a thermosensitive property according to the result of laser light scattering（LLS）.