Radical Copolymerization Research Articles

Removal of trisacryl red using hydrogels composites based on chitosan

This study entails the radical copolymerization synthesis of (2-acrylamido-2-methyl-1-propane sulfonic acid) AMPS, utilizing (N,N’methylene bis-acrylamide) MBAm as a cross-linking agent and potassium persulfate (PPS) as an initiator to produce chitosan-based composite hydrogels. The investigation involved the various masses of chitosan (250, 500, and 1000 mg). The characterization of the obtained composites and the dye adsorption process was carried out using FTIR, TGA, SEM, UV-visible, and STEM techniques. Swelling properties in distilled water were examined, revealing that the swelling rates at temperatures of 25°C and 37°C for the hydrogel of poly(AMPS-g-MBAm)/chitosan (1000 mg) exceed those of hydrogels with poly(AMPS-g-MBAm)/chitosan (250 and 500 mg). Furthermore, the sorption capacities of the dye were investigated, demonstrating that the sorption capacities of poly (AMPS-g-MBAm)/chitosan (1000 mg) at different temperatures surpass those of poly(AMPS-g-MBAm)/chitosan (250mg, and 500 mg).

Graphene-Enhanced Methacrylated Alginate Gel Films for Sustainable Dye Removal in Water Purification.

Self-standing nanocomposite films were prepared by three-dimensional UV-induced radical copolymerization of methacrylated alginate (MALG) with acrylic acid (AA) and reinforced with graphene oxide (GO) to improve both mechanical strength and dye adsorption capacity in wastewater decontamination operations. Dynamic mechanical-thermal analysis revealed variations in storage modulus: the higher the GO content, the higher the storage modulus (E') values. Also, the higher the temperature (associated with a lower and lower water content of films), the larger values of E' for the films of the same composition (E'(25 °C) = 676.6-1538.7 MPa; E'(100 °C) = 886.9-2066.6 MPa), providing insights into the compatibility between GO and the MALG/AA matrix, as well as, assessing the improvement in the nanocomposite's final mechanical properties. These crosslinked films in a dry state exhibited rapid water uptake and relatively short drying times (ca. 30 min at room temperature for the MALG/AA/GO composites) resulting from the swelling-drying studies and water contact angle measurements. The efficacy of methylene blue removal from water assessed via UV-VIS spectrometry revealed excellent results, expressed as an adsorption yield of 70-80% and 85-98% after 30 h and 258 h, respectively, of immersion time of films into an MB aqueous solution of 12.5 mg/L (as the contaminated water model). The reusability of the same films was evaluated by consecutive extraction processes of MB from the composite membranes when the content of desorbed dye was also spectrophotometrically monitored and conducted in acidic conditions (HCl aqueous solutions of pH 2). Overall, the introduction of GO in the developed self-standing MALG/AA nanocomposite films exhibited enhanced mechanical properties and increased efficiency for dye removal applications. Their great reutilization potential was highlighted by low drying times and a good ability to release the dye initially adsorbed. Thus, the prepared films could be suitable materials for sustainable and effective water treatment technologies.

Elastic Interfacial Layer Enabled the High-Temperature Performance of Lithium-Ion Batteries Via Utilization of Synthetic Fluorosulfate Additive

The key to producing high-energy Li-ion cells is ensuring the interfacial stability of Si-containing anodes and Ni-rich cathodes. Herein, 4-(allyloxy) phenyl fluorosulfate (APFS), a multi-functional electrolyte additive that forms a mechanical strain-adaptive solid electrolyte interphase (SEI) comprising LiF and polymeric species, and a thermally stable cathode–electrolyte interface containing S–O and S–F species. The radical copolymerization of vinylene carbonate (VC) with APFS via electrochemical initiation creates a spatially deformable polymeric SEI on the SiG-C (30 wt.% graphite + 70 wt.% SiC composite) anode, with large volume changes during cycling. Moreover, the APFS-promoted interfacial layers reduce Ni dissolution and deposition. Furthermore, APFS deactivates the Lewis acid PF5, thereby inhibiting hydrolyses that produce unwanted HF. These results indicate that the combined use of VC with APFS allows capacity retentions of 72.5% with a high capacity of 143.5 mAh g−1 in SiG-C/LiNi0.8Co0.1Mn0.1O2 full cells after 300 cycles at 45 °C.

Preparation and characterization of magnetic microgels with linear thermosensitivity over a wide temperature range

Abstract Hybrid nanogels that are both thermosensitive and superparamagnetic, and have good biocompatibility are expected to have applications in the biomedical field. In this article, a linearly thermosensitive magnetic microgel was prepared by a radical copolymerization reaction in aqueous dispersion. In this reaction, poly(ethylene glycol) diacrylate was used as a crosslinker, polyvinylpyrrolidone was used as a stabilizer, and 2-methoxyethyl acrylate, poly(ethylene glycol)methyl ether acrylate, and 2-(methacryloyloxy)ethyl acetoacetate were used as copolymer monomers. The thermosensitive magnetic microgel displays a linear volume phase transition in water upon heating over a wide range of temperatures. Transmission electron microscopy, scanning electron microscopy, and dynamic light scattering were used to characterize the morphology and dimensions of the thermosensitive magnetic microgel. This material is expected to be used in magnetically targeted drug delivery systems that require linear drug release.

1,1'- Thiocarbonyldiimidazole Radical Copolymerization for the Preparation of Degradable Vinyl Polymers.

1,1'-Thiocarbonyldiimidazole (TCDI) readily undergoes radical copolymerization with tert-butyl acrylate (tBA), N,N-dimethylacrylamide, and styrene. 1H NMR monitoring of the comonomer reactivity revealed a notable compatibility between TCDI and comonomers, resulting in similar consumption rates when TCDI was introduced at a 10% feed ratio. Furthermore, trithiocarbonate-mediated RAFT copolymerization of TCDI with tBA gave polymers that exhibited a linear increase of molar mass (Mnth = 2-10 kg mol-1) with conversion with relatively low dispersities (1.2-1.4). Importantly, this process enabled a successful chain extension of the produced P(TCDI-co-tBA) copolymer with styrene to form a diblock copolymer. The copolymers generated through this method contain TCDI-derived diimidazolyl thioether moieties, as established through 1H NMR spectroscopy. Additionally, degradation experiments using isopropylamine, benzoyl peroxide, sodium methoxide, and bleach have provided further confirmation of the presence of degradable TCDI moieties in the vinyl copolymer backbone.

Effect of synthesis conditions on molecular characteristics of coumarin and N-vinylpyrrolidone copolymers

Radical copolymerization was used to synthesize copolymers of coumarin and N -vinylpyrrolidone with molecular masses and compositions varying over wide limits. Molecular and hydrodynamic characteristics of the prepared copolymers and their dependence on the synthesis conditions were studied by dynamic and static light scattering.

In-situ regulation of solid electrolyte interface formation by molecular designing of polymer binders for high-performance silicon/graphite anode

A new acrylic acid copolymer is prepared by free radical copolymerization with acrylic acid (AA) and hexafluoro butyl acrylate (HFA). The product is used as a polymer binder for Silicon/Graphite (Si/Gr) anode in a lithium-ion battery. The molecular structure of the copolymer and the electrochemical performance of binders are carefully investigated. The results show that the Si/Gr anode based on AA-HFA copolymers binders has good rate performance and excellent cycle stability after adjusting the amount of HFA. The initial charge/discharge capacity reachs about 771/914 mAh g−1 during the first charge-discharge cycle. Its Initial Coulomb Efficiencie (ICE) is higher than 84 %. The reversible specific capacity can be maintained to 504 mAh g−1 with in 350 cycles at 1 C, while it can reach 220 mAh g−1 at 5 C. The in-depth analysis further show that this kind of AA-HFA copolymer binder can effectively inhibit electrolyte decomposition since solid electrolyte interphases (SEI) can be constructed at a molecular level. This stable interphases can be attributed to the successful combination of the flexible molecular structure of AA-HFA copolymer with the rigid SEI layer formed between the active material and electrolyte. The success of this work provides a promising way to pursue lithium-ion batteries with long cycle life by molecular designing with polymer binders.

Synthesis of Ethylene–Vinyl Acetate Copolymers by Reversible Addition–Fragmentation Chain-Transfer Radical Polymerization

Reversible addition–fragmentation chain-transfer radical copolymerization of ethylene with vinyl acetate in the presence of azobis(isobutyronitrile) and xanthate as a chain-transfer agent was studied. Products containing 12–42 mol % vinyl acetate units were prepared under varied reaction conditions. The glass transition points and degradation temperatures of the polymers were determined. The rheological properties of ethylene–vinyl acetate copolymers were studied in detail. The effect of additions of the copolymers synthesized on the rheological characteristics of diesel fuel was evaluated. The ethylene–vinyl acetate copolymers synthesized reduce the limiting filterability temperature of the diesel fuel.

Thermally reprocessable bio-based polyhydroxyurethane vitrimers

Vitrimers present one way to address growing demand for sustainably sourced, recyclable thermoset polyhydroxyurethanes (PHUs). We employ vinylogous urethane formation for dynamic bonding, using amine-terminated bio-sourced PHUs (prepared via terpolymerization of diglycerol dicarbonate (DGC) with Priamine 1074 and 1,10-diaminodecane (DAD)) as crosslinkers with ketone-functional copolymers. The latter are synthesized via atom transfer radical copolymerization (ATRP) of an alkyl methacrylate (C13MA, with average side-chain length of 13 carbons) with (2-acetoacetoxy) ethyl methacrylate (AAEMA) (initial AAEMA mole fraction = 0.1–0.4). By manipulating copolymer functionality, thermoset PHUs (Young's moduli spanning from 31 ± 1.5 kPa to 133 ± 5.7 kPa) are obtained. Furthermore, as ketone group concentration increases, networks became tighter, with slower relaxation rates and increased apparent activation energy of stress relaxation, in agreement with calculated molecular weight between crosslinks obtained rheologically. Finally, thermoset PHUs can be effectively recycled three times through remolding at 100 °C without compromising their mechanical properties.

Umpolung Isomerization in Radical Copolymerization of Benzyl Vinyl Ether with Pentafluorophenylacrylate Leading to Degradable AAB Periodic Copolymers

AbstractThis study revealed that benzyl vinyl ether (BnVE) shows a peculiar isomerization propagation in its radical copolymerization with an electron‐deficient acrylate carrying a pentafluorophenyl group (PFA). The co‐monomer pair inherently exhibits the cross‐over propagation feature due to the large difference in the electron density. However, the radical species of PFA was found to undergo a backward isomerization to the penultimate BnVE pendant giving a benzyl radical species prior to propagation with BnVE. The isomerization brings a drastic change in the character of the growing radical species from electrophilic to nucleophilic, and thus the isomerized benzyl radial species propagates with PFA. Consequently, the two monomers were consumed in the order AAB (A: PFA; B: BnVE) and the unique periodic consumption was confirmed by the pseudo‐reactivity ratios calculated by the penultimate model: r11=0.174 and r21=6600 for PFA (M1) with BnVE (M2). The pentafluorophenyl ester groups of the resulting copolymers are transformed into ester and amide groups by post‐polymerization alcoholysis and aminolysis modifications. The unique isomerization in the AAB sequence allowed the periodic introduction of a benzyl ether structure in the backbone leading to efficient degradation under acid conditions.

Umpolung Isomerization in Radical Copolymerization of Benzyl Vinyl Ether with Pentafluorophenylacrylate Leading to Degradable AAB Periodic Copolymers.

This study revealed that benzyl vinyl ether (BnVE) shows a peculiar isomerization propagation in its radical copolymerization with an electron-deficient acrylate carrying a pentafluorophenyl group (PFA). The co-monomer pair inherently exhibits the cross-over propagation feature due to the large difference in the electron density. However, the radical species of PFA was found to undergo a backward isomerization to the penultimate BnVE pendant giving a benzyl radical species prior to propagation with BnVE. The isomerization brings a drastic change in the character of the growing radical species from electrophilic to nucleophilic, and thus the isomerized benzyl radial species propagates with PFA. Consequently, the two monomers were consumed in the order AAB (A: PFA; B: BnVE) and the unique periodic consumption was confirmed by the pseudo-reactivity ratios calculated by the penultimate model: r11 =0.174 and r21 =6600 for PFA (M1 ) with BnVE (M2 ). The pentafluorophenyl ester groups of the resulting copolymers are transformed into ester and amide groups by post-polymerization alcoholysis and aminolysis modifications. The unique isomerization in the AAB sequence allowed the periodic introduction of a benzyl ether structure in the backbone leading to efficient degradation under acid conditions.

Measurement of the Adhesion Force of a Living Sessile Organism on Antifouling Coating Surfaces Prepared with Polysulfobetaine-Grafted Particles.

An antifouling polymer brush-like structure was fabricated by a simple and versatile dip-coating method of sulfobetaine containing copolymer-grafted silica nanoparticles (SiNPs) and alkyl diiodide cross-linkers. Surface-initiated atom transfer radical copolymerization of 3-(N-2-methacryloyloxyethyl-N,N-dimethyl)ammonatopropanesulfonate (MAPS) and N,N-dimethylaminoethyl methacrylate (DMAEMA) was carried out from initiator-immobilized SiNPs to give poly(MAPS-co-DMAEMA)-grafted SiNPs (MAPS/DMAEMA = 9/1, mol/mol) with diameters of 150-170 nm. The SiNP-g-copolymer/2,2,2-trifluoroethanol solution was dip-coated on silicon and glass substrates. Successive treatment with 1,4-diiodobutane in methanol gave a hydrophilic cross-linked coating film for the SiNP-g-copolymer. The cross-linked particle brushes did not peel off from the substrate even after washing with water in an ultrasonic cleaner despite the simple physical absorption of the SiNP-g-copolymer on the substrate surface. The adhesion force of the tentacle of a living barnacle cyprid on a glass surface covered with the cross-linked SiNP-g-copolymer was directly measured by scanning probe microscopy in seawater. The coating film exhibited extremely low adhesion to the cypris larva in the seawater, expecting this to be an effective antifouling property.

Polyacrylamide quaternary ammonium salts based on stable adsorption in soil and its application on the control of soil-borne fungal disease

Currently, soil-borne fungal disease (SBFD) have caused a huge damage in agriculture, and small molecule soil disinfectants have been widely used for the prevention and control of SBFD, which could not only kill the chlamydospore of pathogenic fungi, but also completely destroy the microbial community and its functional diversity in the soil, and is not conducive to subsequent plant planting. Therefore, how to effectively inhibit plant pathogenic fungi while maintaining the general balance of microbial population in the soil to facilitate subsequent plant planting come to be critical problem in the prevention and control of SBFD. In this work, a series of polyacrylamide containing quaternary ammonium salts (PAM-X) were synthesized based on the radical copolymerization of acrylamide (AM) and acrylamide containing different quaternary ammonium salts groups (AMX). Owing to the entanglement between polymer chains and soil, PAM-X could be stably absorbed in the soil, thus effectively delaying the free migration of PAM-X chains in soil, and reducing the probability of being leached from soil, which might be the key to obtain novel polymeric quaternary ammonium salts that have less impact on the environment. Banana Fusarium wilt, also known as “banana cancer”, caused by Fusarium oxysporum f. sp. cubense (Foc), was chosen as a typical soil-borne pathogen disease to verify the rationality of the above thoughts. The results showed PAM-X had well anti-Foc4 activities in soil, and could maintain the general balance of microbial population in the soil, which are almost non-toxic to earthworms in soil and fish, thus provides a new prevention and control method for SBFD.

Study on Temperature-Controlled Branching Behavior with Self-Condensing Atom Transfer Radical Copolymerization of Latent Inimer and Styrene

Study on Temperature-Controlled Branching Behavior with Self-Condensing Atom Transfer Radical Copolymerization of Latent Inimer and Styrene

Thermal- and radiation-sensitive hydrogel based on hydroxyethyl cellulose and manganese dioxide nanoparticles for synergistic chemoradiotherapy of breast cancer

A thermal- and radiation-sensitive nanocomposite hydrogel-based drug delivery system (DDS) composed of hydroxyethyl cellulose (HEC), poly(N-isopropylacrylamide) (PNIPAAm), and manganese dioxide nanoparticles (MnO2 NPs) was developed for in vitro synergistic chemoradiotherapy of breast cancer cells. For this aim, MnO2 NPs were synthesized in super basic medium, and then their surfaces were modified by a methacrylate-end capped silane coupling agent. The thermal- and radiation-sensitive hydrogel was then synthesized through a free radical copolymerization of HEC, NIPAAm monomer, and modified NPs in the presence of a crosslinker. The lower critical solution temperature (LCST) for the DDS was obtained as 37.5-40°C by de-swelling test at various temperatures. The developed hydrogel was physically loaded with doxorubicin (Dox), and its drug loading capacity and in vitro thermal-triggered drug release behavior were investigated. Anticancer activity of the fabricated DDS/Dox in chemotherapy, radiotherapy, and synergistic chemoradiotherapy were assessed by MTT-assay, and it was found that the dosage of 5 μgmL−1 with applying 2 Gy at 48 hours is the optimum for the synergistic chemoradiotherapy of breast cancer cells. This low concentration of DDS as well as low radiation dose can be lead to proper therapy outcomes with minimum side effects.

Organosilicon copolymers containing triazole and triethoxysilyl groups as the basis for promising functional hydrophobic materials

New functional heat-resistant poly (1-vinyl-1,2,4-triazole-co-triethoxyvinylsilane) (poly (VT-co-TEVS)) copolymers of various compositions containing triazole and triethoxysilyl groups in the side chains were synthesized by radical copolymerization. Elemental analysis, Fourier transform infrared spectroscopy, NMR spectroscopy, gel permeation chromatography, dynamic light scattering, scanning electron microscopy, thermogravimetric analysis, and differential scanning calorimetry were used to study the composition and structure of poly (VT-co-TEVS) copolymers. The weight average molecular weight of the copolymers varies from 21 to 174 kDa. The reactivity ratios of comonomers in copolymerization (rVT = 4.004 and rTEVS = 0.227) indicate the high reactivity of VT. The resulting copolymers exhibit high thermal stability up to 270 °C. Modification of flexible chain poly (VT-co-TEVS) copolymers was carried out using hydrolytic polycondensation of triethoxysilyl groups. Monitoring of the hydrodynamic diameters of the synthesized copolymers showed intermacromolecular crosslinking of polymer chains due to the formation of Si–O–Si siloxane bonds. Based on spatially cross-linked polyorganosiloxanes containing a functional 1,2,4-triazole fragment, hydrophobic heat-resistant polymeric materials were obtained.

A simple photocatalytic assisted strategy by MIL-100 (Fe) for fabrication of polymer based on H-bonding as filtrate reducer to resist salt and temperature in ultra-deep wells

Improving the performance of water-based drilling fluids for high temperature, salt and calcium resistance in the exploration of deep and ultra-deep wells is a matter of great urgency. In this study, MIL-100 (Fe) nanosphere catalyst with regular shape, uniform size and good monodispersity is prepared ahead of time. XRD, SEM and BET tests indicates that the MIL-100 (Fe) owning large specific surface areas, adjustable pore sizes and high porosity can display to be a photocatalyst. Based on the excellent photocatalytic activity under visible light, a new one-pot method strategy was supposed to achieve the graft modification on N atom in acrylamide using aziridine, and obtained the multi-amine allyl monomer. Finally, the poly (AM/AMPS/PSMM) (PAAP) filtrate reducer with significant hydrogen bonding effect was successfully synthesized by free radical copolymerization with acrylamide (AM), 2-acrylamide-2-methylpropanesulfonic acid (AMPS) and the pre-synthesized multi-amine allyl monomer. Due to the three dimensional hydrogen bonding interaction and resulted supramolecular association structure, the PAAP-based drilling fluids exhibit outstanding rheological and filtration properties even after aging at high temperatures and high salinity. The filtration volume after aging at 180 °C for 16 h is only 6.0 mL, meanwhile, the 20 wt% NaCl and 1.5 wt% CaCl2 copolymer base slurry aged at 180 °C both show the satisfactory filtration loss and offering performance higher than commercial filtrate reducers. Specifically, after aging at 180 °C, the filtration losses of DSP-1/BM and DSP-2/BM were 19.8 and 37.2 mL with 20 wt% NaCl contamination, respectively, while the filtration loss of PAAP was only 10.8 mL. Even under both 1.5 wt% CaCl2 contamination and 180 °C aging, the filtration loss of PAAP was only 11.0 mL, whereas the filtration loss of DSP-1 and DSP-2 reached 26.0 and 20.0 mL. Finally, the filtration control mechanism of poly (AM/AMPS/PSMM) was proposed via XPS test, hydrogen bonding analysis, filter cake morphologies observation by SEM and particle size distribution measurement.

Unveiling the Role of Compositional Drifts on the Tack of Pressure‐Sensitive‐Adhesives

AbstractPressure‐sensitive‐adhesives (PSAs) are pervasive in electronic, automobile, packaging, and biomedical applications due to their ability to stick to numerous surfaces without undergoing chemical reactions. These materials are typically synthesized by the free radical copolymerization of alkyl acrylates and acrylic acid, leading to an ensemble of polymer chains with varying composition and molecular weight. Here, reversible addition−fragmentation chain‐transfer (RAFT) copolymerizations in a semi‐batch reactor are used to tailor the molecular architecture and bulk mechanical properties of acrylic copolymers. In the absence of cross‐links, the localization of acrylic acid toward the chain ends leads to microphase separation, creep resistance, and enhanced tack. However, in the presence of Al(acac)3 crosslinker, the creep resistance remains unchanged and mostly the large‐strain mechanical properties are affected. This behavior is attributed to microphase separation, but also to a change in the energy required to break physical associations, and untangle and elongate associative polymers to large deformations.

SYNTHESIS AND ANTIVIRAL ACTIVITY OF COPOLYMERS OF OXYCINNAMIC ACID WITH N-VINYLAMIDES

Radical copolymerization of coumarin with N-vinylamides (N‑vinylpyrrolidone, N-methyl-N-vinylacetamide, N-vinylformamide) was used to prepare copolymers of various natures and varied molecular masses. After the subsequent reactions in polymer chains, water-soluble copolymers of salts of oxycinnamic acid and its hydrazides were obtained. The synthesized copolymers of salts and hydrazides of oxycinnamic acid with N-vinylamides have low cytotoxicity and demonstrate the pronounced antiviral activity against human respiratory syncytial virus (strain A2).

Degradable Poly(styrene sulfonate) Polyanions for Biomedical and Electrochemical Applications

AbstractThe synthesis of poly(styrene sulfonate) with hydrolysable ester groups in the main chain is reported. The material is obtained by free radical copolymerization of either styrene sulfonate sodium salt (SSNa) or styrene sulfonate alkyl esters (SSA) with the cyclic ketene acetal 2‐methylen‐1,3,6‐trioxocane (MTC). As for other systems made from cyclic ketene acetals, the reactions are difficult to control and give copolymers with high polydispersity index. MTC homopolymer is obtained as a side product in both cases. Thermal cleavage of the alkyl protective groups of the poly(styrene sulfonate alkyl esters) to obtain the target polystyrene sulfonate anions remains incomplete. Thus, direct synthesis of the polyanion from SSNa and MTC is the more efficient process, especially since the poly(SSNa‐co‐MTC) copolymer can be easily separated from MTC homopolymer. 1H‐NMR analytics indicates MTC repeat unit contents of 2–11%, depending on the initial SSNa to MTC ratio. The MTC ester groups of the copolymers are hydrolyzed in aqueous conditions, with and without enzyme, and a marked decrease in the molar mass is observed after hydrolysis. This confirms that these copolymers have the designed intended break points in the main chain, and could become a part of fully degradable electroactive polymer systems.