Radical Polymerization Of Acrylic Acid Research Articles

Transforming watermelon (Citrullus lanatus) rind into durable superabsorbent hydrogels for enhanced soil water retention properties and adsorbs dye in water

Innovative superabsorbent hydrogels were synthesized from watermelon rind (WR), an abundant agricultural waste. The process involved free radical polymerization of acrylic acid (AA) and acrylamide (AAm) with WR particles activated by ammonium persulfate (APS), resulting in (AA-co-AAm)/WR hydrogels with high equilibrium swelling capacities of 749 ± 32 g/g. Notably, after eight cycles, the WR hydrogel maintained 94.88 % of its initial swelling capacity, significantly outperforming the (AA-co-AAm) hydrogel without WR (13.80 % retention). This durability, combined with excellent water retention across various soil textures and high adsorption capacity for methylene blue (MB), underscores the WR hydrogel as a superior soil moisture conservation agent. This study marks a significant advance in recycling organic waste and enhancing water management in agricultural soils, demonstrating the potential for sustainable hydrogel development.

Modulation of ion-conducting groups in aqueous terpolymer binders to boost the electrochemical performance of silicon-based anodes

Silicon anodes hold great promise for the next-generation energy dense lithium-ion batteries (LIBs) due to their high specific capacity, yet the capacity of silicon anodes rapidly decays during repeated charge/discharge processes, which can hardly be alleviated via conventional binders due to the poor mechanical properties, insufficient ion/electronic conduction, and weak adhesion force. Herein, a random terpolymer (AMS) with fast ion transport and robust adhesion force was developed via the radical polymerization of acrylic acid (AA), acrylamide (AM) and 2-acrylamide-2-methylpropanesulfonic acid (AMPS), and used as aqueous binder for silicon/graphite (Si/C) anodes. The carboxyl and amide groups from AA and AM can form numerous of hydrogen bonds with the silicon particles, leading to a strong adhesion effect, while the sulfonic acid groups can construct fast channels for the rapid transport of lithium ions. Finally, the Si/C anode using the AMS411 binder delivers a high specific capacity of 322.48 mAh g−1 along with the superior operation stability at 0.5C (high-capacity retention ratio of 80.8 % after 500 cycles). This work provides that the incorporation of specific functional groups effectively enhances the overall electrochemical performance of the silicon-based anodes.

Adsorption mechanism of the novel amphoteric dispersant and its effect on structure and properties of hydration products

The novel amphoteric dispersant (NAD) was prepared by free radical polymerization of acrylic acid (AA), vinyl butylpolyoxyethylene ether (VBPE), N,N-dimethyl-methacryloxyethyl-aminopropyl sulfonate (DMAPS) and acrylate sulfated starch (ASS). It is characterized that the introduction of zwitterionic monomer as side groups and modified starch as branch chains. The chemical structure and its effects on the fluidity, strength, durability and microstructure of cement-based composites containing clay were tested. The results indiacted that zwitterions can improve the chelating adsorption capacity and eliminate the influence of chloride ions, while modified starch branch chain can improve the effect of slow coagulation and water retention. NAD has excellent dispersing and mud resistance effect, which makes the interface of cement hydration products clear, regular shape, uniform distribution and compact structure.The dispersion mechanism was proposed and it is think that NAD was mainly adsorbed on the interface of cement particles by zwitterion chelation adsorption and on the interface of the mud particles by anion groups. Meanwhile, the polyoxyethylene and the starch branch chains synergistic to form spatial barrier layer, showing excellent effects on blocking mud water absorption, improving dispersing and regulating hydration products structure. The research results have positive significance for the developing highly effective anti-mud dispersants.

Developing a carbon composite hydrogel with a highly conductive network to improve strain sensing performance

Both carbon aerogels and conductive hydrogels have provoked immense research interest as flexible sensing materials. However, conventional carbon aerogels show limited stretchability, while conductive hydrogels generally show limited conductivity. Herein, we develop a carbon composite hydrogel with a highly conductive network by encapsulating a cellulose fiber-derived carbon aerogel with a liquid metal-based conductive hydrogel formed by the in situ free radical polymerization of acrylic acid. The as-prepared carbon composite hydrogel inherits its high conductivity from the cellulose fiber-derived carbon aerogel and its good stretchability, adhesion and self-healing properties from the liquid metal-based hydrogel. Moreover, the carbon composite hydrogel possesses a high tensile strength and toughness due to the rigid network of the carbon aerogel. When serving as the tensile strain sensing material, the carbon composite hydrogel shows a very high sensitivity (gauge factor = 13.1 in the strain range of 400–500%), ultralow detection limit (0.1%), quick response and recovery time (166 ms at the strain of 1%) and excellent durability (1000 cycles under at 10% and 100% strains). In addition, the carbon composite hydrogel can obtain good temperature tolerance, adapt to high humidity and sustain its good sensing performance at low and high temperatures simply by coating a layer of glycerin on its surface. This work broadens the prospects for the design and preparation of conductive hydrogel-based strain sensors, and it facilitates their application in monitoring the biomedical signals of humans.

The effects of degassing, neutralization, and dewatering on the CMC-g-poly (acrylic acid-co-methacrylic acid) hydrogel

CMC-g-poly (acrylic acid-co-methacrylic acid) hydrogel was prepared by free radical polymerization of acrylic acid (AA) and methacrylic acid (MAA) onto carboxymethyl cellulose (CMC) backbone using ammonium persulfate (APS) as an initiator and N, N′-methylene bisacrylamide (MBA) as a crosslinker. For investigating the effects of before and after treatments of the hydrogel on the swelling equilibrium, gel fraction, and weight loss, 3 sets of experiments with 5 samples were designed and the effect of degassing (using N2), neutralization with NaOH 1 M, and two stages of dewatering with acetone and ethanol was studied. The results confirmed the positive effects of all the after-treatment stages. The final data indicate that sample (v) with N2 as reaction atmosphere, one neutralization stage, and two dewatering stages exhibit a maximum swelling of 167 g/g, maximum gel fraction of 61.4%, and also maximum weight loss of 38.6%. These outcomes show that these treatments exhibit hydrogel with a good swelling ratio which is desirable in smart delivery systems, healthcare, and biomedical applications. The optimized sample was characterized by FT-IR, SEM, and TGA too.

A systematic study of tert‐butylacrylamide‐methyl acrylate‐acrylic acid radical solution terpolymerization

AbstractMulti‐functional polymers used for personal care products can be synthesized by radical polymerization of acrylic acid (AA) in alcohol/water solutions with non‐functional monomers such as methyl acrylate (MA) and N‐tert‐butylacrylamide (t‐BuAAm). However, solvents capable of forming or disrupting hydrogen bonds cause the polymerization kinetics of these monomers to deviate from their polymerization behaviour in bulk and non‐polar solvents. In this work, a previous mechanistic model developed for MA/t‐BuAAm copolymerization is extended to represent the terpolymerization system MA/t‐BuAAm/AA. The additional kinetic coefficients required for the system are estimated from fitting to AA homopolymerizations and AA/MA and AA/t‐BuAAm copolymerizations conducted in an ethanol/water solution. In‐situ nuclear magnetic resonance (NMR) spectroscopy is used to follow monomer conversions and composition drift behaviour, with the molar mass distributions of the polymer products characterized by size‐exclusion chromatography. Although AA is more reactive than MA in non‐polar solvents, the reactivities of the two monomers equalize under the experimental conditions examined. Thus, the batch and semi‐batch terpolymerization data collected are represented equally well by a reduced acrylate/t‐BuAAm copolymerization model and the full terpolymerization implementation.

Design, Development and in vitro Evaluation of Hydrogels Prepared by Free Radical Polymerization of Acrylic Acid (AAc) Containing a Model Antidiabetic Drug

Abstract: Introduction: The controlled release of medicaments in the management of diabetes is desirable to have a better therapeutic activity of the drug. Objectives: In the present study hydrogels were prepared as a controlled drug delivery system taking Rosiglitazone as a model drug. Materials and Methods: Hydrogels were created using the Free Radical Polymerization approach, with the crosslinker N, N′-Methylene bisacrylamide serving as a binding agent for the polymerization. To create a polymeric network, ammonium persulphate has been used as a polymerization inducer for AAc to poly (acrylic acid) in the existence of polyvinyl alcohol (PVP). A maximum of fifteen formulations were created with various concentrations of polymers and crosslinking agents to test the swelling, diffusion coefficients, ESR, and in vitro drug release properties of the drugs tested. The FT-IR and DSC techniques were used to determine the drug's compatibility with the polymers. The XRD studies were carried out to understand the nature of the drug contained within the hydrogel formulation. The morphologies of the surface were determined using SEM. Results and Discussion: A greater swelling was observed in the basic pH range and a marginal swelling was observed in the acidic pH range according to the swelling studies. The ESR affirmed that the pH of the hydrogels was indeed a factor in the swelling of the gels. The results of the diffusion study revealed that the diffusion coefficient has risen as a result of the reduction in cross-linker concentration and the increase in acrylic acid concentration in the solution. The in vitro release of drug data revealed that the swelling has been increased as a result of the increased concentration of acrylic acid, which resulted in the increased release of the drug. However, when the concentrations of PVP and cross-linker were increased, it was discovered that the drug release was decreased. Conclusion: AAc-PVP based hydrogel was found to be a promising controlled drug delivery system for the treatment of Rosiglitazone, according to the findings of this study. Keywords: Hydrogels, PVP Acrylic acid, Free Radical Polymerization, Antidiabetic Drug.

Extreme-environment-adapted eutectogel mediated by heterostructure for epidermic sensor and underwater communication

In recent years, gel-based ion conductor has been widely considered in wearable electronics because of the favorable flexibility and conductivity. However, it is of vital importance, yet rather challenging to adapt the gel for underwater and dry conditions. Herein, an anti-swelling and anti-drying, intrinsic conductor eutectogel is designed via a one-step radical polymerization of acrylic acid and 2, 2, 2‑trifluoroethyl methacrylate in binary deep eutectic solvents (DESs) medium. On the one hand, the synergistic effects of hydrophilic/hydrophobic heteronetworks can elicit the integrity stability of eutectogel in liquid environment. It is proved that both the mechanical property and conductivity are maintained after immersing in different salt, alkaline and acid solution and organic solvent for one month. On the other hand, the eutectogel inherits well conductivity (93 mS/m), anti-drying and antibacterial properties from DESs. Based on the above features, the resulting eutectogel can be assembled as smart sensor for stable information transmission in air and underwater with fast response time (1 s), high sensitivity (Gauge factor = 1.991) and long-time reproducibility (500 cycles, 70 % strain). Considering the simple preparation and integration of multiple functions, the binary cooperative complementary principle can provide insights into the development of next-generation conductive soft materials.

Preparation and characterization of pH‐sensitive carboxymethyl cellulose‐based hydrogels for controlled drug delivery

AbstractA novel biopolymer‐based hydrogel with pH‐responsive behavior was synthesized by free radical polymerization of acrylic acid and methacrylic acid onto carboxymethylcellulose. The effects of initiator concentration, crosslinker concentration, acrylic acid and methacrylic acid total volume and acrylic acid percentage on water absorbency were studied using central composite design with the response surface method (RSM). The results indicate that the maximum water absorbency in distilled water is 103 g g−1 and the optimum conditions determined using RSM are: initiator concentration, 0.006105 mol L−1; crosslinker concentration, 0.009035 mol L−1; acrylic acid and methacrylic acid total volume, 2 mL; acrylic acid percentage, 50%, in a system of 35 mL total volume. The optimized hydrogel was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis, and its pH‐responsive behavior was also evaluated using acidic and basic solutions for its possible use in control drug delivery. In this respect, ofloxacin was used as a drug model and experimental data showed that the hydrogel is a possible candidate for injectable drug delivery. © 2022 Society of Industrial Chemistry.

A novel economical friendly treatment approach: Composite hydrogels

There are many chemical indicators of drinking water pollution. These include heavy metals, radioactive materials, inorganic chemicals, organic chemicals, disinfectants, and disinfectant additives. Common methods for removing these contaminants from aqueous solutions include chemical precipitation, membrane processes, ion exchange processes, biological processes, adsorption, and chemical reactions. Each of these methods has limitations in application. Many studies have been performed on the use of graphene in filters. Graphite oxide (GO) platelets were prepared using a modified Hummers method. By employing GO platelets, GO/poly (acrylic acid – maleic acid) superabsorbent composites were synthesized by a free radical polymerization of acrylic acid and maleic acid as a monomer, using N, N -methylenebisacrylamide as cross-linker and ammonium persulfate as initiator. The well-dispersed GO platelets in the polymer networks result in a significant improvement in absorbencies in distilled water solutions. The superabsorbent nanocomposite also exhibits a superior water-retention ability compared with the control under the same conditions. GO/P(AA-MA) composite was investigated using felid emission scanning electron microscopy (FE-SEM) and Fourier transform infrared (FTIR); GO/P (AA-MA) composite is a highly effective absorbent of crystal violet (CV) and can be used to remove CV from aqueous solution. The kinetics of dye adsorption has been studied in terms of pseudo-first-order and pseudo-second-order rate expression. The results indicated that the adsorption process followed two models and demonstrated that intraparticle diffusion plays a significant role in the adsorption mechanism.

Nanocomposite hydrogel based on sodium alginate, poly (acrylic acid), and tetraamminecopper (II) sulfate as an efficient dye adsorbent

In this study, a novel nanocomposite hydrogel (NCH) was prepared by in situ crosslinking and radical polymerization of acrylic acid (AA) in the presence of sodium alginate (Na-Alg), followed by loading of Cu2+ ions and reaction with ammonia. The main advantage of the synthesized NCH is the high adsorption of dye due to the large contact area. The structure of the NCH was studied by FT-IR spectroscopy, TEM, and SEM. TEM showed that the size of nanoparticles is about 5–30 nm. The adsorption of dye was studied by changing the different factors. The removal efficiency of Crystal Violet (CV) and Malachite Green (MG) was found to be more than 96% at concentration of 10 mg/L and pH = 6. The dye adsorption on the NCH is well described by Freundlich isotherm and pseudo-second-order kinetic models. The reusability experiments showed that about 95% of the initial adsorption was obtained after eight cycles.

Kaolin-Enhanced Superabsorbent Composites: Synthesis, Characterization and Swelling Behaviors

One type of low-cost and eco-friendly organic‒inorganic superabsorbent composite (SAPC) was synthesized by free radical polymerization of acrylic acid (AA), starch (ST), sodium alginate (SA) and kaolin (KL) in aqueous solution. The structure and morphology of the SAPC were characterized by Fourier transform infrared spectrometer (FT-IR), scanning electron microscope (SEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The influence of different reaction conditions on water absorption of SAPC, i.e., SA and KL contents, AA neutralization degree (ND), potassium persulfate (KPS) and N, N′-methylenebisacrylamide (MBA) loading were systematically studied. Under the optimal synthesis conditions, very high water absorption of 1200 g/g was achieved. The swelling kinetic mechanism of SAPC was studied by pseudo-second order swelling kinetics model and Ritger‒Peppas model. The performances of SAPC under different environments were tested and results revealed that this new SAPC had excellent swelling capacity, high water retention, good salt tolerance in monovalent salt solution (NaCl solution) and good pH tolerance between 4 and 10.

Crystal growth inhibition of gypsum under normal conditions and high supersaturations by a copolymer of phosphino-polycarboxylic acid

Scale formation is a bottleneck of most industrial and domestic water equipment, in particular, of oilfield water systems. Therefore, high-performance and environmentally-benign chemical scale inhibitors are highly needed. Phosphino-polycarboxylic acid (PPCA) is a low-in-phosphorous scale inhibitor with high inhibition efficiency, but its synthesis and performance analyses have been rarely disclosed. In this work for the first time, a PPCA copolymer is synthesized by a simple method based on free radical polymerization of acrylic acid and phosphinic acid monomers and directly employed for gypsum scale inhibition. The formation of PPCA was verified by FTIR and 31PNMR spectroscopies, and then its inhibition performance was evaluated by the complexometric determination of the Ca2+ concentration. The PPCA (2.5 ppm) showed 100% inhibition efficiency at a saturation index of 0.31 at the room temperature and without pH regulation after 24 h with practically no detectable gypsum crystallites even after two months, while the commercial ATMP showed a low inhibition efficiency of 30%. The Field Emission Scanning Microscopy (FESEM) images of the PPCA-inhibited and uninhibited samples revealed that the typical gypsum microfibers are distorted and reduced in size significantly in the inhibited sample. At a still higher saturation index of 1.47 (saturation ratio of 10), the inhibition efficiency of PPCA reduced to 16% and 24% for two dosages of 2.5 and 10 ppm which was attributed to the higher ion activity coefficients at the extremely high ionic strength, and hence, a much higher thermodynamic driving force. The rate constants for these two high supersaturation conditions and low PPCA dosages were also calculated and discussed.

Biodegradable macro-porous CMC-polyaniline hydrogel: synthesis, characterization and study of microbial elimination and sorption capacity of dyes from waste water

Certainly water pollution control will play a key role in environmental health. Therefore, researchers are attempting to reduce the ecological effects of water pollution by creating restrictions in the use of chemicals or water reuse. Among all the available techniques, adsorption method attracted much attention due to the higher efficiency, cost-effectiveness and simplicity. So, in this work, novel biodegradable hydrogel based on carboxymethyl cellulose (CMC) and polyaniline (PANI) was introduced to remove toxic dyes from wastewater. The synthesis process was accomplished in two steps: free radical polymerization of acrylic acid (AA) on the CMC (0.25 g) in the presence of ammonium per sulfate (APS) as radical initiator (0.2 g) and N,N-methylene-bis-acrylamide (MBA) as crosslinker (0.1 g) at 70 °C, and after 30 min, growing PANI chains on the synthesized CMC-PAA hydrogel by radical polymerization of aniline (1.0 mL) in acidic condition (20 mL of hydrochloric acid 1.0 M) to form macro-porous conductive hydrogel (CMC-PAA-PANI). The resulted hydrogel showed high antibacterial activity and excellent biodegradability by natural soil microorganisms with decomposition to 91.7 %. Also, the final hydrogel exhibited reasonable conductivity and pH sensitivity properties.

Synthesis and characterization of double-network hydrogels based on sodium alginate and halloysite for slow release fertilizers

In this work, novel sodium alginate–based double-network hydrogel beads were prepared and applied for the water-retention and slow release of fertilizers (WSF). The WSF beads were prepared by ion-crosslinking and the free radical polymerization of acrylic acid, acrylamide, and polymerizable β-cyclodextrin in the presence of urea-loaded halloysites. The WSF beads were characterized using SEM, FTIR, and TGA. Their swelling capacity and water retention were measured by a weighing method and their slow-release behavior was studied by spectrophotometry. The water retention and slow release results showed that the fertilizer displayed improved urea release and water retention properties, indicating that halloysite nanotubes clearly improved the performance of fertilizers. In addition, the experimental data of the slow release of urea in water and soil better fitted the Korsmeyer-Peppas model compared with the Higuchi model, a zero-order model or a first order mode. The release behavior of the fertilizer beads followed a Fickian diffusion mechanism.

Adhesive Materials Based on Modified Low Molecular Copolymer of Ethylene with Vinyl Acetate

Adhesive material based on low molecular copolymer of ethylene with vinyl acetate and polymer complex synthesized by radical polymerization of acrylic acid in the presence of e-caprolactam was developed. The compound of the adhesive was optimized, and the influence of composition and concentration of the complex, in addition to fine-grained filler (chalk), on the stickiness and adhesive strength of compositions to substrates of various natures being studied. It was shown that the adhesive characteristics of the developed adhesive compositions are superior to the corresponding indices of a composition based on low molecular polyethylene, which allows recommending them for application as construction mastic resins and as a base for label pastes and compounds for spraying on polymer films.

Adsorption of Cu (II)and Co (II) from aqueous solution using lignosulfonate/chitosan adsorbent

In practical application, the adsorption capacity, adsorption kinetics, recycling and production cost of adsorbent affect the application of adsorbent. In this study, porous lignosulfonate/chitosan adsorbent was prepared by simple radical polymerization of acrylic acid in the mixed solution of lignosulfonate and chitosan. The porous and large surface area of adsorbent provides more adsorption sites for heavy metal ions. A variety of characterization methods were used to characterize the appearance and structure of the adsorbent. Adsorbent can effectively adsorb heavy metal ions in aqueous solution, and has the best removal effect for Cu2+ and Co2+. The adsorption capacity of adsorbent for Co2+ is 386 mg g−1, and for Cu2+ is 283 mg g−1. 0.01 g adsorbent was used to adsorb 100 mg L−1 Cu2+, and the adsorption equilibrium was reached within 60 min. When the amount of adsorbent reaches 0.03 g, the removal rate of heavy metal ions of 100 mg L−1 can reach 99%. In this study, an adsorbent based on acrylic resin was developed.

Synthesis, characterization and adsorption studies of nano-composite hydrogels and the effect of SiO2 on the capacity for the removal of Methylene Blue dye

Nanocomposite hydrogels were produced by free radical polymerization of acrylic acid and N-vinylpyrrolidone in the presence of SiO2 nanoparticles. The chemical and morphological structures of the hydrogels were determined using Fourier transform infra-red spectroscopy (FT-IR) and field emission scanning electron microscopy (FESEM). The nanocomposite hydrogels were used for the adsorption and desorption of Methylene Blue dye from wastewater. Wastewater was referred to distilled water that contained Methylene Blue dye under laboratory conditions. The carbon, hydrogen and nitrogen contents of the dye, hydrogels and dye-adsorbed hydrogels were determined by elemental analysis. The influences of SiO2 nanoparticles and copolymerization on the adsorption capacity were studied. The maximum dye removal of 98.3 % was obtained with AA-co-VP (3:1) copolymeric hydrogel. The synthesized hydrogels could be evaluated as adsorbents in wastewater treatment, effectively.

Tough and self-healable nanocomposite hydrogels from poly(acrylic acid) and polyacrylamide grafted cellulose nanocrystal crosslinked by coordination bonds and hydrogen bonds

Developing self-healable hydrogels with excellent mechanical performance is important for their potential applications. In this paper, tough and self-healable dual physically crosslinked nanocomposite hydrogels reinforced with polyacrylamide grafted cellulose nanocrystal (CNC-g-PAM) were fabricated by in situ free radical polymerization of acrylic acid (AA) monomers in the presence of FeCl3 (0.75% of AA mole) and CNC-g-PAM (1–3% of AA mass). The primary network of PAA/CNC-g-PAM nanocomposite hydrogels was constructed via coordination bonds between carboxylic groups from PAA and Fe3+ ions, while CNC-g-PAM served as both reinforcing nanofillers and physical crosslinkers via hydrogen bonds between PAA matrix and PAM chains on the surface of CNC. The nanocomposite hydrogels exhibited simultaneously improved elastic modulus, tensile strength and elongation at break with the increase of CNC-g-PAM loading. The dynamic nature of both coordination bonds and hydrogen bonds endowed the nanocomposite hydrogels with excellent energy dissipation, self-recovery ability and autonomous self-healing capacity.

Autonomous Chitosan-Based Self-Healing Hydrogel Formed through Noncovalent Interactions

A facile strategy was developed for the formation of an autonomous chitosan-based self-healing hydrogel. This hydrogel was fabricated using in situ free radical polymerization of acrylic acid (AA) ...