Polymerization Route Research Articles

Dual Z-scheme core-shell PANI-CeO2-Fe2O3-NiO heterostructured nanocomposite for dyes remediation under sunlight and bacterial disinfection

Nowadays, environmental pollution due to discharge of organic pollutants from food, textile, and pharmaceutical industries into clean water and development of contagious diseases due to pathogenic organisms provide impetus to material researcher to fabricate novel design for efficient photocatalyst and antimicrobial agents. In this regard, designing a core-shell heterojunction catalyst based on metal oxides is considered an auspicious approach. In present study, combating the problems of singular oxides, core-shell PANI-CeO2-Fe2O3–NiO nanocomposite (PCFN) and CeO2–Fe2O3–NiO nanocomposite (CFN) was synthesized through sol-gel and oxidative polymerization route with cetyletrimethylammonium bromide (CTAB) as surfactant. The XRD, FTIR, and Raman confirmed the formation of nanocomposites with core-shell morphology composed of PANI (shell) and oxides (Core) in PCFN with a particle size of 52 nm (TEM). Surprisingly, PCFN has lower band gap, e−/h+ recombination, and larger charge transfer character than CFN. The decomposition test using MB and MO dyes showed that PCFN degraded 99%, 98%, while CFN degraded only 73% and 54%, respectively, under 50 min sunlight illumination. The reusability was assessed up to 7th cycle for PCFN. The influence of operational parameters (catalyst dose, dye concentration, pH) was tested for PCFN. Further, the antimicrobial action against S. aureus (gram + ve), E. coli (gram -ve) were also tested. The supreme performance of PCFN has been credited to heterostructure dual Z-scheme formation and core-shell morphology supported with PANI, which suppresses the e−/h+ recombination process by promoting their separation. The present finding indicated that the PCFN is a promising modifier for bacterial disinfection and acts as a superb photocatalyst through core-shell formation with PANI support.

Enhanced sunlight-absorption of Fe2O3 covered by PANI for the photodegradation of organic pollutants and antimicrobial inactivation

• Fabrication of core–shell S-scheme heterojunction Fe 2 O 3 -PANI nanocomposite via simple solution method. • Booted photodegradation of diverse organic pollutants under sunlight. • The enhanced antimicrobial characteristics against various bacterial strains. • The improved charge carrier’s kinetics via S-scheme with PANI. • A promising material against bacterial disinfection and an excellent stable photocatalyst. The current study focused on preparing S-scheme heterojunction Fe 2 O 3 -PANI nanocomposite and pristine Fe 2 O 3 using surfactant-assisted sol–gel and polymerization routes. The structural conformation was assessed through XRD diffractograms that confirmed the Fe 2 O 3 phase in both samples. FTIR data traces the metal–oxygen and carbon-related bonds. PL results showed that the recombination rate is retarded in nanocomposite. TEM images confirmed the covering of PANI over Fe 2 O 3 . EDX mapping showed that Fe, C, N, and O were present in the grown nanocomposite. XPS study revealed the binding energies of constituent atoms. The optical energy bandgap 2.8 and 2.7 eV for Fe 2 O 3 and Fe 2 O 3 -PANI was observed through UV–Vis analysis. The photocatalytic test against methyl blue (MB), eosin yellow (EY), and methyl red (MR) dyes were executed for 50 min under direct sunlight. The Fe 2 O 3 -PANI showed 99.8, 98.5, and 99.6% degradation efficiency against MB, EY, and MR dyes, respectively, which was higher than Fe 2 O 3 . The recyclability assessment confirmed the reusability upto four cycles. The antimicrobial property against E. coli, P-aeruginosa, K-pneumoniae, S. aureus, and P. vulgaris bacterial strains revealed a higher response for Fe 2 O 3 -PANI with the zone of inhibition 30, 31, 31, 30, and 30 nm, respectively. The enhanced performance of Fe 2 O 3 -PANI is being credited to S-scheme heterostructure supported with PANI, which can hinder the recombination process and support electron/hole separation. The results indicated that the as-grown nanocomposite could be a promising candidate against bacterial disinfection and an excellent stable photocatalyst.

Synthesis and encapsulation of 1, 4-butanediol esters as energy storage phase change materials for overheating protection of electronic devices

Development and application of thermal energy storage phase change materials (PCMs) with different temperature ranges, non-toxic, high latent heat and thermostability has been the focus of research. This study aims to synthesize a series of diester PCMs with high latent heat and thermostability based on the esterification of 1, 4-butanediol and fatty acids, following microencapsulation of the synthesized diester for overheating protection application. The obtained diester PCMs show a phase change temperature range of 30–80 °C, latent heat up to 240 J/g and volatilization temperature over 230 °C. Considering the suitable phase change temperature for overheating protection, octadecanoic acid 1, 4-butanediol ester was selected and encapsulated with silica as shell by a novel one-pot interfacial polymerization route. The microencapsulated phase change material (MEPCM) achieves a high encapsulation rate of 88.4 % and a satisfactory latent heat capacity of about 211 J/g. After consecutive heating and cooling cycles, the retention rate of thermal storage capacity exceeds 98 %, showing excellent thermal cycling stability. When used in overheating protection, the MEPCM exhibits effective temperature regulation and thermal management performance. During the application of overheating protection, a remarkable temperature hysteresis was observed on a MEPCM treated semiconductor chilling chip due to the heat storage of the MEPCM. The results imply that the MEPCM can provide effective overheating protection as a passive thermal management system.

Polyglycerols as Multi-Functional Platforms: Synthesis and Biomedical Applications.

The remarkable and unique characteristics of polyglycerols (PG) have made them an attractive candidate for many applications in the biomedical and pharmaceutical fields. The presence of multiple hydroxy groups on the flexible polyether backbone not only enables the further modification of the PG structure but also makes the polymer highly water-soluble and results in excellent biocompatibility. In this review, the polymerization routes leading to PG with different architectures are discussed. Moreover, we discuss the role of these polymers in different biomedical applications such as drug delivery systems, protein conjugation, and surface modification.

Sulfur-doped graphitic carbon nitride (S-g-C3N4) as an efficient corrosion inhibitor for X65 pipeline steel in CO2- saturated 3.5% NaCl solution: Electrochemical, XPS and Nanoindentation Studies

The present study reports the role of sulfur-doped graphitic carbon nitrides (S-g-C3N4) as a self- assembly corrosion inhibitor for X-65 steel in 3.5% NaCl solution enriched with CO2. The S-g-C3N4 was synthesized via simple pyrolysis and polymerization route. Detailed physiochemical characterization was carried out using XRD, Raman, FTIR, UV, and XPS analysis. Surface analysis such as FE-SEM and AFM studies reveals a uniform coating of S-g-C3N4 over the steel surface. Electrochemical techniques were adopted to investigate the efficiency of S-g-C3N4 on steel corrosion mitigation. Maximum inhibition efficiency of 98% and 94% at concentration of S-g-C3N4 (0.3 wt%) for polarization and impedance methods were achieved. Also, the DFT and MD simulation studies evidenced that S-g-C3N4 forms a protective layer over the steel surface. The excellent inhibition efficiency of the S-g-C3N4 is due to the presence of sulfur heteroatom thus has more affinity towards steel surface. This sulfur doped g-C3N4 could open up new opportunities in corrosion and materials protection area.

Nanomagnetic strontium ferrite nitrogen doped carbon (SrFe2O4-NC): Synthesis, characterization and excellent supercapacitor performance

A novel nitrogen-doped carbon strontium ferrite (SrFe2O4-NC) nanocomposite with a particle size of 8–10 nm was obtained using the polymeric route. Bimetallic precursors based on iron (III) and strontium chloride were produced with urea and formaldehyde polymers and the precursors were heated at 700 °C in an inert atmosphere to form the SrFe2O4-NC nanocomposite with high surface area (approximately 170.4 m2/g). The prepared SrFe2O4-NC nanocomposite shows ferromagnetic nature with saturation magnetization value of approximately 15 emu/g. Using cyclic voltammetry (CV), galvanic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS), the supercapacitor capabilities of the SrFe2O4-NC nanocomposite were investigated in 5 M KOH. The SrFe2O4-NC nanocomposite electrode material demonstrates a higher specific capacitance of approximately 895 F/g. High performance of the supercapacitor could be due to their good cyclic stability, high charge - discharge rate, and high energy density. As a result, our focus was on the fabrication of cost-effective and higher performance electrode materials.

Identification of Crucial Intermediates in the Formation of Humins from Cellulose-Derived Platform Chemicals Under Brønsted Acid Catalyzed Reaction Conditions.

Humins are one of the undesirable products formed during the dehydration of sugars as well as the conversion of 5-hydroxymethylfurfural (HMF) to value-added products. Thus, reducing the formation of humins is an important strategy for improving the yield of the aforementioned reactions. Even after a plethora of studies, the mechanism of formation and the structure of humins are still elusive. In this regard, we have employed density functional theory-based mechanistic studies and microkinetic analysis to identify crucial intermediates formed from glucose, fructose, and HMF that can initiate the polymerization reactions resulting in humins under Brønsted acid-catalyzed reaction conditions. This study brings light into crucial elementary reaction steps that can be targeted for controlling humins formation. Moreover, this work provides a rationale for the experimentally observed aliphatic chains and HMF condensation products in the humins structure. Different possible polymerization routes that could contribute to the structure of humins are also suggested based on the results. Importantly, the findings of this work indicate that increasing the rate of isomerization of glucose to fructose and reducing the rate of reaction between HMF molecules could be an efficient strategy for reducing humins formation.

Thermal and Calorimetric Investigations of Some Phosphorus-Modified Chain Growth Polymers 2: Polystyrene

In this paper, we report on the thermal degradation behaviours and combustion attributes of some polymers based on polystyrene (PSt). Here, both additive and reactive strategies were employed, through the bulk polymerization route, where the modifying groups incorporated P-atom in various chemical environments. These included oxidation states of III or V, and the loading of phosphorus was kept at ca. 2 wt.% in all cases. The characterization techniques that were employed for the recovered products included spectroscopic, thermal, and calorimetric. It was found that the presence of different modifying groups influenced the degradation characteristics of the base polymer, and also exerted varying degrees of combustion inhibition. In all cases, the modification of the base matrix resulted in a noticeable degree of fire retardance as compared to that of the virgin material. Therefore, some of the modifications presented have the potential to be explored on a commercial scale.

Reversible addition fragmentation chain transfer copolymerization of functional myrcene with styrene

AbstractThe introduction of functionality is essential to the surface, bulk and mechanical properties of poly(diene‐styrene). In this work, copolymerizations of hydroxyl (My‐OH) and epoxide (My‐EPO) functionalized myrcenes with styrene by a solvent‐free reversible addition fragmentation chain transfer polymerization route have been performed. In both cases, the copolymerizations were processed with functional diene preferentially inserted (rMy‐OH/rSt, 1.28 ± 0.02/0.81 ± 0.02; rMy‐EPO/rSt, 1.15 ± 0.01/0.91 ± 0.02), providing a series of composition drifted copolymers with controlled functionality degree and molecular weight by feeding ratios of comonomer and chain transfer agent. The copolymers have remarkably low contact angles with water, an indication of potentially good miscibility with polar additives. In addition, the in‐chain included hydroxyl and epoxide groups could further provide a very versatile ‘intermediate’ that can be used to prepare various functional polymers, block and graft copolymers. © 2022 Society of Chemical Industry

Thermal and Calorimetric Investigations of Some Phosphorus-Modified Chain Growth Polymers 1: Polymethyl Methacrylate.

The thermal and calorimetric characterizations of polymethyl methacrylate-based polymers are reported in this paper. The modifying groups incorporated the phosphorus atom in various chemical environments, including oxidation states of III, or V. Both additive and reactive strategies were employed, where the loading of phosphorus was kept at 2 wt% in all cases. The plaques, obtained through the bulk polymerization route, were subjected to a variety of spectroscopic, thermal and combustion techniques. The results showed that the different modifying groups exerted varying nature, degrees and modes of combustion behaviors, which also included in some cases an additive, and even an antagonistic effect. In the case of covalently-bound phosphonate groups, early cracking of the pendent ester moieties was shown to produce phosphoric acid species, which in turn can act in the condensed phase. For the additives, such as phosphine and phosphine oxide, limited vapor-phase inhibition can be assumed to be operative.

Magnetic responsive mesoporous alginate/β-cyclodextrin polymer beads enhance selectivity and adsorption of heavy metal ions

Mesoporous (~7–8 nm) biopolymer hydrogel beads (HNTs-FeNPs@Alg/β-CD) were synthesised via ionic polymerisation route to separate heavy metal ions. The adsorption capacity of HNTs-FeNPs@Alg/β-CD was higher than that of raw halloysite nano tubes (HNTs), iron nanoparticles (FeNPs), and bare alginate beads. FeNPs induce the magnetic properties of adsorbent and metal-based functional groups in and around the hydrogel beads. The mesoporous surface of the adsorbent permits access of heavy metal ions onto the polymer beads to interact with internal active sites and the mesoporous polymer network. Maximum adsorption capacities of lead (Pb), copper (Cu), cadmium (Cd), and nickel (Ni) were 21.09 mg/g, 15.54 mg/g, 2.47 mg/g, and 2.68 mg/g, respectively. HNTs-FeNPs@Alg/β-CD was able to adsorb heavy metals efficiently (75–99%) under environment-relevant concentrations (200 μg/L) from mixed metal contaminants. The adsorption and selectivity trends of heavy metals were Pb > Cu > Cd > Ni, despite electrostatic binding strength of Cd > Cu > Pb > Ni and covalent binding strength of Pb > Ni > Cu > Cd. It demonstrated that not only chemosorption but also physisorption acts as the sorption mechanism. The reduction in surface area, porosity, and pore volume of the expended adsorbent, along with sorption study results, confirmed that pore filling and intra-particle diffusion played a considerable role in removing heavy metals.

Poly(N-methyl pyrrole) decorated rGO nanocomposite: A novel ultrasensitive and selective carbon monoxide sensor

An ultrasensitive and selective carbon monoxide (CO) sensor based on poly(N-methyl pyrrole)/reduced graphene oxide (P(NMP)/rGO) nanocomposites working at room temperature (RT) has been presented. A unique three-step approach has been introduced to ensure the preparation of a highly conductive and water-soluble rGO. P(NMP)/rGO nanocomposite was materialized through the inexpensive and straightforward self-assembled micellar soft-template polymerization route in the presence of rGO. The P(NMP)/rGO based sensor demonstrates outstanding response upon exposure to a broad concentration of CO ranging from 10 ppm to 275 ppm. The experimental results revealed that incorporation of rGO with P(NMP) nanosphere improved the sensor response (231.5 % to 75 ppm), leading to fast response and recovery characteristics (40 s / 36 s) and excellent selectivity at RT. The lowest detection limit of P(NMP)/rGO nanocomposite-based sensor for CO is calculated to be 1.042 ppm. Based on the outcomes of this investigation, it is believed that the proposed sensor, with its inexpensive and simple construction method, along with its remarkable performance towards CO, might be a wonderful option for real-time detection of CO.

Nitrogen-Doped Carbon Flowers with Fe and Ni Dual Metal Centers for Effective Electroreduction of Oxygen

Carbon-based nanocomposites have been attracting extensive attention as high-performance catalysts in alkaline media towards the electrochemical reduction of oxygen. Herein, polyacrylonitrile nanoflowers are synthesized via a free-radical polymerization route and used as a structural scaffold and precursor, whereby controlled pyrolysis leads to the ready preparation of carbon nanocomposites (FeNi-NCF) doped with both metal (Fe and Ni) and nonmetal (N) elements. Transmission electron microscopy studies show that the FeNi-NCF composites retain the flower-like morphology, with the metal species atomically dispersed into the flaky carbon petals. Remarkably, despite a similar structure, elemental composition, and total metal content, the FeNi-NCF sample with a high Fe:Ni ratio exhibits an electrocatalytic performance towards oxygen reduction reaction (ORR) in alkaline media that is similar to that by commercial Pt/C, likely due to the Ni to Fe electron transfer that promotes the adsorption and eventual reduction of oxygen, as evidenced in X-ray photoelectron spectroscopic measurements. Results from this study underline the importance of the electronic properties of metal dopants in the manipulation of the ORR activity of carbon nanocomposites.

Three-dimensional nano assembly of nickel cobalt sulphide/polyaniline@polyoxometalate/reduced graphene oxide hybrid with superior lithium storage and electrocatalytic properties for hydrogen evolution reaction

Engineering hierarchical nanostructures with enhanced charge storage capacity and electrochemical activity are vital for the advancement of energy devices. Herein, a highly ordered mesoporous three-dimensional (3D) nano-assembly of Nickel Cobalt Sulphide/Polyaniline @Polyoxometalate/Reduced Graphene Oxide (NiCo2S4/PANI@POM/rGO) is prepared first time via a simple route of oxidative polymerization followed by a hydrothermal method. Morphological analysis of the resulting hybrid reveals the sheet-like structures containing a homogeneous assembly of PANI@POM and NiCo2S4 on the graphene exterior maintaining huge structural integrity, large surface area and electrochemically active centres. The electrochemical analysis of the nanohybrid as the anode of the lithium-ion battery (LIB) has delivered ultra-huge reversible capacity of 735.5 mA h g−1 (0.1 A g−1 after 200 cycles), superb capacity retention (0.161% decay/per cycle at 0.5 A g−1 for 1000 cycles), and significant rate capability (355.6 mA h g−1 at 2 A g−1). The hydrogen evolution reaction (HER) measurement also proves remarkable activity, extremely low overpotential and high durability. The extraordinary performance of the nanohybrid is due to the presence of abundant electroactive centres, high surface area and a large number of ion exchange channels. These outstanding results prove the advantages of a combination of NiCo2S4, graphene sheets, and PANI@POM in energy devices.

Autonomous Visualization of Damage in Polymers by Metal-Free Polymerizations of Microencapsulated Activated Alkynes.

The development of autonomous materials with desired performance and built‐in visualizable sensing units is of great academic and industrial significance. Although a wide range of damage indication methods have been reported, the “turn‐on” sensing mechanism by damaging events based on microcapsule systems, especially those relying on chemical reactions to elicit a chromogenic response, are still very limited. Herein, a facile and metal‐free polymerization route with an interesting reaction‐induced coloration effect is demonstrated. Under the catalysis of 1,4‐diazabicyclo[2.2.2]octane (DABCO), the polymerizations of difunctional or trifunctional activated alkynes proceed very quickly at 0 °C in air. A series of polymers composed of stereoregular enyne structure (major unit) and divinyl ether structure (minor unit) are obtained. Both the catalyst and monomers are colorless while the polymerized products are deep‐colored. This process can be applied for the damage visualization of polymers using the microencapsulation technique. Microcapsules containing the reactive alkyne monomer are prepared and mixed in a DABCO‐dispersed polymer film. Both the external and internal damage regions of this composite film can be readily visualized once the reaction is initiated from the ruptured microcapsules. Moreover, the newly formed polymer automatically seals the cracks with an additional protection function.

En Route to CO2-Based (a)Cyclic Carbonates and Polycarbonates from Alcohols Substrates by Direct and Indirect Approaches

This review is dedicated to the state-of-the art routes used for the synthesis of CO2-based (a)cyclic carbonates and polycarbonates from alcohol substrates, with an emphasis on their respective main advantages and limitations. The first section reviews the synthesis of organic carbonates such as dialkyl carbonates or cyclic carbonates from the carbonation of alcohols. Many different synthetic strategies have been reported (dehydrative condensation, the alkylation route, the “leaving group” strategy, the carbodiimide route, the protected alcohols route, etc.) with various substrates (mono-alcohols, diols, allyl alcohols, halohydrins, propargylic alcohols, etc.). The second section reviews the formation of polycarbonates via the direct copolymerization of CO2 with diols, as well as the ring-opening polymerization route. Finally, polycondensation processes involving CO2-based dimethyl and diphenyl carbonates with aliphatic and aromatic diols are described.

Facile precipitation microfluidic synthesis of Monodisperse and inorganic hollow microspheres for Photocatalysis

AbstractBACKGROUNDHollow microspheres have potential applications for wide‐range fields, especially photocatalysis, attracting tremendous attention in material science. However, conventional synthesis of hollow microspheres involves complicated procedures, high cost and poor yields, greatly impeding their development. Due to the limitations of raw material for the polymerization or hydrolysis routes so far the hollow materials prepared in a microfluidics chip were limited to some specific substances.RESULTSHerein, a controllable precipitating reaction strategy in droplets was presented to form the hollow structure from easily accessible industrial chemical materials (such as nitrates of Zinc, Copper and Cobalt, and Ferrous sulfate). After generating monodisperse droplets and followed introducing precipitant into the droplets in a microfluidics chip, the spherical shell was constructed through the accumulation of precipitated particles at the oil/water interface of droplets and further particle growth on the inner shell. As a result, hollow microspheres with a Janus shell of different inner and outer morphology were formed. The photocatalytic activities of these hollow microspheres were evaluated for RhB photodegradation oxidation based on heterogeneous photo‐Fenton. The photocatalytic activities of the fresh hollow samples showed better than their solid samples or their oxidized hollow samples.CONCLUSIONWith microfluidic technology, the transition‐metallic inorganic hollow microspheres can be rapid, low‐costly manufactured through direct precipitation reaction in droplets. The prepared α‐Co(OH)2 hollow microspheres showed promising photocatalytic activity. © 2021 Society of Chemical Industry (SCI).

High efficient degradation of organic dyes by polypyrrole‐multiwall carbon nanotubes nanocomposites

AbstractOver the years, there has been an emphasis on the improvement of novel materials for photocatalytic processes for practical application in treating wastewater. In this sense, the ultrasonic‐assisted in‐situ chemical polymerization route was used to synthesize polypyrrole‐multiwall carbon nanotubes (PPy‐MWCNTs) nanocomposites. The transmission electron microscopy (TEM), X‐ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy (XPS), and ultraviolet visible (UV–vis) analysis were employed to study the impact of MWCNTs on the properties of PPy. TEM showed that the PPy‐MWCNTs nanocomposites consist of spherical PPy with 80 nm particle size, while the MWCNTs showed inner and outer diameters of 7 nm and 13 nm, respectively. XRD analysis showed that the crystallinity of the PPy increased with MWCNTs loading. The potential of PPy‐MWCNTs nanocomposites as photocatalysts was evaluated via the photodegradation of rhodamine B (RhB) and methylene blue (MB) dyes. The photodegradation efficiency was found to have improved with increasing MWCNTs loading. Almost 99.36% and 78.30% of RhB and MB dye degradation were achieved after 35 min of reaction for the highest loading of MWCNTs. The remarkable nanocomposite photocatalytic activity was attributed to the optical bandgap energy (Eg) reduction with the addition of MWCNTs. These results foreshadow the potential use of the PPy‐MWCNTs nanocomposites for water purification.

Green Synthesis of Lactone‐Based Conjugated Polymers for n‐Type Organic Electrochemical Transistors

AbstractAs new and better materials are implemented for organic electrochemical transistors (OECTs), it becomes increasingly important to adopt more economic and environmentally friendly synthesis pathways with respect to conventional transition‐metal‐catalyzed polymerizations. Herein, a series of novel n‐type donor–acceptor‐conjugated polymers based on glycolated lactone and bis‐isatin units are reported. All the polymers are synthesized via green and metal‐free aldol polymerization. The strong electron‐deficient lactone‐building blocks provide low‐lying lowest unoccupied molecular orbital (LUMO) and the rigid backbone needed for efficient electron mobility up to 0.07 cm2 V−1 s−1. Instead, polar atoms in the backbone and ethylene glycol side chains contribute to the ionic conductivity. The resulting OECTs exhibit a normalized maximum transconductance gm,norm of 0.8 S cm−1 and a μC* of 6.7 F cm−1 V−1 s−1. Data on the microstructure show that such device performance originates from a unique porous morphology together with a highly disordered amorphous microstructure, leading to efficient ion‐to‐electron coupling. Overall, the design strategy provides an inexpensive and metal‐free polymerization route for high‐performing n‐type OECTs.

Designed incorporation of semi-crystalline domains into structured latex particles via solvent-aided emulsion polymerization

We describe an emulsion polymerization route towards the design of structured latex particles containing semi-crystalline domains with improved mechanical properties.