Graft Polymerization Of Acrylic Acid Research Articles

A new method for synthesis of modified cellulose‐graft‐poly(acrylic acid) copolymer using 4‐cyano‐4‐[(phenylcarbothioyl)solfanyl]pentanoic acid to serve as RAFT agent

AbstractIn this study, cellulose was first treated with 4‐cyano‐4‐((phenyl carbonothioyl)solfanyl) pentanoic acid to serve as the reversible addition‐fragmentation chain transfer polymerization (RAFT) agent, then the controlled grafting polymerization of acrylic acid was successfully performed. A well‐defined, cellulose‐graft‐acrylic acid copolymer (Cell‐g‐PAA), has been prepared by RAFT polymerization technique using three different approaches: RAFT agent was prepared by substitution of dithiobenzoate magnesium bromide with 4,4'‐azobis(4‐cyanopentanoic acid) in ethyl acetate as a solvent, mediated cellulose (Cell) block as the macromolecular Cell‐RAFT agent and (cellulose‐co‐acrylic acid) copolymer with alternating sequence. The resulting (Cell‐RAFT) for “living” free radical polymerization was then heated in the adjacent acrylic acid monomer for the development of the controlled graft copolymer onto cellulose. The structures of the intermediate, graft copolymer were investigated by FT‐IR, DSC, 1H NMR, scanning electron microscopy, and thermo gravimetric. The results demonstrate that the preparation of graft copolymers was successfully confirmed. This approach would provide an extensive classification of molecular designs to obtain modern types of tailored hybrid materials derived from natural polysaccharides and synthetic polymers. Also, using a macro‐initiator is an excellent method for synthesizing new materials.

Free radical graft polymerization of hydroxyethyl methacrylate and acrylic acid on polyetherimide membrane surface via redox system to improve anti-fouling and oil resistance performance

In this paper, a new scheme of graft polymerization of acrylic acid (AA) and hydroxyethyl methacrylate (HEMA) initiated by the generation of free radicals in a redox system was used to modify the surface of polyetherimide (PEI) membranes and to improve the antifouling and oil resistance properties. Various physicochemical characterization techniques (ATR-FTIR, XPS, TG, SEM, AFM, etc.) confirmed the successful grafting of hydrophilic monomers onto the PEI membrane surface. Further, the effects of different monomer concentrations on graft density, permeation separation, contamination resistance, and mechanical properties were investigated. Both PEI-g-PAA and PEI-g-PHEMA showed better hydrophilicity (WCA decreased from 60° in PEI to 33° and 45°, respectively), efficient separation (75–84%) in oil-containing wastewater filtration tests with methyl tert-butyl ether (MTBE) and petroleum ether with a slight decrease in mechanical strength. In addition, bovine serum albumin (BSA) and MTBE were selected as contaminants to examine the antifouling properties. Compared to the flux recovery rate (FRR) of 75% for the original PEI membranes, the grafted membranes almost wholly recovered the permeate flux with a simple backwash of ultrapure water. In summary, the results of the above study suggest the development of a novel and simple preparation strategy for surface grafting modification of PEI membranes, which will facilitate the subsequent research of PEI materials in membrane development, and the resulting grafted membranes will be of developmental and exploratory value in the field of oil and water treatment.

Femtosecond laser texturing assisted cold plasma hydrophilization of polytetrafluoroethylene surface

Polytetrafluoroethylene (PTFE) is one of the most widely used engineering polymers, but PTFE-based bonding pairs are prone to failure due to its natural hydrophobicity induced weak interfacial bonding strength. Herein, we propose to improve the hydrophilicity of PTFE surface by femtosecond laser texturing assisted cold plasma modification. Specifically, PTFE surface is firstly textured by femtosecond laser ablation, and then modified by either direct cold plasma treatment or cold plasma induced graft polymerization of acrylic acid. The synergetic treatment roughens the PTFE surface on both micro and nano scales and introduces a large amount of oxygen-containing groups, making the treated surface hydrophilic (water contact angle < 30°). The hierarchically rough and hydrophilic PTFE surface favors its bonding with Cu by forming a mechanically interlocked and robust adhesive interface, and the maximum shearing strength and peeling strength of the bonding pairs were measured to be 2.75 MPa and 6.37 N/mm, respectively. The laser texturing assisted plasma modification enables durable surface hydrophilization and adhesive property improvement for PTFE compared with other previously reported methods, and thereby offers new insights into the fabrication of high-performance PTFE-based bonding components, as well as other functional units that require high-efficiency surface hydrophilization and robust bonding.

Fabrication of 3D-printed PLA filter with immobilized Prussian blue for aqueous cesium removal

This study explores a method to immobilize Prussian blue (PB) on a 3D-printed filter made of polylactic acid (PLA) to selectively remove cesium (Cs) ions from water. A pristine 3D-printed filter made of PLAwas prepared by the fused deposition modeling (FDM) based 3D printer. The surface of the pristine PLA filter was activated through a hydrolysis reaction (in sodium hydroxide solution; PLA-OH) and grafting polymerization of acrylic acid (PLA-OH/AA) to introduce hydrophilic functional groups on the PLA filter surface. This surface modification process, believed to be beneficial for forming stable PB particles, was analyzed using various characterization methods, such as Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. Furthermore, PB was immobilized in the presence of the surface-modified filter (PLA-OH54/AA), and its Cs adsorption behavior was investigated. The maximum adsorption capacity (qm) obtained using the Langmuir isotherm model was 3.67mg/g, and the adsorption kinetic was well interpreted by the pseudo-second-order model. Moreover, the column test results indicated the effective continuous Cs removal by the prepared PB-immobilized 3D filter (PLA-OH54/AA-PB). The potential of the prepared PLA-OH54/AA-PB filter as a 3D filter-type adsorbent for decontaminating radioactive Cs was demonstrated herein.

Modified corn stalk carboxymethyl cellulose, acrylic acid and SBA‐15 based composite hydrogel used for agricultural water retention

AbstractSBA‐15 is successfully incorporated into a composite superabsorbent hydrogel polymer (SAHP) by in situ graft polymerization of acrylic acid (AA) on a carboxymethyl cellulose (CMC) backbone using SBA‐15 as a filler. The structure and properties of the SAHPs are studied in detail by means of a variety of characterization methods, including Fourier transform infrared spectroscopy, X‐ray diffraction, and field emission scanning electron microscopy. And the effects of the originating mate‐rials (such as SBA‐15, initiator, cross‐linker, ratio of CMC to AA, and neutralization of AA) and pH on the water absorption properties are discussed. The obtained results show that the introduction of SBA‐15 have significant effect on the intrinsic structure of the superabsorbent. Importantly, the composite SAHP exhibit higher thermal stability and significant swelling as well as water retention capacity. The prepared SAHP show good sensitivity to various surfactant solutions, which not only have water retention applications in agriculture but also show potential applications in the field of biomaterials.

Electron beam irradiation modified carboxymethyl chitin microsphere-based hemostatic materials with strong blood cell adsorption for hemorrhage control.

Timely control of coagulopathy bleeding can effectively reduce the probability of wound infection and mortality. However, it is still a challenge for microsphere hemostatic agents to achieve timely control of coagulopathy bleeding. In this work, the CCM-g-AA@DA hemostatic agent based on carboxymethyl chitin microspheres, CCM, was synthesized using electron beam irradiation-induced grafting polymerization of acrylic acid and coupling with dopamine. Irradiation grafting endowed the microspheres with excellent adsorption performance and a rough surface. The microspheres showed a strong affinity to blood cells, especially red blood cells. The maximum adsorption of red blood cells is up to approximately 100 times that of the original microspheres, the CCM. The introduction of dopamine increased the tissue adhesion of the microspheres. At the same time, the microspheres still possessed good blood compatibility and biodegradability. Furthermore, the CCM-g-AA@DA with Fe3+ achieved powerful procoagulant effects in the rat anticoagulant bleeding model. The bleeding time and blood loss were both reduced by about 90% compared with the blank group, which was superior to that of the commercially available collagen hemostatic agent Avitene™. In summary, the CCM-g-AA@DA hemostatic agent shows promising potential for bleeding control in individuals with coagulation disorders.

Poly(acrylic acid-co-2-acrylamido-2-methyl-1-propanesulfonic acid)-grafted chitosan hydrogels for effective adsorption and photocatalytic degradation of dyes.

As a result of the growth of industrialization and urbanization, the water ecosystem is contaminated by various pollutants, including heavy metal ions and dyes. The use of low-cost and environmentally friendly dye adsorbents has been investigated. A hydrogel was fabricated via graft polymerization of acrylic acid (AA) and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) onto chitosan. The hydrogel was used as a dye adsorbent and support for a zinc oxide (ZnO) powder photocatalyst. The adsorption capacity of the bare hydrogel was greater towards cationic dyes than anionic dyes. Grafting P(AA-co-AMPS) exhibited a 23-time increase in adsorption capacity towards crystal violet (CV) compared to pristine chitosan. The effect of the AA-AMPS molar ratio on CV adsorption was studied. A hydrogel with an AA-AMPS ratio of 10 : 1 had the highest adsorption capacity towards CV in water, removing 91% of the dye in 12 h. The maximum adsorption capacity was 2023 mg g-1. The adsorption kinetics and isotherm were described by the pseudo-second-order model and the Langmuir model, respectively. ZnO particles were in situ synthesized within the 10 : 1 hydrogel to facilitate the recovery of the photocatalyst. The ZnO hydrogel composite could remove 95% and 92% of CV from solutions on the 1st and 2nd cycle, respectively. In addition, the hydrogel composite containing only 8.7 wt% of ZnO particles effectively degraded adsorbed CV under sunlight and could be reused without requiring a chemical regeneration or photocatalyst recovery procedure. This hydrogel composite is an effective dual-functional material for the adsorption and photodegradation of dye pollutants in wastewater.

An eco-friendly strategy using a double-current two-phase cell system for electrografting of polyacrylic acid

• Electrochemical synthesis of polyacrylic acid. • Proposed mechanism for the electrochemical synthesis of PAA. • Optimization of conditions for electropolymerization of acrylic acid. • Design of a double-current two-phase cell system. In this study, we succeeded in synthesizing polyacrylic acid in a double-current two-phase cell system containing water and ethyl acetate on a Cu electrode. The more detailed steps for grafting polymerization of acrylic acid on the copper electrode are as follows: (1) Electrochemical reduction of p -dinitrobenzene ( DNB ) to 4-nitroaniline ( 4NA ) in ethyl acetate by applying a potential of -0.1 V vs. Ag/AgCl. (2) Conversion of 4NA to corresponding diazonium cation through its reaction with NaNO 2 in the aqueous phase. (3) Electrochemical generation of Cu + from Cu electrode in the aqueous phase. (4) Reduction of diazonium cation by Cu + and formation of aryl radical and (5) polymerization of acrylic acid on copper electrode initiated by aryl radicals. The structural properties and characteristics of the deposited polyacrylic acid layer is fully characterized using different spectroscopic techniques, electrochemical and surface analysis studies. The present method is efficient (82.2% AE) and the experimental results confirm our strategy in creating an attractive architecture of a non-porous insulating film on the electrode surface.

IR-initiated preparation method of high performance nanofiltration membranes using graft polymerization of acrylic acid onto polyacrylonitrile surface

IR-initiated preparation method of high performance nanofiltration membranes using graft polymerization of acrylic acid onto polyacrylonitrile surface

Hydrophilized Ultrafiltration Membranes Synthesized from Acrylic Acid Grafted Polyethersulfone for Downstream Processing of Therapeutic Insulin and Cobalamin

The present study focuses on synthesis of novel high-performance acrylic acid (AA) grafted polyethersulfone (PES) ultrafiltration (UF) membranes for purification of small therapeutic biomolecules such as urea, insulin, and cobalamin. The membranes were indigenously synthesized by adding polyethylene glycol (PEG) of 6 kDa M.Wt. as a pore former and subsequent grafting of AA using 2 to 6 wt.% concentrations under UV-induced photo grafting. Scanning electron microscopy reveals that the PEG additive profoundly influences the pore density on the membrane surface. FTIR spectra confirm the graft polymerization of AA with the PES substrate. Separation performance of the grafted membranes was evaluated to establish the trade-off between the degree of grafting and MWCO. From the experimental results, the pure water flux (PWF) of 6% grafted PES membrane was enhanced from 8.5 (PES [0] [6]) to 18.20 l m−2 h−1 (PES [6 +] [6]) in the presence of PEG pore former, respectively. The grafting concentration window of 2–6% resulted in selective membranes to altogether remove uremic toxins into the permeate with retention of high molecular size proteins. Hence, 5 and 6 wt.% AA grafted membranes exhibited > 90% rejection for insulin and cobalamin biomolecules along with 24.5 and 23.8 l m−2 h−1 bar−1 permeability towards urea, respectively. The process results correlate well with the MWCO values of membranes ranging from 1 to 10 kDa. This work provides the efficacy of these grafted membranes for potential application in the downstream processing of therapeutic biomolecules such as insulin and cobalamin.

Polymerization of acrylic acid on chitosan by gamma radiation and its application for the removal of metal ions from aqueous solutions

Synthesis of green adsorbent materials for the removal of pollutants is a research priority for sustainable environment. A green hydrogel adsorbent based on graft polymerization of acrylic acid on chitosan was performed using different doses of gamma radiation (5, 10, 15, 20, 30 kGy). The formed hydro-gels were characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Gelation percent, swelling in different pH solutions, scanning electron microscopy (SEM). The results indicated the complex formation between chitosan and Polyacrylic acid. The hydrogel exhibit a higher gelation percent with increasing irradiation dose, and a much higher selling ability at alkaline medium. The thermal stability of the hydrogel was found to slightly decrease at 30 kGy. The hydrogel prepared at 20 kGy exhibited the highest thermal stability. The hydro-gels were applied for the removal of Cu2+, Co2+ ions from simulated water solutions, and showed potential results. The electron spin resonance (ESR) measurements to absorbed Cu2+ indicated that the polymer active groups were regarded as strong field ligand on Cu2+.

Enhanced adhesion and electrochemical performance of Si anodes with gum arabic grafted poly(acrylic acid) as a water‐soluble binder

AbstractGum arabic grafted poly(acrylic acid) (GA‐g‐PAA) is synthesized as a mechanically robust water‐soluble binder for silicon (Si) anodes in lithium‐ion batteries by graft polymerization of acrylic acid onto GA backbone via a free radical reaction. 1H NMR and Fourier transform infrared spectroscopies and thermogravimetric analysis are systematically conducted to confirm the grafting polymerization process. GA‐g‐PAA with different grafting length of PAA shows enhanced adhesion strength and excellent flexibility after grafting. Optimal Si‐GA‐g‐8PAA electrode displays better cyclic stability, higher Coulombic efficiency and superior rate properties compared with a Si electrode with linear PAA binder. The Si‐GA‐g‐8PAA electrode exhibits a high electrical conductivity, low interfacial/charge transfer resistance and high lithium‐ion diffusion coefficient. GA‐g‐8PAA binder with grafted structure not only can maintain the mechanical and electrical integrity of the electrode, facilitating favorable electrochemical kinetics, but also assists in preserving a stable solid electrolyte interphase on Si surface upon long‐term cycling. Such a facile strategy for designing a novel grafted binder shows potential for practical application on high‐capacity anode materials with large volume change. © 2021 Society of Industrial Chemistry.

Effective strategy for UV-mediated grafting of biocidal Ag-MOFs on polymeric membranes aimed at enhanced water ultrafiltration

Ultrafiltration membranes with antifouling and antibacterial properties are greatly beneficial for all industrial applications and to supply safe water worldwide. Improving these properties while maintaining both high productivity and high water quality remains a challenge. This work proposes the surface functionalization of an ultrafiltration membrane obtained via UV-initiated grafting polymerization of acrylic acid (AA) and silver-containing metal–organic frameworks (Ag-MOFs), with the goal to achieve combined bactericidal and hydrophilic properties. The effectiveness of different modification pathways is evaluated, including Ag-MOFs blending into the AA solution followed by grafting, as well as in-situ synthesis of Ag-MOFs over the surface of AA-grafted membranes, with in-depth characterization of the resulting materials. The steady-state water fluxes with a feed water laden with organics are improved from two to three-fold for the functionalized membranes compared to the commercial one, while the rejection of macromolecules is maintained at greater than 99%. Significantly, fouling is partly reversible with all enhanced surfaces: the flux recovery ratio following cleaning varies between 3.8% and 20% compared to near zero for the pristine membrane. Noteworthy bacterial inactivation reaches up to 90% for E. coli and 95% for S. aureus, respectively, for surface-grafted membranes. Silver leaching and surface characterization analyses indicate a strong immobilization of Ag-MOFs on membranes and imply long-lasting antimicrobial as well as antifouling activities.

Simultaneous Grafting Polymerization of Acrylic Acid and Silver Aggregates Formation by Direct Reduction Using γ Radiation onto Silicone Surface and Their Antimicrobial Activity and Biocompatibility.

The modification of medical devices is an area that has attracted a lot of attention in recent years; particularly, those developments which search to modify existing devices to render them antimicrobial. Most of these modifications involve at least two stages (modification of the base material with a polymer graft and immobilization of an antimicrobial agent) which are both time-consuming and complicate synthetic procedures; therefore, as an improvement, this project sought to produce antimicrobial silicone (PDMS) in a single step. Using gamma radiation as both an energy source for polymerization initiation and as a source of reducing agents in solution, PDMS was simultaneously grafted with acrylic acid and ethylene glycol dimethacrylate (AAc:EGDMA) while producing antimicrobial silver nanoparticles (AgNPs) onto the surface of the material. To obtain reproducible materials, experimental variables such as the effect of the dose, the intensity of radiation, and the concentration of the silver salt were evaluated, finding the optimal reaction conditions to obtain materials with valuable properties. The characterization of the material was performed using electronic microscopy and spectroscopic techniques such as 13C-CPMAS-SS-NMR and FTIR. Finally, these materials demonstrated good antimicrobial activity against S. aureus while retaining good cell viabilities (above 90%) for fibroblasts BALB/3T3.

Starch-Based Super Water Absorbent: A Promising and Sustainable Way to Increase Survival Rate of Trees Planted in Arid Areas.

This research aimed to scale up the production of starch-based super water absorbent (SWA) and to validate the practical benefits of SWA for agricultural applications. SWA was successfully prepared in an up-scaling production by radiation-induced graft polymerization of acrylic acid onto cassava starch. Chemical characterization by FTIR and thermal characterization by TGA showed results that differentiated starting materials from the prepared SWA, thus confirming effective preparation of starch-based SWA via radiation-induced graft polymerization. SEM results visibly revealed a highly porous morphology of the synthesized SWA, substantiating its high swelling ability. Results from the field tests, performed for two seasons, revealed that the prepared SWA was able to increase the survival rate of young rubber trees planted in arid area by up to 40%, while simultaneously enhancing the growth characteristics of the young rubber trees.

Plasma-Initiated Graft Polymerization of Acrylic Acid onto Fluorine-Doped Tin Oxide as a Platform for Immobilization of Water-Oxidation Catalysts.

The discovery of new and versatile strategies for the immobilization of molecular water-oxidation catalysts (WOCs) is crucial for developing clean energy conversion devices [e.g., (photo)electrocatalytic cells for water splitting]. The traditional approach for surface attachment to transparent conductive oxides [e.g., fluorine doped tin oxide (FTO)] is via synthetic modification of the ligand architecture to incorporate functional groups such as carboxylic acids (-COOH) or phosphonates (-PO3H2) prior to immobilization. However, challenges arising from desorption and the cumbersome derivatizations steps have limited the scope and applications of surface-bound WOCs. Herein, we report the successful immobilization of underivatized Ru(II)-based WOCs (Ru-Cat1 = [Ru(tpy) (bpy) (H2O)]2+ (tpy = 2,2':6'2″-terpyridine and bpy = 2,2'-bipyridine) and Ru-Cat2 = [Ru(Mebimpy) (bpy) (H2O)]2+ (Mebimpy = 2,6-bis(1-methylbenzimidazol-2-yl) pyridine)) and the Ru(II) polypyridyl chromophore Ru-C3 = [Ru(bpy)3]2+ onto a FTO plasma-grafted poly(acrylic acid) surface (PAA|FTO). Various characterization techniques such as attenuated total reflectance Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy, and cyclic voltammetry measurements provide evidence for the plasma-induced grafted PAA|FTO film and immobilization. Surface stability and electrocatalytic properties of these new hybrid composite films upon cycling were investigated at different pH values. Immobilized Ru-Cat1 and Ru-Cat2 onto PAA|FTO displayed pH-dependent (RuIII/RuII) couples and onset potentials indicative of PCET (proton-coupled electron transfer) reactions. Based on cyclic voltammetry results and spectroscopic monitoring, the immobilized WOCs Ru-Cat1 and Ru-Cat2 exhibited a higher surface stability in neutral aqueous solutions relative to Ru-C3 upon electrochemical oxidation. We attribute the surface PCET and stability to the presence of a water ligand in the coordination sphere of immobilized Ru-Cat1 and Ru-Cat2 which can H-bond with negatively charged carboxylate groups of the cross-linked PAA brushes. Our findings demonstrate that the plasma-grafted polymeric network onto FTO offers a versatile platform to directly anchor unmodified homogeneous WOCs or chromophores for potential applications in solar-to-fuel energy conversion.

Crosslinkable aqueous binders containing Arabic gum-grafted-poly (acrylic acid) and branched polyols for Si anode of lithium-ion batteries

Arabic gum grafted poly (acrylic acid) (GA- g -PAA) is prepared through a free radical graft polymerization of acrylic acid onto Arabic gum. Crosslinkable aqueous binder is developed by combining GA-g-PAA and branched polyols (pentaerythrotol, PER; triethanolamine, TEOA) as crosslinking agent for Si anodes of lithium-ion batteries. The aqueous composite binder undergoes crosslinking at about 110 °C to form robust crosslinked networks, matching well with the processing temperature of the electrode sheet in industry. GA-g-PAA/PER binder displays higher adhesion strength than GA-g-PAA and GA-g-PAA/TEOA. The Si electrode with GA-g-PAA/PER exhibits a slightly better cycling stability at 0.2C for 100 cycles, better rate capability than GA-g-PAA and GA-g-PAA/TEOA. At a high rate of 1C, Si electrode with GA-g-PAA/P delivers a higher specific capacity of 1968.1 mAhg −1 with a better capacity retention of 57.5% when compared with those with GA-g-PAA and GA-g-PAA/T binder. • Crosslinkable aqueous binder (GA-g-PAA/PER) is designed for Si anodes in lithium-ion batteries. • Branched polyols as crosslinking agents can decrease the crosslinking temperature. • The binder can improve the adhesion strength and the distribution of Si anodes. • Si anodes with the crosslinkable aqueous binder show the excellent rate capability.

Enhanced osteogenic activity and antibacterial performance in vitro of polyetheretherketone by plasma-induced graft polymerization of acrylic acid and incorporation of zinc ions.

Polyetheretherketone (PEEK) has been widely used in the fields of orthopedics and trauma, but weak osteointegration and bacterial infection affect its long-term stability and repair effects. Surface modification is an effective way to improve the osteogenic and antibacterial activity of PEEK implants. In the present study, a layer of acrylic acid (AA) polymer coating loaded with zinc ions (Zn2+) was constructed on the surface of PEEK (PEEK-AA-Zn) using a strategy of combining plasma-induced graft polymerization with a chemical immersion technique. Successful construction of the AA coating remarkably enhanced the hydrophilicity of PEEK, and effectively loaded and released Zn2+. In vitro cell culture using MC3T3-E1 preosteoblasts showed that the Zn2+ released from PEEK-AA-Zn promoted cell proliferation and elevated gene expression levels of alkaline phosphatase (ALP), osteocalcin (OCN) and bone sialoprotein (BSP). Antibacterial tests revealed that PEEK-AA-Zn efficiently inhibited the proliferation of Staphylococcus aureus (S. aureus). These results suggest that the combined method of graft polymerization and ion incorporation endows PEEK with excellent osteogenic and antibacterial activity, which provides a wide range of possibilities for developing PEEK implants with multifunctional properties for bone tissue repair.

Partially lithiated ternary graft copolymer with enhanced elasticity as aqueous binder for Si anode

AbstractPartially lithiated ternary graft copolymers were synthesized through free radical graft polymerization of acrylic acid (AA), lithium acrylate (LiAA) and hydroxyethyl acrylate (HEA) onto polyvinyl alcohol (PVA). With optimized feeding molar ratio of AA/LiAA/HEA (2:1:2), the ternary graft copolymer with partial lithiation shows the best flexibility, elasticity and adhesion strength comparing to PVA‐g‐PAA and PVA‐g‐P(AA‐HEA) when used as aqueous binder for Si anode. The Si anode using PVA‐g‐P(AA‐LiAA‐HEA) with the optimized molar ratio of AA‐LiAA‐HEA exhibits better cycling stability and rate performance, delivering a capacity of 2265 mAh g−1 with a capacity retention of 82.4% after 200 cycles at 1A g−1. Even at a high current of 10 A g−1, the Si electrode still obtained a high capacity of 1300 mAh g−1.

Acrylic acid functionalized graphene oxide: High-efficient removal of cationic dyes from wastewater and exploration on adsorption mechanism

A novel p(AA)-g-GO material was prepared by grafting polymerization of acrylic acid (AA) onto graphene oxide (GO) skeleton, presenting efficient removal of dyes from wastewater, because the layer spacing of GO is expanded and successfully introduced numerous polar carboxyl groups. The study revealed a rapid adsorption kinetic process and the adsorption capacity for methylene blue (MB) increases with pH, contact time, initial dye concentration and temperature. The maximum adsorption capacity is about 1448.2 mg/g at 25 °C for MB according to the Langmuir isotherm. More importantly, the adsorbent maintains excellent adsorption capacity after five cycles of adsorption-desorption and has remarkable selective separability for methylene blue/methyl orange mixed solution at pH = 10. Furthermore, the equilibrium adsorption capacities for other cationic dyes as malachite green (MG), basic fuchsin (BF) and rhodamine B (RhB) reached 582.1, 571.7 and 437.1 mg/g, respectively. Additionally, the mechanism analysis indicated that electrostatic interactions, π-π conjugation and hydrogen bonding are the predominant forces for adsorbing cationic dyes. Therefore, p(AA)-g-GO is an outstanding adsorbent and has a potential application prospect in the treatment of dye wastewater.