Acrylic Acid Units Research Articles

Acrylic acid and vinylamine copolymers: Anomalous acidity and association with short polyacids

Acrylic acid and vinylamine copolymers represent one of the simplest polyampholyte structures. The acid-base and solution properties of these copolymers are hardly studied, and there are no works devoted to the synthesis of a set of copolymers with different compositions. We have synthesized a set of acrylic acid and vinylamine copolymers containing from 21 to 95 mol% acrylic acid units. The copolymers show the hydrodynamic properties and solubility of typical polyampholytes. Potentiometric titration revealed unusual acid-base properties of the new copolymers. The addition of HCl to the copolymers in the form of sodium/potassium salt results in only partial protonation of carboxyl anions and amine groups, including the acidic range (pH 2.5). This abnormally high acidity of acrylic acid and vinylamine copolymers is probably due to the formation of strong intra- and intermolecular hydrogen or ionic bonds between partially protonated and protonated groups: ∼COO−+H3N∼, COOH∙∙∙:NH2∼, ∼H2N:∙∙∙ +H3N∼. Poly(vinylamine) and copolymers are able to stabilize curcumin in aqueous medium, significantly increasing its concentration in the neutral pH range. Polymers with high content of amine groups prevent curcumin degradation, probably by converting it to a more stable anionic form. New copolymers are promising substances for the creation of nucleic acid carriers for gene therapy and genetic engineering. The copolymer containing 21 % acrylic acid is comparable to poly(vinylamine) in terms of interaction with oligonucleotides, but yields more homogeneous polyplexes without the impurity of positively charged and potentially toxic particles.

Amphiphilic pH-responsive ABC triblock copolymers via RAFT-mediated aqueous PISA and comparison with their A-b-(B-co-C) diblock copolymer counterparts

The influence of the macroRAFT agent architecture on the morphology of the self-assemblies obtained by aqueous RAFT dispersion polymerization in PISA is studied by comparing amphiphilic AC, A(B-co-C) diblocks and ABC triblock copolymers, constituted of N,N-dimethylacrylamide (DMAm = A), acrylic acid (AA = B) and N-cyanomethylacrylamide (CMAm = C) monomer units. The aim of this study is to better understand the impact of the presence of pH-sensitive acrylic acid units and their spatial distribution in block copolymers. Generally, the presence of a fully protonated intermediate block of PAA between the two blocks (based on PDMAm and PCMAm) favors the formation of higher-order morphologies. These ABC triblock copolymers assemblies are pH-responsive and can undergo morphological transitions through the controlled deprotonation or protonation of the PAA segment, but do not completely dissociate at high pH (i.e. when AA units are fully ionized) unlike their A(B-co-C) diblock counterparts, where the pH-responsive monomer unit is homogeneously distributed within the solvophobic block.

Effect of pH on the incorporation of acrylic acid units in the core of polymer nanoparticles prepared by PISA and on their morphology

The molar fraction and ionization of acrylic acid (αAA) in the monomer feed affect the chemical composition, the composition profile and the particle morphology in PISA.

Electrospun Poly(acrylic acid-co-4-styrene sulfonate) as Potential Drug-Eluting Scaffolds for Targeted Chemotherapeutic Delivery Systems on Gastric (AGS) and Breast (MDA-Mb-231) Cancer Cell Lines.

Potential drug-eluting scaffolds of electrospun poly(acrylic acid-co-styrene sulfonate) P(AA-co-SS) in clonogenic assays using tumorigenic gastric and ovarian cancer cells were tested in vitro. Electrospun polymer nanofiber (EPnF) meshes of PAA and PSSNa homo- and P(AA-co-SS) copolymer composed of 30:70, 50:50, 70:30 acrylic acid (AA) and sodium 4-styrene sulfonate (SSNa) units were performed by electrospinning (ES). The synthesis, structural and morphological characterization of all EPnF meshes were analyzed by optical and electron microscopy (SEM-EDS), infrared spectroscopy (FTIR), contact angle, and X-ray diffraction (XRD) measurements. This study shows that different ratio of AA and SSNa of monomers in P(AA-co-SS) EPnF play a crucial role in clonogenic in vitro assays. We found that 50:50 P(AA-co-SS) EPnF mesh loaded with antineoplastic drugs can be an excellent suppressor of growth-independent anchored capacities in vitro assays and a good subcutaneous drug delivery system for chemotherapeutic medication in vivo model for surgical resection procedures in cancer research.

Uncommon Polyketides from Penicillium steckii AS-324, a Marine Endozoic Fungus Isolated from Deep-Sea Coral in the Magellan Seamount

Four unusual steckwaic acids E–H (1–4), possessing a rarely described acrylic acid unit at C-4 (1–3) or a double bond between C-12 and C-13 (4) are reported for the first time, along with four new analogues (5–8) and two known congeners (9 and 10). They were purified from the organic extract of Penicillium steckii AS-324, an endozoic fungus obtained from a deep-sea coral Acanthogorgiidae sp., which was collected from the Magellan Seamount at a depth of 1458 m. Their structures were determined by the interpretation of NMR and mass spectroscopic data. The relative and absolute configurations were determined by NOESY correlations, X-ray crystallographic analysis, and ECD calculations. All compounds were tested for their antimicrobial activities against human- and aquatic-pathogenic bacteria and plant-related pathogenic fungi.

PAAO cryogels from amidoximated P(acrylic acid-co-acrylonitrile) for the adsorption of lead ion

Lead ion is a common heavy metal pollutant and extremely harmful to human health. Therefore, the research about the adsorption and removal of lead ion from sewage and the development of lead ion sorbents keeps greatly significant. In this study, poly(acrylic acid-co-acrylonitrile) (PAAN) cryogels were prepared by cryo-polymerization. After the treatment with hydroxylamine, the amidoximated PAAO cryogels were applied to remove lead ion from lead-contaminated water. The porous structure and high water permeability of the cryogel could fully facilitate the exposure of active sites to efficiently adsorb lead ion. PAAO cryogels showed a high adsorption capacity of 450 mg/g for lead ion. After the first adsorption–desorption cycle, the adsorption capacity of PAAO cryogels regenerated with alkali solution increased to 650 mg/g and remained in the next six cycles. The pseudo-second-order kinetic model and the intraparticle diffusion model fit the adsorption kinetics of lead ion well, indicating its chemi-sorption feature of PAAO cryogel sorbent. The FTIR and XPS studies suggested that carboxyl group of acrylic acid unit as well as the amidoxime group of modified AN unit contributed the enhanced adsorption ability for lead ion.

3D Printable, Biomimetic Adhesive, and Self-healing Acrylic Elastomers for Customized Attachable Strain Sensor

The advances in flexible electronics, soft robotics, and many other fields resulted in increased demands for high-performance self-healing elastomers (SHEs). In this work, novel SHEs were prepared by photo-initiated copolymerization of acrylic acid and alkyl acrylates. The as-obtained SHEs exhibited 100% autonomous self-healing efficiency at ambient temperature due to the formation of hydrogen bonding between the hydroxyl groups of acrylic acid unit and carbonyl groups of alkyl acrylate unit. The strong supramolecular interaction yielded SHEs with 3D printing capability, high stretchability, and remarkable adhesion properties. Meanwhile, biomimetic adhesion was developed by solvent-wetting method to enable convenient adherence of SHEs on various substrates. Furthermore, the introduction of carboxylic ionic liquid led to the formation of a nonleaking and attachable ionogel by 3D printing for strain sensing applications. The as-obtained strain sensor precisely detected various gestures of human fingers, and successfully recognized sign language through a comprehensive analysis of electronic signals. In sum, the high-performance SHEs look promising for future SHE-based intelligent products thanks to their common raw feedstocks, 3D printing capability, and multi-functional characteristics.

Robust Hydrogel Adhesive with Dual Hydrogen Bond Networks.

Hydrogel adhesives are attractive for applications in intelligent soft materials and tissue engineering, but conventional hydrogels usually have poor adhesion. In this study, we designed a strategy to synthesize a novel adhesive with a thin hydrogel adhesive layer integrated on a tough substrate hydrogel. The adhesive layer with positive charges of ammonium groups on the polymer backbones strongly bonds to a wide range of nonporous materials’ surfaces. The substrate layer with a dual hydrogen bond system consists of (i) weak hydrogen bonds between N,N-dimethyl acrylamide (DMAA) and acrylic acid (AAc) units and (ii) strong multiple hydrogen bonds between 2-ureido-4[1H]-pyrimidinone (UPy) units. The dual hydrogen-bond network endowed the hydrogel adhesives with unique mechanical properties, e.g., toughness, highly stretchability, and insensitivity to notches. The hydrogel adhesion to four types of materials like glass, 316L stainless steel, aluminum, Al2O3 ceramic, and two biological tissues including pig skin and pig kidney was investigated. The hydrogel bonds strongly to dry solid surfaces and wet tissue, which is promising for biomedical applications.

Blend membranes based on N1-alkyl-substituted imidazolium functionalized polymers and aromatic polyethers: influence of N1-alkyl substituent on properties and alkaline stability

N1-alkyl (octyl and dodecyl)-substituted imidazolium-based PVBC homopolymers have been synthesized via N-quaternization reaction of N1-alkyl imidazole and PVBC precursor homopolymer bearing reactive benzyl chloride moieties. Due to their poor film forming properties and water solubility, these homopolymers were blended with aromatic polyethers bearing main chain pyridine units at different compositions in order to study the effect of alkyl chain length on morphology, water uptake, swelling ability and chemical stability of the prepared membranes. The B2 blend membrane with the highest N1-dodecyl-substituted imidazolium PVBC content (65 wt%) exhibited the highest water uptake (54%) despite its lower IEC value compared to the corresponding one containing N1-octyl-substituted imidazolium PVBC, low swelling ratio and a phase separated morphology. Evaluation of the chemical stability in 3.6 M KOH solution at 80 °C for 7 days revealed the degradation of imidazolium via ring opening, as evidenced by ATR-FT-IR spectroscopy. Therefore, new blends having as second constituent, the N1-alkyl-substituted imidazolium functionalized poly(PVBC-co-AA20) copolymers containing acrylic acid units were fabricated targeting to the improvement of chemical stability via ionic cross linking. The prepared D1 and D2 blend membranes containing 60 and 65 wt% dodecyl-imidazolium functionalized poly(PVBC-co-AA20) copolymer content, respectively, were flexible, exhibited moderate IECs (1.47–1.60 meq/g) and sufficient water uptakes (up to 30%). D2 blend membrane showed excellent chemical stability after testing in 3.6 M KOH solution at 80 °C for 30 days, as confirmed by ATR-FT-IR spectroscopy and TGA analysis. The excellent chemical stability can probably be attributed to the steric hindrance effect of N1 dodecyl substituent which effectively protects the C2 position of imidazolium from hydroxide attack as well as to the formation of a dense, ionic cross-linked structure that hinders hydroxide penetration.

Lignin-based nanogels for the release of payloads in alkaline conditions

Bio-based nanoparticles are promising materials in agriculture because they enable a controlled release of agrochemicals to plants. The release can be more specific by engineering nanoparticles with stimuli-responsive properties. Herein, we reported lignin-based nanogels which can release payloads in alkaline conditions. Lignin methacrylate was emulsified in miniemulsion droplets and graft copolymerized with acrylic acid to form core-shell nanogels. The successful incorporation of acrylic acid and lignin units in the nanogels was confirmed by FT-IR, H-NMR and XPS spectroscopies. TEM and dynamic light scattering analysis demonstrated that the nanogels were spherical and uniformly dispersed in the aqueous phase. AFM nanoindentation and thermal analysis indicated that the nanogels were mechanically and thermally durable. Lignin-based nanogels exhibited a pH-responsive swelling at high amounts of acrylic acid. Various hydrophobic payloads were encapsulated in high yield and could be preferentially released in alkaline conditions. Lignin-based nanogels are therefore the potential nanocarrier for the controlled release of agrochemicals such as pesticides or fungicides.

Synthesis of Amphiphilic Copolymers of Acrylic Acid and Styrene with the Desired Microstructure and Their Properties

The regularities of the controlled synthesis of amphiphilic copolymers of styrene and acrylic acid mediated by dithiobenzoate and trithiocarbonates as reversible addition fragmentation chain transfer agents in a 1,4-dioxane solution are considered. The influence of the general composition and chain microstructure on the dispersion stability and hydrodynamic sizes of polymer particles of copolymers containing from 40 to 90 mol % of acrylic acid units is studied. It is shown that in dilute aqueous media random copolymers are dispersed to individual compacted coils owing to the intrachain hydrophobic association of styrene units. The addition of two poly(acrylic acid) blocks to such a copolymer improves its dispersibility in water, and the attachment of two polystyrene blocks makes it insoluble in water because of the interchain association of polystyrene units. The synthesized copolymers possess surface activity, and when applied to a hydrophilic glass surface, they moderately hydrophobize it. In general, this synthetic approach opens up broad prospects for obtaining a wide range of new polymer macromolecules with different properties from one pair of traditional monomers.

Synthesis and Structure of Grafted Copolymers of Acrylic Acid and Low Molecular Weight Polyethylene

The synthesis was performed of grafted copolymers of acrylic acid on low molecular weight polyethylene in the presence of benzoyl peroxide in o-xylene solution. The formation of copolymers was proved by the methods of functional analysis of carboxyl groups and FTIR spectroscopy. The patterns of synthesis are shown, which made it possible to obtain graft copolymers in a wide range of compositions. X-ray diffraction analysis demonstrated that the presence of acrylic acid units in the copolymer leads to a decrease in the crystallinity of the copolymers compared to the initial low molecular weight polyethylene.

Amphiphilic Copolymers of Acrylic Acid and n-Butyl Acrylate with the Predetermined Microstructure: Synthesis and Properties

Features of the synthesis of n-butyl acrylate copolymers with acrylic acid in 1,4-dioxane by free radical reversible addition-fragmentation chain transfer (RAFT) polymerization mediated by symmetric trithiocarbonates are considered. It is shown that the living mechanism of polymerization is realized in the studied systems. The chemical nature of the RAFT agent dictates different chain microstructures (random block or random) of the copolymers. The effect of chain microstructure on the properties of the copolymers containing about 90 mol % of acrylic acid units is studied by differential scanning calorimetry, contact angle measurements, turbidimetry, potentiometric titration, and dynamic light scattering. It is demonstrated that all the copolymers in the solid phase have similar properties: a single glass transition temperature close to the glass transition temperature of polyacid and a good water wettability. In dilute aqueous solutions, the properties of the copolymers are different: at the inherent pH, random copolymer macromolecules form large associates, while random block copolymers are dispersed into individual coils or micelles. All the copolymers are weaker polyacids compared with PAA; the random block copolymers are characterized by the compaction of macromolecules at small degrees of ionization. Our studies provide evidence that reversible addition-fragmentation chain transfer polymerization is an efficient tool for the targeted insertion of nonpolar units into a polyelectrolyte chain and it can be used for the fine-tuning of its properties.

Optical glucose biosensor based on photonic interpenetrating polymer network with solid-state cholesteric liquid crystal and cationic polyelectrolyte

A patterned photonic array of dots with a photonic interpenetrating polymer network (IPN) structure consisting of intertwined photonic solid-state cholesteric liquid crystals (CLCsolid) and cationic polyelectrolyte networks was utilized for glucose detection. The photonic CLCsolid network was prepared using a reactive mesogen mixture (RMM 727, Merck) doped with the chiral dopant CB1511(S)-4-cyano-4´-(2-methylbutyl)biphenyl (CB15), followed by ultraviolet (UV) curing and chiral dopant extraction. The networked cationic polyelectrolyte was prepared by infiltrating a monomer mixture of DMAEMA222-dimethylaminoethyl methacrylate (DMAEMA) and acrylic acid (AA) (85:15 mol%) and a crosslinker of TPGDA33Tripropylene glycol diacrylate (TPGDA) into the extracted space of the CLCsolid network, UV curing under a photomask, washing the unreacted monomers outside the dots, and immobilizing the glucose oxidase (GOx) at the AA units via a coupling reaction with EDC44N-(3-dimethylaminopropyl)-N-ethylcarbodiimide (EDC). The prepared patterned photonic dots display a clear pH response in terms of a redshift with decreasing pH because the intertwined poly(DMAEMA) (PDMAEMA) is a typical weak cationic polyelectrolyte which protonates and expands at pH values below its pKb. Thus, the enzymatic reaction of GOx with glucose causes a decrease in pH, expansion of the PDMAEMA, and a redshift of the reflected photonic color. The optimized photonic optical sensor shows a linear range of 0.7–12 mM with a detection limit of 0.021 mM, superior selectivity, and excellent spike test results with real blood serum. The developed photonic IPN sensor is attractive because it is cost-effective, battery-free, and allows easy naked-eye optical detection without the need for sophisticated analytical instrumentation.

Systematic study of catalytic degradation of nitrobenzene derivatives using core@shell composite micro particles as catalyst

Polystyrene-poly(N-isopropylmethacrylamide-acrylic acid) [Pst@pnIPM-Ac] core@shell micro particles were synthesized by two step method and used as template for the fabrication of silver nanoparticles (silver-NPs). Silver-NPs were loaded in shell of core@shell micro particles from in-situ reduction of AgNO3 salt using NaBH4 as reductant. Pure Pst@pnIPM-Ac core@shell micro particles and silver-NPs endowed silver-Pst@pnIPM-Ac core@shell composite micro particles were characterized by Fourier transform infrared spectroscopy (FT-Ir), UV visible spectroscopy (UV vis), transmission electron microscopy (TEM) and dynamic light scattering (DLS). Morphological analysis revealed that micro particles showed core@shell morphology while the diameter of Pst core and pnIPM-Ac shell was found in range of 0.12 to 0.14 μm and 0.081 to 0.083 μm, respectively. Pst@pnIPM-Ac micro particles showed response to change in pH of the medium due to presence of acrylic acid (Ac) unit in polymer network. Catalytic properties of silver-Pst@pnIPM-Ac core@shell hybrid micro particles were checked by reducing the nitrobenzene derivatives (NbD) possessing different substitute at para position of aromatic ring [p-nitro toluene (p-NT) and p-chloro nitrobenzene (p-CNB)] using NaBH4 as reductant. Values of apparent rate constant (kapp) were found to be 0.1532 and 0.103 min−1 for the reduction of p-NT and p-CNB, respectively. Effect of concentration of NaBH4 and catalyst dose on the value of kapp for reduction of p-NT was also investigated. Kinetic analysis illustrated that NbD reduction followed Langmuir-Hinshelwood mechanism. Prepared silver-Pst@pnIPM-Ac composite micro particles catalyst was found to be efficient for reduction of NbD. Recyclability and reusability of reported catalyst was also checked for the reduction of p-NT. It was observed that silver-Pst@pnIPM-Ac core@shell composite micro particles maintained the percentage activity in the range of 97–100 % for three successive cycles for the reduction of p-NT. The protocol adopted for the catalytic reduction of p-NT was proved to be effective.

Enhanced Heat Resistance and Adhesive Strength of Styrene-Acrylic Triblock Copolymer Elastomers by Incorporating Acrylic Acid.

Herein, we present an industrially applicable strategy to enhance the heat resistance and adhesive properties of ABA triblock copolymer-based elastomers composed of styrene (St) and n-butyl acrylate (nBA) by incorporating acrylic acid (AA) at different segments. Three types of triblock copolymers, namely, poly(St-r-AA)-b-poly(nBA)-b-poly(St-r-AA), poly(St)-b-poly(nBA-r-AA)-b-poly(St), and poly(St)-b-poly(nBA)-b-poly(St), were synthesized by reversible addition–fragmentation chain-transfer (RAFT) polymerization. Large-scale RAFT polymerization afforded industrially applicable AA-containing triblock copolymers with moderate molecular weights and predetermined comonomer compositions (St/nBA/AA = 15/83/2–24/73/3, number-average molecular weight (Mn) = 30,000–110,000, and resulting product > 200 g). The heat resistance and pressure-sensitive adhesive properties of the triblock copolymers were evaluated. Among them, poly(St-r-AA)-b-poly(nBA)-b-poly(St-r-AA), having poly(nBA) as the middle soft segment and poly(St-r-AA) as hard segments at both ends, exhibited excellent heat creep resistance and increased adhesiveness to stainless steel. The feasibility to manipulate the heat resistance and adhesive properties by incorporating AA units into hard and soft segments, in addition to the ease of operation, high block efficiency, and metal-free nature owing to the RAFT process, is highly beneficial for practical applications of these copolymers.

Enhanced scale inhibition against Ca3(PO4)2and Fe2O3in water using multi-functional fluorescently-tagged antibacterial scale inhibitors

P-Free copolymers display enhanced scale (Ca3(PO4)2and Fe2O3) inhibition, improved antibacterial performance, and reliablein situfluorescence detection of concentration.

Polyelectrolyte coated individual silica nanoparticles dispersed in concentrated divalent brine at elevated temperatures for subsurface energy applications

Individual sub-60 nm polyelectrolyte coated silica nanoparticles (SiNPs) were stabilized in concentrated brine at temperatures up to 120 °C. The particles have potential applications in enhanced oil recovery, CO2 sequestration, and underground delivery of encapsulated payloads. The polyelectrolyte copolymer was grafted to modified silica particles with a general thermal method in DMSO that is broadly applicable to many types of nanoparticles and polymers with less significant hydrolysis than in aqueous based approaches. SiNPs were first coated with amine functional groups and then with poly(2-acrylamido-2-methyl-1-propanesulfonic acid-co-acrylic acid) (poly(AMPS-co-AA)) through a thermally driven amidation of the acrylic acid units in a dimethyl sulfoxide (DMSO) rich medium. Permanent aggregation and bridging were limited by controlling reaction time for temperatures up to 130 °C. The amine coated SiNP were dispersed as individual particles and the polyelectrolyte formed small flocs in DMSO. Upon transfer of the grafted SiNP from DMSO to a fully aqueous medium the hydrodynamic diameters (Dh) ranged from 30–60 nm. The particles were colloidally stable in API brine (2 wt% CaCl2 and 8 wt% NaCl) at 90 °C and pHs of 5.5–9.5 for 19 days. At 120 °C, minor aggregation to 130 nm was observed after 19 days at pH 5.5, whereas the stability decreased to 1 day at neutral pH. The particles were highly mobile in a column packed with 40–50 mesh Ottawa sand with a recovery of 82.2 % of the injected NPs. The exceptional colloidal stability and low retention in packed columns can be attributed to the steric protection of 2-acrylamido-2- methyl-1-propanesulfonic acid (AMPS) segments from particle-particle and particle-sand attractive forces, and multipoint grafting through the AA anchor groups.

Effects of comb-like PCE and linear copolymers on workability and early hydration of a calcium sulfoaluminate belite cement

Fluidity control and setting adjustment are two critical issues for practical applications of calcium sulfoaluminate cement because of rapid hydration. A commonly used comb-like polycarboxylate superplasticizer (PCE) and linear copolymers (PAS) of acrylic acid (AA) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) with varied monomer ratio were synthesized to study their impacts on fluidity and early hydration of calcium sulfoaluminate belite cement (CSAB). Results show that the linear PAS polymers are very effective in dispersing fresh cement pastes (fcps) and effectively inhibit early hydration of the cement. More AA unit in the PAS molecules leads to stronger inhibition effect on cement hydration. Compared with the PAS polymers, PCE exhibits almost no inhibition effect on cement hydration despite the high initial dispersibility. Thus, cement pastes containing PAS polymers exhibits excellent fluidity retention compared with the PCE containing fcp due to strong retardation effect of the PAS polymers on early formation of AFt crystals.

Metallo-Supramolecular Hydrogels from the Copolymers of Acrylic Acid and 4-(2,2':6',2″-terpyridin-4'-yl)styrene.

Hydrophilic copolymers containing 2,2′:6′,2″-terpyridine moieties and acrylic acid (AA) units poly (acrylic acid-co-4-(2,2′:6′,2″-terpyridin-4′-yl)styrene) (P(AA-co-TPY)) were synthesized and characterized. Coordinated with different transition metal ions, the dilute aqueous solution of the copolymers exhibited red-shifted UV-vis absorption peaks of π-π* transition from 317 to 340 nm. Further, interacting with iron ions, the copolymer showed new absorption peaks at a longer wavelength region (570 nm) and the absorption intensity enhanced with increase of the ion concentration. When enough ions were added to coordinate with the 2,2′:6′,2″-terpyridine moieties, novel metallo-supramolecular hydrogels were obtained due to the formation of metal coordination bonds between polymer back bones and transition metal ions (Ni2+, Zn2+, Cd2+, Fe2+ and Cu2+), which acted as self-assembly crosslinking structures. The mechanical strength and morphology of the resulting metallo-supramolecular hydrogels have been investigated.