Showing papers on "Acrylic acid published in 2013"
TL;DR: In this paper, a facile and versatile strategy for the preparation of self-healing hydrogels containing double networks of both physically and chemically cross-linked polymers was developed.
238 citations
TL;DR: It is shown that a zwitter-wettable surface, a surface that has the ability to rapidly absorb molecular water from the environment while simultaneously appearing hydrophobic when probed with water droplets, can be prepared by using hydrogen-bonding-assisted layer-by-layer (LbL) assembly of poly(vinyl alcohol) (PVA) and poly(acrylic acid) ( PAA).
Abstract: Antifogging coatings with hydrophilic or even superhydrophilic wetting behavior have received significant attention due to their ability to reduce light scattering by film-like condensation. However, under aggressive fogging conditions, these surfaces may exhibit frost formation or excess and nonuniform water condensation, which results in poor optical performance of the coating. In this paper, we show that a zwitter-wettable surface, a surface that has the ability to rapidly absorb molecular water from the environment while simultaneously appearing hydrophobic when probed with water droplets, can be prepared by using hydrogen-bonding-assisted layer-by-layer (LbL) assembly of poly(vinyl alcohol) (PVA) and poly(acrylic acid) (PAA). An additional step of functionalizing the nano-blended PVA/PAA multilayer with poly(ethylene glycol methyl ether) (PEG) segments produced a significantly enhanced antifog and frost-resistant behavior. The addition of the PEG segments was needed to further increase the nonfreezin...
207 citations
TL;DR: In this article, an acid functionalized multi-walled carbon nanotube (MWCNT) was modified by three hydrophilic polymers during an in situ polymerization reaction.
150 citations
TL;DR: In this paper, the reversible addition-fragmentation chain transfer (RAFT) polymerization of acrylic acid (AA) in water was studied in detail at different pHs using 4-cyano-4-thiothiopropylsulfanyl pentanoic acid (CTPPA) as a control agent and 4,4′-azobis(4-cyanopentaneic acid) (ACPA), as an initiator.
Abstract: The reversible addition–fragmentation chain transfer (RAFT) polymerization of acrylic acid (AA) in water was studied in detail at different pHs using 4-cyano-4-thiothiopropylsulfanyl pentanoic acid (CTPPA) as a control agent and 4,4′-azobis(4-cyanopentanoic acid) (ACPA) as an initiator. Well-defined hydrophilic macromolecular RAFT agents (PAA-CTPPA) were obtained and further used directly in water for the polymerization of styrene. The corresponding polymerization-induced self-assembly (PISA) process was evaluated at different pHs and it was shown that working in acidic conditions (pH = 2.5) led to well-defined amphiphilic block copolymer particles (Đ < 1.4) of small size (below 50 nm). When the pH increased, the control over the growth of the polystyrene (PS) block was gradually lost. Chain extension experiments of PAA-CTPPA with N-acryloylmorpholine (NAM), a hydrosoluble and non-pH sensitive monomer, performed at different pHs showed that the very first addition–fragmentation steps that occurred in wate...
149 citations
TL;DR: This system, combined with CdSe quantum dots and ascorbic acid, has an exceptional turnover number and initial turnover frequency for the photocatalytic production of H2 in water, which is the highest efficiency to date for [FeFe]-hydrogenase mimics.
Abstract: Exceptional Poly(acrylic acid)-Based Artificial [FeFe]-Hydrogenases for Photocatalytic H2 Production in Water Light, polymer, action : A set of watersoluble poly(acrylic acid) catalysts PAA-gFe2S2 containing {Fe2S2}, an [FeFe]hydrogenase active-site mimic, is synthesized. This system, combined with CdSe quantum dots and ascorbic acid, has an exceptional turnover number and initial turnover frequency (27135 and 3.6 s ) for the photocatalytic production of H2 in water, which is the highest efficiency to date for [FeFe]-hydrogenase mimics. Angewandte Chemie
142 citations
TL;DR: A series of calcium hydroxyapatite (HAP) catalysts were synthesized with a Ca/P ratio ranging from 1.3 to 1.89 by a co-precipitation method that involved changing the pH of the calcium precursors.
142 citations
TL;DR: Several interpenetrating network (IPN) hydrogels were made by free radical in situ crosslink copolymerization of acrylic acid and hydroxy ethyl methacrylate in aqueous solution of sodium alginate for adsorption of two important synthetic dyes.
139 citations
TL;DR: A fine-tuning of the hydrophobic-hydrophilic balance by varying the molecular weight of the polymers and the pH of the aqueous solutions, as well as the composition for the block copolymers, shows that larger relative size of the PDMAEMA blocks leads to an increasing tendency to form micellar aggregates and a decrease of the LCST of theaqueous solution, which is consistent with the increasing copolymer hydrophobicity.
Abstract: A series of poly(2-(dimethylamino) ethyl methacrylate) (PDMAEMA) homopolymers and poly(2-(dimethylamino)ethyl methacrylate)-b-poly(acrylic acid) (PDMAEMA-b-PAA) diblock copolymers were synthesized by atomic transfer radical polymerization. Thanks to a fine-tuning of the hydrophobic–hydrophilic balance by varying the molecular weight of the polymers and the pH of the aqueous solutions, as well as the composition for the block copolymers, the lower critical solution temperature (LCST) and the aggregation–dissolution kinetics of PDMAEMA homopolymers and PDMAEMA-b-PAA block copolymers can be adjusted. For the block copolymers, the results show that larger relative size of the PDMAEMA blocks leads to an increasing tendency to form micellar aggregates and a decrease of the LCST of the aqueous solution, which is consistent with the increasing copolymer hydrophobicity. A significant difference of the stimuli-responsive behavior between PDMAEMA-rich and PAA-rich copolymers is observed, because the former exhibit t...
127 citations
TL;DR: The formation of new bands in FTIR spectra of grafted sample confirmed the grafting of acrylic acid onto the cellulosic fiber and confirmed the applicability of Langmuir isotherm that assumed a monolayer coverage and uniform activity distribution on the adsorbent surface.
117 citations
TL;DR: The results demonstrated that the PAA layers on the surface of MSNs-PAA exhibited opened and closed states at different pH values, and thus could regulate the uptake and release of salidroside.
107 citations
TL;DR: In this paper, a series of poly(l-lactide)-b-poly(acrylic acid) (PLLA-b-PAA) diblock copolymers with a range of hydrophobic or hydrophilic block lengths were designed in order to tune the size of the resultant cylindrical micelles using a crystallization-driven self-assembly (CDSA) approach.
Abstract: A series of poly(l-lactide)-b-poly(acrylic acid) (PLLA-b-PAA) diblock copolymers with a range of hydrophobic or hydrophilic block lengths were designed in order to tune the size of the resultant cylindrical micelles using a crystallization-driven self-assembly (CDSA) approach. The precursor poly(l-lactide)-b-poly(tetrahydropyran acrylate) (PLLA-b-PTHPA) was synthesized by a combination of ring-opening polymerization (ROP) and reversible addition-fragmentation chain transfer (RAFT) polymerization. The CDSA process was carried out in a tetrahydrofuran/water (THF/H2O) mixture during the hydrolysis of PTHPA block at 65 °C using an evaporation method. A majority of PLLA-b-PAA diblock copolymers resulted in the formation of cylindrical micelles with narrow size distributions (Lw/Ln < 1.30) as determined by transmission electron microscopy (TEM) and dynamic light scattering (DLS). Furthermore, the length of PLLA block was found to control the length of the resultant cylindrical micelles while the length of PAA b...
TL;DR: In this article, the adsorption of different organic acids and their influence on the pH-dependent charging, salt tolerance and so the colloidal stability of magnetite nanoparticles are compared.
TL;DR: In this article, the effect of the type of epoxidation processes of soybean oil on the characteristics of ESOs, AESOs, and poly(methyl metacrylate) copolymers (AESO-co-PMMA) has been investigated.
Abstract: The effect of the type of epoxidation processes of soybean oil on the characteristics of epoxidized soybean oils (ESOs), acrylated epoxidized soybean oils (AESOs), and acrylated epoxidized soybean oil - poly(methyl metacrylate) copolymers (AESO-co-PMMA) has been investigated. Two epoxidation processes were used: an in situ chemical epoxida- tion using hydrogen peroxide and formic acid, and a chemo-enzymatic epoxidation using 2 enzymes: Novozyme ® 435 (CALB) and a homemade lipase/acyltransferase (CpLIP2). ESOs containing different numbers of epoxide groups/molecule were synthesized. A commercial ESO (Vikoflex ® 7170) was employed and it had the highest number of epoxide groups. Acrylation of ESOs was carried out using acrylic acid, and copolymerized with a methyl methacrylate monomer. The chemo-enzymatic epoxidation produced high acid value, particularly from the CpLIP2 (! 46-48%) and indicated the for- mation of epoxidized free fatty acids. In contrast, the ESO synthesized from the chemical epoxidation showed a very low acid value, < 0.6%. The AESOs synthesized from the CALB-based ESO and the chemical-based ESO showed a similar number of acrylate groups/molecule while that from the CpLIP2-based ESO showed a very low number of acrylate groups because the carboxylic groups from the epoxidized free fatty acids impeded the acrylation reaction. The lower the number of acrylate groups the lower was the crosslink density, the Tg, and the gel content in the AESO-co-PMMA copolymer.
TL;DR: The results revealed that folate conjugated micelles showed higher activity in FR + OVCAR-3 cells but not in FR - A549 cells, and Micelle stabilization via cross-linking could indeed increase the toxicity of the drug carrier.
TL;DR: In this paper, the authors discuss and update the latest advances on synthesis of acrylic acid derivatives from unsaturated hydrocarbons and carbon dioxide, and propose a direct carboxylation of olefins or alkynes with carbon dioxide.
Abstract: Carbon dioxide utilization has continued to capture the interest of chemists worldwide due to global warming associated with positive carbon accumulation. As an environmentally friendly C1 feedstock, the reaction of carbon dioxide has been extensively investigated for several decades. On the other hand, acrylic acid is a valuable industrial product that is widely used for various important purposes in industry. From the point view of atom- and process-economical chemistry, the most concise and promising route for acrylic acid derivatives synthesis would be direct carboxylation of olefins or alkynes with carbon dioxide. In this review, we would like to discuss and update the latest advances on synthesis of acrylic acid derivatives from unsaturated hydrocarbons and carbon dioxide.
TL;DR: In this article, the impact of chemical structure of four new-generation superplasticizers on their efficiency in cementitious pastes was studied using gel permeation chromatography (GPC) and Fourier transformed infrared spectroscopy (FTIR).
TL;DR: In this paper, shape memory hydrogels containing crystalline domains were produced by micellar copolymerization of acrylic acid with the hydrophobic comonomer n-octadecyl acrylate in an aqueous NaCl solution of sodium dodecyl sulfate (SDS).
Abstract: A novel way for the production of shape memory hydrogels containing crystalline domains is described. Hydrogels were prepared by micellar copolymerization of acrylic acid with the hydrophobic comonomer n-octadecyl acrylate (C18) in an aqueous NaCl solution of sodium dodecyl sulfate (SDS). The presence of NaCl causes the SDS micelles to grow and thus enables solubilization of large amounts (16% w/v) of C18 in the micellar solution. DSC measurements show that the swollen hydrogels, possessing 61–84% water, melt and crystallize with a change in temperature. Independent of the hydrophobe level between 20 and 50 mol %, the melting and crystallization temperatures of the hydrogels are 48 ± 2 and 43 ± 2 °C, respectively. The hydrogels exhibit 3 orders of magnitude change in the elastic modulus when the temperature changes between below and above the melting temperature of the crystalline domains. The blocky structure of the network chains formed by micellar polymerization is responsible for the drastic change in...
TL;DR: In this article, a 21-carbon dicarboxylic acid (C21DA) and a 22-carbon tricaroxylacetic acid (c22TA) were prepared by the Diels-Alder addition of tung oil fatty acids with acrylic acid and fumaric acid, respectively, and subsequently converted to the corresponding di- and triglycidyl esters.
TL;DR: In this paper, carbon nanotubes were used as an inert filler in the frontal polymerization (FP) of poly(acrylic acid) (PAA) and poly(methacrylic acids) (MCA) in order to obtain macroporosity and high biocompatibility.
Abstract: Deep Eutectic Solvents (DESs) formed between Acrylic Acid (AA) and Choline Chloride (CCl) exhibit certain properties of ionic liquids (e.g. high viscosity) that make them suitable for frontal polymerization (FP). The use of DESs not only as a monomer but also as the solvent prevents the use of additional solvents (i.e. typically of organic nature) and offers a green tool for the synthesis of functional composites. We have recently explored this approach for the preparation of poly(acrylic acid) (PAA) and poly(methacrylic acid). In this work, we have taken advantage of the outstanding capability of DESs to solubilize and/or disperse a number of substances to incorporate – in a homogeneous fashion – carbon nanotubes (in this particular case, N-doped MWCNT – CNxMWCNTs) in the polymerizable DES. Interestingly, CNxMWCNTs also played the role of an inert filler in FP. The resulting PAA–CNxMWCNT composites exhibited some distinct features as compared to previous PAA also obtained via DES-assisted FP. For instance, PAA–CNxMWCNT composites can undergo swelling depending on the pH, as bare PAA. However, the presence of CNxMWCNTs allows the formation of a macroporous structure after submission to a freeze-drying process, the achievement of which was not possible in bare PAA. The combination of structural (e.g. macroporosity) and functional (e.g. stimuli responsive) properties exhibited by these materials besides an eventually high biocompatibility – coming from the green character of the DES-assisted synthesis – should make the resulting macroporous PAA–CNxMWCNT composites excellent candidates for their future application as biomaterials.
TL;DR: In this paper, the authors described an all-in-one role, providing the monomer, the active filler, and the polymerization medium for frontal polymerization (FP).
Abstract: The deep eutectic solvents (DESs) based on the mixtures of a variety of ammonium salts and hydrogen bond donors containing acrylic acids and acrylamides are capable of sustaining frontal polymerization (FP). The selection of ammonium salt affects the reactivity and allows FP at relatively low temperature but with full conversion. Also, full conversion allows us to use these polymers for biomedical applications (e.g., drug delivery systems) as the unreactive ammonium salts can be released from the resulting polymer without by-products. We call these components “active fillers,” which can be ammonium salts with biological or pharmaceutical importance. For instance, we prepared poly(acrylic acid) loaded with lidocaine hydrochloride (a common anesthetic), the release of which was found to occur in a controlled fashion. The ammonium salts also create a sufficiently high viscosity to suppress buoyancy-driven convection without additional materials. The DES here described played an all-in-one role, providing the monomer, the active filler, and the polymerization medium for FPs. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
TL;DR: In this paper, 6-12 nm iron oxide nanoparticles were synthesized and coated with poly(acrylic acid) chains of molecular weight 2100 g mol(-1) based on a quantitative evaluation of the dispersions, the bare and coated particles were thoroughly characterized.
TL;DR: In this article, copolymer of maleic acid and acrylic acid (PMA-100), combining with polyvinyl butyral (PVB) hollow fiber ultrafiltration membrane were applied into a complexation-ultrafiltration process for the removal of heavy metal ions from an aqueous solution.
TL;DR: A facile method for production of functional carbonaceous materials from renewable resources that can be used for treatment of aqueous streams containing small concentrations of ionic liquid, 1-butyl-3-methyl-imidazolium chloride, is provided.
Abstract: Functional carbonaceous material (FCM) loaded with carboxylic groups was prepared by hydrothermal carbonization of cellulose in the presence of acrylic acid. The resulting FCM was used as adsorbent for recovery of a water-soluble ionic liquid, 1-butyl-3-methyl-imidazolium chloride ([BMIM][Cl]). The FCM consisted of microspheres (100–150 nm) and had a low surface area (ca. 20 m2/g), but exhibited adsorption capacity comparable to that of commercial activated carbon which can be attributed to the presence of high content of polar oxygenated groups (−OH, −C═O, −COOH) as revealed by spectral analyses. Sorption of [BMIM][Cl] onto FCM adsorbent could be well-described by pseudo-second-order kinetics. Thermodynamic and adsorption isothermal analyses revealed that the adsorption process was spontaneous, exothermic, and could be described by the Freundlich adsorption model. The FCM adsorbent could be regenerated effectively and recycled for at least three times without loss of adsorption capacity. The results of t...
TL;DR: This formulation of photoresponsive hydrogels and ionogels based on poly(N-isopropylacrylamide) copolymerised with pendant spiropyran groups does not show degradation of their photo-induced shrinking ability after multiple washings in deionised water and repeated switching over a 2 month period.
Abstract: Up to now, photoresponsive hydrogels and ionogels based on poly(N-isopropylacrylamide) copolymerised with pendant spiropyran groups require exposure to external acidic solution (usually milimolar HCl) to generate the swollen gel prior to photo-triggered contraction. This serious functional limitation has been solved by copolymerising acrylic acid into the gel matrix, to provide an internal source of protons. Due to the relative pKa values of acrylic acid and the spiropyran and merocyanine isomers, the protonation and deprotonation occurs internally within the gel and there is no need for an external source of protons. Furthermore, the shrinking–expansion cycles of these gels in deionised water are repeatable, as protonation throughout the gel does not rely on movement of protons from an external acidic solution into the bulk gel. In contrast to previous formulations, these gels do not show degradation of their photo-induced shrinking ability after multiple washings in deionised water and repeated switching over a 2 month period.
TL;DR: In this article, a new strategy to obtain functionalized acrylate monomers is introduced using the Passerini three-component reaction (Passerini-3CR), which is characterized by excellent atom economy and structurally diverse products.
Abstract: A new strategy to obtain functionalized acrylate monomers is introduced using the Passerini three-component reaction (Passerini-3CR). This straightforward one-pot synthesis is characterized by excellent atom economy and structurally diverse products. By using acrylic acid and a variety of aldehydes and isocyanides, a set of several acrylate monomers was synthesized. Subsequent free radical polymerization yielded polyacrylates with tunable properties depending on the used components for the Passerini reaction. For instance, by varying the aldehyde component from acetaldehyde to heptanal, control over the glass transition in the final polymer was achieved. Moreover, for highly polar acrylate monomers a thermoresponsive behavior (upper critical solution temperature; UCST) was observed in methanol and/or ethanol.
TL;DR: The triblock copolymers have great potential for bone tissue engineering because of their low cytotoxicity in cell viability test and obvious nucleation and growth of hydroxyapatite in the gels.
TL;DR: In this paper, a simple and straightforward strategy towards self-stabilized poly(acrylic acid)-block-poly(butyl acrylate), PAA-b-PBA, block copolymer particles via an ab initio RAFT-controlled emulsion polymerization was described.
TL;DR: In this article, the photocatalytic activity of poly(vinyl alcohol)/poly(acrylic acid)/TiO 2 /graphene oxide nanocomposite hydrogels was evaluated on the base of the degradation of pollutants by using UV spectrometer.
Abstract: Poly(vinyl alcohol)/poly(acrylic acid)/TiO 2 /graphene oxide nanocomposite hydrogels were prepared using radical polymerization and condensation reaction for the photocatalytic treatment of waste water. Graphene oxide was used as an additive to improve the photocatalytic activity of poly(vinyl alcohol)/poly(acrylic acid)/TiO 2 nanocomposite hydrogels. Both TiO 2 and graphene oxide were immobilized in poly(vinyl alcohol)/poly(acrylic acid) hydrogel matrix for an easier recovery after the waste water treatment. The photocatalytic activity of poly(vinyl alcohol)/poly(acrylic acid)/TiO 2 /graphene oxide nanocomposite hydrogels was evaluated on the base of the degradation of pollutants by using UV spectrometer. The improved removal of pollutants was due to the two-step mechanism based on the adsorption of pollutants by nanocomposite hydrogel and the effective decomposition of pollutants by TiO 2 and graphene oxide. The highest swelling of nanocomposite hydrogel was observed at pH 10 indicating that poly(vinyl alcohol)/poly(acrylic acid)/TiO 2 /graphene oxide nanocomposite hydrogels were suitable as a promising system for the treatment of basic waste water.
TL;DR: In this paper, a superabsorbent hydrogel composites were prepared using waste linear low density polyethylene (LLDPE), acrylic acid (AA), and modified montmorillonite (OMMT) clay through emulsion polymerization.
TL;DR: A novel dual-stimuli responsive double hydrophilic graft copolymer system, poly(acrylic acid)-g-poly(N-vinylcaprolactam) (PAA-g-PNVCL), which could respond to changes in pH and temperature simultaneously is reported.