Showing papers on "Acrylic acid published in 2009"
TL;DR: In this paper, the one-step aqueous route production of carbonaceous materials loaded with carboxylic groups using hydrothermal carbonization of glucose in the presence of acrylic acid is described.
Abstract: The present study concerns the one-step aqueous route production of carbonaceous materials loaded with carboxylic groups using hydrothermal carbonization of glucose in the presence of acrylic acid. This method provides a “green” solvent and surfactant free access to hydrophilic functionalized carbons with very good water dispersivity. The resulting materials were characterized using various methods including, FT-IR, Zeta Potential, N2 adsorption, Raman Spectroscopy, SEM, TGA, and 13C solid-state NMR. Among other possible applications of these types of materials, here, we discuss their use as adsorbents for heavy metals removal from aqueous solutions
492 citations
TL;DR: In this article, the luminescence properties of hexagonal sodium gadolinium fluoride nanoparticles co-doped with Ho3+ and Yb3+ were evaluated following 980 nm excitation.
Abstract: The luminescence properties of hexagonal sodium gadolinium fluoride nanoparticles co-doped with Ho3+ and Yb3+ (NaGdF4:Ho3+/Yb3+), prepared using a thermal decomposition synthesis route, were evaluated following 980 nm excitation. The synthesized nanoparticles were easily dispersed in nonpolar solvents, showed an extremely narrow particle distribution, and were determined to have a mean diameter of 15.6 ± 1.2 nm. The predominantly green upconversion emission was observed to increase with increasing Ho3+ concentration due to an enhanced energy transfer (ET) from the neighboring Yb3+ ions. Post-synthesis, the nanoparticles were dispersed in water via modification of the capping oleic acid (OA) ligand. Upconversion emission intensity was observed to decrease upon dispersion in aqueous media likely due to an increase in nonradiative decay pathways. A total ligand exchange with poly(acrylic acid) (PAA) resulted in slightly more intense upconversion emission relative to oxidation of the OA to azelaic acid.
345 citations
TL;DR: The designed poly(NIPAAm-co-AAc- co-HEMAPTMC) hydrogel of this report may offer an attractive biomaterial-centered treatment option for ischemic cardiomyopathy.
261 citations
TL;DR: In this article, the polyvinylidene fluoride (PVDF) membrane was prepared via immersion precipitation technique and modified by UV photo-grafting of hydrophilic monomers on the top membrane surface.
215 citations
TL;DR: In this article, four anthracene based sensitizers, 3-(anthracene-9-yl)-2-cyanoacrylic acid (M1), 2-cyanos-3-(10-methoxyanthracene 9-yl)ACrylic acid(M2), 2-(anthrasylmethylene) malonic acid (m3), and 2-((10methoxideyanthrasyl) methylene)malonic acid(m4)) were designed and synthesized to understand the binding modes of anchoring groups on the nanocry
Abstract: Four anthracene based sensitizers, 3-(anthracene-9-yl)-2-cyanoacrylic acid (M1), 2-cyano-3-(10-methoxyanthracene-9-yl)acrylic acid (M2), 2-(anthracene-9-ylmethylene) malonic acid (M3), and 2-((10-methoxyanthracene-9-yl)methylene)malonic acid (M4) were designed and synthesized to understand the binding modes of anchoring groups ( and ) on the nanocrystalline TiO2(101) surface and on the efficiency of dye-sensitized solar cells (DSSCs). All four sensitizers have been fully characterized using ATR-FTIR, UV−vis, and CV. These sensitizers were tested in DSSCs using 0.05 M I2, 0.5 M 1,2-dimethyl-3-n-propylimidazolium iodide (DMPI), and 0.5 M lithium iodide (LiI) in methoxypropionitrile (MPN) redox electrolyte. The sensitizers having a monocarboxylic acid group, i.e., M1 and M2, have shown marginally higher IPCE and efficiency than M3 and M4 having dicarboxylic acid groups. To have a detailed understanding of this behavior, the adsorption and binding energies to the TiO2 surface of these dyes have been investiga...
185 citations
TL;DR: IR spectroscopy and PXRD are sensitive to changes in local chemical environments and local structure, which makes them especially useful in elucidating the nature of miscibility in binary mixtures when DSC results are inconclusive or variable.
Abstract: Purpose
To evaluate drug-polymer miscibility behavior in four different drug-polymer amorphous solid dispersion systems, namely felodipine-poly(vinyl pyrrolidone) (PVP), nifedipine-PVP, ketoconazole-PVP, and felodipine-poly(acrylic acid) (PAA).
181 citations
TL;DR: In this article, a novel wheat straw-g-poly(acrylic acid) (WS/PAA) superabsorbent composite by graft polymerization with wheat straw powder and acrylic acid in aqueous solution was discussed and the effect of wheat straw on water absorbency was discussed.
177 citations
TL;DR: In this article, a graft copolymerization with sodium alginate, acrylic acid and sodium humate in aqueous solution, using N,N’ -methylenebisacrylamide as a crosslinker and ammonium persulfate as an initiator, was studied.
176 citations
TL;DR: In this article, a tadpole-shaped inorganic/organic hybrid poly(tert-butyl acrylate) was prepared by RAFT polymerization of tertbutyl-acrylate (tBA) using a POSS-containing chain transfer agent (CTA).
Abstract: Tadpole-shaped inorganic/organic hybrid poly(tert-butyl acrylate) was prepared by RAFT polymerization of tert-butyl acrylate (tBA) using a POSS-containing chain transfer agent (CTA). The polymerization kinetics showed a pseudofirst-order behavior with a short induction period; the number-average molecular weights linearly increase with conversion. In conjunction with low polydispersity (PDI < 1.3), this confirms a controlled polymerization. POSS-PtBA was further hydrolyzed into amphiphilic, tadpole-shaped poly(acrylic acid) (POSS-PAA). The self-assembly behavior of POSS-PAA in aqueous solution at pH = 8.5 was investigated by transmission electron microscopy (TEM) as well as static and dynamic light scattering (SLS and DLS). The results show that POSS-PAA self-assembles in water into rather large aggregates where the POSS moieties are dispersed in the particle. The size (average radius ≈ 60 nm by DLS) is nearly independent of the chain length of PAA. The aggregates are pH-responsive, contracting when decre...
173 citations
TL;DR: The tissue responses of PDMS implants coated with PVA/PAA IPN films were studied by 6-week implantation in the cortex of rats, which suggest the hydrogel coating is feasible and favorable to neural electrode applications.
170 citations
TL;DR: In this article, a review of the conversion of lactic acid to other important commodity chemicals, such as poly L•lactic acid, acrylic acid, 2, 3•pentanedione, pyruvic acid, propanoic acid, 1, 2•propanediol, acetaldehyde, ethyl lactate, using chemical or biological catalysts, and the economy analysis of conversions are depicted.
Abstract: Owning to its biobased organic acid, low cost and multiple reactive functionalities as it contains both one carboxylic acid group and hydroxyl group, lactic acid has been described as a commodity chemical sleeping giant. In this review, the conversion of lactic acid to other important commodity chemicals, such as, poly L‐lactic acid, acrylic acid, 2, 3‐pentanedione, pyruvic acid, propanoic acid, 1, 2‐propanediol, acetaldehyde, ethyl lactate, using chemical or biological catalysts, and the economy analysis of conversions are depicted. The conversion would provide a new way for the solution of the present oil crisis.
TL;DR: In this article, a polyethersulfone (PES) membrane was modified by blending with a copolymer of acrylonitrile (AN) and acrylic acid (AA), followed by grafting bovine serum albumin (BSA) onto the surface of the membrane.
TL;DR: Analysis of the (1)H and (13)C NMR spectra clearly demonstrated that the chemical reactions of GMA with carboxyl groups and alcohols of the macromolecules in an aqueous solution are dependent on pH conditions.
Abstract: Transesterification and epoxide ring-opening reactions are two mechanism routes that explain chemical modifications of macromolecules by glycidyl methacrylate (GMA). Although the coupling reaction of the GMA with macromolecules has widely been investigated, there are still mechanisms that remain to be explained when GMA is processed in an aqueous solution at different pH conditions. To this end, reaction mechanisms of poly(vinyl alcohol) (PVA) and poly(acrylic acid) (PAAc) by GMA in water in acidic and basic conditions were investigated thoroughly. The presence of hydroxyl groups in PVA and carboxyl groups in PAAc allowed for a better evaluation of the reaction mechanisms. The analysis of the 1H and 13C NMR spectra clearly demonstrated that the chemical reactions of GMA with carboxyl groups and alcohols of the macromolecules in an aqueous solution are dependent on pH conditions. At pH 3.5, the GMA reacts with both the carboxylic and the hydroxyl groups through an epoxide ring-opening mechanism. At pH 10.5...
TL;DR: The results indicate that the adsorption equilibrium can be achieved within 3-5 min and, the hydrogel composite has a higher adsorbent capacity for NH(4)(+) in a wide pH levels ranged from 4.0 to 9.0.
TL;DR: Characterization of insulin-loaded micelles and their drug release in solutions with various glucose concentrations were further studied and demonstrated that the drug release rate can be controlled by variation of glucose concentration.
Abstract: Poly(ethylene glycol)-block-poly(acrylic acid-co-acrylamidophenylboronic acid) [PEG114-b-(PAA63-co-PAAPBA107)] was synthesized by the modification of poly(ethylene glycol)-block-poly(acrylic acid) (PEG114-b-PAA170) with 3-aminophenylboronic acid (APBA). Glucose-responsive PEG114-b-(PAA63-co-PAAPBA107) self-assembled into core−shell micelles with the hydrophobic core composed of PAAPBA and hydrophilic shell composed of PEG in aqueous solution. The swelling and disaggregating behaviors of micelles responding to glucose were investigated by using light scattering in aqueous solution at pH 7.4. Characterization of insulin-loaded micelles and their drug release in solutions with various glucose concentrations were further studied. The results demonstrated that the drug release rate can be controlled by variation of glucose concentration.
TL;DR: In this article, the authors developed simple protocols for the coating of sub-10 nm nanoparticles and evaluated the colloidal stability of dispersions in various environments using static and dynamic light scattering.
Abstract: Applications of nanoparticles in biology require that the nanoparticles remain stable in solutions containing high concentrations of proteins and salts, as well as in cell culture media. In this work, we developed simple protocols for the coating of sub-10 nm nanoparticles and evaluated the colloidal stability of dispersions in various environments. Ligands (citric acid), oligomers [phosphonate-terminated poly(ethylene oxide)], and polymers [poly(acrylic acid)] were used as nanometer-thick adlayers for cerium (CeO2) and iron (gamma-Fe2O3) oxide nanoparticles. The organic functionalities were adsorbed on the particle surfaces via physical (electrostatic) forces. Stability assays at high ionic strengths and in cell culture media were performed by static and dynamic light scattering. Of the three coatings examined, we found that only poly(acrylic acid) fully preserved the dispersion stability over the long term (longer than weeks). The improved stability was explained by the multipoint attachments of the chains onto the particle surface and by the adlayer-mediated electrosteric interactions. These results suggest that anionically charged polymers represent an effective alternative to conventional coating agents.
TL;DR: In this paper, a slow-release agrochemical formulation based on cross-linked poly(acrylic acid) hydrogels and liquid fertilizers (LF) was prepared by free radical copolymerization of acrylic acid (AA) and N,N′-methylenebisacrylamide directly in the LF solution.
Abstract: New slow-release agrochemical formulations based on cross-linked poly(acrylic acid) hydrogels and liquid fertilizers (LF) were prepared by free radical copolymerization of acrylic acid (AA) and N,N′-methylenebisacrylamide directly in the LF solution. Two NPK liquid fertilizer compositions containing urea and potassium and ammonium phosphates were employed. For comparison, AA was also polymerized under identical conditions in distilled water. The resulting products were characterized by FTIR spectroscopy and scanning electron microscopy, and their water absorption and slow-release properties were determined. The results showed that the swelling degree (SD) of the hydrogels synthesized depended on the overall concentration of reactants (monomers and initiator), LF composition and cross-linking agent, and initiator concentrations. By appropriately combining these reaction parameters, superabsorbent hydrogels with SDs in distilled water ranging from a few hundred to 1000 g of water/g of xerogel can be obtaine...
TL;DR: In this article, a super-absorbent hydrogel has been synthesized with chemically modified pulverized wheat straw (CMPWS) and acrylic acid (AA) in aqueous solution.
TL;DR: In this paper, a broad parameter range of acrylic acid discharges was investigated over a wide range of energy inputs over a broad range of regimes, ranging from low to high energy input.
Abstract: To perform a systematic study over a broad parameter range of acrylic acid discharges, we varied the energy input W/F over a wide range. Five different regimes could be identified (from low to high energy input): regime I, where oligomerization takes place; regime II, the radical-dominated plasma polymerization of acrylic acid; regime III, a transition regime showing etching/ oxidation effects; regime IV, where the plasma polymerization resembles the one observed for CO 2 /C 2 H 4 discharges; and regime V, where etching effects yield a reduction in deposition rate. These results show that the polymerization mechanism can be described as a function of the energy input W/F. Specifically, a parameter range where acrylic acid can be replaced by CO 2 /C 2 H 4 discharges has been identified.
TL;DR: In this article, a series of copolymer hydrogel networks were synthesized using poly(ethylene glycol) diacrylate (PEGDA) as the crosslinker and acrylic acid (AA), 2-hydroxyethyl acrylate(HEA), or poly(chemical glycol)-acrylated (PEGA) as comonomers.
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TL;DR: Of the three coatings examined, it was found that only poly(acrylic acid) fully preserved the dispersion stability over the long term (longer than weeks), suggesting that anionically charged polymers represent an effective alternative to conventional coating agents.
Abstract: Applications of nanoparticles in biology require that the nanoparticles remain stable in solutions containing high concentrations of proteins and salts, as well as in cell culture media. In this work, we developed simple protocols for the coating of sub-10 nm nanoparticles and evaluated the colloidal stability of dispersions in various environments. Ligands (citric acid), oligomers (phosphonate-terminated poly(ethylene oxide)) and polymers (poly(acrylic acid)) were used as nanometer-thick adlayers for cerium (CeO2) and iron (gamma-Fe2O3) oxide nanoparticles. The organic functionalities were adsorbed on the particle surfaces via physical (electrostatic) forces. Stability assays at high ionic strength and in cell culture media were performed by static and dynamic light scattering. Among the three coating examined, we found that only poly(acrylic acid) fully preserved the dispersion stability on the long term (> weeks). The improved stability was explained by the multi-point attachments of the chains onto the particle surface, and by the adlayer-mediated electrosteric interactions. These results suggest that anionically charged polymers represent an effective alternative to conventional coating agents.
TL;DR: The use of PEAA instead of PAA or PMAA in film assembly enabled the construction of hydrogen-bonded LbL films that can be released by applying temperature as a trigger at near-physiological pH values, which makes such release layers attractive candidates for future tissue engineering applications.
Abstract: A hydrogen-bonded layer-by-layer (LbL) technique was used to build multilayers of neutral, temperature-responsive polymers such as poly(N-isopropylacrylamide) (PNIPAM), poly(N-vinylcaprolactam) (PVCL), poly(vinyl methyl ether) (PVME), or poly(acrylamide) (PAAm) with a polycarboxylic acid such as poly(acrylic acid) (PAA), poly(methacrylic acid) (PMAA), or poly(ethacrylic acid) (PEAA). For all multilayers involving temperature-responsive polymers, the temperature used during or after self-assembly had a significant effect on film stability with pH changes. The proximity of the self-assembly or post-self-assembly temperature to the critical temperature of phase separation of a neutral polymer from solution resulted in a higher pH stability of multilayers. However, for polymers with a lower critical solution temperature (LCST) such as PNIPAM, PVCL, or PVME within PNIPAM/PMAA, PVCL/PMAA, or PVME/PMAA multilayers, the critical pH of film disintegration (pHcrit) increased in the temperature range from 10 to 37 °...
TL;DR: Potassium modification significantly improved the selectivity and durability of NaY zeolites during lactic acid dehydration reaction as discussed by the authors, achieving a selectivity of 2.8K/NaY catalyst.
TL;DR: The cytotoxicity measurement by MTT assay indicated that PAAc-b-PDLLA was low toxic in HeLa cells with an IC50 value of 2.8 mg mL−1, which suggests that PADLLA could be used as a safe candidate for pH-responsive drug delivery.
TL;DR: Aqueous polyurethane-acrylic hybrid emulsions were prepared by semibatch emulsion polymerization of a mixture of acrylic monomers (styrene, butyl acrylate and acrylic acid).
Patent•
21 Sep 2009TL;DR: In this article, a method for producing biodegradable polymer mixtures was proposed, to the use of a biodegrable polymer mixture for the production of molded parts, films or fibers.
Abstract: The present invention relates to a biodegradable polymer mixture comprising i) 40 to 95 wt.-% based on the total weight of components i to ii, at least one polyester based on aliphatic or aliphatic-aromatic dicarboxylic acids and aliphatic dihydroxy compound; ii) 5 to 60 wt.-% based on the total weight of components i to ii, polyalkylene carbonate, in particular polypropylene carbonate; iii) 0 to 60 wt.-% based on the total weight of components i to iii, at least one biodegradable homo- or copolyester selected from the group consisting of polylactic acid, polycaprolactone, polyhydroxyalkanoates and an inorganic or organic filler; iv) 0 to 10 wt.-% based on the total weight of components i to ii of a styrene, acrylic acid ester and/or methacrylic acid ester based copolymer containing an epoxide group and v) 0 to 15 wt.-% of an additive selected from the group consisting of lubricants, antiblocking agents, antistatic agents, UV absorbers, UV stabilizers, thermal stabilizers, dyes, pigments, softeners, fertilizers and pesticides ingredients. The present invention further relates to a method for producing biodegradable polymer mixtures, to the use of biodegradable polymer mixtures for the production of molded parts, films or fibers as well as molded parts, and to films or fibers comprising biodegradable polymer mixtures.
TL;DR: In this paper, chemical surface modifications involving 1% sodium hydroxide (NaOH) and 1% acrylic acid (AA) treatments are applied to woven banana fabric and it is used as reinforcement in an unsaturated polyester matrix.
Abstract: Chemical surface modifications involving 1% sodium hydroxide (NaOH) and 1% acrylic acid (AA) treatments are applied to woven banana fabric and it is used as reinforcement in an unsaturated polyester matrix. Vacuum bagging technique was used to prepare the woven banana fiber-reinforced unsaturated polyester composites with four different volume percentages of fibers (5, 10, 15, and 20%). The effects of fiber-loading and fiber surface treatments on the flexural, impact and water absorption properties of the composites were investigated. The acrylic acid treatment results in improved mechanical and water absorption properties of the composites compared to the alkali treatment and untreated fiber composites. The treatment effects on the banana fibers have been characterized by means of infrared spectroscopy (FTIR) and microscopy analysis (SEM). The moisture absorption test showed that acrylic acid-treated woven banana fabric composites exhibit less water absorption than both alkali-treated and untreated woven...
TL;DR: In this paper, a simplified method to prepare functional polyethersulfone (PES) membranes with pH sensitivity and ion exchange capacity by blending cross-linked poly (acrylic acid) (PAA) sub-micrometer-scale gels was provided.
TL;DR: In this paper, the reaction kinetics of lactic acid were investigated with a flow apparatus in water at high temperatures (450°C) and high pressures (40-100 MPa).
Abstract: Reaction of lactic acid was investigated with a flow apparatus in water at high temperatures (450 °C) and high pressures (40–100 MPa). The major products obtained from the reaction of lactic acid were acrylic acid, acetaldehyde, and the minor products were acetic acid and propionic acid. The maximum selectivity of acrylic acid was 44% at 23% lactic acid conversion that was obtained at 450 °C, 100 MPa and a residence time of 0.8 s. The reaction kinetics could be modeled by considering two pathways defined as a dehydration pathway to acrylic acid and a combined reaction pathway that consisted of decarboxylation and decarbonylation to acetaldehyde. The data and the kinetic analysis consistently show that both dehydration and the combined decarboxylation and decarbonylation reactions continue to be promoted in supercritical water as pressure (water density) increases. However, high water densities increase the selectivity of the dehydration reaction.
TL;DR: In this article, the authors reported the preparation and characterization of copolymer poly-{styrene-acrylic acid} with monomeric ratio of styrene and acrylic acid of 9:1 using benzoyl peroxide as initiator and furthermore filled with nanosilver in water/acetone (1:40v/v).