Radical Polymerization Process Research Articles

Preparation of viscosity-reducing polycarboxylate superplasticizer (PCE) and its role in low water-to-cement ratio system

Owing to the low water-cement ratio (less than 0.25) of ultra-high-performance concrete (UHPC) materials, the system exhibits increased viscosity, diminished slurry flow, and challenges in pouring during the construction process, which compromise its workability. Consequently, the development of highly efficient viscosity-reducing polycarboxylate superplasticizer (PCE) is of paramount importance. In this study, we synthesized a series of viscosity-reducing polycarboxylate superplasticizers(JN-PCE) utilizing allyl polyethylene glycol ether (APEG), acrylic acid (AA), and sodium methallyl sulfonate (SMAS) as raw materials through the process of free radical polymerization. Fourier-transform infrared spectroscopy, nuclear magnetic resonance, gel permeation chromatography, and energy-dispersive X-ray spectroscopy were employed to characterize the materials. Subsequent evaluations of surface tension, fluidity, adsorption performance, and Marsh time demonstrated that these superplasticizers exhibited commendable dispersion and remarkable viscosity-reducing properties within a low water-cement ratio system. At a water-cement ratio of 0.18, the Marsh time of the JN-type PCE was reduced by 40% while maintaining the same fluidity, thereby underscoring the effective viscosity-reducing capabilities of the synthesized polycarboxylate superplasticizer.

α-Trifluoromethylated Quinolines as Safe and Storable PET-Donor for Radical Polymerizations.

In the quest for powerful, safe, and storable photoinduced-electron transfer (PET) donors, the attention is turned to the α-trihalomethylated amine moiety that is not studied in the context of PET-reductants. The thermal and photophysical properties of α-trifluoromethylated quinolines are thus studied and their reducing abilities evaluated as initiators of polymerization reactions. Polymers of high molecular weights are obtained through a radical polymerization process and the PET-donor can be stored within the monomer for several months without losing its efficiency. Mechanistic investigations, combining spectroscopic analysis and theoretical calculations, confirm the mode of activation of these electron donors and the generation of radical intermediates through single electron transfer.

Low-cost, all-organic, hydrogen-bonded thin-film composite membranes for CO2 capture: Experiments and molecular dynamic simulations

Despite the excellent separation performance of organic-inorganic hybrid membranes, such as mixed-matrix membranes, their commercial application remains challenging due to difficulties in uniformly dispersing inorganic fillers and achieving good interfacial contact over large areas. In this paper, we present high-performance, thin-film composite (TFC) membranes made from low-cost, all-organic materials using a commercially attractive and straightforward process for CO2 capture. The TFC membranes were prepared on a porous polysulfone support using 2,4,6-triaminopyrimidine (TAP) dispersed in comb-shaped polymerized poly(oxyethylene methacrylate) (PPOEM), synthesized through a free radical polymerization process. The organic filler TAP functioned as a hydrogen bond inducer, controlling the free volume and reducing gas diffusivity, thereby enhancing CO2 selectivity over larger gases such as N2 and CH4. Incorporating 2 wt% TAP significantly improved separation performance by primarily reducing N2 and CH4 permeances, achieving a CO2 permeance of 1140 GPU, with CO2/N2 and CO2/CH4 selectivities of 43.3 and 15.0, respectively. The achieved performance significantly surpassed that of Pebax-based membranes and successfully met the target criteria for post-combustion CO2 capture. Variations in free volume, molecule aggregation, hydrogen bonding, and interaction energies between gases and membranes were thoroughly investigated via molecular dynamic (MD) simulations. This high-performance TFC membrane, created through simple and facile methods using entirely organic materials, achieves commercial standards for post-combustion CO2 capture.

Smart Hydrogel Based on Derivatives of Natural α-Amino Acids for Efficient Removal of Metal Ions from Wastewater.

A novel class of hydrogels, rich in a variety of functional groups capable of interacting/complexing with metal ions was successfully synthesized. This was achieved by using acryloyl derivatives of natural α-amino acids, specifically ornithine and cystine. The δ-amino group of ornithine was modified with an acryloyl group to facilitate its attachment to the polymer chain. Additionally, N,N'-bisacryloylcystine, derived from cystine, was employed as the cross-linker. The hydrogel was obtained through a process of free radical polymerization. This hydrogel, composed only from derivatives of natural amino acids, has proven to be a competitive sorbent and has been effectively used to remove heavy metal pollutants, mainly lead, copper, and silver ions, from aqueous media. The maximum sorption capacities were ca. 155 mg·g-1, 90 mg·g-1, and 215 mg·g-1, respectively for Pb(II), Cu(II), and Ag(I). The material was characterized by effective regeneration, maintaining the sorption capacity at around 80%, 85%, and 90% for Cu(II), Ag(I), and Pb(II), respectively, even after five cycles. The properties of sorption materials, such as sorption kinetics and the effect of pH on sorption, as well as the influence of the concentration of the examined metal ions on the swelling ratio and morphology of the gel, were investigated. The EDS technique was employed to investigate the composition and element distribution in the dry gel samples. Additionally, IR spectroscopy was used to identify the functional groups responsible for binding the studied metal ions, providing insights into their specific interactions with the hydrogel.

Nanoscale Surface Chemical Patterning of Soft Polyacrylamide with Elastic Modulus Similar to Soft Tissue.

Nanometer-scale control over surface functionalization of soft gels is important for a variety of applications including controlling interactions with cells for in vitro cell culture and for regenerative medicine. Recently, we have shown that it is possible to transfer a nanometer-thick precision functional polymer layer to the surface of relatively stiff polyacrylamide gels. Here, we develop a fundamental understanding of the way in which the precision polymer backbone participates in the polyacrylamide radical polymerization and cross-linking process, which enables us to generate high-efficiency transfer to much softer hydrogels (down to 5 kPa) with stiffness similar to that of soft tissue. This approach creates hydrogel surfaces with exposed nanostructured functional arrays that open the door to controlled ligand presentation on soft hydrogel surfaces.

Fabrication, optimization, and in vitro validation of penicillin-loaded hydrogels for controlled drug delivery

Bacterial infections present a major global challenge. Penicillin, a widely used antibiotic known for its effectiveness and safety, is frequently prescribed. However, its short half-life necessitates multiple high-dose daily administrations, leading to severe side-effects. Therefore, this study aims to address these issues by developing hydrogels which control the release of penicillin and alleviate its adverse effects. Various combinations of aspartic acid and acrylamide were crosslinked by N′, N′-methylene bisacrylamide through a free radical polymerization process to prepare aspartic acid/acrylamide (Asp/Am) hydrogels. The fabricated hydrogels underwent comprehensive characterization to assess physical properties and thermal stability. The soluble and insoluble fractions and porosity of the synthesized matrix were evaluated by sol-gel and porosity studies. Gel fraction was estimated at 88–96%, whereas sol fraction was found 12–4% and porosity found within the 63–78% range for fabricated hydrogel formulations. Maximum swelling and drug release were seen at pH 7.4, demonstrating a controlled drug release from hydrogel networks. The results showed that swelling, porosity, gel fraction, and drug release increased with higher concentrations of aspartic acid and acrylamide. However, integration of N′, N′-methylene bisacrylamide exhibited the opposite effect on swelling and porosity, while increasing gel fraction. All formulations followed the Korsymer–Peppas model of kinetics with ‘r’ values within the range of 0.9740–0.9980. Furthermore, the cytotoxicity study indicated an effective and safe use of hydrogel because the cell viability was higher than 70%. Therefore, these prepared hydrogels show promise candidates for controlled release of Penicillin and are anticipated to be valuable in clinical applications.

Mussel-adhesive chemistry inspired conductive hydrogel with self-adhesion, biocompatibility, self-recovery and fatigue-resistance performances as flexible sensing electronics

Conductive hydrogels are ideal candidates for wearable strain sensors due to their intrinsic stretchability and conductivity. However, it’s still a challenge to fabricate a conductive hydrogel with a combination performance of high mechanical strength, self-adhesion, sensitivity, self-recovery capability, fatigue-resistant ability and biocompatibility. Herein, a dual-network hydrogel (TG/P-LP) composed of 2,2,6,6-tetra-methylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibers (TOCNs) supported graphene (GN), Laponite-oxidized polydopamine (LP) and polyacrylic acid-co-poly acrylamide (P) hydrogel matrix was synthesized via a facile in-situ radical polymerization process. The optimized biocompatible TG/P-LP hydrogel exhibits a high mechanical strength, self-adhesive performance, intrinsic self-recovery capability (95.7 % in 60 min) and anti-fatigue property. The hydrogel-based strain sensor exhibits a wide strain range (0 ∼ 600 %) and a high sensitivity (GF = 12). This work designs a novel hydrogel-based sensor with excellent mechanical properties, long-term fatigue resistance, high strain sensitivity and wearability, demonstrating enormous potential in the applications of human motion detection and human–machine interaction.

Fluorescent zinc acrylate resins containing coumarin structures with enhanced antifouling performance

The demand for non-toxic antifouling coatings has led to the development of multifunctional antifouling coatings. In this work, a series of coumarin acids with fluorescence were first prepared via the Knoevenagel condensation reaction. Then, multifunctional zinc acrylate resins were produced successfully by employing an acrylic acid monomer, ZnO, and coumarin acids by free radical polymerization and polycondensation processes. The self-polishing and antifouling properties of the resins were investigated by dynamic simulation experiments, E. coli growth inhibition experiments, algae adhesion inhibition experiments, and marine environment antifouling experiments. The results show that the zinc acrylate resins containing the coumarin structures not only have good self-polishing performance but also have better antifouling performances than the zinc acrylate resin containing benzoic acid. This work not only reveals the antifouling mechanism of the multifunctional resins, but also provides a new strategy for the development of environmentally friendly antifouling coatings.

PH-responsive biomass-based hydrogels for 5-fu delivery: Investigating the influential role of itaconic acid content on structural characteristic, swelling behavior, and drug loading capacity

The pH-responsive hydrogel was synthesized through an eco-friendly free radical polymerization process, utilizing ionic acid (IA), N, N-dimethyl acrylamide (DAAm), and double-bond modified vanillin (VMA). The P(DAAm-co-IA-co-VMA) hydrogel exhibited favorable compressive strength, swelling behavior, temperature sensitivity, pH sensitivity, salt solution sensitivity, and biocompatibility. Additionally, the study investigated the influence of varying IA monomer content on these properties. The evaluation of drug loading and release capabilities utilized 5-fluorouracil (5 Fu) as the model medicinal. The results showed that the P(DAAm-co-IA-co-VMA) hydrogel's cumulative release percentage was greater in the simulated intestinal fluid compared to the simulated gastric fluid, indicating its potential for oral drug delivery applications.

An Innovative Approach for Tailoring Molecularly Imprinted Polymers for Biosensors-Application to Cancer Antigen 15-3.

This work presents a novel approach for tailoring molecularly imprinted polymers (MIPs) with a preliminary stage of atom transfer radical polymerization (ATRP), for a more precise definition of the imprinted cavity. A well-defined copolymer of acrylamide and N,N'-methylenebisacrylamide (PAAm-co-PMBAm) was synthesized by ATRP and applied to gold electrodes with the template, followed by a crosslinking reaction. The template was removed from the polymer matrix by enzymatic/chemical action. The surface modifications were monitored via electrochemical impedance spectroscopy (EIS), having the MIP polymer as a non-conducting film designed with affinity sites for CA15-3. The resulting biosensor exhibited a linear response to CA15-3 log concentrations from 0.001 to 100 U/mL in PBS or in diluted fetal bovine serum (1000×) in PBS. Compared to the polyacrylamide (PAAm) MIP from conventional free-radical polymerization, the ATRP-based MIP extended the biosensor's dynamic linear range 10-fold, improving low concentration detection, and enhanced the signal reproducibility across units. The biosensor demonstrated good sensitivity and selectivity. Overall, the work described confirmed that the process of radical polymerization to build an MIP material influences the detection capacity for the target substance and the reproducibility among different biosensor units. Extending this approach to other cancer biomarkers, the methodology presented could open doors to a new generation of MIP-based biosensors for point-of-care disease diagnosis.

Gum karaya polymer-based biodegradable silver nanocomposite hydrogel through green approach for photocatalytic dye degradation and antimicrobial activity

The rise in industrialization and population growth has elevated water pollution to a critical environmental concern. This study introduces a novel polymer-mediated silver nanocomposite hydrogel for antibacterial activity and photocatalytic dye degradation for environmental remediation. In this study, silver nanocomposite hydrogels were developed using Karaya gum (KG), acrylamide, N-isopropyl acrylamide (NI), and 2-Bismethacryloyloxy ethyl phosphate (BMEP) as a crosslinker through a radical polymerization process. These hydrogels were utilized as templates for the eco-friendly synthesis of silver nanoparticles by employing an aqueous Canthium leaf extract as a reducing and stabilizing agent. Various analytical methods, including FTIR, UV–Vis, XPS, FESEM, EDX, XRD, AFM, and HRTEM, are characterized by the green synthesized KG-NIB-Ag nanocomposite hydrogel. Evaluation of the KG-NIB-Ag hydrogel involved examining its chemical composition, morphology, size, crystallinity, surface properties, bandgap, and chemical purity. TEM analysis validated an average crystallite size 33.2 nm. Moreover, the photocatalytic performance of the green-synthesized KG-NIB-Ag nanocomposite hydrogel was utilized to examine the degradation of Congo red dye under visible light irradiation. The findings of this study demonstrate that the degradation efficiency of CR reached approximately 73.25 % within 90 min, with a corresponding kinetic rate constant of 0.032 min−1. Furthermore, the antibacterial efficacy of the Ag nanocomposite hydrogel was evaluated against both Staphylococcus aureus and Escherichia coli. The disc diffusion method was employed to assess its antibacterial activity, and the diameter of the inhibition zones was measured. This study introduces an innovative and influential strategy for environmental remediation, emphasizing the potential of KG-NIB-Ag nanocomposite hydrogel in tackling ecological challenges associated with wastewater treatment across various industries.

A universal method for preparing biomass derived topologically defective carbons with superior catalytic performance in cationic radical polymerization

This study aims to develop a universal preparation method for biomass-derived topologically defective carbons and reveal the catalytic mechanism of such carbons for cationic radical polymerization. Firstly, bamboo fiber-derived topologically defective carbon (BFTC) is prepared by an ammonia-assisted heat treatment method. BFTC can significantly promote the chemical oxidative polymerization of 3-aminophenylboronic acid (a typical cationic radical polymerization process) and obtain high molecular weight products, which is mainly attributed to the rich topological defect structure of BFTC. Secondly, the ammonia-assisted heat treatment method is applied to two other biomasses, and the derived carbons have similar microstructure and chemical composition to BFTC, indicating the universality of this method at the material preparation level; meanwhile, these derived carbons also exhibit excellent catalytic properties when they promote 3-aminophenylboronic acid (ABA) polymerization, which further confirms the universality of this method from the perspective of material properties. Finally, research on the catalytic mechanism shows that there is an interaction based on partial electron transfer between the topological defects of the carbon catalyst and ABA or ABA-derived radical. This effect promotes the rapid derivatization of ABA into cationic radical, and also improves the stability of the radical, thereby achieving efficient polymerization of ABA around the topological defect active center. Therefore, this study confirms the universality of the ammonia-assisted heat treatment method to prepare biomass-derived topologically defective carbon, and such defective carbons are likely to serve as catalysts for cationic radical polymerization.

Polymer-encapsulated Sm-doped nano-hydroxylapatite and its antibacterial property☆

Hydroxylapatite (HAp), owing to its excellent biocompatibility, is a promising carrier for lanthanide ions to encourage antibacterial activity. However, hydroxylapatite powder would still require modification to ensure the optimal integration of antibacterial characteristics. In this study, Sm-doped nano-hydroxylapatite (SmHAp) was synthesized by spontaneous mineralization of amorphous SmHAp precursors, which ensures a homogeneous distribution of Sm3+ within bulk SmHAp. Powder X-ray diffraction and its Pawley fitting results for SmHAp indicate the lattice substitution of Ca2+ with Sm3+, resulting in the lattice distortion in SmHAp compared to pure HAp. Meanwhile, polymer-encapsulated Sm-doped nano-hydroxylapatite composite (p_SmHAp) was synthesized by a dual-step polymerization involving UV curing of an outer crust and heat treatment for bulk reaction completion. Irgacure 2959 and a toluene solution of AIBN were used as catalysts for the radical polymerization process. The antibacterial property of p_SmHAp was evaluated by observing the growth of Sporosarcina pasteurii (ATCC 11859) both in the solid and the liquid medium, correlating with the Sm fraction and SmHAp’s crystallinity in p_SmHAp. These bacteriostatic rings' diameters exceed 20 mm, demonstrating that p_SmHAp with a SmHAP/p_SmHAp mass ratio of 0.1 and Sm/(Ca+Sm) molar ratio of 0.05−0.1 effectively releases Sm3+, serving as a strong antibacterial agent.

Light-Mediated Polymerization Catalyzed by Carbon Nanomaterials.

Carbon nanomaterials, specifically carbon dots and carbon nitrides, play a crucial role as heterogeneous photoinitiators in both radical and cationic polymerization processes. These recently introduced materials offer promising solutions to the limitations of current homogeneous systems, presenting a novel approach to photopolymerization. This review highlights the preparation and photocatalytic performance of these nanomaterials, emphasizing their application in various polymerization techniques, including photoinduced i) free radical, ii) RAFT, iii) ATRP, and iv) cationic photopolymerization. Additionally, it discusses their potential in addressing contemporary challenges and explores prospects in this field. Moreover, carbon nitrides, in particular, exhibit exceptional oxygen tolerance, underscoring their significance in radical polymerization processes and allowing their applications such as 3D printing, surface modification of coatings, and hydrogel engineering.

An orthogonal approach for the synthesis of graft copolymers: Visible light induced free radical polymerization and iniferter processes

Graft copolymers with polystyrene main and poly(ethylene glycol) methyl ether acrylate side chains are synthesized via an orthogonal approach combining visible light induced free radical polymerization and iniferter processes. The method relies on a deliberately designed, double functional monomer, 2,2,2-(triphenylethyl)styrene (TPES), containing both polymerizable and iniferter units.

Ultrafast Sunlight-Induced Polymerization: Unveiling 2-Phenylnaphtho[2,3-d]Thiazole-4,9-dione as a Unique Scaffold for High-Speed and Precision 3D Printing.

A series of 15 dyes based on the 2-phenylnaphtho[2,3-d]thiazole-4,9-dione scaffold and 1 compound based on the 2,3-diphenyl-1,2,3,4-tetrahydrobenzo[g]quinoxaline-5,10-dione scaffold are studied as photoinitiators. These compounds are used in two- and three-component high-performance photoinitiating systems for the free radical polymerization of trimethylolpropane triacrylate (TMPTA) and polyethylene glycol diacrylate (PEGDA) under sunlight. Remarkably, the conversion of TMPTA can reach ≈60% within 20s, while PEGDA attains a 96% conversion within 90s. To delve into the intricate chemical mechanisms governing the polymerization, an array of analytical techniques is employed. Specifically, UV-vis absorption and fluorescence spectroscopy, steady-state photolysis, stability experiments, fluorescence quenching experiments, cyclic voltammetry, and electron spin resonance spin trapping (ESR-ST) experiments, collectively contribute to a comprehensive understanding of the photochemical mechanisms. Photoinitiation capacities of these systems are determined using real-time Fourier transformed infrared spectroscopy (RT-FTIR). Of particular interest is the revelation that, owing to the superior initiation ability of these dyes, high-resolution 3D patterns can be manufactured by direct laser write (DLW) technology and 3D printing. This underscores the efficient initiation of free radical polymerization processes by the newly developed dyes under both artificial and natural light sources, presenting an avenue for energy-saving, and environmentally friendly polymerization conditions.

Designing magnetic catalysts based on gold nanoparticles supported by ethylenediamine tetraacetic acid functionalized amino‐modified poly(N‐isopropyl acrylamide) for reduction of nitro compounds in water

AbstractA novel smart catalyst was developed with amino‐modified thermo‐responsive poly(N‐isopropyl acrylamide) (PNIPAM) grafts on silica‐coated magnetic nanoparticles using the conventional free radical polymerization process. By this methodology, the polymer was successfully grafted mainly onto silica‐modified iron oxide nanoparticles (Fe3O4@Si). The PNIPAM‐grafted Fe3O4@Si was then subjected to ethylenediamine treatment to produce the amino‐functionalized support (Fe3O4@Si@PNIPAM‐NH2), which was subsequently modified with carboxyl functional groups by using EDTA (ethylenediaminetetraacetic acid) to create Fe3O4@Si@PNIPAM‐NH2‐EDTA. Au nanoparticles were then decorated on this support through its two amines and four carboxylates. Different methods were used to study this novel catalyst, including inductively coupled plasma, Fourier transport infrared spectroscopy, TGA, dynamic light scattering, SEM, energy‐dispersive X‐ray analysis, vibrating sample magnetometry, XRD and elemental CHN analysis. The reduction of several aryl‐nitro derivatives demonstrated a significant catalytic activity for the as‐synthesized gold catalyst (Fe3O4@Si@PNIPAM‐NH2‐EDTA‐Au). The Au catalyst can be successfully removed from the reaction components using a magnetic field and used again in eight successive reduction reactions without significant gold leaching and loss of catalytic activity. © 2024 Society of Industrial Chemistry.

Hybrid deterministic and stochastic approach for dynamic simulation of photoinduced atom-transfer radical polymerization processes with microscopic resolution

Among the various polymerization mechanisms available for producing polymers, photoinduced atom-transfer radical polymerization (photoATRP) stands out as a promising technique. By utilizing light as an external stimulus, photoATRP facilitates the production of well-defined polymers with precise distributions. The demand for advanced polymeric materials synthesis necessitates a deep understanding of polymer chains at the molecular level. As molecular weight distribution (MWD) is a key quality index of polymers, developing models with embedded MWD information holds significance for process design and optimization tasks. In this work, an accelerated hybrid deterministic and stochastic approach is proposed for simulating dynamic photoATRP processes. The proposed approach demonstrates computational efficiency and flexibility, enabling precise predictions for the evolution of both macroscopic and microscopic properties of polymers. An application to a batch photoATRP system model is presented to illustrate the validity and performance of the proposed hybrid approach.

SYNTHESIS OF COPOLYMERS OF STEARYLMETHACRYLATE AND STEARYLACRYLATE WITH N-SUBSTITUTED ACRYLAMIDES IN THE PRESENCE OF REVERSIBLE CHAIN TRANSFER AGENTS AND STUDY OF THEIR EFFECT ON THE LOW-TEMPERATURE PROPERTIES OF DIESEL FUEL

The features of copolymerization of stearylacrylate (SA) and stearylmethacrylate with N-isopropylacrylamide and N,N-dimethylacrylamide in the presence of dibenzyltrithiocarbonate and 2-cyanoisopropyldodecyltrithiocarbonate as agents of reversible chain transfer have been studied. The choice of agents of reversible chain transfer (RAFT-agents) is due to the fact that sulfur-containing compounds with cyanoisopropyl radicals are most effective in the polymerization of methacrylic monomers, while benzyltrithiocarbonates are more active in the polymerization of acrylic monomers, as well as styrene and acrylonitrile. It has been established that polymerization of stearyl methacrylate (SMA) in the presence of RAFT-agents proceeds without a gel effect up to a high conversion. At the same time, although polystеarylmethacrylate samples are characterized by relatively high values of polydispersity coefficients (Mn/Mw) for controlled radical polymerization processes, they are nevertheless somewhat lower than for polymers of similar conversion synthesized in the absence of chain transfer agents. It has been shown that the process of copolymerization of stearyl acrylate and stearylmethacrylate with N-isopropylacrylamide and N,N-dimethylacrylamide in the presence of dibenzyltrithiocarbonate and 2-cyanoisopropyldodecyltrithiocarbonate proceeds without gelation to high conversions. The synthesized copolymers are characterized by a relatively narrow molecular weight distribution: the polydispersity coefficients of polymer samples vary from 1.18 to 1.57 in the case of using N-isopropylacrylamide and from 1.21 to 1.47 when using N,N-dimethylacrylamide as a comonomer to higher alkyl acrylates, which is typical for processes of radical polymerization proceeding in a controlled manner. At the same time, the synthesized copolymers exhibit a significant depressant effect when they are introduced into diesel fuel at a concentration of 1600 ppm. It has been established that copolymers of stearylmethacrylate and stearylacrylate with polar nitrogen-containing monomers have a more effective effect on the low-temperature properties of diesel fuel than homopolymers of stearylmethacrylate and stearylacrylate. At the same time, additives based on copolymers of stearylmethacrylate with N-isopropylacrylamide with a composition of 70/30 mol.% and stearylacrylate with N-isopropylacrylamide with a composition of 20/80 mol.% had the most significant effect on the low-temperature characteristics of the fuel.

An anionic polyethersulfone membrane modified by poly(2-acrylamide-2-methylpropanesulfonic acid sodium salt) grafted carbon nanotubes

Polyethersulfone membrane is easy to be polluted, and the negative surface would help enhance improve the permeability and the anti-pollution performance; so how to anchor polymer brushes with negative groups to polyethersulfone membrane surface is a challenge. In this paper, polymer brushes of poly(2-acrylamide-2-methylpropanesulfonic acid sodium salt) is first grafted to carbon nanotubes to form an organic-inorganic hybrid additive, which is further anchored onto the membrane surface of polyethersulfone by blending method. The graft reaction is proceeded by surface initiated electrochemical atom transfer radical polymerization, where the introduction of electrochemical part is because it could help better control the growth of polymer brushes compared with the pristine atom transfer radical polymerization process. The carbon nanotubes grafted with poly(2-acrylamide-2-methylpropanesulfonic acid sodium salt) could anchor on the membrane surface because the there is a self-assemble process of organic-inorganic hybrid additive during phase inversion method, where the inorganic part carbon nanotubes firmly embedded into the membrane and the organic part can be fixed on membrane surface. The polyethersulfone membrane exhibits enhanced surface hydrophilicity, improved the permeability of the membrane, and good anti-fouling performance due to the negative charge and electrostatic repulsion brought by anionic surface of the modified membrane. When the mass of nanotubes grafted with poly(2-acrylamide-2-methylpropanesulfonic acid sodium salt) in the casting solution is 20 mg, the water flux can reach 365.5 L m−2 h−1, and the rejection ratios of both BSA and CR are close to 100% with good flux recovery and anti-fouling effect performance.