Acrylic Acid Content Research Articles

Measurement and modeling of solubilities and diffusion coefficients of carbon dioxide in poly(ethylene-co-acrylic acid)

We measured and modeled the solubilities and diffusion coefficients of carbon dioxide (CO2) in poly(ethylene-co-acrylic acid) (PEAA) over temperatures of 373–473 K and pressures of up to 20 MPa. The measured solubilities of CO2 in PEAA obeyed Henry’s law and decreased with an increase in the acrylic acid content of the copolymer. The Sanchez-Lacombe equation of state could be applied to correlate the measured solubilities. The temperature dependence of the CO2 solubilities in PEAA was found to be similar to that in polyethylene with analysis using Henry’s law. Further, the gas solubility and acrylic acid content were the influential factors for determining the diffusivity of CO2, which could be modeled based on the free volume theory.

Pectin-based hydrogels with adjustable properties for controlled delivery of nifedipine: development and optimization

Pectin-co-poly acrylic acid (Pec-co-poly (AA)) hydrogels are imperative and new type of chemically cross-linked hydrogels. A research was conducted to develop pH-sensitive, controlled release, and biocompatible hydrogels by free radical polymerization and scrutinize the suitability of Pec-co-poly (AA) hydrogels as drug carriers. Different formulations were designed using central composite model. N,N-Methylenebisacrylamide (MBA) was used as a cross-linker and benzoyl peroxide (BPO) as an initiator. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) showed that hydrogels are thermally stable. Hydrogels have a porous structure, clearly expressed by scanning electron microscopy (SEM). Fourier transform infrared spectroscopy (FTIR) results concede the grafting reaction of AA on pectin. Hydrogels were figured out for pH-responsive behaviour by dynamic and equilibrium swelling ratio at low and high pH. The effects of pectin and acrylic acid (AA) content on swelling were also studied and revealed an increasing trend in swelling with increasing concentration of either pectin or AA. Similarly, developed hydrogels were also evaluated for different modalities for drug loading and release employing nifedipine as model drug. Constructed models are found to be suitable prediction tools, with contour plots and response surface plots providing an easy tool for estimation of response nature over entire setting of variables. It is concluded that highly stable Pec-co-poly (AA) hydrogels are developed. These have potential to be used as carrier for controlled delivery of nifedipine.

PH-Sensitive Nanocomposite Hydrogels Based on Poly(Vinyl Alcohol) Macromonomer and Graphene Oxide for Removal of Cationic Dyes from Aqueous Solutions

In this study, a pH-sensitive nanocomposite hydrogel based on poly(vinyl alcohol) (PVA)/graphene oxide (GO) was prepared and used as a potential adsorbent for the removal of crystal violet (CV) and methylene blue (MB) from aqueous solutions. The prepared nanocomposite hydrogels were fully characterized and their swelling capacity and gel content were investigated by changing the GO and acrylic acid (AA) content. Adsorption experiments were carried out as a function of contact time, concentration, temperature, pH and dosage. The adsorption process was favored at higher pHs, followed pseudo second-order kinetics while the adsorption equilibrium data well fitted to the Langmuir isotherm model with the maximum capacity of 173.2 and 169.6 mg g−1 for MB and CV, respectively. A thermodynamic study showed the spontaneity nature of the adsorption process for MB and CV. The removal percentage of MB dye increased with increase of temperature from 25 to 55 °C while the adsorption of CV dye showed the opposite trend. This different trend can be attributed to the differences in the pattern of adsorption.

Dual physically and chemically cross-linked polyelectrolyte nanohydrogels: Compositional and pH-dependent behavior studies

This study describes the composition-property relationship of a dual chemically and physically cross-linked nanohydrogel (NHG) containing a high concentration of hydrophilic pH-sensitive acrylic acid (AA). The physical and chemical cross-linking were incorporated using the aggregation of hydrophobic butyl acrylate (BA) and covalent bond of a bifunctional monomer (ethylene glycol dimethacrylate), respectively. Implementing a direct one-pot semi-batch emulsion polymerization technique in an acidic condition yielded monodispersed (PDI < 0.2) NHGs with a collapsed hydrodynamic radius of 60–100 nm. Titration studies revealed the significant effect of the chemical and physical cross-linking on the amounts of accessible carboxyl groups and their ionization behavior. These NHG dispersions displayed good colloidal stability over a wide pH and duration, the Donnan equilibrium is responsible for the observed swelling behavior of these NHGs.

Preparation and Characterization of Superabsorbent Polymers Based on Sawdust.

Sawdust, a cheap by-product of the timber and forestry industry, was considered as a framework structure to prepare superabsorbent polymer with acrylic acid (AA) and acrylamide (AM), the synthetic monomers. The effects of initiator content, crosslinker content, AA content, AM content, degree of neutralization of AA, and reaction temperature on the swelling rate of superabsorbent polymer were investigated. The synthesized polymer was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Under optimal synthesis conditions, the results showed that the swelling rate of the polymer in deionized water and 0.9% NaCl solution reached 738.12 and 90.18 g/g, respectively. The polymer exhibits excellent swelling ability, thermal stability, and reusability. After the polymer was introduced into the samples (soil or coal), the water evaporation rate of the samples was significantly reduced, and the saturated water holding capacity and pore structure were also significantly improved.

Green Preparation of Hyphaene thebaica Fiber Grafted Acrylic Acid for Adsorption of Pb (II) ions from Aqueous Solution

In this study, a green chemistry approached was employed in the preparation of Hyphaene thebaica fiber grafted polyacrylic acid via microwave assisted method using potassium persulfate as chemical initiator. The optimum percentage grafting 92% was achieved under 5g concentration of acrylic acid, 0.2g concentration of potassium persulfate (KPS) and 2 minutes reaction time. The grafted sample was characterized using the following techniques, FTIR, SEM and XRD. The prepared graft copolymer was examined for adsorption of Pb (II) ions from aqueous solution in batch mode systems. The adsorption parameters such as pH, initial metal ion concentration and contact time were also studied. The Langmuir and Freundlich isotherm models were applied to simulate the equilibrium adsorption experimental data. The Langmuir model fitted well with experimental data with maximum adsorption capacity (qmax) of 20.37 mg/g at 45 minutes. Higher regression coefficient obtained confirmed the suitability of the Langmuir isotherm model which assumed monolayer coverage on the adsorbent surface. The adsorption studies revealed the efficacy of the grafted fiber for removal of Pb (II) ions from dilute aqueous solutions.

Quantification of Optimal Reaction Parameters for the Synthesis of a Polysaccharide‐Based Graft Copolymers Using Combined Shannon's Entropy and Data Envelopment Analysis

AbstractThe traditional process of synthesis of desired materials involves a trial and error approach, which consumes considerable time and resources. Therefore, it is necessary to implement computer‐aided optimizing techniques for the precise synthesis of desired material. This paper presents a novel modeling approach for precise synthesis of graft copolymers of poly(acrylic acid) and Tamarind seed polysaccharide (xyloglucan). Different sets of variables generated through experimental study have been analyzed for the quantification of optimal reaction variables and parameters using combined Shannon's entropy and data envelopment analysis (DEA). Experimental data from the grafting reaction such as concentration of acrylic acid, temperature, and time are used to validate the model and a good agreement between model predictions and experimental data is observed. The proposed innovative green approach for designing the precise synthesis of xyloglucan based graft copolymers may help in identifying the optimal conditions for polymerization reaction to reach targeted materials more efficiently.

Ultraviolet-initiated graft polymerization of acrylic acid onto thin-film polyamide surface for improved ethanol dehydration performance of pervaporation membranes

In this study, polyacrylic acid (PAA) was grafted onto a polyamide (PA) surface through ultraviolet-initiated graft polymerization to improve the pervaporative dehydration of aqueous alcohol solutions. The PA layer was formed on the surface of a polyacrylonitrile support by the interfacial polymerization of 1,4-bis(3-aminopropyl)piperazine and trimesoyl chloride. Afterward, the PAA was deposited under varying grafting conditions—different acrylic acid concentrations, periods of irradiation time, and irradiation distances. Attenuated total reflectance-Fourier transform infrared and X-ray photoelectron spectra indicated the presence of more carboxyl groups on the membrane surface after grafting PAA. Images from field emission scanning electron microscopy and atomic force microscopy illustrated that the membrane became rougher. PAA also improved the membrane hydrophilicity. The dehydration of 90 wt% aqueous ethanol solutions by pervaporation demonstrated that the flux and water concentration in permeate were enhanced from 803 ± 55 to 830 ± 59 g m−2 h−1 and 84.9 ± 2.5 to 99.5 ± 0.3 wt%, respectively. Furthermore, the PAA-PA membranes showed stable performance at wide operating conditions.

Biocompatibility and adhesive strength properties of poly(methyl acrylate-co-acrylic acid) as a function of acrylic acid content

Metals and metal alloys are widely used in medical devices that contact blood and/or tissue, and various coating materials for the metal parts have been proposed to improve surface properties such as biocompatibility. This study aims to understand the performance of new coating materials, copolymers of methyl acrylate and acrylic acid, in terms of their biocompatibility and adhesive strength to a metal surface. Blood compatibility was investigated through platelet and coagulation system responses. Cytocompatibility was studied in three cell-line types (endothelium, smooth muscle, and fibroblasts) in terms of cell viability and morphology; these tests showed that compatibility depended on the cell types and acrylic acid content of the copolymers. Because of their blood compatibility and adhesion strength, the methyl acrylate and acrylic acid copolymers containing 10–24 mol% acrylic acid were found to be excellent candidates as potential coating materials for devices contacting blood.

Controlled synthesis and self-assembly of amphiphilic copolymers based on 2,2,3,3,4,4,5,5-octafluoropentyl acrylate and acrylic acid

The reversible addition–fragmentation chain transfer (RAFT) polymerization of 2,2,3,3,4,4,5,5-octafluoropentyl acrylate (OFPA) in the presence of different concentrations of S,S-dibenzyl carbonotrithioate as chain transfer agent (CTA) was investigated. The estimate of Ctr was defined using the size-exclusion chromatography measurements. Copolymers of acrylic acid and OFPA with different microstructure were synthesized by three methods: block copolymerization, copolymerization of acrylic acid and OFPA, and chemical modification of copolymer of tert-butyl acrylate and OFPA. Copolymerization of abovementioned monomer pairs was studied. The reactivity ratios were calculated by using the Fineman–Ross and Kelen–Tudos models, as well as the method of least squares. Aggregation behavior of the obtained amphiphilic copolymers at the air/water interface was defined by the Langmuir monolayer technique. Monomolecular films of amphiphilic copolymers were studied using atomic force microscopy. The effect of the chain microstructure, the acrylic acid content in the copolymer, and subphase pH on the isotherm curves were shown.

Preparation and properties of porous P(St-MMA-AA) microsphere anti-glare film

Monodisperse nanoparticles can form two-dimensional or three-dimensional colloidal crystals with periodic ordered structure by self-assembly. They are widely application in optical devices, sensors, electronic devices and drug delivery. Photonic crystals consisting of spherical colloidal particles periodically have various properties and strong designability. Its performance and application have great research value. In order to ensure the transmittance of anti-static, anti-glare and anti-radiation (three-proof) nano-material films, the mist is often not ideal, which limits the practical application of anti-glare films. P(St-MMA-AA) microspheres with different pore sizes were prepared by adjusting the content of acrylic acid. The effects of particle size, concentration and pore structure of microspheres on the transmittance and mist of colloidal crystal coatings were investigated. It was found that increasing the pore structure of microspheres could improve the transmittance of colloidal crystal coatings and keep the mist constant. The experimental results show that the porous colloidal film can reach the standard transmittance when the concentration is 0.01%. It has good anti-glare and acid resistance. The application of porous nanoparticles in high transmittance anti-glare coating is further broadened. This colloidal crystal coating deposits polymer microspheres on the substrate by self-assembly. The preparation method has the advantages of simple equipment, good repeatability, easy operation, non-toxicity and easy synthesis, low cost of raw materials, high yield and environmental friendliness.

Surface modification of polysulfone ultrafiltration membranes by free radical graft polymerization of acrylic acid using response surface methodology

In this research, polysulfone (PSf) ultrafiltration (UF) membranes were prepared by a phase inversion method. Surface modification of the PSf membranes was carried out via grafting of acrylic acid as a hydrophilic monomer by free radical graft polymerization initiated by redox reaction. A central composite design (CCD) of response surface methodology (RSM) was applied to design the experiments. The process variables were acrylic acid concentration (CAA), redox system contact time (T1), and acrylic acid polymerization time (T2), while the contact angle (CA), pure water flux (PWF), and flux recovery ratio (FRR) were considered as the responses. Analysis of variance (ANOVA) demonstrated that the second-order polynomial models were appropriate and significant. The optimal conditions for variables was found to be CAA of 1.6 mol/L, T1 of 41.9 min, and T2 of 101.7 min. The predicted responses were 52.9° for CA, 149 L/m2 h for PWF, and 74.5% for FRR, which were in good agreement with the results obtained from the confirmation experiments, with values of about 53.2°, 145.3 L/m2 h, and 74.3%, respectively. A comparison of the results between the optimized and unmodified membranes indicated that the CA of the modified membrane was reduced significantly, about 30.5%, and FRR was increased considerably, about 32.2%, indicating that the modified membranes possessed enhanced fouling resistance, while the PWF declined 40%. Membrane characterization also revealed that acrylic acid was grafted uniformly on the membrane surface, and the modified membranes became smoother, as observed by SEM and AFM. Moreover, the pore size of the modified membranes as measured by MWCO was smaller than that of the unmodified membrane.

Development and application of a transcriptional sensor for detection of heterologous acrylic acid production in E. coli

BackgroundAcrylic acid (AA) is a widely used commodity chemical derived from non-renewable fossil fuel sources. Alternative microbial-based production methodologies are being developed with the aim of providing “green” acrylic acid. These initiatives will benefit from component sensing tools that facilitate rapid and easy detection of in vivo AA production.ResultsWe developed a novel transcriptional sensor facilitating in vivo detection of acrylic acid (AA). RNAseq analysis of Escherichia coli exposed to sub-lethal doses of acrylic acid identified a selectively responsive promoter (PyhcN) that was cloned upstream of the eGFP gene. In the presence of AA, eGFP expression in E. coli cells harbouring the sensing construct was readily observable by fluorescence read-out. Low concentrations of AA (500 μM) could be detected whilst the closely related lactic and 3-hydroxy propionic acids failed to activate the sensor. We further used the developed AA-biosensor for in vivo FACS-based screening and identification of amidase mutants with improved catalytic properties for deamination of acrylamide to acrylic acid.ConclusionsThe transcriptional AA sensor developed in this study will benefit strain, enzyme and pathway engineering initiatives targeting the efficient formation of bio-acrylic acid.

Molecular Evaluation of Oral Immunogenicity of Hepatitis B Antigen Delivered by Hydrogel Microparticles.

The development of oral vaccine formulation is crucial to facilitate an effective mass immunization program for various vaccine-preventable diseases. In this work, the efficacy of hepatitis B antigen delivered by bacterial nanocellulose/poly(acrylic acid) composite hydrogel microparticles (MPs) as oral vaccine carriers was assessed to induce both local and systemic immunity. Optimal pH-responsive swelling, mucoadhesiveness, protein drug loading, and drug permeability were characterized by MPs formulated with minimal irradiation doses and acrylic acid concentration. The composite hydrogel materials of bacterial nanocellulose and poly(acrylic acid) showed significantly greater antigen release in simulated intestinal fluid while ensuring the integrity of antigen. In in vivo study, mice orally vaccinated with antigen-loaded hydrogel MPs showed enhanced vaccine immunogenicity with significantly higher secretion of mucosal immunoglobulin A, compared to intramuscular vaccinated control. The splenocytes from the same group demonstrated lymphoproliferation and significant increased secretion of interleukin-2 cytokines upon stimulation with hepatitis B antigen. Expression of CD69 in CD4+ T lymphocytes and CD19+ B lymphocytes in splenocytes from mice orally vaccinated with antigen-loaded hydrogel MPs was comparable to that of the intramuscular vaccinated control, indicating early activation of lymphocytes elicited by our oral vaccine formulation in just two doses. These results demonstrated the potential of antigen-loaded hydrogel MPs as an oral vaccination method for hepatitis B.

Improved mechanical and rheological properties of recycled polyethylene by acrylic acid-assisted melt grafting of glycidyl methacrylate

ABSTRACTThe use of glycidyl methacrylate (GMA) and acrylic acid (AAc) as grafting monomers to improve the mechanical properties, particularly tensile strength, of recycled polyethylene (R-PE) is reported in this study. The AAc monomer was implemented to improve the stability of radical chains which could undergo GMA grafting. When the content of GMA and AAc was 1.2% and 0.6%, respectively, the tensile strength increased from 17.26 to 29.3 MPa, the elongation at break increased from 107% to 647%, and the melt index decreased from 3.42 to 0.97 g/10 min. The sensitivity of the dynamic behaviour of R-PE-g-(AAc-co-GMA) to temperature was also reduced relative to R-PE. Differential scanning calorimetry (DSC) results showed that the melting temperature was increased and the crystallisation temperature of R-PE-g-(AAc-co-GMA) was reduced. The fracture morphology of the samples was also shown by scanning electron microscope (SEM) observations to transition from brittle fracture to ductile fracture upon undergoing the grafting process.

Charged microgels adsorbed on porous membranes - A study of their mobility and molecular retention

The high flexibility of microgel synthesis provides a tremendous playground to tune properties of microgels, resulting in a broad variety of gels with tailor-made functionalities. Functionalized on membranes, microgels offer direct tuning of filtration properties of microgel-membrane composites. Regarding microgels as soft model colloids, the investigation of microgel-membrane interaction gives insight into the early formation of fouling layers and their stability. While it is known though that microgel properties strongly depend on the support, only few studies analyzed the behavior of microgels on porous surfaces as needed for membrane applications.In this study poly-(N-isopropylacrylamide) (PNIPAM) based microgels serve as soft model colloids. By successively increasing the concentration of the comonomer acrylic acid (AAc) we tune the charge of the microgels in neutral environment. We systematically study the transversal movement of the differently charged gels adsorbed on a porous polyethersulfone (PES) membrane as a function of convective flow and coating conditions. A 3D-printed online screening module allows us to observe single microgel movement under flow induced shear forces. The microgels exhibit a charge dependent mobility on the porous surface. We use the gained fundamental knowledge of microgel adsorption to achieve 65% retention of a charged dye on PNIPAM-co-AAc modified ultrafiltration and microfiltration membranes while neutral solutes pass.

PH-Sensitive Hydrogel from Polyethylene Oxide and Acrylic acid by Gamma Radiation

Hydrogel as a good water absorbent has attracted great research interest. A series of hydrogel based on polyethylene oxide (PEO) and acrylic acid (AAc) was prepared by applying gamma radiation with variation in the concentration of acrylic acid. Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) were used to characterize the PEO/ AAc hydrogel. The properties of the prepared hydrogels such as gel content, swelling behavior, tensile strength, and pH sensitivity were evaluated. The formation of the hydrogels was confirmed from FTIR spectra. SEM images showed the inner porous structure of the hydrogels. The dose of gamma radiation was optimized to get a hydrogel with good swelling property and mechanical strength. The swelling ratio and gel content of the hydrogels were increased with increasing acrylic acid content. The pH of the solutions affected the swelling which indicated the pH-responsive property of the prepared hydrogels. Swelling of the prepared hydrogels in sodium chloride salt solutions decreased with increasing the ionic strength.

Homogeneous hydrogels made with acrylic acid, acrylamide and chemically functionalized carbon nanotubes

Carbon nanotubes (CNTs) chemically functionalized were used to synthesize a series of novel nanocomposite hydrogels by in situ polymerization with acrylic acid (AA) and acrylamide (AM). A novel strategy was developed to prepare these hydrogels. CNTs were functionalized following a three-step chemical procedure: (i) purified carbon nanotubes (CNTsp) were partially surface oxidized to obtain CNTs with hydroxyl, carbonyl and carboxyl groups on their sidewalls (CNTsoxi), (ii) CNTsoxi were reacted with oxalyl chloride to obtain CNTs functionalized with acyl chloride groups (CNTsOCl), and (iii) CNTsOCl were reacted with acrylic acid (AA). The product, AA modified CNTsOCl (CNTsOCl-AA) was used to prepare the (CNTsOCl-AA-AM) nanocomposite hydrogels, where anhydride groups were tethered to the surface of the CNTsOCl-AA. The swelling process in water was evaluated as a consequence of the anhydride group hydrolysis, which broke some chemical links between CNTsOCl-AA and crosslinked AA-AM network. Equilibrium-swelling values of all hydrogels increased as the content of AA increased and were larger for AA-AM hydrogels than for CNTsOCl-AA-AM nanocomposite hydrogels. Young’s moduli of CNTsOCl-AA-AM nanocomposite hydrogels prepared with 1 or 2 wt.% AA, reached larger values than those measured for AA-AM hydrogels. This tendency was reversed when the AA content was raised to 3 wt.%.

Synthesis of a starch–acrylic acid–chitosan copolymer as flocculant for dye removal

ABSTRACTFlocculants prepared with modified natural polymers have recently attracted extensive attention in the field of water treatment. In this work, acrylic acid was successfully grafted onto the backbones of starch and chitosan by free radical polymerization. The synthesis parameters of initiator concentration, reaction temperature, and neutralization degree of acrylic acid were optimized as 0.4 wt %, 50 °C, and 70%, respectively, according to the flocculation performance. The ternary copolymer starch–acrylic acid–chitosan (SAAC) could completely remove Acid Blue 113 from 100 mg/L of simulated wastewater (color removal efficiency 99.7%) at the flocculant dosage of 100 mg/L. The SAAC also had effective flocculation capability in a wide range of flocculant dosages and pH values of wastewater. The ternary copolymer based on two natural polymers has enormous potential as flocculant with its advantages of low price, ecofriendliness, and high performance. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47437.

Preparation of Xylan–Acrylic Acid Polymer with High Molecular Weight and its Application as a Dye Removal Flocculant

Xylan is found in natural products and can be used for preparing value-added products. The main purpose of this study was to produce a xylan-based polymer (xylan–acrylic acid [Xy–AA]) as a flocculant for removing ethyl violet dye from wastewater. In this study, the polymerization reaction of xylan and acrylic acid (AA) was optimized by response surface methodology (RSM). It was indicated that the maximum charge density of –5.87 mmol/g and molecular weight of 352,028 g/mol were obtained for Xy–AA polymer under the conditions of 20.53 g/L xylan concentration, 0.31 xylan/AA molar ratio, 2.5 h reaction time, and 72 °C reaction temperature. The polymer was characterized by charge density analyzer, Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H-NMR), and thermogravimetric analysis (TGA). The application of the product as a flocculant for removing the ethyl violet from simulated dye solution was evaluated. The results showed that the optimal dye removal of 97.08% was achieved under the conditions of 50 mg/L dye concentration, 120 mg/L Xy–AA concentration, pH 10, and 30 °C. The flocculation mechanism was also discussed.