Showing papers on "Methacrylic acid published in 2014"
TL;DR: In this paper, a magnetic composite poly(styrene-methacrylic acid) microsphere, was prepared using oleic acid-coated magnetic nanoparticles as seeds by microemulsion copolymerization of styrene (St) and methacric acid (MAA), and the lipase from Candida rugosa was then covalently bound to the magnetic polymercoated microspheres by using 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide hydrochloride (EDAC) as an activation re
Abstract: A magnetic composite poly(styrene-methacrylic acid) microsphere, was prepared using oleic acid-coated magnetic nanoparticles as seeds by microemulsion copolymerization of styrene (St) and methacrylic acid (MAA). The lipase from Candida rugosa was then covalently bound to the magnetic polymer-coated microspheres by using 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide hydrochloride (EDAC) as an activation reagent. The immobilization of lipase could enhance the thermal and pH stability of lipase activity when compared to free lipase. The immobilized lipase microspheres were characterized by lipase activity assays, Fourier transform infrared spectroscopy, powder X-ray diffraction, transmission electron microscopy, and vibrating-sample magnetometer techniques. The bound lipase showed high activities to soybean oil transesterification with methanol to produce biodiesel. It was found that the oil conversion of 86% was attained at a reaction temperature of 35 °C for 24 h. The immobilized lipase is stable with re...
175 citations
TL;DR: The proposed online coupling of in-tube solid phase microextraction with direct analysis in real time mass spectrometry (DART-MS) was realized for the first time and applied in the analysis of triazine herbicides in lake water and orange juice, showing satisfactory recovery and reproducibility.
Abstract: Online coupling of in-tube solid phase microextraction (IT-SPME) with direct analysis in real time mass spectrometry (DART-MS) was realized for the first time and applied in the analysis of triazine herbicides in lake water and orange juice. We incorporated single-wall carbon nanotubes (SWNTs) into a polymer monolith containing methacrylic acid (MAA) and ethylene dimethacrylate (EDMA) to form a novel poly(methacrylic acid-co-ethylene dimethacrylate-co-single wall carbon nanotubes) (poly(MAA-EDMA-SWNT)) monolith, which was then used in IT-SPME for enrichment of six triazine herbicides from water samples. With the online combination of IT-SPME with DART-MS, the analytes desorbed from the monolith were directly ionized by DART and transferred into MS for detection, thus rapid determination was achieved. Compared with regular DART-MS method, this online IT-SPME-DART-MS method was more sensitive and reproducible, because of the IT-SPME procedures and the isotope-labeled internal standard used in the experiment...
166 citations
TL;DR: In this article, two types of zeolites, hydrophilic zeolite A and hydrophobic ZSM-5, were synthesized for removal of basic yellow 28 (BY28) from aqueous solutions.
114 citations
TL;DR: The rational synthesis of low-polydispersity diblock copolymer vesicles in concentrated solution via polymerization-induced self-assembly using reversible addition-fragmentation chain transfer (RAFT) polymerization of benzyl methacrylate is reported.
Abstract: Block copolymer self-assembly is normally conducted via post-polymerization processing at high dilution. In the case of block copolymer vesicles (or "polymersomes"), this approach normally leads to relatively broad size distributions, which is problematic for many potential applications. Herein we report the rational synthesis of low-polydispersity diblock copolymer vesicles in concentrated solution via polymerization-induced self-assembly using reversible addition-fragmentation chain transfer (RAFT) polymerization of benzyl methacrylate. Our strategy utilizes a binary mixture of a relatively long and a relatively short poly(methacrylic acid) stabilizer block, which become preferentially expressed at the outer and inner poly(benzyl methacrylate) membrane surface, respectively. Dynamic light scattering was utilized to construct phase diagrams to identify suitable conditions for the synthesis of relatively small, low-polydispersity vesicles. Small-angle X-ray scattering (SAXS) was used to verify that this binary mixture approach produced vesicles with significantly narrower size distributions compared to conventional vesicles prepared using a single (short) stabilizer block. Calculations performed using self-consistent mean field theory (SCMFT) account for the preferred self-assembled structures of the block copolymer binary mixtures and are in reasonable agreement with experiment. Finally, both SAXS and SCMFT indicate a significant degree of solvent plasticization for the membrane-forming poly(benzyl methacrylate) chains.
106 citations
TL;DR: A versatile synthetic method for the in situ self-assembly of magnetic-nanoparticle-functionalized polymeric nanomorphologies, including spherical micelles and rod-like and worm-like micells and vesicles, with high efficacy as MRI contrast agents and potential utility as theranostic delivery vectors is reported.
Abstract: We report a versatile synthetic method for the in situ self-assembly of magnetic-nanoparticle-functionalized polymeric nanomorphologies, including spherical micelles and rod-like and worm-like micelles and vesicles. Poly(oligoethylene glycol methacrylate)-block-(methacrylic acid)-block-poly(styrene) (POEGMA-b-PMAA-b-PST) triblock copolymer chains were simultaneously propagated and self-assembled via a polymerization-induced self-assembly (PISA) approach. Subsequently, the carboxylic acid groups in the copolymers were used to complex an iron ion (FeII/FeIII) mixture. Iron oxide nanoparticles were then formed in the central block, within the polymeric nanoparticles, via alkaline coprecipitation of the iron(II) and (III) salts. Nanoparticle morphologies, particle sizes, molecular weights, and chemical structures were then characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), size exclusion chromatography (SEC), and 1H NMR measurements. TEM micrographs showed that the averag...
80 citations
TL;DR: By in vitro cellular experiments, it was confirmed that the porphyrazine-loaded micelles were PDT-active against A549 cells, and the corona composition strongly influenced their in vitro PDT activity, which decreased with increasing PEGylation, correlating with the cellular uptake of the micells.
Abstract: We describe the preparation of well-defined multicompartment micelles from polybutadiene-block-poly(1-methyl-2-vinyl pyridinium methyl sulfate)-block-poly(methacrylic acid) (BVqMAA) triblock terpol...
79 citations
TL;DR: In this article, a low supercooling microencapsulated n-octadecane (MicroC18) with OMA-methacrylic acid (MAA) copolymer as shell using suspension-like polymerization was developed.
78 citations
TL;DR: In this paper, poly(methacrylic acid) (p(MAc)) microgels were synthesized by inverse suspension polymerization and used as a template for copper, nickel, and cobalt nanoparticle preparation.
Abstract: Poly(methacrylic acid) (p(MAc)) microgels were synthesized by inverse suspension polymerization and used as a template for copper, nickel, and cobalt nanoparticle preparation. Upon absorption of Co(II), Ni(II), and Cu(II) by p(MAc) microgels from related aqueous solutions, the metal ion laden microgels were treated with sodium borohydride (NaBH4) to obtain the corresponding metal nanoparticles within the p(MAc) network as p(MAc)–M (M: Co, Ni, Cu). The microgels and metal nanoparticle containing composites were visualized and analyzed by Optical Microscopy, SEM, and TEM analysis. Thermal properties and the metal nanoparticle content of the prepared composites were investigated by TG analysis. However, the exact amounts of metal nanoparticles entrapped within the microgels was calculated by AAS measurements after dissolution of the metal nanoparticles within p(MAc) the microgel composites by concentrated HCl acid treatment. The prepared p(MAc)–M composites were employed as a catalyst for the degradation of some organic dyes such as Eosin Y (EY), and methyl orange (MO), and reduction of nitro aromatic pollutants such as 2-nitrophenol (2-NP), 4-nitrophenol (4-NP), 4-nitroaniline (4-NA) to their corresponding amino phenols. More importantly, we report the simultaneous degradation of EY and 4-NP reduction catalyzed by p(MAc)–Cu microgel composites. Various parameters effecting the degradation of dyes and nitro compound reduction such as metal types, and their amounts, temperature and amount of reducing agent were investigated.
77 citations
TL;DR: The amphoteric drug molecule tetracycline, which contains groups with pKa 3.4-9.9, was used as a template for conjugating molecularly imprinted polymers (MIPs) and as a quencher for CdTe quantum dot (QD) fluorescence.
76 citations
TL;DR: A molecular-imprinted polymer nanoparticles (MIP-NP) for the selective preconcentration of 2,4-dichlorophenoxyacetic acid (2,2′-azobisisobutyronitrile) is described and the method was applied to the determination of 2-4-D in the urine and different water samples.
Abstract: A molecular-imprinted polymer nanoparticles (MIP-NP) for the selective preconcentration of 2,4-dichlorophenoxyacetic acid (2,4-D) is described. It was obtained by precipitation polymerization from methacrylic acid (the functional monomer), ethylene glycol dimethacrylate (the cross-linker), 2,2′-azobisisobutyronitrile (the initiator) and 2,4-D (the template molecule) in acetonitrile solution. The MIP-NPs were characterized by thermogravimetric analysis, and by scanning electron microscopy. Imprinted 2,4-D molecules were removed from the polymeric structure using acetic acid in methanol (15:85 v/v %) as the eluting solvent. The sorption and desorption process occur within 10 min and 15 min, respectively. The maximum sorbent capacity of the molecular imprinted polymer is 89.2 mg g �1 . The relative standard deviation and limit of detection for water samples by introduced selective solid phase extraction were 4.2% and 1.25 μ gL �1 , and these data for urine samples were 4.7% and 1.80 μ gL �1 , respectively. The method was applied to the determination of 2,4-D in the urine and different water samples.
72 citations
TL;DR: Water-borne phosphine-functionalized core-cross-linked micelles (CCM) consisting of a hydrophobic core and a hydophilic shell were obtained as stable latexes by reversible addition-fragmentation chain transfer (RAFT) in water in a one-pot, three-step process.
Abstract: Water-borne phosphine-functionalized core-cross-linked micelles (CCM) consisting of a hydrophobic core and a hydrophilic shell were obtained as stable latexes by reversible addition-fragmentation chain transfer (RAFT) in water in a one-pot, three-step process. Initial homogeneous aqueous-phase copolymerization of methacrylic acid (MAA) and poly(ethylene oxide) methyl ether methacrylate (PEOMA) is followed by copolymerization of styrene (S) and 4-diphenylphosphinostyrene (DPPS), yielding P(MAA-co-PEOMA)-b-P(S-co-DPPS) amphiphilic block copolymer micelles (M) by polymerization-induced self-assembly (PISA), and final micellar cross-linking with a mixture of S and diethylene glycol dimethacrylate. The CCM were characterized by dynamic light scattering and NMR spectroscopy to evaluate size, dispersity, stability, and the swelling ability of various organic substrates. Coordination of [Rh(acac)(CO)2 ] (acac=acetylacetonate) to the core-confined phosphine groups was rapid and quantitative. The CCM and M latexes were then used, in combination with [Rh(acac)(CO)2 ], to catalyze the aqueous biphasic hydroformylation of 1-octene, in which they showed high activity, recyclability, protection of the activated Rh center by the polymer scaffold, and low Rh leaching. The CCM latex gave slightly lower catalytic activity but significantly less Rh leaching than the M latex. A control experiment conducted in the presence of the sulfoxantphos ligand pointed to the action of the CCM as catalytic nanoreactors with substrate and product transport into and out of the polymer core, rather than as a surfactant in interfacial catalysis.
TL;DR: In this article, the NH4-3HPMo11VO40 (APMV) active phase supported on Cs3PMo12O40 (CPM) was used for selective oxidation of isobutane to methacrolein and methacrylic acid.
TL;DR: In this paper, a series of well-defined amphiphilic poly(methacrylic acid)-poly(benzyl methacrylate) (PMAA-PBzMA) diblock copolymers are synthesized via polymerization-induced self-assembly using an alcoholic dispersion polymerization formulation.
TL;DR: The aqueous phase conversion of the first generation isoprene oxidation products can potentially contribute to tropospheric aqueously phase budgets of important carbonyl and dicarbonyl components which are expected to be conducive to the formation of aqSOA.
Abstract: Kinetic and mechanistic studies were conducted on the isoprene oxidation products methacrolein, methyl vinyl ketone, methacrylic and acrylic acid reacting with hydroxyl and nitrate radicals and sulfate radical anions in aqueous solution by use of the laser flash photolysis technique and a reversed-rate method for kinetics. High-performance liquid chromatography/mass spectrometry was applied for product analysis. The kinetic investigations show the highest reactivity of the hydroxyl radical followed by sulfate and nitrate radicals. For methacrolein and methyl vinyl ketone the following rate constants have been determined at 298 K: k(OH+methacrolein) = (9.4 ± 0.7) × 109 M−1 s−1, k(OH+methylvinylketone) = (7.3 ± 0.5) × 109 M−1 s−1, k(NO3+methacrolein) = (4.0 ± 1.0) × 107 M−1 s−1, k(NO3+methylvinylketone) = (9.7 ± 3.4) × 106 M−1 s−1, k(SO4−+methacrolein) = (9.9 ± 4.9) × 107 M−1 s−1 and k(SO4−+methylvinylketone) = (1.0 ± 0.2) × 108 M−1 s−1. Temperature and pH dependencies of the reactions of OH, NO3 and SO4− with methacrolein, methyl vinyl ketone, methacrylic and acrylic acid as well as Arrhenius parameters have been obtained and discussed. Product studies were performed on the OH radical induced oxidation of methacrolein and methyl vinyl ketone. In the reaction of methacrolein + OH methylglyoxal and hydroxyacetone were identified as first oxidation products with yields of 0.099 and 0.162. Methylglyoxal was primarily produced in the oxidation of methyl vinyl ketone with a yield of 0.052. For both precursor compounds the formation of glycolaldehyde was observed for the first time with yields of 0.051 and 0.111 in the oxidation of methacrolein and methyl vinyl ketone, respectively. Furthermore, highly functionalised C4 compounds were determined from the oxidation of both precursor compounds, but for the first time for methyl vinyl ketone. Reaction schemes were developed based on known peroxyl radical reaction mechanisms. The aqueous phase conversion of the first generation isoprene oxidation products can potentially contribute to tropospheric aqueous phase budgets of important carbonyl and dicarbonyl components which are expected to be conducive to the formation of aqSOA.
TL;DR: In selectivity study, it was found that imprinting results increased affinity of the material toward Zn(2+) ion over other competitor metal ions with the same charge and close ionic radius.
TL;DR: Conceptually new one-pot photoinduced sequential click reactions were implemented to yield novel block copolymers with the ability for cell adhesion to furnish desired bioactive blockCopolymer PMMA-b-PCL-NAC.
Abstract: Conceptually new one-pot photoinduced sequential click reactions were implemented to yield novel block copolymers with the ability for cell adhesion. Poly(e-caprolcatone) possessing clickable functional groups at the chain ends, namely α-alkynyl-ω-alkenyl-poly(e-caprolactone) (A-PCL-MA), was prepared by ring-opening polymerization of e-caprolactone using propargyl alcohol in the presence of stannous octoate at 110 °C followed by esterification with methacrylic acid. Azide-functional poly(methyl methacrylate) (PMMA-N3) was prepared independently by atom transfer radical polymerization (ATRP) followed by an azidation process using sodium azide. Finally, A-PCL-MA was reacted with PMMA-N3 and N-acetyl-l-cysteine (NAC) in a one-pot process through photoinduced sequential click reactions to furnish desired bioactive block copolymer (PMMA-b-PCL-NAC). A matrix for cell adhesion was then prepared from the yielded block copolymer PMMA-b-PCL-NAC and cell proliferation on the matrix was measured. Cells from the Vero ...
TL;DR: The results indicated that the OEG-based monomers are promising for responsive MIP preparation, and the proposed imprinted material is efficient for thermally modulated capture and release of target protein.
Abstract: In this study, oligo(ethylene glycol) (OEG)-based thermoresponsive molecularly imprinted polymers (MIPs) for lysozyme on the surface of magnetic nanoparticles were synthesized. Thermoresponsive monomer 2-(2-methoxyethoxy)ethyl methacrylate, chelate monomer N-(4-vinyl)-benzyl iminodiacetic acid, and acidic monomer methacrylic acid were selected as the ingredients for preparing the MIP layer. The thermoresponsive behavior of the novel imprinted magnetic nanoparticles was evaluated by dynamic light scattering and swelling ratios measurements. Interestingly, in analysis of lysozyme, the capture/release process could be modulated by changing the temperature, avoiding tedious washing steps. Meanwhile, high adsorption capacity (204.1 mg/g) and good selectivity for capturing lysozyme were achieved. Additionally, surface imprinting with magnetic nanoparticles as substrate allowed for short adsorption time (2 h) and rapid magnetic separation. Furthermore, the proposed imprinted magnetic nanoparticles were used to s...
TL;DR: This work takes advantage of the transformation of lidocaine hydrochloride into deep-eutectic solvents (DESs) to incorporate polymerizable counterparts into DESs, such that polymer-drug complexes are synthesized by free-radical frontal polymerization without the use of a solvent.
Abstract: This work takes advantage of the transformation of lidocaine hydrochloride into deep-eutectic solvents (DESs) – ionic liquid analogues – to incorporate polymerizable counterparts into DESs, such that polymer–drug complexes are synthesized by free-radical frontal polymerization without the use of a solvent. DESs are formed through hydrogen bonding of an ammonium salt with a hydrogen-bond donor (HBD). It is demonstrated that lidocaine hydrochloride – as the ammonium salt – is able to form DESs with acrylic acid and methacrylic acid. The properties of DESs allow frontal polymerization in the bulk with full conversion achieved in a one-pot synthesis, yielding monoliths of polymers loaded with a high concentration of drug. In in vitro experiments, the sustained release of the drug takes place in a controlled manner triggered by the pH, ionic strength and solubility of the drug in the medium. Such control is owed to the swelling of polymers as well as to the specific interactions between the drug and the polymers already established in the DES precursor. Finally, it is noteworthy that different monomers (such as HBD) and crosslinkers can be used, thus expanding the possibilities of drug delivery systems for transdermal technologies by exploiting the DES chemistry.
TL;DR: Several semi and full IPN type hydrogels were prepared by varying initiator and crosslinker concentration and also monomer to chitosan mass ratio and were characterized and used for removal of methyl violet and congo red dye from water.
TL;DR: In this article, the authors used a nanocomposite with immobilized colloidal TiO 2 nanoparticles to investigate photocatalytic degradation of three different groups of anionic azo dyes in aqueous solutions under solar light simulating source.
TL;DR: It was observed that the polymer synthesized at the MAA/TEOS molar ratio of 6:1 was much more selective for cholesterol than the one prepared at the ratio of 1:5, thus suggesting that selective binding sites ascribed to the carboxyl group from MAA play a central role in the imprinting effect created on MIP.
TL;DR: Methacrylic acid, an important monomer for the plastics industry, was obtained in high selectivity (up to 84%) by the decarboxylation of itaconic acid using heterogeneous catalysts based on Pd, Pt and Ru.
Abstract: Methacrylic acid, an important monomer for the plastics industry, was obtained in high selectivity (up to 84%) by the decarboxylation of itaconic acid using heterogeneous catalysts based on Pd, Pt and Ru. The reaction takes place in water at 200–2508C without any external added pressure, conditions significantly milder than those described previously for the same conversion with better yield and selectivity. A comprehensive study of the reaction parameters has been performed, and the isolation of methacrylic acid was achieved in 50% yield. The decarboxylation procedure is also applicable to citric acid, a more widely available bio-based feedstock, and leads to the production of methacrylic acid in one pot in 41% selectivity. Aconitic acid, the intermediate compound in the pathway from citric acid to itaconic acid was also used successfully as a substrate.
TL;DR: In this article, molecular imprinted polymers on GO nanosheets (MIPs/GO) for desulfurization are synthesized using dibenzothiophene (DBT) as template, methacrylic acid (MAA) as monomer and ethylene glycol dimethacrylate (EGDMA) as crosslinker.
Abstract: Molecularly imprinted polymers on GO nanosheets (MIPs/GO) for desulfurization are synthesized using dibenzothiophene (DBT) as template, methacrylic acid (MAA) as monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker. The formation of this hybrid material is verified by Fourier transform infrared spectroscopy, thermal gravimetric and atomic force microscopy analysis. The adsorption results show that the prepared MIPs/GO exhibit excellent adsorption capacity (up to 181.9 mg g−1 at 298 K) and fast mass transfer and binding kinetics for DBT. The kinetics and isotherm data can be well described by the pseudo-first-order kinetic model and the Freundlich isotherm, respectively. Competitive adsorption experiments demonstrate that MIPs/GO show higher affinity toward target molecule DBT than toward structural analogue benzothiophene.
TL;DR: In vivo implantation in a subcutaneous rabbit model supported the in vitro results of a rapid degradation rate of microspheres and provided only a mild and transient inflammatory reaction comparable to that of the control group.
TL;DR: The MWNTs@MMIPs exhibited good affinity with a maximum adsorption capacity of 49.26 μmol g(-1) and excellent selectivity toward bisphenol A and combined with high-performance liquid chromatography analysis, the MWNT’s were employed to extract bispenol A in tap water, rain water, and lake water successfully.
TL;DR: Binding experiments demonstrated that Fe3O4@MPIPs possessed excellent binding properties, including high adsorption capacity and specific recognition, as well as fast adsor adaptation kinetics and a fast phase separation rate.
TL;DR: The obtained results indicate that the temperature of photografting and concentration of the grafting mixture are key parameters that determine the quality of the prepared MIPs.
TL;DR: In this article, a novel potentiometric sensor based on ion imprinted polymer inclusion membrane (IPIM) was prepared from the modification of multiwalled carbon nanotube (MWCNT) based molecularly imprinted polymers for the trace determination of the pesticide 2,4-D (2.4-dichlorophenoxyacetic acid) in natural water samples.
TL;DR: The assembly of low-fouling polymer capsules with redox-responsive behavior and intracellular degradability is reported in this article, where Thiol-containing poly(2- ethyl-2-oxazoline) (PEtOxMASH) brushes are synthesized by atom transfer radical polymerization.
Abstract: The assembly of low-fouling polymer capsules with redox-responsive behavior and intracellular degradability is reported. Thiol-containing poly(2- ethyl-2-oxazoline) (PEtOxMASH) brushes are synthesized by atom transfer radical polymerization (ATRP) of oligo(2-ethyl-2-oxazoline)methacrylate and glycidyl methacrylate (GMA) and subsequent ring-opening reaction of the GMA. Sequential deposition of PEtOxMA SH /poly(methacrylic acid) (PMA) multilayers onto silica (SiO2) particle templates and crosslinking through disulfide formation yield stable capsules after the removal of the SiO2 templates by buffered hydrofl uoric acid (HF). The redox-responsive nature of the disulfide crosslinking groups enables the degradation of these capsules under simulated intracellular conditions at pH 5.9 and 5 m M glutathione (GSH). Furthermore, capsule degradation is observed after incubation with dendritic (JAWS II) cells. Even at high capsule-to-cell ratios, PEtOxMASH capsules show only negligible cytotoxicity. Quartz crystal microgravimetry (QCM) studies, using 100% human serum, reveal that films prepared from PEtOxMASH exhibit low-fouling properties. The degradation and low-fouling properties are promising for application of PEtOxMASH films/capsules for the delivery and triggered release of therapeutics.