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The poor processing and rheological properties of highly filled composites caused by the high loading of fillers can be improved with the use of maleic anhydride grafted polyethylene wax (PEWM) as compatibilizer and lubricant. In this study, two PEWMs with different molecular weights were synthesized by melt grafting, and their compositions and grafting degrees were characterized by Fourier transform infrared (FTIR) spectroscopy and acid-base titration. Subsequently, magnesium hydroxide (MH)/linear low-density polyethylene (LLDPE) composites with 60 wt% of MH were prepared using polyethylene wax (PEW) and PEWM, respectively. The equilibrium torque and melt flow index tests indicate that the processability and fluidity of MH/MAPP/LLDPE composites are significantly improved with the addition of PEWM. The addition of PEWM with a lower molecular weight leads to a substantial reduction in viscosity. The mechanical properties are also increased. The limiting oxygen index (LOI) test and cone calorimeter test (CCT) show that both PEW and PEWM have adverse effects on flame retardancy. This study provides a strategy to simultaneously improve the processability and mechanical properties of highly filled composites. [ABSTRACT FROM AUTHOR]

This study presents a novel approach for preparing a porous carbon electrode material from waste biomass with significant advantages, such as low-priced, simple synthesis process, environmental sustainability, and outstanding electrochemical performance, making it highly relevant in the area of energy storage for supercapacitors (SCs). Verbena straw with a loose hollow structure is selected as the precursor, the proposed K 2 CO 3 /NaCl synergistic preparation route successfully yields a highly efficient porous activated carbon electrode material (VSC-800) with a high surface area of 2055 m2 g−1, plentiful pores (1.262 cm3 g−1), and enriched oxygen and nitrogen self-doping. Impressively, VSC-800 exhibits outstanding specific capacitance of 438 F g−1 at 0.5 A g−1. Furthermore, a high specific capacitance of 362.3 F g−1 is achieved by flexible all-solid-state symmetric SCs utilizing a PVA/KOH gel electrolyte at 0.5 A g−1, resulting in an impressive energy density of 21.3 Wh kg−1. This work provides a feasible approach for the environmentally friendly utilization of waste biomass materials and emphasizes the immense promise of utilizing waste biomass-derived porous carbon in creating flexible all-solid-state SCs with exceptional performance. [Display omitted] • Waste verbena straw utilized as a precursor in the synthesis of 3D hierarchical porous carbon. • Eco-friendly process with NaCl-assisted melting and K 2 CO 3 activation. • The VSC-800 demonstrates a remarkably high specific capacitance of 438 F g−1 at 0.5 A g−1. • All-solid-state VSC-800//VSC-800 SCs achieved an outstanding energy density of 21.3 Wh kg−1. [ABSTRACT FROM AUTHOR]

[Display omitted] • The effect of pretreatments on the deposition of Cr(III) conversion coating was investigated. • The chemical composition of different Cr(III)-converted foils was investigated. • The surface free energy on the different Cr(III)-converted foils was studied. • The wettability of GMA-g-PBE melts on the substrate was investigated. • The interfacial bond mechanism was studied by computational simulation techniques. Good adhesive strength and joint durability are necessary for aluminum (Al)/polymer laminated film for lithium-ion battery packages. A pretreatment method involving alkaline degreasing followed by acid pickling was employed to treat the Al foil surface to facilitate the deposition of trivalent chromium [Cr(III)] conversion coating on the surface. The adhesive strength between propylene-based elastomer grafted glycidyl methacrylate (GMA-g-PBE) and Cr(III)-converted Al foil pretreated with 0.5 M HF pickling was 51% higher than Cr(III)-converted Al foil without pretreatment. Moreover, the effect of different pretreatments on the interfacial bond strength of GMA-g-PBE/Cr(III)-converted Al foil was studied from macroscopic to microscopic perspectives. The results indicate that the pretreatment of 0.5 M HF pickling results in complete coverage of the Cr(III) compounds and the formation of a thicker Cr(III) conversion coating on the Al foil compared to other pretreatments. A higher content of Cr(III) compounds results in an increased surface free energy of Cr(III)-converted Al foil, improving the wettability of adhesive melt on the substrate and enhancing the adhesion strength. Moreover, quantum chemical calculations and molecular dynamics simulations were used to investigate the interface bonding mechanism, and the results indicate that GMA in the adhesive exhibits a higher binding energy with Cr(III) oxides and hydroxides compared to Al oxides and hydroxides. [ABSTRACT FROM AUTHOR]

In this study, an environmentally friendly molybdate (Mo) conversion coating was deposited on the surface of aluminum (Al) foil for use as the packaging film of lithium‐ion battery, and the surface morphology and chemical composition were characterized by field emission scanning electron microscopy (FE‐SEM), atomic force microscopy (AFM), energy dispersive spectroscopy (EDS), and X‐ray photoelectron spectroscopy (XPS). The XPS results show that the conversion coating is composed of MoO3, MoOx, Al2O3, and (MoO3)x(P2O5)y. Then, the effects of treatment time on the corrosion resistance of Al foil and the adhesive strength between Mo‐treated Al foil and maleic anhydride (MAH)‐grafted polypropylene (MPP) were investigated. It is revealed that both the peeling strength and the corrosion resistance of Mo‐treated Al foil increase with the treatment time. [ABSTRACT FROM AUTHOR]

Highlights • PBI was coated on the silk screen stencil film to improve its abrasion resistance. • PBI coating can greatly improve the abrasion resistance of silk screen stencil film. • 8 μm thick PBI coating can adequately protect the silk screen stencil film against wear. Abstract It is of practical significance to prolong the service life of the silk screen plate used for screen printing by a simple method. To our knowledge, no attempt has been made to coat silk screen stencil film with polybenzimidazole (PBI) to improve its abrasion resistance against squeegee in order to prolong the service life of the silk screen plate. In this study, the synthesized PBI with 2,6-disubstituted benzimidazole structure was coated on the silk screen stencil film by solution casting, and its effect on the morphology, roughness and abrasion resistance of stencil film was investigated by scanning electron microscope, atomic force microscope and Taber abrasion tester. The abrasion resistance of the silk screen stencil films with 1 and 19 μm thick PBI coating is improved by 18.6% and 87.6% compared with that of pure stencil film, respectively. The stencil film undergoes two wear stages: the first stage with a larger mass loss is characterized by the wear of photosensitive film; and the second one with a relatively smaller mass loss is characterized by the wear of both photosensitive film and silk screen. The thickness of PBI coating has an important effect on the substrate strength and surface properties of films during the wear, thus resulting in changes in the abrasion resistance of stencil films. It shows that 8 μm thick PBI coating is enough to protect the stencil film from wear. [ABSTRACT FROM AUTHOR]

Abstract In this study, the effects of polybenzimidazole (PBI) and polyacrylic acid (PAA) modified carbon black (MCB) on the anti-UV-weathering and thermal properties of PVC composites were investigated. The optimal mass ratios of PBI and MCB to PVC are 0.1 wt% and 0.2 wt%, respectively, and the resultant 1PBI/2MCB/PVC composite membrane with a thickness of about 60 μm can block over 99% of UV light below 380 nm. The UV absorption mechanism was investigated by the optional band gap (Eg) and the fluorescence spectroscopy. The incorporation of PBI and MCB results in a decrease in Eg, from 4.96 eV for PVC membrane to 2.90 eV for 1PBI/2MCB/PVC composite membrane, and MCB can quench the fluorescence of PBI by photon-induced electron transfer to further protect PVC. The results of accelerated UV-weathering experiment indicate that the incorporation of PBI and MCB can improve the anti-UV-weathering property of PVC. The thermal degradation behaviors of PVC and its composite membranes in air and N 2 atmosphere were also investigated. The highest char residue (13.7 wt%) is obtained in 1PBI/2MCB/PVC composite membrane at 800 °C in N 2 atmosphere, with an increase of 73.4% compared with that of PVC membrane, which may be because PBI and MCB can synergistically accelerate the carbonization of PVC molecules to rapidly form stable char residue. [ABSTRACT FROM AUTHOR]

[Display omitted] • The formation mechanism of AMC is proposed from the perspective of ionic reaction. • HCO 3 − is the best carbon source form for preparing AMC. • The preparation conditions of AMC can be quantified. • Sodium and potassium ions have different effects on the particle diameter of AMC prepared from different magnesium sources. • Cl-AMC has smaller basic units and higher fastest decomposition temperature than S-AMC. In this study, the synthesis and formation mechanism of anhydrous magnesium carbonate (AMC) using hydrothermal method is proposed from the perspective of ionic reaction. Validation experiments were conducted, and the effect of the pH of the reaction solution and the form of carbon source on AMC preparation was investigated. It is found that HCO 3 − can accelerate crystal growth and reduce crystal size, and the preparation conditions of AMC can be quantified. The AMC particles were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The AMC prepared using urea as carbon source has a small particle size in the presence of ion pairs of Na+/Cl− or K+/SO 4 2−. AMC prepared using magnesium chloride as magnesium source has smaller composition units than those prepared using magnesium sulfate as magnesium source. The effects of ions types, reaction temperature, reaction time and filling degree on the phase transition and crystal growth of AMC are also discussed. [ABSTRACT FROM AUTHOR]

The purpose of this study is to investigate the curing kinetics of neat and pre-crosslinked or non-crosslinked carboxyl-terminated butadiene acrylonitrile liquid rubber (CTBN) toughened epoxies cured with isophorone diamine (IPDA) using non-isothermal and isothermal differential scanning calorimetry. The results show that CTBN has a complex effect on the curing process of epoxy/IPDA systems. The carboxyl groups of CTBN can accelerate the curing reactions, while the phase-separated CTBN particles and the dilution of curing ingredients caused by CTBN addition can hinder the curing reactions, resulting in an increase in activation energy. Interestingly, the activation energy of pre-crosslinked CTBN/epoxy systems decreases compared to their non-crosslinked counterparts because of the enhanced curing effect of the benzoic acid produced by benzoyl peroxide (BPO). An autocatalytic Kamal's model is successfully used to describe the curing process of epoxy systems studied. [ABSTRACT FROM AUTHOR]

• The grafting degree of carbon fiber was adjusted by adjusting the absorbed dose. • Grafting glycidyl methacrylate process of carbon fiber was optimized under low dose. • A large number of homopolymers appeared on the surface of the grafted carbon fiber. Functionalization of high modulus carbon fiber (HMCF) with high carbon content and strong surface inertness is a huge challenge. In our previous work, glycidyl methacrylate (GMA) was grafted onto the surface of HMCF through acid-activated synergistic ionizing radiation. However, grafting process was not optimized and need to be improved. In this study, the influence of absorbed dose on the grafting of GMA onto HMCF was investigated. The grafting degree of HMCF was able to effectively controlled by adjusting absorbed dose. The grafting degree of HMCF reaches a maximum value of 17.9%. After grafting, a great number of homopolymers appeared on the surface of HMCF. This result effectively reduces the waste of grafting monomers and energy, ultimately achieving better modification results at lower absorbed doses. [ABSTRACT FROM AUTHOR]

Abstract: Although epoxy resins can be substantially toughened by addition of a reactive liquid rubber, the improvement in toughness is inevitably accompanied by a significant loss in elastic modulus and yield strength. This paper presents a novel route for preparing the liquid rubber/epoxy composites with high yield strength, Young׳s modulus and impact strength. By this new method, the epoxy composites with different grades of carboxyl terminated butadiene acrylonitrile copolymer (CTBN) and cured by different curing agents were prepared, and their mechanical properties were characterized. It is found that no matter what grades of CTBN, also regardless of curing agents, the composites prepared by the new method always exhibit much higher impact strength, yield strength and Young׳s modulus than the corresponding traditional composites, proving the new method to be somewhat universal. Especially, some CTBN/epoxy composites exhibit even higher yield strength and Young׳s modulus than that of pure epoxy. [Copyright &y& Elsevier]

Polyvinylidene fluoride‐hexafluoropropylene (PVDF‐HFP) is a standard electrolyte membrane and binder material for lithium‐ion batteries (LIBs) because of the benefits of membrane formation and strong mechanical properties. Still, its use is limited due to unavoidable defects such as high crystallinity and poor electrochemical performance. In this paper, a larger specific surface area and three‐dimensional (3D) permeable lamellae carboxylated g‐C3N4 (HCN) were successfully prepared by HNO3 and introduced into the PVDF‐HFP to obtain a high‐performance composite separator. The wettability and electrolyte absorption of PVDF‐HFP separator can be improved through the carboxylated HCN. More crucially, because PVDF‐HFP has several active sites and low crystallinity, adding HCN can greatly increase the ionic conductivity of separators. The ionic conductivity of PH‐HCN at 25 °C is 0.52 S cm−1, 4.7 times higher than the initial PVDF‐HFP membrane, and the oxidation potential can reach 4.8 V. The assembled lithium‐ion batteries half‐cell has a capacity of 71 % at a 5 C rate and 94 % after 400 cycles at a 2 C rate. Therefore, the improved separator has the potential to be applied to high‐performance LIBs. [ABSTRACT FROM AUTHOR]

Maleic anhydride-modified homopolymerized polypropylene (PP-g-MAH) and maleic anhydride-modified polyolefin elastomer (POE-g-MAH) were used as bulking agents to improve the poor processing and mechanical properties of highly filled composites due to high filler content. In this study, a series of linear low-density polyethylene (LLDPE)/magnesium hydroxide (MH) composites were prepared by the melt blending method, and the effects of the compatibilizer on the mechanical properties, flame retardancy, and rheological behavior of the composites were investigated. The addition of the compatibilizer decreased the limiting oxygen index (LOI) values of the composites, but they were all greater than 30.00%, which belonged to the flame retardant grade. Mechanical property tests showed that the addition of the compatibilizer significantly increased the tensile and impact strengths of the LLDPE/60MH (MH addition of 60 wt%) composites. Specifically, the addition of 5 wt% POE-g-MAH increased 154.07% and 415.47% compared to the LLDPE/60MH composites, respectively. The rotational rheology test showed that the addition of the compatibilizer could effectively improve the processing flow properties of the composites. However, due to the hydrocarbon structure of the compatibilizer, its flame retardant properties were adversely affected. This study provides a strategy that can improve the processing and mechanical properties of highly filled composites. [ABSTRACT FROM AUTHOR]

In this study, an aluminum (Al) foil used for lithium ion battery packaging film was treated with titanium (Ti)/zirconium (Zr) solution containing hexafluorotitanic acid and hexafluorozirconic acid using tannic acid as a colorant and metavanadate as an accelerator, respectively, and a golden conversion coating was successfully deposited on the surface of Al foil. The morphology and composition of the coating were characterized by scanning electron microscopy, energy dispersive spectroscopy, and X‐ray photoelectron spectroscopy, and the hydrophilicity was assessed by contact angle measurement. The effect of Ti/Zr treatment on the adhesion properties of Al foil was evaluated by T‐peeling test and compared with that of traditional chromate‐phosphate treatment. The results show that tannic acid contributes to the formation of the golden coating, and metavanadate accelerates the formation of the conversion coating. The results also indicate that the Ti/Zr‐based conversion coating is mainly composed of Al2O3, Al (OH)3, AlF3, TiO2/ZrO2, NH4VO3, and V2O5. The Ti/Zr treatment cannot only improve the heat‐sealing strength, but also the T‐peeling strength by approximately 12 times compared with that of untreated Al foil. Thus, Ti/Zr treatment has the potential to replace the traditional chromate conversion treatment. [ABSTRACT FROM AUTHOR]

In this study, high-energy electron beam irradiation was used for the first time for graft polymerization of acrylic acid onto the surface of carbon black (CB) to prepare water-dispersible CB. The grafted CB was characterized by Fourier transform infrared spectroscopy, thermo-gravimetric analysis and X-ray photoelectron spectroscopy. The results indicate that polyacrylic acid (PAA) has been successfully grafted onto the surface of CB. The particle size and dispersion stability of unmodified and modified CBs in aqueous solution were determined by dynamic light scattering, transmission electron microscopy and ultraviolet–visible spectrophotometer. The results show that the grafted CB has smaller average aggregate size and better dispersion than unmodified CB. In addition, there is no significant difference in the grafting degree among grafted CBs prepared in nitrogen and air at different irradiation doses, indicating that oxygen and irradiation dose have a negligible effect on the grafting degree of PAA. [ABSTRACT FROM AUTHOR]

Biomaterial-associated infections critically compromise the functionality and performance of the medical devices, and pose a serious threat to human healthcare. Recently, natural DNase enzyme has been recognized as a potent material to prevent bacterial adhesion and biofilm formation. However, the vulnerability of DNase dramatically limits its long-term performance in antibacterial applications. In this work, DNase-mimicking polymer brushes were constructed to mimic the DNA-cleavage activity as well as the macromolecular scaffold of the natural DNase. The bacteria repellent efficacy of DNase-mimicking polymer brush-functionalized surface was comparable to that of the DNase-functionalized surface. More importantly, due to their inherent stability, DNase-mimicking polymer brushes presented the much better performance in inhibiting bacterial biofilm development for prolonged periods of time, as compared to the natural DNase. The as-developed DNase-mimicking polymer brush-functionalized surface presents a promising approach to combat biomaterial-associated infections. [ABSTRACT FROM AUTHOR]

In order to recover lithium from brine with a high Mg2+/Li+ ratio, a positively charged nanofiltration (NF) membrane was prepared by depositing polydopamine (PDA)-coated graphitic carbon nitride (g-C3N4) as the interlayer (PDA-g-C3N4) and the interfacial polymerization (IP) of polyethyleneimine (PEI) and trimesoyl chloride (TMC) was carried out. Under optimal conditions, the water contact angle of the composite membrane is only 55.5° and the isoelectric point (IEP) is 6.01. The final positively charged NF membrane (M5) exhibits high permeance (10.19 L·m−2·h−1·bar−1) and high rejection of Mg2+ (98.20%) but low rejection of Li+ (13.33%). The separation factor (SF) is up to 48.08, and the Mg2+/Li+ ratio of the permeate is 0.036 in the simulated brine. In conclusion, the M5 membrane shows a good separation performance for salt lake brine (SF = 12.79 and Mg2+/Li+ ratio of the permeate = 1.43) and good fouling resistance. Therefore, the positively charged M5 membrane with PDA-g-C3N4 as the interlayer has the potential to be used for the recovery of lithium from brine. [ABSTRACT FROM AUTHOR]

Silane-cross-linked sulfonated poly(imide benzimidazole) (CSiSPIBI) membranes were prepared using γ-(2,3-epoxypropoxy) propyltrimethoxysilane (KH560) as a cross-linker, and the cross-linked structure was characterized using Fourier transform infrared spectroscopy and solubility test. The resulted cross-linked membranes were further doped with phosphoric acid (PA) by means of the acid–base interaction with the alkaline imidazole ring and the electrostatic interaction with siloxane. The results show that PA-doped CSiSPIBI membranes have high proton conductivity due to the formation of a new proton transport pathway between PA and sulfonic acid. Under high temperature and low humidity conditions, the proton conductivity of PA-doped sulfonated membranes is one to two orders of magnitude higher than that of non-PA-doped membranes and PA-doped non-sulfonated membranes. The silane-cross-linked membranes display improved chemical stability and mechanical strength, especially the oxidative stability. The complete dissolution time in Fenton's reagent increases from 510 min for the sulfonated polyimide/polybenzimidazole blend membrane to 1450 min for the silane-cross-linked membrane. [ABSTRACT FROM AUTHOR]

Ionic cross-linked sulfonated polyimides containing bis-benzimidazole rings have been prepared from 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA), 6,6′-bis[2-(4-aminophenyl)benzimidazole] (BAPBI) and 3,3′-bis(4-sulfophenoxy)- benzidine (BSPOB). A new cross-linker, 4,4′-bibromomethenyl diphenyl ether, is used to induce covalent cross-linking between halogen and imidazole groups in SPIBI chains via a facile thermally activated reaction. The resulted covalent and ionic cross-linked membranes show an improved resistance to hydrolytic attack in deionized water at 80 °C (more than two months) and free radical attack in Fenton's solution (more than 690 min) as compared to non-cross-linked SPIBIs (less than two days and 270 min, respectively). Cross-linking also results in a reduction in proton conductivity due to the blockage of a hydrophilic channel. However, all the prepared CBr-ySPIBI-x membranes show a proton conductivity higher than 10 −2 S cm −1 under hydrous condition. This could be attributed to the fact that more cross-linking sites are contained in each repeating unit, which ensures enough cross-linking degree at high sulfonation level. All these results suggest that CBr-ySPIBI-x membranes have a great potential for applications in the proton exchange membrane fuel cells. [ABSTRACT FROM AUTHOR]

The strategic importance of developing environmentally friendly PVC biomass plasticizers with excellent anti-migration and plasticizing effects cannot be overstated. This paper delves into the synthesis and application of bio-based isosorbide di-epoxidized oleate (IDEO) as a secondary biomass plasticizer in polyvinyl chloride (PVC) films. Explored were the synergistic effects between IDEO and dioctyl phthalate (DOP), alongside an assessment of the influence of the compound plasticizer on the properties of PVC products. The partial substitution of DOP resulted in PVC films with improved thermal stability, flexibility, and migration resistance. IDEO-10/PVC, in particular, exhibited a 64% increase in tensile strength compared to DOP/PVC and maintained thermal stabilization for over 280 min at 180 °C. With a glass transition temperature (Tg) of 33 °C, a plasticizing efficiency of 148%, and excellent cold resistance properties, IDEO-10/PVC outperformed DOP/PVC. IDEO-10/PVC migration resistance was significantly lower than in the original PVC resin with only DOP plasticizers under three different polar conditions. Transmittance remained above 87% after 10 days of UV irradiation. Molecular dynamics simulation further confirmed the synergistic plasticizing effect between IDEO and DOP at an IDEO addition of 10 phr. The environmentally friendly approach holds significant promise for the scaled-up application of PVC. [ABSTRACT FROM AUTHOR]

A new symmetrical diamine that contains benzimidazole ring, 6,6'-bis[2-(4-aminophenyl)benzimidazole], was synthesised directly from p-aminobenzoic acid and 3,3'-diaminobenzidine via benzimidazolisation condensation. The diamine monomer was polymerised with various commercial dianhydrides by a conventional two-step polymerisation reaction to obtain the corresponding polyimides. The obtained polyimides were amorphous and could be used to produce flexible, yet tough, transparent films exhibiting excellent thermal stability with glass transition temperatures of 334 °C to 412 °C and 5 % weight loss temperatures above 540 °C in nitrogen. These polymers also demonstrated outstanding mechanical properties with a tensile strength of 177 MPa to 224 MPa and a tensile modulus of 3.5 GPa to 5.7 GPa. The excellent thermal and mechanical properties of these polyimides are most likely attributable to the rigid-rod structure and the presence of hydrogen bond between the macromolecular chains. [ABSTRACT FROM AUTHOR]

ABSTRACT Three novel cardanol-based phenalkamines with good stability have been successfully prepared by Mannich reaction using phenolic compounds with paraformaldehyde and hexamethylenediamine (or its mixture with other amines). The structure of the prepared phenalkamines has been analyzed using liquid chromatography-mass spectrometry, nuclear magnetic resonance, and Fourier transform infrared spectroscopy. The curing kinetics of the prepared epoxy resin/phenalkamine systems has been investigated using differential scanning calorimetry (DSC), and determined by Kissinger, Flynn-Wall-Ozawa, and Crane methods. Furthermore, the thermal properties of the cured materials have been evaluated using DSC and thermogravimetric analysis, and the mechanical properties of the cured materials have been analyzed systematically. The results demonstrate that the phenalkamine 1 (PAA1) had a lower reactivity and better toughness than phenalkamine 2 (PAA2) and phenalkamine 3 (PAA3). In addition, PAA1 is a solid curing agent, while PAA2 and PAA3 are liquid curing agents, which were more convenient for practical usage. Results indicate that the properties of the prepared phenalkamines strongly depend on the structures. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 472-480 [ABSTRACT FROM AUTHOR]

[Display omitted] • Focus on the influence of hydrophobic alkyl chains on the plasticization properties of citrate. • To study the mechanism of plasticization and tensile failure of citrate/PVC composites. • Reveal the microstructure and energy changes of PVC composites during elastic deformation and plastic deformation. In this work, the citrate plasticizers with different alkyl chain lengths, tributyl citrate (TBC), trihexyl citrate (THC), trioctyl citrate (TOC) and tridecyl citrate (TDC) were synthesized by esterification reaction. The effects of hydrophobic alkyl chains on plasticization properties of citrate were studied by using a combination of characterization techniques and molecular dynamics (MD) simulation. Tensile tests showed that the elasticity of citrate/PVC was basically negatively correlated with the length of citrate hydrophobic alkyl chain, while its strength was positively correlated. The citrate plasticizer migration stability test indicated that in deionized water and 50 % (v/v) ethanol solution, the mobility of TBC was the highest and that of TOC was the lowest. The MD simulation results found that the interaction between PVC and citrate mainly included hydrogen bonding (OH-Cl), van der Waal force (COO-Cl), and the mutual winding between the alkyl chain of citrate and the PVC chain. Among them, TBC, THC and TOC can be spontaneously dispersed in PVC resins, but TDC cannot, because its long hydrophobic alkyl chains make TDC more inclined to self-polymerize and form large hydrophobic aggregation zones. However, in the suitable range (number of carbon atoms ≤ 8), longer alkyl chains can be effective in improving the stability of citrate in resins. Thus, for citrates, alkyl chains of 8 carbons perform better. Our research is helpful to understand the effect of molecular structure on the plasticizer of citrate and propose an optimized citrate structure with higher performance. [ABSTRACT FROM AUTHOR]

A novel phosphorylated graphene oxide (PGO)-reinforced polybenzimidazole (PBI) composite membrane was prepared for high-temperature proton exchange membrane fuel cell (HT-PEMFC). PGO was prepared by phosphorylation of graphene oxide (GO) with phosphoric acid (PA), and its structure was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), energy dispersive spectrometry (EDS), and ion exchange capacity (IEC) measurement. Then, PGO was added into PBI to prepare composite membranes, with excellent oxidation and thermal stability, outstanding mechanical properties, strong PA uptake and high proton conductivity. The PBI composite membrane with 1.5 wt.% of PGO exhibits the highest tensile strength (38.4 MPa) and excellent proton conductivity (17.6 mS·cm−1 at 180 ℃ without moisture) after immersion in PA aqueous solution, which is 1.31 and 1.15 times higher than that of pure PBI and PBI/GO composite membranes, respectively. Thus, PGO-reinforced PBI composite membranes have promising applications in HT-PEMFC. [ABSTRACT FROM AUTHOR]

Layered double hydroxides (LDHs) that are generally used as thermal stabilizers of poly(vinyl chloride) (PVC) can also have catalytic effects on the dechlorination of PVC. In this study, benzimidazole derivative (OBPB) modified ZnAl-LDH (OBPB@ZLDH) was synthesized and incorporated into PVC, and the effects of OBPB@ZLDH and the physical blend of OBPB and ZLDH (OBPB/ZLDH) on the dechlorination of PVC were investigated by Congo red test and discoloration test. The results indicated that OBPB/ZLDH could improve the thermal stability of PVC. The composition and chemical structure of PVC composites after discoloration test were studied by energy dispersive X-ray spectroscopy and attenuated total internal reflectance-infrared spectroscopy. The results revealed that the products derived from the reaction between HCl released in the thermal degradation of PVC and OBPB/ZLDH could accelerate the dechlorination and oxidization of PVC at low temperature. Therefore, it has potential applications in the dechlorination of PVC to prepare hydrochars for use as alternative fuels at low temperature. • The bleaching effect is found on PVC/OBPB/ZLDH.composite. • PVC/OBPB/ZLDH shows the lowest Cl/C ratio (0.23) after discoloration test. • OBPB/ZLDH blend has potential applications in the dechlorination of PVC to prepare hydrochars. [ABSTRACT FROM AUTHOR]

In this study, an environmentally friendly cerium (Ce) conversion coating was deposited onto the surface of aluminum (Al) foil for preparing the packaging material of lithium‐ion batteries, and its morphology, composition, and formation mechanisms were investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM), energy‐dispersive spectroscopy (EDS), and X‐ray photoelectron spectroscopy (XPS). The packaging material consisting of six layers was prepared by hot pressing using casting polypropylene (CPP) as the inner layer and maleic anhydride (MAH) grafted polypropylene (mPP) as the inner adhesive. The adhesion properties of untreated and Ce‐treated Al foils were characterized by T‐peeling test. The results show that Ce conversion coating is mainly composed of cerium dioxide (CeO2) and cerium sesquioxide (Ce2O3), and Ce treatment leads to a significant increase in the adhesive strength between Al foil and mPP. [ABSTRACT FROM AUTHOR]

Fly ash (FA) derived from the combustion of coal is considered a potential reinforcing filler for polymers, but its application is somewhat limited by the number of hydroxyl groups on the surface. In this study, FA was modified with sodium hydroxide (NaOH) (denoted as OH‐FA), resulting in an increase in the number of OH groups on the surface of FA and thus improvement of the interfacial adhesion between FA and polyvinyl chloride (PVC). OH‐FA was subjected to ball milling to induce mechanochemical activation aided by a new polyether titanate coupling agent (ETi4) (denoted as M‐ETi4‐OH‐FA). The results show that the functional groups of ETi4 can interact with the OH groups on the surface of FA via electrostatic interactions, chemical interactions, intra‐ and intermolecular hydrogen bonds by ball milling, which can increase the compatibility and interfacial bonding between FA and PVC, and improve the mechanical and thermal characteristics of PVC composites. Significantly, the impact strength and yield strength of M‐ETi4‐OH‐FA/PVC composite reaches 6.2 kJ/m2 and 64.9 MPa, which is increased by 86.8% and 13.6% compared with that of PVC, and by 18.2% and 14.6% compared with that of ETi4‐OH‐FA/PVC, respectively. The thermal stability is also higher than that of other PVC composites, and the rapidest degradation temperature reaches 297°C, which is 16°C higher than that of pure PVC. [ABSTRACT FROM AUTHOR]

In this study, a simple and efficient hydrothermal carbonization method was proposed to synthesize anhydrous magnesium carbonate (MgCO3) particles with block-, cube-, corncob-, and sphere-like morphologies, and their crystal phase, chemical structure, and thermal stability were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA), respectively. The four MgCO3 particles were, respectively, incorporated into polyvinyl chloride (PVC) to prepare the composites, and the mechanical properties of MgCO3/PVC composites were investigated. The results show that four MgCO3 particles can reinforce and toughen PVC, and cube-like MgCO3 (A-MC) shows the best modification effect. [ABSTRACT FROM AUTHOR]

In this paper, a new polyether titanate coupling agent (Ti4000) was used to modify basic magnesium carbonate (BMC), and Ti4000 modified BMC (Ti4000‐BMC) was characterized by X‐ray powder diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and X‐ray photoelectron spectroscopy. Then, PVC composites were prepared by adding BMC or Ti4000‐BMC into soft PVC matrix via melt blending, and their flame retardancy was examined by limiting oxygen index (LOI), UL‐94 test, and cone calorimeter test. The results show that BMC can effectively improve flame resistance and suppress smoke production of pure soft PVC. As a result, the LOI is increased from 23.9% for pure soft PVC to 29.2% for Ti4000‐BMC/PVC composite with 50 phr Ti4000‐BMC (50%Ti4000‐BMC/PVC), and the composite passes the V0 rating in UL‐94 test, the peak heat release rate, total heat release, peak smoke production rate, and total smoke production are decreased from 343.10 kW/m2, 94.50 MJ/m2, 0.17 m2/s, and 27.20 m2/kg for pure soft PVC to 234.20 kW/m2, 70.20 MJ/m2, 0.02 m2/s, and 2.30 m2/kg for 50%Ti4000‐BMC/PVC composite, respectively. The analysis of char residues suggests that Ti4000‐BMC/PVC composites form the most compact char layer structure, indicating that the soft PVC composites show better char forming ability. In addition, the yield strength is increased from 4.4 MPa for pure soft PVC to 12.9 MPa for 50%Ti4000‐BMC/PVC composite, with an increase of 193.2%, and it shows good reinforcement effect on the soft PVC matrix. [ABSTRACT FROM AUTHOR]

• Malachite green adsorption behavior on four types of commercial activated carbons was studied. • The effect of pore and surface chemical properties for malachite green adsorption is confirmed. • Malachite green adsorption performance on activated carbon depends on the total specific surface area. Malachite green (MG) separation from wastewater has always been a research focus in the field of environment. Removal of MG from aqueous solution using activated carbon has been studied or verified. Because of the different preparation materials and processes, the physicochemical properties of activated carbons differ significantly, and it is not clear which parameter affects on MG adsorption and to what extend it is. Four types of commercial activated carbon were selected to study their MG adsorption performances systematically, such as adsorption contact time, equilibrium adsorption capacities, Langmuir and modified Langmuir equations fitting, adsorption thermodynamics and effect of pH. The study of contact time showed that MG adsorption on four activated carbons fits the pseudo-second-order equation in the initial stage. However, the adsorption kinetics is found to follow pseudo-first-order equation with the increase of adsorption capacities. Consistent with the results reported in the literature, the adsorption mechanism of MG on activated carbon is monolayer physisorption. We associated MG adsorption behavior on four activated carbons with the specific surface area from different pore structures and content of surface chemical groups, respectively. The results showed that the strong acidic groups have the detrimental influence on the MG adsorption, while the total specific surface area has a notable effect, showing a positive linear relationship between the total specific surface area and the adsorption capability. Therefore, the total specific surface area could be used as a key parameter to determine the adsorption performance of MG on activated carbon. [ABSTRACT FROM AUTHOR]

[Display omitted] • N 8888 NTf 2 /TBP/NaClO 4 system increases the Li+ extraction efficiency compared with TBP/NaClO 4 system. • N 8888 NTf 2 /TBP/NaClO 4 system decreases the stripping acidity compared with TBP/LiNTf 2 system. • Cation loss of ionic liquid can be avoided in the extraction process in N 8888 NTf 2 /TBP/NaClO 4 system. • The extraction mechanism of N 8888 NTf 2 /TBP/NaClO 4 system is proposed. A new extraction system, tetraoctylammonium bis(trifluoromethylsulfonyl)imide (N 8888 NTf 2)/tri- n -butyl phosphate (TBP)/sodium perchlorate (NaClO 4), is proposed for extracting lithium (Li) from magnesium (Mg)-rich solution. This system can increase the Li+ extraction efficiency compared with TBP/NaClO 4 system and decrease the stripping acidity compared with TBP/bis(trifluoromethylsulfonyl)imide lithium (LiNTf 2) system. Cation loss of ionic liquid can also be avoided in the extraction process. Under optimal conditions, the Li+ extraction efficiency reaches 82.3% and the Li+/Mg2+ separation factor reaches 254. The Li+ stripping efficiency reaches about 100% when 0.5 mol·L−1 HCl is used as stripping agent. The extraction mechanism of N 8888 NTf 2 /TBP/NaClO 4 system is proposed based on experimental results and verified by Fourier transform infrared spectroscopy (FT-IR), slope analysis, and simulation calculation using Gaussian software. N 8888 NTf 2 /TBP/NaClO 4 system is highly stable over seven extraction cycles. This new extraction system has a great potential for selective extracting Li+ from Mg2+ rich brine. [ABSTRACT FROM AUTHOR]

Abstract In this study, carbon microspheres (CMSs) were prepared using l (+)-ascorbic acid by hydrothermal carbonization and then modified with a polyether titanate coupling agent (eTi 4000) and a self-synthesized biopolymer coupling agent (CCS), respectively. These modified CMSs (mCMSs) were added into poly(vinyl chloride) (PVC) to prepare mCMSs/PVC composites. The results suggest that CCS has a better modification effect than eTi 4000 , which imparts CCS-CMSs/PVC composites with good thermal stability and mechanical properties. The impact strength of CCS-CMSs/PVC composite (8.7 kJ m−2) is remarkably increased by 64.2% compared with that of CMSs/PVC composite (5.3 kJ m−2), and its rapidest decomposition temperature (309 °C) is increased by 29 °C and 16 °C in comparison with that of PVC and CMSs/PVC composite, respectively. The interfacial interaction between PVC and mCMSs is evaluated by dielectric loss and DMA. In conclusion, CCS is an effective biopolymer coupling agent that can endow CCS-CMSs/PVC composites with good comprehensive properties. [ABSTRACT FROM AUTHOR]

Highlights • OPBI with panchromatic UV absorption is synthesized. • OPBI can effectively improve the UV resistance of PVC. • OPBI can improve the mechanical properties of PVC. • OPBI can improve the thermal stability of PVC. Abstract The exposure of poly(vinyl chloride) (PVC) materials to ultraviolet (UV) light can result in the destruction of the molecular structure and consequently a reduction of their mechanical properties. In this study, polybenzimidazole (OPBI) with panchromatic UV absorption was prepared by solution polycondensation and then used as a light stabilizer to improve the UV-resistance properties of PVC. PVC/OPBI composite films with different compositions were prepared by solution casting method, and the effects of OPBI content and UV irradiation time on the properties of these films were investigated by Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, thermogravimetric analysis, dynamic mechanical analysis and tensile test. The results show that OPBI has excellent UV absorption properties in the region of 220–420 nm and high thermal stability with a 3.0% weight loss at 550 °C in nitrogen atmosphere. The PVC/OPBI composite films also show excellent mechanical properties with a yield strength of 46.1–53.4 MPa, which can be attributed to the strong interactions among benzene rings, heterocyclic imidazole and chlorine atoms between OPBI and PVC. The special conjugated structure of OPBI allows the PVC/OPBI composite films to have high UV absorption and excellent mechanical properties, thus making it a promising light stabilizer. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Hydrophobic bamboo flour was prepared by melt blending method. • AKD modified WPCs show high water resistance and low swelling ratio. • AKD modified WPCs show better mechanical properties than alkali treated composites. Abstract In this study, bamboo flour (BF) was chemically modified using alkyl ketene dimer (AKD) or alkali treatment for the preparation of high-density polyethylene/bamboo flour (HDPE/BF) composites with or without compatibilizer maleic anhydride grafted high-density polyethylene (HDPE- g -MAH). The modified BF was characterized by Fourier transformation infrared (FTIR) spectroscopy and contact angle measurement, and the mechanical properties, morphology and water resistance of the HDPE/BF composites were investigated and compared. The results show that highly hydrophobic BF can be obtained by a simple procedure using a common paper sizing agent AKD. AKD can react with the hydroxyl groups in cellulose to form β-keto ester. The combination of AKD treatment and addition of HDPE- g -MAH is more effective in improving the mechanical properties of HDPE/BF composites than using them alone. The impact strength, flexural strength and modulus of HDPE/A-BF/MAH composite are increased by 100.0%, 197.1% and 61.8% compared with that of HDPE/U-BF composites, and the water absorption and thickness swelling are decreased by 87.7% and 87.4% after immersion in water for one week, respectively. These results indicate that HDPE/BF composites with good mechanical properties and high water resistance can be obtained by AKD treatment. [ABSTRACT FROM AUTHOR]

In this study, three typical D–π–A type heteroaromatic organic dyes containing carbazole (CBZ), phenothiazine (PTZ), and phenoxazine (POZ) moiety as electron donor cores and linked to g-C 3 N 4 with amide covalent bonds were synthesized. Thereafter, we studied the long-term photochemical stability and degradation mechanism of the associated dye-sensitised g-C 3 N 4 with covalent linkage or weak interaction. The results revealed that most of the dyes degraded and became unstable after absorption on g-C 3 N 4 under light irradiation. Interestingly, after the target dyes were linked to g-C 3 N 4 with amide covalent bonds, the photostability could be effectively promoted and improved to high levels of stability. For POZ-S dye covalent bond-linked sample g-C 3 N 4 /POZ-S, ∼90.5% percent of the dyes were reserved, whereas only ∼25.3% remained for the physically absorbed dye sample g-C 3 N 4 +POZ-S after 30 min of irradiation aging test. Moreover, the obtained g-C 3 N 4 /POZ-S sample exhibited enhanced H 2 evolution activity with photocatalytic H 2 production rates that were approximately 96- fold of that of pure g-C 3 N 4. Then, we applied various instrumental analysis and DFT calculation to clarify the mechanism involved with dye photostability and degradation pathway. The typical decarboxylation process was confirmed, and such an unfavourable reaction process could be effectively inhibited if the target dye is linked to g-C 3 N 4 with amide covalent bond instead of the weak interaction. Overall, the existed covalent bond is the key factor for enhancing both the photochemical stability and photocatalytic activity of organic dye-sensitised g-C 3 N 4 for hydrogen evolution. [Display omitted] • Three typical heteroaromatic organic dyes functionalised g-C 3 N 4 with amide covalent bonds. • The typical decarboxylation process was confirmed, which could be inhibited by proposed strategy. • The covalent bond is the key factor for enhancing durability and activity of dye-sensitised g-C 3 N 4. [ABSTRACT FROM AUTHOR]

In this study, calcium sulfate whisker (CSW) was modified with a newly synthesized polyether titanate coupling agent (eTi 4000 ) and four commercial coupling agents, including two silane coupling agents (KH560 and KH570) and two titanate coupling agents (KR38S and KR138S), respectively, and then the modified calcium whisker (mCSW) was incorporated into poly(vinyl chloride) (PVC) by melt blending to prepare mCSW/PVC composites. The morphologies, mechanical properties and thermal stability of these mCSW/PVC composites were compared. The results reveal that the four commercial coupling agents have slightly better reinforcing effect, while eTi 4000 shows much better toughening effect. Moreover, the mCSW/PVC composite modified by eTi 4000 shows higher storage modulus than those modified by commercial coupling agents in dynamic stress mode. The energy dissipation mechanism of these mCSW/PVC composites during the impact process was analyzed, and their interfacial interactions were evaluated quantitatively by the damping ratio. The mCSW/PVC composite modified by eTi 4000 exhibits better thermal stability than their counterparts modified by the commercial coupling agents. Generally, eTi 4000 is an effective coupling agent for CSW, and it can endow mCSW/PVC composites with better balanced properties. [ABSTRACT FROM AUTHOR]

A three-layer membrane (TLM) of radiation grafting graphene oxide reinforced polybenzimidazole/porous polybenzimidazole/radiation grafting graphene oxide reinforced polybenzimidazole (PBI-RGO/PPBI/PBI-RGO) was fabricated and then doped with phosphoric acid (PA) for high temperature proton exchange membranes (HT-PEMs) in anhydrous atmosphere. These TLMs have a sandwich structure and the diameter of most pores falls in the range between 500 nm and 2 μm. PA doped TLMs display excellent mechanical strength and oxidative stability. The tensile strength of PA doped PBI-RGO/PPBI/PBI-RGO membranes ranges from 22.7 to 38.5 MPa, which is significantly higher than that of PA doped PPBI membrane (7.9 MPa). The introduction of RGO and porous structure can improve the proton conductivity of membranes. The proton conductivity of PA doped PBI-RGO/PPBI-80/PBI-RGO membrane is 113.8 mS·cm −1 at 170 °C without humidity, with an increase of 4.9 times compared with that of PA doped PBI membrane. The sandwich structure endows the membrane with lower PA leakage and higher proton conductivity, thus making it a promising membrane for HT-PEM applications. [ABSTRACT FROM AUTHOR]

In this work, the effects of acetylation modification on the plasticization properties of citrates (triethyl citrate (TEC), acetyl triethyl citrate (ATEC), tributyl citrate (TBC) and acetyl tributyl citrate (ATBC)) were investigated by using a combination of characterization techniques and molecular dynamics (MD) simulation. The tensile test show that the acetylated ATEC and ATBC have better plasticizing efficiency compared to their non-acetylated counterparts, and consequently the tensile strength and elongation at break of ATEC/PVC (ATBC/PVC) are 13.9% (18.7%) and 8.3% (2.2%) higher than those of TEC/PVC (TBC/PVC), respectively. The MD simulation results corroborate these observations and further reveal the reason for these changes. The research mainly includes three aspects: 1. Effect mechanism of acetylation modification on the interaction between citrate and PVC; 2. The changes of microstructure, energy and motion state of PVC composites during tensile process; 3. Tensile failure mechanism of PVC composites under large tensile force. In addition, the effect of acetylation treatment on toxicity of citrate was also studied. Thus, our study contributes to better understanding of the plasticizing mechanisms of citrate and proposes an optimized citrate structure with higher performance. [Display omitted] • Focus on the influence of acetylation modification on the plasticization properties of citrate. • To study the mechanism of plasticization and tensile failure of citrate/PVC composites. • Reveal the microstructure and energy changes of PVC composites during elastic deformation and plastic deformation. [ABSTRACT FROM AUTHOR]

In this study, the grafting polymerization of methyl methacrylate (MMA) monomer and maleic anhydride/diallyl phthalate (MAH/DAP) co-monomer onto the surface of carbon black (CB) were carried out at room temperature and normal pressure by γ-ray irradiation. The surface chemistry of grafted CBs were characterized by infrared spectroscopy (IR), thermo-gravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The results show that there are some remanent polymers on the surface of modified CBs after extract for 48 h, indicating that poly(methyl methacrylate) (PMMA) and poly(MAH-co-DAP) have been successfully grafted onto the surface of CB without using initiator due to the high energy of γ-ray irradiation. Dynamic light scattering (DLS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) reveal that the grafted CBs have smaller average aggregate size and better dispersibility than that of CB in absolute ethanol. In addition, it was found that the amount of oxygen groups and the irradiation doses/dose rates have little effect on the grafting degree of CB. [ABSTRACT FROM AUTHOR]

The curing kinetics of epoxy resin/rubber blends containing different contents of epoxidized carboxyl-terminated butadiene acrylonitrile (ECTBN) with different epoxidation degrees is studied using non-isothermal differential scanning calorimetry (DSC) at different heating rates. Kissinger method is used to calculate the apparent activation energies, and Málek method is used to determine the most suitable kinetic model characterizing the curing process. The results show that the curing reaction is catalyzed by the hydroxyl and carboxyl groups in ECTBNs, whereas hindered by the viscosity increment owing to addition of rubber. Within the chemical reaction control stage, the curing process could be well described by the two-parameter autocatalytic kinetic model of Šesták–Berggren, and the simulated curves calculated by Šesták–Berggren model show a good agreement with that experimentally determined. [ABSTRACT FROM AUTHOR]

A binary blend of polypropylene (PP)/recycled polyethylene terephthalate (rPET) and ternary blends of PP/rPET (80/20 w/w) compatibilized with different amounts (5 and 15 mass%, respectively) of a new compatibilizer, PP grafted with maleic anhydride in presence of diallyl phthalate (PP-g-MAH/DAP), are prepared using a twin-screw extruder. The non-isothermal crystallization kinetics and the crystallization morphologies are investigated by differential scanning calorimetry and polarized optical microscopy (POM), respectively. The crystallization temperature and rate of the binary blend increase during the non-isothermal crystallization process, indicating that rPET phase has nucleation ability for crystallization of the PP matrix. However, the crystallization temperatures and rates of the ternary blends slightly decrease because of the chemical reaction between MAH and the rPET terminal groups. Applying the equations proposed by Jeziorny, Ozawa, and Mo to analyze the non-isothermal crystallization kinetics of pure PP and PP in the binary and ternary PP/rPET blends, agreement is found between the experimental results and Mo method. The crystallization activation energy increases in the binary PP/rPET blend, which is ascribed to the confinement effect on the motion of the PP chains by large rPET particles, and this confinement effect is mitigated with the inclusion of PP-g-MAH/DAP. POM observation confirms the heterogeneous nucleation of rPET on PP and the restriction of crystallization of PP by the incorporation of PP-g-MAH/DAP. [ABSTRACT FROM AUTHOR]

Interests on lithium extraction from the Chinese salt-lake brines have regained momentum due to the growing demand of lithium for application in electric vehicles. Characterized by a high Mg2+/Li+ ratio (MLR), the Chinese salt-lake brine has troubled scientists and engineers for decades. Recent progress has shown significant advantages of membrane technologies. This review summarizes the membrane technologies utilized for lithium extraction, including membrane extraction (ME), nanofiltration (NF), lithium ion-sieve (LIS), electrodialysis (ED), and forward osmosis (FO). The fundamental concepts and separation mechanisms of ME and chemical exchange are introduced. Positive NF membranes, ion-selective ED membranes are discussed in detail in terms of materials design for high permselectivity. Maintaining the high selectivity and adsorption capacity are discussed for LIS membranes. Solutions to design single ion-selective separation membranes by hybrid of mobility and affinity are discussed for the urgent lithium extraction problem. Carbon neutral FO is proposed for the concentration of lithium-enriched brines with a focal on a low structure parameter substrate and a high rejection for highly saline brine. The fundamental and engineering strategies for lithium extraction from high MLR brine will be of strong interest for the harvesting of valuable metal resources from complicated brine. [Display omitted] • Membrane technologies for lithium extraction from high Mg2+/Li+ salt-lake brine are reviewed. • Extraction lithium from salt-lake brine is an integrated process of separation and enrichment. • Equilibrium separation based on affinity is proposed as the highly efficient technology for ion separation and enrichment. • Carbon neutral forward osmosis is proposed for the concentration of lithium-enriched brine. • Hybrid membrane processes are required to transform lithium from brine to lithium chemicals. [ABSTRACT FROM AUTHOR]

Abstract: Four low bandgap polymers, combining an alkyl thiophene donor with benzo[c][1,2,5]thiadiazole, 2,3-diphenylquinoxaline, 2,3-diphenylthieno[3,4-b]pyrazine and 6,7-diphenyl-[1,2,5]thiadiazolo[3,4-g]quinoxaline acceptors in a donor–acceptor–donor architecture, were synthesized via FeCl3 oxidative polymerization. The molecular weights of the polymers were improved by introducing o-dichlorobenzene (ODCB) as the reaction solvent instead of the commonly used solvent, chloroform. The photophysical, electrochemical and photovoltaic properties of the resulting polymers were investigated and compared. The optical bandgaps of the polymers vary between 1.0 and 1.9eV, which is promising for solar cells. The devices spin-coated from an ODCB solution of P1DB:[70]PCBM showed a power conversion efficiency of 1.08% with an open-circuit voltage of 0.91V and a short-circuit current density of 3.36mAcm−2 under irradiation from an AM1.5G solar simulator (100mWcm−2). [Copyright &y& Elsevier]

• Physicochemical properties of expanded graphite can be well controlled. • Adsorption performance of expanded graphite for malachite green was studied systematically. • Mechanism of malachite green adsorption on expanded graphite is single-layer physical adsorption. • Expanded graphite has a high Regeneration efficiency by distilled water washing. Expanded graphite (EG) has the advantages of simple preparation and environmental friendliness etc, making it a potential adsorbent for dye wastewater purification. This study investigates a series of EGs prepared from natural flake graphite (NFG) to adsorb malachite green from simulated wastewater. The equilibrium adsorption data were analyzed by the theroy equations and thermodynamic study. The results showed that all EGs adsorption data could be well fitted by the Langmuir equation. The adsorption behavior of malachite green on EG is a spontaneous physical process, which follows the π-π stacking mechanism. The specific surface area can be used to identify the adsorption capacity of EGs. Regeneration experiments showed that the EG still remains high removal efficiency after five cycles, which process does not need any chemical reagent washing. [ABSTRACT FROM AUTHOR]

Abstract: Preparation of carbon nanosheet via ultrasound irradiation of carbon black under ambient conditions was reported for the first time. The structure of resulting carbon nanosheet was characterized by TEM, HRTEM, EDX and AFM. The experimental results showed that the carbon nanosheet is composed of ordered graphite carbon layers with a thickness of several nanometers. [Copyright &y& Elsevier]

In this study, nano-TiO2 sulfonated with 1,3-propane sultone (STiO2) was incorporated into the chitosan (CS) matrix for the preparation of CS/STiO2 nanocomposite membranes for fuel cell applications. The grafting of sulfonic acid (–SO3H) groups was confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis and energy-dispersive X-ray spectroscopy. The physicochemical properties of these prepared membranes, such as water uptake, swelling ratio, thermal and mechanical stability, ion exchange capacity and proton conductivity, were determined. The proton conducting groups on the surface of nano-TiO2 can form continuous proton conducting pathways along the CS/STiO2 interface and thus improve the proton conductivity of CS/STiO2 nanocomposite membranes. The CS/STiO2 nanocomposite membrane with 5 wt% of sulfonated TiO2 showed a proton conductivity (0.035 S·cm−1) equal to that of commercial Nafion 117 membrane (0.033 S·cm−1). The thermal and mechanical stability of the nanocomposite membranes were improved because the interfacial interaction between the -SO3H group of TiO2 and the –NH2 group of CS can restrict the mobility of CS chains to enhance the thermal and mechanical stability of the nanocomposite membranes. These CS/STiO2 nanocomposite membranes have promising applications in proton exchange membrane fuel cells. [ABSTRACT FROM AUTHOR]

• A zwitterion-carbon nitride functionlized nanofiltration membrane was fabricated. • The membrane was positively charged at pH < 7.33. • The mass ratio of Mg/Li decreased from 73.0 to 1.85 after nanofiltration process. A nanofiltration (NF) membrane with positive charges capable of separating Mg2+ and Li+ from high Mg/Li ratio brine was prepared by interfacial polymerization of 1, 4-bis (3-aminopropyl) piperazine (BAPP)/trimesoyl chloride monomers, and then nano graphitic carbon nitride (g-C 3 N 4) functionalized with zwitterion (BHC-CN) was introduced into the active layer of the fabricated membrane. Salt permeation and selectivity were improved with the increase of BHC-CN content to 0.02% in BAPP solution. The morphology and surface chemical composition of BHC-CN were detected. The surface Zeta potential test indicates that the membrane fabricated with BHC-CN is positively charged at pH < 7.33. The presence of small aggregates on the surface of the membrane may increase the effective filtering area of the membrane and thus improve the permeability. It also exhibits long-time stability and excellent separation of Mg2+ and Li+, and the Mg/Li ratio is decreased from 73 in the feed to 1.85 in the permeation. Moreover, the resulted membrane shows good fouling resistance. In conclusion, the membrane has potential advantages in water softening and recovering Li+ from brine with high Mg/Li ratio. [ABSTRACT FROM AUTHOR]

In this study, hyperbranched polybenzimidazole (HBPBI) was synthesized and coated on polyethylene membrane surface with terephthaldehyde (TPA) cross-linker to obtain high-performance CHBPBIE separator for application in lithium ion battery (LIB). The introduction of benzimidazole, amino and carboxyl groups to TPA cross-linked HBPBI (CHBPBI) could improve the wettability, electrolyte uptake, heat resistance and thermal stability of CHBPBIE separator. The absorption of the liquid electrolyte is increased from 90% for the control separator to 181% for CHBPBIE separator. More importantly, the cross-linked coating structure can greatly improve the ionic conductivity of CHBPBIE separator, and it is 0.77 mS cm−1 at 25 °C, which is increased by 10.6 times compared with that of the control PE separator. The LIB half cells assembled with CHBPBI modified separator shows 73% increase in power capability at 7 C rate and a discharge capacity retention rate of 91.1% after 400 cycles at 2 C rate. Thus, the modified separator has the potential for use in high-performance LIB. Image 1 • Some modified functional and novel separators were presented. • The novel layer could further enhance wettability and thermal stability. • The cross-linked coating structure facilitates fast the ion transport. • Coin cells using the modified separator exhibited remarkable performance. [ABSTRACT FROM AUTHOR]

• The fast and slow pyrolysis of walnut shell at 400–800 °C was studied. • The formation mechanism of bio-char in fast pyrolysis is almost the same as that in slow pyrolysis. • The quinone group content could be used as a signal to exhibit the stabilization of oxygen in bio-char. • The bio-char in the fast pyrolysis is easier for microcrystalline. Fast and slow pyrolysis are good means of biomass transformation. Studying the formation of bio-char is not only helpful to intensify the transformation of biomass, but also to improve its performance. However, little work has been reported on the similarities and differences of bio-chars in fast and slow pyrolysis. We investigated the fast and slow pyrolysis of walnut shell at 400–800 °C to find the evolvement law of bio-char. It was found that the formation mechanism of bio-char in fast pyrolysis is almost the same as that in slow pyrolysis. There are two stages in the formation of bio-char: the generation of free radicals caused by the covalent bond breaking at temperature less than 600 °C; the reduce of free radicals through the condensation reactions from 600 to 800 °C. The contents of various oxygen-containing functional groups presented regularity with the increase of pyrolysis temperature, in which the quinone group increases with the pyrolysis temperature increasing, which phenomenon could be used as a signal to exhibit the stabilization of oxygen in bio-char. The bio-char yields, free radicals and quinone contents are slightly higher in slow pyrolysis. The graphite crystals in bio-char have the tendency of microcrystallization with the increase of temperature, in which progress the fast pyrolysis has superiority at the low temperature. [ABSTRACT FROM AUTHOR]

The combination of synergistic agent with intumescent flame retardant (IFR) systems provides a promising way to prepare high performance IFR composites. In this study, the effects of the synthetic zeolite 4 A in combination with the IFR system consisting of ammonium polyphosphate (APP) and tris (2-hydroxyethyl) isocynurate (THEIC) on thermal degradation, mechanical properties, flame retardancy and char formation of high-density polyethylene composites were investigated by limiting oxygen index (LOI) measurement, cone calorimetry, scanning electron microscopy and laser Raman spectroscopy. The LOI value of HD/FR/Z-0.5 composite with an optimum content of 0.5 wt. % zeolite 4 A and 25 wt. % of total flame retardant reaches 26.3 %. A low loading of zeolite 4 A can improve the bench-scale combustion performance as determined by cone calorimetry, and promote the formation of more compact char residue with a highly graphitic structure. However, a low loading of zeolite in combination with the IFR system consisting of APP and THEIC produces no significant changes in mechanical performance. • Zeolite 4 A combined with IFR system was used to prepare flame-retardant HDPE composites. • A low loading of zeolite 4 A can improve LOI and flame-retardant performance. • Zeolite can decrease total smoke production and carbon dioxide evolution of polymer. • Zeolite promotes the formation of compact char layer with high graphitic degree. • A low loading of zeolite produces no significant effects on mechanical performance. [ABSTRACT FROM AUTHOR]