Free Radical Copolymerization Research Articles

Synthesis of novel bentonite/pectin-grafted-poly(crotonic acid-co-acrylic acid) hydrogel nanocomposite for adsorptive removal of safranin O dye from aqueous solution

ABSTRACT This novel work is devoted to the synthesis of the bentonite/pectin-grafted-poly(crotonic acid-co-acrylic acid (AA-co-CA) hydrogel nanocomposite by free-radical copolymerisation method for exploring its potential towards safranin O dye removal. The prepared nanocomposite was characterised by different techniques revealing the presence of numerous functionalities, porous nature and greater swelling % at basic pH. The pHpzc of the nanocomposite was determined to be 4. Maximum of 97.09% of safranin O dye removal take place under optimised conditions, that is, 0.03 g of bentonite dose (bentonite to net hydrogel weight ratio (1.295%), with pH of 7, nanocomposite dose of 5 g/l for 120 min. The dye concentration was 500 mg/l at the temperature of 25°C. Effect of ionic strength confirmed the greatest decrease in adsorption capacity in the presence of divalent cations. The highest R2 and the lowest error margins of the Freundlich isotherm and pseudo-second-order kinetic models make these models well fitted to the experimental data. Further, the spontaneous and exothermic nature of the process was confirmed by the negative values of ΔG and ΔH, respectively. The enhanced adsorption of safranin O dye by the prepared nanocomposite was informed by several mechanisms, including electrostatic, pore filling and H-bonding. A comparison of the adsorption capacity of the prepared nanocomposite with various other adsorbents was also studied. Stability of the prepared adsorbent was revealed from its recovery upto five cycles in different desorption media. Finally, the treatment of the adsorbent with real textile wastewater showed its removal efficiency as 95.8% highlighting its promising nature for treating large industrial wastewater.

Facile synthesis of an acrylic acid-co-2-acrylamide-2-methylpropanesulfonic acid copolymer / polyvinylpyrrolidone semi-IPN hydrogel with excellent swelling and anti-leakage properties

Water scarcity becomes an increasingly serious problem for humankind due to climate change and population growth, especially the water leakage in arid and semi-arid areas. Hydrogel polymers show increasingly important roles on water resources utilization. A novel hydrogel copolymer, acrylic acid-co-2-acrylamide-2-methylpropanesulfonic acid copolymer / polyvinylpyrrolidone (P(AA-co-AMPS)/PVP) semi-interpenetrating network (semi-IPN) hydrogel, was designed and successfully synthesized via a facile one-pot free radical copolymerization method. The main parameters during the synthesis process were optimized, including relative contents of polymer monomers, cross-linking agent, initiator and neutralization agent. Physical characterizations demonstrate that, P(AA-co-AMPS)/PVP hydrogel shows porous three-dimensional network structure, including a crosslinked network structure in P(AA-co-AMPS) copolymers and their intermolecular hydrogen bonding interactions with linear PVP. The as-synthesized P(AA-co-AMPS)/PVP hydrogel not only can deliver superior water absorbing capability (up to 1689.95 g g−1) and good reswelling performance, but also shows excellent water anti-leakage performance when being composed with red clay, demonstrating its multi-role applications in future sustainable agriculture.

Preparation and properties of a metal-organic frameworks polymer material based on Sa-son seed gum capable of simultaneously absorbing liquid water and water vapor

Atmospheric water harvesting (AWH) technology has attracted significant attention as an effective strategy to tackle the global shortage of freshwater resources. Work has focused on the use of hydrogel-based composite adsorbents in water harvesting and water conservation. The approaches adopted to make use of hygroscopic inorganic salts which subject to a “salting out” effect. In this study, we report the first use of modified UIO-66-NH2 as a functional steric cross-linker and Sa-son seed gum was used as polymeric substrate to construct super hygroscopic hydrogels by free radical copolymerization. The maximum water uptake on SMAGs (572 cm3·g−1) outperforms pure UIO-66-NH2 (317 cm3·g−1). Simultaneously, our first attempt to use it for anti-evaporation applications in an arid environment (Lanzhou, China) simulating sandy areas. The evaporation rate of the anti-evaporation material treated with 0.20 % super moisture-absorbent gels (SMAGs) decreased by 6.1 % over 64 h period under natural condition in Lanzhou, China. The prepared material can not only absorb liquid water but also water vapor, which can provide a new way for water collection and conservation technology. The design strategy of this material has wide applications ranging from atmospheric water harvesting materials to anti-evaporation technology.

Utilizing methacrylated lignin as a sustainable macro-crosslinker for synthesizing innovative PVA/AMPS composites crosslinked hydrogel nanofibers: A potential application for lithium-ion battery separators

There are significant issues with commercial separators that must be resolved before they can be used in high-energy-density batteries. These problems include low porosity, poor electrolyte wetting, and low mechanical properties. This study presents a facile method for preparing composite crosslinked hydrogel nanofibers of polyvinyl alcohol (PVA) with 2-acrylamide-2-methylpropanesulfonic acid (AMPS) for lithium-ion battery separators by utilizing methacrylated lignin (LMA) as a bio-based crosslinker. Initially, LMA was synthesized by grafting glycidyl methacrylate (GMA) onto lignin via esterification. Subsequently, a crosslinked hydrogel nanofiber membrane (PVA/AMPS-LMA) was electrospun with varying LMA fractions, which were polymerized by combining free radical copolymerization and esterification reactions. The effectiveness of LMA as a crosslinker was assessed against the N, N′-methylene bisacrylamide (MBA). The study showed that using LMA as a crosslinker significantly improved the membrane's properties. The PVA/AMPS-LMA separator displayed superior features such as mechanical strength, thermal stability, porosity, electrolyte uptake, ionic conductivity, and lithium-ion transference number, when compared with PVA/AMPS, PVA, and Celgard separators. Specifically, the PVA/AMPS-LMA separator demonstrated a high mechanical strength of 24.9 MPa, strong thermal stability at 170 °C with no shrinkage, high porosity (84.3 %), and electrolyte uptake (661.4 %). It also exhibited exceptional ionic conductivity (2.75 mS/cm) and a notable lithium-ion transference number (tLi+ = 0.717). In coin batteries, the PVA/AMPS-LMA separator retained over 96 % capacity (142.4 mAh/g) after 200 cycles at 1C. This performance exceeded that of PVA/AMPS, PVA, and Celgard separators, suggesting that PVA/AMPS-LMA separators have the potential to replace their commercial counterparts.

A superabsorbent and pH-responsive copolymer-hydrogel based on acemannan from Aloe vera (Aloe barbadensis M.): A smart material for drug delivery

Combining natural polysaccharides with synthetic materials improves their functional properties which are essential for designing sustained-release drug delivery systems. In this context, the Aloe vera leaf mucilage/hydrogel (ALH) was reacted with acrylic acid (AA) to synthesize a copolymerized hydrogel, i.e., ALH-grafted-Polyacrylic acid (ALH-g-PAA) through free radical copolymerization. Concentrations of the crosslinker N,N′-methylene-bis-acrylamide (MBA), and the initiator potassium persulfate (KPS) were optimized to study their effects on ALH-g-PAA swelling. The FTIR and solid-state NMR (CP/MAS 13C NMR) spectra witnessed the formation of ALH-g-PAA. Scanning electron microscopy (SEM) analysis revealed superporous nature of ALH-g-PAA. The gel fraction (%) of ALH-g-PAA was directly related to the concentrations of AA and MBA whereas the sol fraction was inversely related to the concentrations of AA and MBA. The porosity (%) of ALH-g-PAA directly depends on the concentration of AA and MBA. The ALH-g-PAA swelled admirably at pH 7.4 and insignificantly at pH 1.2. The ALH-g-PAA offered on/off switching properties at pH 7.4/1.2. The metoprolol tartrate was loaded on different formulations of ALH-g-PAA. The ALH-g-PAA showed pH, time, and swelling-dependent release of metoprolol tartrate (MT) for 24 h following the first-order kinetic and Korsmeyer-Peppas model. Haemocompatibility studies ascertained the non-thrombogenic and non-hemolytic behavior of ALH-g-PAA.

Flexible and thermoresponsive AEMR-pNIPAM/Cs0.33WO3 composite hydrogel film with NIR shielding potential for smart windows and smart curtains

Thermoresponsive flexible smart windows and smart curtains having high near-infrared (NIR) shielding and tuned visible light transmittance are essential for improving the energy efficiency of the buildings. The lower critical solution temperature (LCST) of the cross-linked poly(N-isopropylacrylamide) (pNIPAM) hydrogel film was precisely modified to a desired LCST value at 27.4 °C through the free radical copolymerization with 10 wt% of acrylated epoxidized methyl ricinoleate (AEMR). Cs0.33WO3 as NIR shielding nanoparticles (particle size < 200 nm) were synthesized via high energy ball milling method with AEMR as a surfactant for high NIR shielding efficiency and dispersion—the composite flexible hydrogel films with different wt% (0.3, 0.5,0.7, and 0.9 wt%) of Cs0.33WO3 nanoparticles were fabricated to analyze the NIR shielding efficiency and thermal insulation performance. The copolymeric hydrogel film with 0.7 wt% of Cs0.33WO3 nanoparticles (0.7-CWO) demonstrates a significant reduction in the NIR transmittance (15.0 % to 2.3 %) and variation in visible light transmittance from 73.6 % to 15.7 % while undergoing temperature-induced phase transition. The smart window fabricated with composite hydrogel film exhibits good integral luminous transmittance (Tlum, 380–780 nm, 68.7 %, below LCST) and justifiable solar modulation ability (ΔTsol, 300–2500 nm, 53.6 %). A model house was designed to monitor the indoor temperature difference, and a noticeable variation of 7 °C was observed in the house with and without 0.7-CWO film. Further, the developed composite material showed improvement in flexibility, water resistance, and thermal stability, confirming its usage for energy-saving smart windows or smart curtains.

Supramolecular self‐assembled nanoparticles for targeted therapy of myocardial infarction by enhancing cardiomyocyte mitophagy

AbstractMyocardial infarction accompanied by diabetes mellitus is accepted as the most serious type of coronary heart disease, and among the current treatment strategies, the precise delivery of protective drugs for inhibiting cardiomyocyte apoptosis is still a challenge. In this study, we developed a biodegradable nanoparticles‐based delivery system with excellent macrophage escape, cardiac targeting, and drug release properties to achieve targeted therapy of myocardial infarction. Specifically, a copolymer of p(DMA–MPC–CD) combining self‐adhesion, hydration lubrication, and targeting peptide binding site was successfully prepared by free radical copolymerization, and it was self‐assembled on the surface of melatonin‐loaded dendritic mesoporous silica nanoparticles (bMSNs) following the integration of adamantane‐modified cardiac homing peptide (CHP) based on supramolecular host–guest interaction. Importantly, a hydration layer formed around the zwitterionic phosphorylcholine groups of the multifunctional nanoparticles, which was confirmed by the enhancement in hydration lubrication and reduction in coefficient of friction, prevented the nanoparticles from phagocytosis by the macrophages. The in vivo bioluminescence imaging test indicated that the nanoparticles were endowed with satisfied cardiac targeting capability, and the in vivo mice study demonstrated that the intravenous injection of drug‐loaded nanoparticles (namely bMSNs–Mel@PDMC–CHP) effectively reduced cardiomyocyte apoptosis, alleviated myocardial interstitial fibrosis, and enhanced cardiac function.

Hydrophilic Modification of Polytetrafluoroethylene (PTFE) Capillary Membranes with Chemical Resistance by Constructing Three-Dimensional Hydrophilic Networks.

Polytetrafluoroethylene (PTFE) capillary membranes, known for the great chemical resistance and thermal stability, are commonly used in membrane separation technologies. However, the strong hydrophobic property of PTFE limits its application in water filtration. This study introduces a method whereby acrylamide (AM), N, N-methylene bisacrylamide (MBA), and vinyltriethoxysilane (VTES) undergo free radical copolymerization, followed by the hydrolysis-condensation of silane bonds, resulting in the formation of hydrophilic three-dimensional networks physically intertwined with the PTFE capillary membranes. The modified PTFE capillary membranes prepared through this method exhibit excellent hydrophilic properties, whose water contact angles are decreased by 24.3-61.2%, and increasing pure water flux from 0 to 1732.7-2666.0 L/m2·h. The enhancement in hydrophilicity of the modified PTFE capillary membranes is attributed to the introduction of hydrophilic groups such as amide bonds and siloxane bonds, along with an increase in surface roughness. Moreover, the modified PTFE capillary membranes exhibit chemical resistance, maintaining the hydrophilicity even after immersion in strong acidic (3 wt% HCl), alkaline (3 wt% NaOH), and oxidative (3 wt% NaClO) solutions for 2 weeks. In conclusion, this promising method yields modified PTFE capillary membranes with great hydrophilicity and chemical resistance, presenting substantial potential for applications in the field of water filtration.

Mucoadhesive, antioxidant, and lubricant catechol-functionalized poly(phosphobetaine) as biomaterial nanotherapeutics for treating ocular dryness.

Dry eye disease (DED) is associated with ocular hyperosmolarity and inflammation. The marketed topical eye drops for DED treatment often lack bioavailability and precorneal residence time. In this study, we investigated catechol-functionalized polyzwitterion p(MPC-co-DMA), composed of 2-methacryloyloxyethyl phosphorylcholine (MPC) and dopamine methacrylamide (DMA) monomers, as potential topical nanotherapeutics for DED. The copolymers were synthesized via random free-radical copolymerization, producing different proportions of catecholic functionalization. All as-prepared polymer compositions displayed good ocular biocompatibility. At a feeding ratio of 1:1, p(MPC1-co-DMA1) can facilitate a robust mucoadhesion via Michael addition and/or Schiff base reaction, thus prolonging ocular residence time after 4 days of topical instillation. The hydration lubrication of MPC and radical-scavenging DMA endow the nano-agent to ease tear-film hyperosmolarity and corneal inflammation. A single dose of p(MPC1-co-DMA1) (1mg/mL) after 4 days post-instillation can protect the cornea against reactive oxygen species, inhibiting cell apoptosis and the over-expression of pro-inflammatory factors (IL-6 and TNF-α). In clinical assessment, DED-induced rabbit eyes receiving p(MPC1-co-DMA1) could increase lacrimal fluid secretion by 5-fold higher than cyclosporine A. The catechol-functionalized polyzwitterion with enhanced lubricity, mucoadhesion, and anti-oxidation/anti-inflammation properties has shown high promise as a bioactive eye drop formulation for treating DED.

Synthesis, performance and mechanism of shrinkage-reducing agents with water-reducing function for cement-based materials

Three shrinkage-reducing agents (SRAs) possessing a water-reducing capacity with different structures were synthesized by aqueous free radical copolymerization. Their structures were characterized by Gel Permeation Chromatography (GPC), specific anion charge density, and Fourier Transform Infrared Spectrometer (FTIR) measurements. Their abilities to reduce surface tension and their adsorption and dispersing effectiveness in cement paste as well as their impacts on cement hydration and compressive strength, autogenous shrinkage, drying shrinkage, and pore structure of cement mortar were investigated. Results clearly showed that the three synthesized SRAs with a water-reducing function reduced the surface tension of pore solution, with the water-reducing SRA with butyl exerting the most significant effect due to its lower molecular mass. They enhanced the flowability of cement paste because of their adsorption on cement grains. The water-reducing SRA with dimethyl amino exhibited higher adsorption amounts on cement grains due to higher charge density, resulting in higher initial flowability of cement paste and more significant hydration retardation. Their presence decreased the autogenous shrinkage of cement mortar by reducing the surface tension of pore solution, delaying the cement hydration, and decreasing the capillary pore volume. Their addition also mitigated the drying shrinkage due to the synergistic effect of surface tension reduction, pore structure coarsening, and porosity (2.5–50 nm) reduction. Among the three, the water-reducing SRA with butyl demonstrated a higher capability of reducing the drying shrinkage and had a favorable effect on the compressive strength of mortar at later ages.

Mechanism-Guided Discovery of Cleavable Comonomers for Backbone Deconstructable Poly(methyl methacrylate).

The development of cleavable comonomers (CCs) with suitable copolymerization reactivity paves the way for the introduction of backbone deconstructability into polymers. Recent advancements in thionolactone-based CCs, exemplified by dibenzo[c,e]-oxepine-5(7H)-thione (DOT), have opened promising avenues for the selective deconstruction of multiple classes of vinyl polymers, including polyacrylates, polyacrylamides, and polystyrenics. To date, however, no thionolactone CC has been shown to copolymerize with methacrylates to an appreciable extent to enable polymer deconstruction. Here, we overcome this challenge through the design of a new class of benzyl-functionalized thionolactones (bDOTs). Guided by detailed mechanistic analyses, we find that the introduction of radical-stabilizing substituents to bDOTs enables markedly increased and tunable copolymerization reactivity with methyl methacrylate (MMA). Through iterative optimizations of the molecular structure, a specific bDOT, F-p-CF3PhDOT, is discovered to copolymerize efficiently with MMA. High molar mass deconstructable PMMA-based copolymers (dPMMA, Mn > 120 kDa) with low percentages of F-p-CF3PhDOT (1.8 and 3.8 mol%) are prepared using industrially relevant bulk free radical copolymerization conditions. The thermomechanical properties of dPMMA are similar to PMMA; however, the former is shown to degrade into low molar mass fragments (<6.5 kDa) under mild aminolysis conditions. This work presents the first example of a radical ring-opening CC capable of nearly random copolymerization with MMA without the possibility of cross-linking and provides a workflow for the mechanism-guided design of deconstructable copolymers in the future.

Preparation and characterization of palmitic acid/polymer composite phase change materials supported with cross-linked poly(limonene-co-ethylene glycol dimethacrylate) copolymers for low-temperature thermal applications

Limonene-based polymers have a growing interest as being renewable source-derived materials. Here, highly cross-linked porous polymers were synthesized by free radical copolymerization of water-in-oil (w/o) high internal phase emulsions (HIPEs) of limonene and ethylene glycol dimethacrylate (EGDMA). The bio-derived monomer content in the total monomer composition was set to 50 vol%. To vary the openness and permeability of the resulting porous copolymers, synthesized poly(limonene-co-EGDMA) (PLE-x) copolymers were processed via two different approaches as extraction (E) and lyophilization (L). Ultimately, the ring-porous PLE-E or PLE-L copolymers with different degrees of permeability were used as supporting matrices for the development of form-stable palmitic acid@poly(limonene-co-EGDMA) (PA@PLE-E and PA@PLE-L) composite phase change materials (PCMs). The chemical structure, pore morphology, specific surface area, and thermal properties of the PLE based supports and PA@PLE-E / PA@PLE-L composite PCMs were explored. BET specific surface areas of the ring-porous PLE-E and PLE-L frameworks were measured to be 20.5 m2.g−1 and 4.8 m2.g−1. In addition to that, the latent heats of the resulting composite PCMs were found to be 77.4 J.g−1 and 64.1 J.g−1, while the peak melting temperatures were 63.4 °C and 60.7 °C, for PA@PLE-E and PA@PLE-L, respectively. The bio-derived matrices based thermally stable leak-proof PA@PLE-x composite PCMs with proper latent heat storage (LHS) characteristics are ideal candidates as energy materials for passive solar heating applications due to their favorable phase change temperatures.

Degradable Alternating Copolymers by Radical Copolymerization of 2-Methylen-1,3-dioxepane and Crotonate Esters.

Producing backbone degradable copolymers via free-radical copolymerization is a promising, yet challenging method to develop more sustainable materials for many applications. In this work, we present the copolymerization of 2-methylen-1,3-dioxepane (MDO) with crotonic acid derivative esters. MDO can copolymerize by radical ring-opening polymerization incorporating degradable ester moieties in the polymer backbone, although this can often be difficult due to the very unfavorable reactivity ratios. Crotonic acid derivatives, on the other hand, can be easily produced completely from biomass but are typically very difficult to (co)polymerize due to low propagation rates and very unfavorable reactivity ratios. Herein, we present the surprisingly easy copolymerization between MDO and butyl crotonate (BCr), which shows the ability to form alternating copolymers. The alternating nature of the copolymer was characterized by MALDI-TOF and supported by the reactivity ratios calculated experimentally (rMDO = 0.105 and rBCr = 0.017). The alternating nature of the copolymers favored the degradability that could be achieved under basic conditions (in 2 h, all chains have molar masses smaller than 2 kg/mol). Last, the work was expanded to other crotonate monomers to expand the portfolio and show the potential of this copolymer family.

Self-healing amino acid-bearing acrylamides/n-butyl acrylate copolymers via multiple noncovalent bonds.

Four amino acid-bearing acrylamides, N-acryloyl-l-threonine (AThrOH), N-acryloyl-l-glutamic acid (AGluOH), N-acryloyl-l-phenylalanine (APheOH), and N-acryloyl-l, l-diphenylalanine (APhePheOH), were selected for copolymerization with n-butyl acrylate (nBA) to develop amino acid-based self-healable copolymers. A series of copolymers comprising amino acid-bearing acrylamides and nBA with tunable comonomer compositions and molecular weights were synthesized by free radical and reversible addition-fragmentation chain-transfer copolymerization. Self-healing and mechanical properties originated from the noncovalent bonds between the carboxyl, hydroxyl, and amide groups, and π-π stacking interactions among the amino acid residues in the side chains were evaluated. Among these copolymers, P(nBA-co-AGluOH) with suitable comonomer compositions and molecular weights (nBA : AGluOH = 82 : 18, Mn = 18 300, Mw/Mn = 2.58) exhibited good mechanical properties (modulus of toughness = 17.3 MJ m-3) and self-healing under ambient conditions. The multiple noncovalent bonds of P(nBA-co-AGluOH)s were also efficient in improving the optical properties with an enhanced refractive index and good transparency.

Reversibly Adhesive, Anti-Swelling, and Antibacterial Hydrogels for Tooth-Extraction Wound Healing.

Oral wound treatment faces challenges due to the complex oral environment, thus, sealing the wound quickly becomes necessary. Although some materials have achieved adhesion and sterilization, how to effectively solve the contradiction between strong adhesion and on-demand removal remains a challenge. Herein, a reversibly adhesive hydrogel is designed by free radical copolymerization of cationic monomer [2-(acryloyloxy) ethyl] trimethylammonium chloride (ATAC), hydrophobic monomer ethylene glycol phenyl ether acrylate (PEA) and N-isopropylacrylamide (NIPAAm). The cationic quaternary ammonium salts provide electrostatic interactions, the hydrophobic groups provide hydrophobic interactions, and the PNIPAAm chain segments provide hydrogen bonding, leading to strong adhesion. Therefore, the hydrogel obtains an adhesion strength of 18.67KPa to oral mucosa and can seal wounds fast within 10s. Furthermore, unlike pure PNIPAAm, the hydrogel has a lower critical solution temperature of 40.3°C due to the contribution of ATAC and PEA, enabling rapid removal with 40°C water after treatment. In addition, the hydrogel realizes excellent anti-swelling ratio (≈80%) and antibacterial efficiency (over 90%). Animal experiments prove that the hydrogel effectively reduces inflammation infiltration, promotes collagen deposition and vascular regeneration. Thus, hydrogel as a multi-functional dressing has great application prospects in oral wound management.

Mesh-size adjustable hydrogel via light and pH induction

The ability of stimuli-responsive hydrogels to swell and shrink is an important property that enables their wide range of applications. We prepared a novel azopyridine-based hydrogel by free radical copolymerization and investigated its multi-responsive behaviors to pH and UV light. The hydrogel swelled rapidly in acidic environments, reaching 303% of its mass in neutral conditions at equilibrium. The hydrogel also swelled significantly in the presence of α-cyclodextrins (α-CDs) due to host–guest interactions, reaching 276% of its mass in distilled water at equilibrium. The hydrogel shrank reversibly under UV light.

Synthesis, performance and mechanism of novel polymer-type shrinkage reducing agents for cement-based materials

Simplifying the synthesis process and preparing a new type of shrinkage reducing agent (SRA) with a low dosage and high efficiency are beneficial for promoting the development of SRA and its application in cement-based materials. This study aims to synthesize three novel polymer-type SRAs with diverse structures through free radical copolymerization and to investigate their performance and working mechanisms in cement-based materials. Results clearly showed that the three synthesized SRAs reduced the surface tension of pore solution, and increased the flowability of cement paste. The SRAs-1 with butyl resulted in higher flowability of cement paste due to lower surface tension. Their addition at a low dosage of 0.5% by cement mass effectively mitigated the shrinkage of cement mortar. Among the three, SRAs-1 with butyl exhibited a higher capability of reducing drying shrinkage due to lower surface tension, lower porosity in the range of 2.5–50 nm, and lower total porosity.

The Triumph of the Spin Chemistry of Fullerene C60 in the Light of Its Free Radical Copolymerization with Vinyl Monomers.

The spin theory of fullerenes is taken as a basis concept to virtually exhibit a peculiar role of C60 fullerene in the free radical polymerization of vinyl monomers. Virtual reaction solutions are filled with the initial ingredients (monomers, free radicals, and C60 fullerene) as well as with the final products of a set of elementary reactions, which occurred in the course of the polymerization. The above objects, converted to the rank of digital twins, are considered simultaneously under the same conditions and at the same level of the theory. In terms of the polymerization passports of the reaction solutions, a complete virtual picture of the processes considered is presented.

Green synthesis of Dextrin‐graft‐poly(allyl amine‐co‐methacrylic acid)/reduced graphene oxide composite and its application for dye and pesticide removal from the aqueous medium

AbstractA Dextrin‐graft‐poly(allyl amine‐co‐methacrylic acid)/reduced graphene oxide (DEXTGP/RGO) is synthesized through the grafting of a combination of allyl amine (AAM) and methacrylic acid (MAA) monomers onto the dextrin polysaccharide backbone by using the free radical copolymerization technique in an aqueous medium, with potassium peroxydisulfate serving as the initiator followed by the partial reduction of graphene oxide (GO). Various characterization techniques including FTIR, 1H/13C NMR, XRD, FESEM, EDAX, and BET analysis are utilized to characterize both the synthesized DEXTGP/RGO composite and graft copolymer. Investigations are conducted on multiple operational variables, including adsorption kinetics, isotherms, and thermodynamic parameters, for the adsorption of both MB and PL. Both intra‐particle diffusion kinetic model and pseudo‐second‐order kinetics are observed to follow for the adsorption of MB, while the Langmuir isotherm model provided a good fit for the equilibrium data. In contrast, the adsorption of PL displayed solely pseudo‐second‐order kinetics, while the equilibrium data shows good agreement with both the Langmuir and Dubinin‐Radushkevich isotherm models. Maximum adsorption capacity ( ) of the RGO composite is found to be 932.56 mg/g for MB and 311.63 mg/g for PL. The thermodynamic analysis revealed that the adsorption of dye and pesticide onto the RGO composite is a spontaneous process.

Synthesis, Characterization and Catechol-Based Bioinspired Adhesive Properties in Wet Medium of Poly(2-Hydroxyethyl Methacrylate-co-Acrylamide) Hydrogels.

Hydrogels consist of crosslinked hydrophilic polymers from which their mechanical properties can be modulated for a wide variety of applications. In the last decade, many catechol-based bioinspired adhesives have been developed following the strategy of incorporating catechol moieties into polymeric backbones. In this work, in order to further investigate the adhesive properties of hydrogels and their potential advantages, several hydrogels based on poly(2-hydroxyethyl methacrylate-co-acrylamide) with N'N-methylene-bisacrylamide (MBA), without/with L-3,4-dihydroxyphenylalanine (DOPA) as a catecholic crosslinker, were prepared via free radical copolymerization. 2-Hydroxyethyl methacrylate (HEMA) and acrylamide (AAm) were used as comonomers and MBA and DOPA both as crosslinking agents at 0.1, 0.3, and 0.5 mol.-%, respectively. The polymeric hydrogels were characterized by Fourier transform infrared spectroscopy (FT-IR), thermal analysis and swelling behavior analysis. Subsequently, the mechanical properties of hydrogels were determined. The elastic properties of the hydrogels were quantified using Young's modulus (stress-strain curves). According to the results herein, the hydrogel with a feed monomer ratio of 1:1 at 0.3 mol.-% of MBA and DOPA displayed the highest rigidity and higher failure shear stress (greater adhesive properties). In addition, the fracture lap shear strength of the biomimetic polymeric hydrogel was eight times higher than the initial one (only containing MBA); however at 0.5 mol.-% MBA/DOPA, it was only two times higher. It is understood that when two polymer surfaces are brought into close contact, physical self-bonding (Van der Waals forces) at the interface may occur in an -OH interaction with wet contacting surfaces. The hydrogels with DOPA provided an enhancement in the flexibility compared to unmodified hydrogels, alongside reduced swelling behavior on the biomimetic hydrogels. This approach expands the possible applications of hydrogels as adhesive materials, in wet conditions, within scaffolds that are commonly used as biomaterials in cartilage tissue engineering.