Polymerization Of Acrylic Acid Research Articles

Lignin-coated liquid metals-induced synthesis of deep eutectic solvent-based hydrogels with environmentally tolerant for strain sensors

In the work, alkali lignin (AL) was used as a coating layer for dispersing liquid metals (LM) in a ternary DES (choline chloride/ethylene glycol/water) system and generating free radical-catalyzed acrylic acid (AA) polymerization. The preparation of flexible sensors had high electrical conductivity (0.33 S·m-1), excellent self-healing and mechanical properties (84.7 KPa). The presence of AL facilitated the dispersion of LM in the DES system and the formation of a flexible hydrogel without the addition of an initiator. Moreover, DES was used as the liquid component of the PAA-AL2@LM2 hydrogel made it more environmentally tolerant and had better water retention. Even at -20 °C, the hydrogel exhibited low electrical resistance (131.4 Ω). The moisture loss of the prepared hydrogel was only 9% after 7 days at room temperature. This work exploited the significant advantages of DES and lignin-based materials in dispersing LM to provide a new technique for the preparation of metal-polymer composite hydrogels, which has great potential in the field of flexible sensors.

Preparation of graphene oxide-supported hydrogel adsorbent for Zn ions removal

A composite hydrogel was prepared using in situ polymerisation of acrylic acid and acrylamide monomers. The prepared hydrogel was improved by addition of graphene oxide nanosheets in the range of 0.1–0.3 wt%. These modified samples were then employed for the adsorption of zinc ions. The batch adsorption experiments were carried out at ambient conditions and pH = 7.0. The adsorbents’ morphological features, structural characteristics and mechanical behaviours were assessed using techniques such as Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and dynamic mechanical thermal analysis. Incorporating graphene oxide into pure hydrogels markedly enhances their mechanical robustness and swelling behaviour. When graphene oxide is added at levels up to 0.2 wt%, there is a notable elevation in the glass-transition temperature and the mechanical modulus of the hydrogels. In contrast, further addition of graphene oxide decreases the mechanical properties due to nanoparticle agglomeration. The water diffusion and the swelling mechanism follow pseudo-Fickian and Schott kinetic models, respectively. The adsorption kinetics followed a pseudo-second-order model, reaching equilibrium within 75 min. The data from the adsorption isotherm conformed well to the Langmuir model.

Ultra-stretchable, robust, self-healable conductive hydrogels enabled by the synergistic effects of hydrogen bonds and ionic coordination bonds toward high-performance e-skins

Ionic conductive hydrogels as electronic skins (e-skins) have showcased pivotal potentials in the realm of human health monitoring and human–machine interfaces. However, developing intelligent hydrogel with remarkable stretchability and mechanical elasticity is yet challenging. Herein, high-performance ion-conducting hydrogels with unprecedented mechanical properties and good transparent, conductive, self-healing properties are constructed via free-radical polymerization of acrylic acid (AA) within the polyvinyl alcohol (PVA) network, and the subsequent freeze–thaw (F-T) treatment and Zr4+ ion immersion crosslinking technique. Profiting from the synergy of multiple intermolecular/intramolecular hydrogen bonds between different polymers and coordination bonds of carboxyl-Zr4+, the resultant PVA/PAA/Zr4+ hydrogel exhibits high transparency (∼97 %), superior conductivity (0.6089 S/m), a long elongation at break (2053 %), robust self-healing efficiency (96.3 %), high deformation-tolerate property, and notable mechanical repeatability. These multifaceted attributes render the hydrogel to serve as an ionic conductor for capacitive/resistive −type strain sensor. The hydrogel-based resistive-type strain sensor features a wide detection range (0.5 %-800 %), rapid response time (150 ms), long-term stability, and consistent output stability, making it promising in monitoring diverse human motions and seamless human–machine interactions. Additionally, the hydrogel sensor demonstrates excellent linear response in ultra-wide range (0–900 % strain), high sensitivity, and excellent cycling stability in a capacitive mode, enabling to be used for accurately detecting the weights of objects. As such, this work advances the development of ionic conductive hydrogel as flexible and wearable electronic devices.

Utilizing acrylic acid polymer hydrogel for 3-D quality assurance in CyberKnife radiotherapy

Dosimetry tools play a crucial role in radiotherapy as they are essential for recording and validating intricate 3-D dose distributions. This research introduces and examines a novel acrylic acid polymer hydrogel (ACAPHG) dosimeter composition designed for 3-D dose verification and quality assurance in the context of radiotherapy treatment. A phantom made of an 80 mm diameter cylindrical glass container was utilized. The phantom contained the hydrogel, which served as the medium for radiation exposure. The water equivalent hydrogel within the phantom was subjected to irradiation by a CyberKnife robotic radiotherapy system. An optical computed tomography (OCT) scanner with sub-millimeter resolution was used to obtain imaging data. The dose distribution of a CyberKnife robotic SRS/SBRT treatment plan for a brain cancer patient was compared to that of the hydrogel's OCT scan using 2-D and 3-D gamma analysis with a criterion of 3% dose difference and 3 mm distance-to-agreement. A gamma pass rate of 94.1% for the 2-D gamma analysis and a pass rate of 99% for the 3-D gamma analysis were calculated within the region at which the treatment planning system data drops to 20% of the maximum dose. The use of the ACAPHG dosimeter in conjunction with the described setup suggests that it has the potential to offer an accurate 3-D verification of complex dose distributions in SRS/SBRT radiotherapy treatments. By employing the ACAPHG dosimeter and utilizing OCT scanning, this dosimeter enables the assessment and validation of intricate dose distributions in these advanced radiotherapy treatments.

Relation of acrylic acid polymerization behavior in deep eutectic solvent to water content: Computer simulation and experiment

Polymerizable deep eutectic solvents (DES) are promising starting materials for preparation of eutectogels and hydrogels that can be applied in drug delivery, as strain sensors and various components of soft electronics. However, the understanding of relationship between the molecular structure, physicochemical properties and polymerization behavior of such systems in pure state and in their mixtures with water is not well studied yet. In this work we report the results of both computer simulation and experimental investigations for polymerizable choline chloride/acrylic acid DES and its mixtures with water. Molecular dynamics was applied to reveal the influence of water on the structure of polymerizable DES at the molecular and supramolecular levels. The diffusion coefficients of DES components with different water content were measured using NMR. The course of photoinduced polymerization of DES/water mixtures was traced using FTIR spectroscopy, while the molar mass and hydrodynamic characteristics of obtained polyacrylic acid were studied by means of static and dynamic light scattering. It was found that addition of water leads to a gradual decrease in size of the acrylic acid clusters that exist in pure DES and is accompanied by an increase in orientation mobility and diffusion coefficients of components. The maximal molar mass was obtained for the polymer prepared by polymerization of DES with 5 wt% of water. This can be attributed to the optimal combination of acrylic acid clusters size and increased mobility of components.

A one-pot strategy for modifying the surface of Ti3C2Tx MXene

Surface modification of MXenes significantly expands their potential for a wide range of applications. Here, we demonstrate a one-pot spontaneous polymerization of acrylic acid onto MXene sheet surfaces using an aryl diazonium coupling agent (nitrobenzene diazonium salt) as an approach to tune MXene interfacial properties. We use this formation of polymer coatings as a coagulation strategy for spinning fibers from liquid crystal MXene dispersions, obtaining densified free-standing fibers with tensile strength and breaking energy of ∼155 MPa and ∼4.5 MJ m−3. This simple method potentially offers a scalable approach for fabricating functional MXene macroarchitectures.

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.

Artificially regulated interphase on natural graphite realizes rapid charge and durable high-temperature cycling of Li-ion batteries

Natural graphite (NG) is a strong competitor in the anode market of Li-ion batteries because of its low cost, rich resource, low energy consumption and low carbon dioxide emission during production. The main problems inhibiting its universal application are its high surface area and the attendant unstable solid/electrolyte interphase (SEI), leading to unsatisfactory cycling and rate performance. In this work, a Li+-conductive, thermally and mechanically stable organic polymer layer is successfully constructed on NG surface by virtue of the simultaneous polymerization and crosslinking reactions of chitosan (CS) and acrylic acid (AA). With controllable thickness, the polymer layer denoted as CSAA significantly decreases the specific surface area of NG, works as an inner SEI substrate greatly mitigating the decomposition of electrolyte, and induces the formation of a LiF-rich SEI outer layer. The SEI resistance and activation energy for charge-transfer reactions are considerably reduced. Benefiting from the superior properties of CSAA-derived SEI, the NG@CSAA anodes exhibit a high initial coulombic efficiency of 94.1 %, fast charge/discharge capability and prolonged cycle life at both 25 °C and 45 °C in the LiFePO4 cathodes-based full cells.

Tough and Elastic Cellulose Composite Hydrogels/Films for Flexible Wearable Sensors.

Cellulose and its composites, despite being abundant and sustainable, are typically brittle with very low flexibility/stretchability. This study reports a solution processing method to prepare porous, amorphous, and elastic cellulose hydrogels and films. Native cellulose dissolved in a water-ZnCl2 mixture can form ionic gels through in situ polymerization of acrylic acid (AA) to poly(acrylic acid) (PAA). The addition of up to 30 vol % AA does not change the solubility of cellulose in the water-ZnCl2 mixture. After polymerization, the formation of interpenetrated networks, resulting from the chemical cross-linking of PAA and the ionic/coordination binding among cellulose/PAA and ZnCl2, gives rise to strong, transparent, and ionically conductive hydrogels. These hydrogels can be used for wearable sensors to detect mechanical deformation under stretching, compression, and bending. Upon removal of ZnCl2 and drying the gels, semitransparent amorphous cellulose composite films can be obtained with a Young's modulus of up to 4 GPa. The rehydration of these films leads to the formation of tough, highly elastic composites. With a water content of 3-10.5%, cellulose-containing films as strong as paper also show typical characteristics of elastomers with an elongation of up to 1300%. Such composite films provide an alternative solution to resolving the material sustainability of natural polymers without compromising their mechanical properties.

Dual crosslinked interpenetrating polymer network-based porous hydrogel membrane for solid-state supercapacitor applications

Hydrogel membranes have emerged as promising candidates for solid-state supercapacitors (SSCs), overcoming limitations associated with traditional liquid electrolytes like leakage, thermal hazards, and flammability. However, single-network hydrogels often suffer from poor mechanical properties, making them inadequate for wearable applications. Herein, solution casting technique is used to develop a novel dual-crosslinked semi-interpenetrating polymer network (semi-IPN) hydrogel membrane through in-situ polymerisation of acrylic acid (AA) in a polyvinyl alcohol (PVA) matrix, followed by doping with KOH solution. By adjusting the composition between PVA and AA, the phase separation pathway is controlled, resulting in a homogeneously distributed porous architecture that enhances ion-conductive pathways. The hydrogel exhibited excellent properties, including high ionic conductivity (174 mS cm−1), considerable tensile strength (5 MPa), and significant elongation at break (460 %). Dielectric studies confirmed its significantly improved capacitive behaviour and low conductivity relaxation characteristics. Additionally, the resulting pseudocapacitor assembled with graphite-silvernanowire-polyaniline based composite electrode demonstrated a high specific capacitance (302 F g−1 at 0.2 A g−1) with outstanding capacity retention (75 % up to 500 cycles). Overall, the incorporation of this novel material provides great potential for high-performance SSC applications.

Preparation of p-isopropylphenol polyoxyethylene ether and evaluation of its performance in concrete

P-isopropenylphenol polyoxylates (IPP-PE) were obtained by alkoxylation reaction using p-isopropylphenol phenol (IPP) and ethylene oxide (EO) as raw materials, and P-PCE polycarboxylic acid superplasticizer was obtained by free radical polymerization of ipp-PE and acrylic acid (AA) under the action of initiator and chain transfer agent. The effects of reaction temperature, acid-ether ratio, amount of chain transfer agent and initiator, and reaction time on the dispersion properties of superplasticizer were studied, and the molecular structure and microscopic morphology of the superplasticizer were characterized by FTIR,1HNMR, and SEM, and the influence of superplasticizer on concrete properties was evaluated by concrete performance tests. The test results determined that the optimal synthesis process of polycarboxylic acid superplasticizer was as follows: reaction temperature 40 °C, n(AA):n(IPP-PE)=6:1, chain transfer agent and initiator were 0.4% and 0.6% of the mass of large monomer, respectively, and the reaction time was 4.5h. The experimental results of the concrete performance test showed that the workability of concrete mixed with the self-made superplasticizer was excellent, and the initial and 1h longitudinal flowability of the superplasticizer reached 228 mm and 215 mm, respectively. The water reduction rate reached 36%, the 28d compressive strength reached 56.8 MPa, the initial slump reached 226 mm, and it had a certain retarding and air entrainment effect.

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.

On the dual crosslinking for functionality enhancement of poly (acrylamide-co-acrylic acid)/chitosan-aluminum (III) ions and its characterization and sensory hydrogel fibers

In this report, we present a dual crosslinking hydrogel fiber made from polyamine saccharides chitosan (CS), synthesized through UV polymerization. This process utilizes Irgacure 2959 and N,N′-Methylenebisacrylamide (MBAA) as initiators, followed by immersion in an aluminum chloride (AlCl3) solution. The resulting hydrogel incorporates a dual crosslinking mechanism, quantitatively studied via Nuclear Magnetic Resonance (NMR) spectroscopy. This mechanism involves chemical crosslinking through radical graft polymerization of acrylamide and acrylic acid onto CS in the presence of MBAA, and physical crosslinking through hydrogen bonding interactions between P(AAm-co-AA) and a metal coordination bond. The mechanical properties of the hydrogel fiber enable it to withstand stresses up to 656 kPa and strains exceeding 300 %. Additionally, the hydrogel fiber exhibits conductivity at 1.96 Scm−1. Serving as a multifunctional material, it acts as a strain sensor and finds utility in optics. Remarkably, it demonstrates the capability to detect human motions such as finger bending and minor deformations like vibrations of the vocal cords. Furthermore, its ability to guide dynamic light makes it promising for optical applications. Consequently, this multifunctional hydrogel fiber emerges as a highly promising candidate for diverse applications in fields such as bioengineering and electronics.

Dual-responsive, highly bacteriostatic and swellable chitosan-based hydrogels loaded with 5-fluorouracil for sustainable release

In this work, a dual-responsive hydrogel for sustainable release of drug was prepared using chitosan grafted with PBA as substrate to form semi-interpenetrating polymer networks (S-IPN) via free-radical crosslinking polymerization of acrylic acid in the presence of MBAA as a crosslinker and KPS as an initiator as well as Fe3+.ions introduced. The results from comprehensive characterization indicated that the as-prepared hydrogel possesses cavity structure with the pores of varying sizes, thus facilitating the accommodation of 5-fluorouracil as a model drug. In addition, the swelling behavior of the hydrogels in different pH buffers and glucose solutions was also investigated. As expected, the prepared hydrogels are pH and glucose responsive due to PAA and phenylboronic acid incorporated into the hydrogel, which enables the slow or sustainable release of drug. Moreover, the release processes were fitted with various kinetic models whereas the release was better described by Korsmeyer-Peppas model or the drug release is mainly governed by the release mechanism of the hydrogel is primarily driven by Fickian diffusion from a mechanical point of view. Hydrogel loaded with drug was found to have good antibacterial effects against E. coli and S. aureus, leading to the potential for various medical-related applications.

Frontal polymerisation of acrylic acid tuned by micellar aggregates in a deep eutectic solvent

A frontal polymerisation (FP) is obtained when a polymerisation creates a spatial front of the reaction. Because of the heat of the reaction associated, a temperature spatial front is also observed. In this paper, the usual chain polymerisation of acrylic acid (AA) is studied when the monomer forms a deep eutectic solvent (DES), i.e. a liquid similar to an ionic liquid. In this DES, AA behaves as a hydrogen donor and ethylammonium chloride as a hydrogen acceptor. The use of a DES is convenient as an effective polymerisation media because the heat of the reaction can be controlled. We study the rate and the heat of polymerisation during the formation of a front using micellar structures where a bifunctional peroxide hydrophobic initiator, abbreviated Luperox, dissolves successfully. Our experiments follow the FP using infrared images and rheology. We found that micellar aggregates of different sizes are interesting modulators of the polymerisation rate and heat of the reaction. Our results show that smaller aggregates produce higher rates of reaction with a decoupled increment of temperature; in contrast to what is observed with bigger aggregates: a slow reaction rate with a coupled moderate heat of reaction.

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.

Depletion-Induced Self-Assembly of Colloidal Particles on a Solid Substrate.

We investigate the depletion contributions to the self-assembly of microcolloids on solid substrates. The assembly is driven by the exclusion of nanoparticles and nonadsorbing polymers from the depletion zone between the microcolloids in the liquid and the underlying substrate. The model system consists of 1 μm polystyrene particles that we deposit on a flat glass slab in an electrolyte solution. Using polystyrene nanoparticles and poly(acrylic acid) polymers as depleting agents, we demonstrate in our experiments that nanoparticle concentrations of 0.5% (w/v) support well-ordered packing of microcolloids on glass, while the presence of polymers leads to irregular aggregate deposition structures. A mixture of nanoparticles and polymers enhances the formation of colloidal aggregate and particulate surface coverage compared to using the polymers alone as a depletion agent. Moreover, tuning the polymer ionization state from pH 4 to 9 modifies the polymer conformational state and radius of gyration, which in turn alters the microcolloid deposition from compact multilayers to flocculated structures. Our study provides entropic strategies for manipulating particulate assembly on substrates from dispersed to continuous coatings.

κ‐Carrageenan/poly(sodium styrenesulfonate‐co‐acrylic acid) macroporous anionic monoliths: Dye adsorption and oil–water separation properties

Abstractκ‐Carrageenan (κC) is a widely used food hydrogel, but its use as an environmental adsorption separation material still needs to be further developed. Herein, a novel macroporous anionic monolith was synthesized by the oil‐in‐water high internal phase emulsion template method. The monolith was obtained by the continuous phase polymerization of sodium styrenesulfonate (NaSS) and acrylic acid (AA), in which κC was introduced to form a semi‐interpenetrating network structure to improve its overall performance. The results showed that the mechanical strength of the monolith increased with κC content. Because of the use of two strong hydrophilic monomers, NaSS and AA, the porous monolith proved to be superoleophobic underwater. In addition, the porous materials had a strong cationic dye adsorption capacity (2455 mg/g for malachite green, 1180 mg/g for methylene blue) and a fast removal rate, good reusability, and oil–water separation. This work highlights their potential application value in the purification of complex water environments.

The Effects of Endoplasmic Reticulum Stress via Intratracheal Instillation of Water-Soluble Acrylic Acid Polymer on the Lungs of Rats.

Polyacrylic acid (PAA), an organic chemical, has been used as an intermediate in the manufacture of pharmaceuticals and cosmetics. It has been suggested recently that PAA has a high pulmonary inflammatory and fibrotic potential. Although endoplasmic reticulum stress is induced by various external and intracellular stimuli, there have been no reports examining the relationship between PAA-induced lung injury and endoplasmic reticulum stress. F344 rats were intratracheally instilled with dispersed PAA (molecular weight: 269,000) at low (0.5 mg/mL) and high (2.5 mg/mL) doses, and they were sacrificed at 3 days, 1 week, 1 month, 3 months and 6 months after exposure. PAA caused extensive inflammation and fibrotic changes in the lungs' histopathology over a month following instillation. Compared to the control group, the mRNA levels of endoplasmic reticulum stress markers Bip and Chop in BALF were significantly increased in the exposure group. In fluorescent immunostaining, both Bip and Chop exhibited co-localization with macrophages. Intratracheal instillation of PAA induced neutrophil inflammation and fibrosis in the rat lung, suggesting that PAA with molecular weight 269,000 may lead to pulmonary disorder. Furthermore, the presence of endoplasmic reticulum stress in macrophages was suggested to be involved in PAA-induced lung injury.

Acrylic acid -co- sodium acrylate copolymers synthetized in supercritical carbon dioxide: Is it possible to pre-neutralize polymers at high pressure?

This study focuses on the polymerization of acrylic acid together with sodium acrylate, commonly performed in traditional solvents, using supercritical carbon dioxide. This compressed polymerization solvent offers benefits like producing pure, dry polymers by a simple depressurization process. Thermally initiated free-radical polymerizations in supercritical CO2 were carried out, aiming to obtain a pre-neutralized polymer at the end of the reaction. The impact of sodium acrylate content on polymer physicochemical properties was analyzed. Conversions ranged from 86.9% to 96.7%, and sodium acrylate incorporation was verified using various analytical methods. The polymerizations displayed characteristic molar mass distributions, indicating continuous and dispersed phase polymerizations. Additionally, rheological measurements of polymer aqueous solutions revealed that viscosity increased with higher average molar mass and was responsive to pH and the presence of monovalent and divalent ions. This CO2-based approach presents a promising method for clean and safe polymer production.