Radical Polymerization Of Methacrylic Acid Research Articles

Highly-efficient selective recognition and rapid enrichment of chrysin by magnetic surface molecularly imprinted polymer

As an important natural nutrient-like substance, chrysin is highly desirable in the field of health food. Here, to achieve the specific and efficient adsorption of chrysin, a magnetic surface molecularly imprinted polymer (chrysin/SMIPs) was fabricated by free radical polymerization of methacrylic acid onto the surface of functionalized magnetic Fe3O4 nanoparticles. The obtained chrysin/SMIPs showed favorable binding ability towards chrysin with 35.27 mg·g−1 maximum adsorption capacity in 20 min, prominent reusability with 9 cycles of adsorption–desorption and superior specific recognition with imprinting factor (IF) of 2.87 and selectivity coefficient (K) of 8.74, 5.64 and 8.64 corresponding to the interferents of genistein, daidzein and quercetin, respectively. Moreover, the chrysin/SMIPs showed high recoveries (91.13 % to 95.12 %) and precisions (RSDs from 2.51 % to 1.32 %) in the extraction of chrysin from real propolis samples. Therefore, chrysin/SMIPs is highly promising for the selective enrichment recovery of chrysin in health food.

Hybrid nanoarchitectonics of cellulose-PMAA/layered double hydroxide: A novel reusable catalyst for the unsymmetrical Hantzsch reaction

In this study, NiCo-layered double hydroxide (LDH) was fabricated in situ on the surface of CB-poly(methacrylic acid) (CB-PMAA) to form CB-PMAA/LDH nanocomposite. CB-PMAA was prepared via the radical polymerization of methacrylic acid (MAA) monomer onto the surface CB molecules. CB-PMAA/LDH was identified by FT-IR, XRD, SEM, EDS, and STA analyses and applied as a robust catalyst for the quick fabrication of biologically active polyhydroquinoline derivatives using unsymmetric Hantzsch reaction. CB-PMAA/LDH exhibits high reactivity for the construction of polyhydroquinolines with high yields (90-97%) under mild reaction conditions and short reaction time (10-20 min). Additionally, CB-PMAA/LDH can be straightforwardly recovered and used up to six reaction cycles without a conspicuous decrease in efficiency.

Organocatalyzed Photo‐Atom Transfer Radical Polymerization of Methacrylic Acid in Continuous Flow and Surface Grafting

The organocatalyzed photo-atom transfer radical polymerization (photoATRP) using 10-phenylphenothiazine as catalyst is studied toward its use in methacrylic acid (MAA) polymerization and surface grafting. The organocatalyzed photoATRP of methyl methacrylate (MMA) is first optimized for continuous flow synthesis in order to assess the livingness of the polymerization. MMA can be polymerized in batch and in flow; however, conversions are limited by the loss of bromine functionality and hence high conversions have to be traded in with increasing dispersities. Also, MAA is polymerized successfully in continuous flow with similar limitations. Flow conditions are transferred to surface grafting from silanized silicon wafers. The presence of ATRP initiators after silanization is confirmed by secondary ion mass spectrometry and X-ray photoelectron spectroscopy. Dense polymethacrylic acid brush films are successfully produced, which is not directly accessible via classical copper-mediated ATRP techniques.

Graphene‐based molecularly imprinted polymer for separation and pre‐concentration of trace polycyclic aromatic hydrocarbons in environmental water samples

ABSTRACTA composite of reduced graphene oxide and pyrene‐imprinted polymer was synthesized and employed as a solid phase for extraction of five selected polycyclic aromatic hydrocarbons (PAHs) from water samples. Gas chromatography‐time of flight/mass spectrometry was employed in the analysis of the extracts. The composite was prepared by a free radical polymerization of methacrylic acid and 4‐vinylpyridine as monomers and ethylene glycol dimethacrylate as a crosslinker. The adsorption studies were carried out through batch binding studies. The binding capacity for the imprinted and non‐imprinted composite was 101.83 and 68.21 µg g−1, respectively. The adsorption followed the pseudo 2nd order and well fitted the Langmuir isotherm. Mean recoveries ranging from 73% to 105.4% for both spiked deionized water and environmental water samples were obtained when the imprinted composites were employed in solid phase extraction of the PAHs. The composites could be re‐used for five times without a significant loss in recoveries. The proposed method was employed for the analysis of spiked environmental water samples and did not show significant changes in the recoveries showing there were no matrix interferences. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45300.

Atom Transfer Radical Polymerization of Methacrylic Acid: A Won Challenge.

Polymerization of acidic monomers is one of the biggest challenges for atom transfer radical polymerization (ATRP). An intramolecular cyclization reaction leading to the loss of the C-X chain-end functionality was found to be the main reason for the partial termination of the growing polymer chains. Three approaches were used to overcome this problem: using Cl as the chain-end halogen, lowering the pH (to 0.9), and increasing polymerization rate. Methacrylic acid (MAA) was polymerized by both electrochemically mediated ATRP and supplemental activator and reducing agent ATRP up to high conversion (>90%), in t ≤ 4 h at 25 °C, using inexpensive and nontoxic reagents (NaCl, diluted HCl, water). Control over molecular weight (MW) dispersity was satisfactory, and MWs were in agreement with theoretical values. The "livingness" of the process was confirmed by an electrochemical switch, used to repeatedly and periodically deactivate/reactivate growing chains.

Functionalized graphene oxide nanoparticles for cancer cell-specific delivery of antitumor drug.

The unique reduction-triggered functional graphene oxide nanoparticles (GON) with well-defined size and uniform distribution were designed as an innovative drug delivery platform for cancer treatment for the first time, via the redox radical polymerization of methacrylic acid from the polyethylene glycol (PEG) modified GON (GON-PEG), following by cross-linking with cystamine. Thermogravimetric analysis demonstrates that the typical PMAA2-GON-PEG carriers contain about 16 wt % PEG segments and 33 wt % poly(methacrylic acid) (PMAA) brushes. PEG moieties are incorporated to make the drug delivery platforms stealthy during blood circulation. Notably, introducing the cross-linked PMAA brushes efficiently minimizes the premature release of doxorubicin (DOX) in the stimulated normal tissues, and accelerates DOX release in the stimulated tumor tissues through response to reduce agent. The carriers showed a 6-fold faster releasing rate at pH 5.0 in the presence of 10 mM glutathione (GSH) (stimulated tumor tissues) than at pH 7.4 with 10 μM GSH (stimulated normal tissues). In vitro cytotoxicity test also showed that the cross-linked PMAA2-GON-PEG (CPMAA2-GON-PEG) carriers had remarkable cytocompatibility, and that the DOX-loaded CPMAA2-GON-PEG had excellent killing capability to SiHa cells.

Temperature effect on template polymerization of methacrylic acid using stereocomplex formation on quartz crystal microbalance substrates

ABSTRACTThe radical polymerization of methacrylic acid (MAA) at 0, 20, 40, and 70 °C was achieved in porous isotactic (it‐) poly(methyl methacrylate) (PMMA) films on quartz crystal microbalance (QCM) substrates, which were prepared by layer‐by‐layer assembled stereocomplex films of it‐PMMA and syndiotactic (st‐) poly(methacrylic acid) (PMAA), followed by the subsequent extraction of st‐PMAA. The MAA polymerization yields increased from 35 to 75%, as the polymerization temperature increased from 0 to 70 °C. Furthermore, infrared spectroscopy revealed that a higher polymerization temperature is necessary to form it‐PMMA/st‐PMAA stereocomplexes via stereoregular polymerization manner that resemble native it‐PMMA/st‐PMAA stereocomplexes. X‐ray diffraction pattern of porous it‐PMMA were also investigated for reaction fields. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 3032–3036

New molecularly-imprinted polymer for carnitine and its application as ionophore in potentiometric selective membranes

Carnitine (CRT) is a biological metabolite found in urine that contributes in assessingseveral disease conditions, including cancer. Novel quick screening procedures for CRT are therefore fundamental. This work proposes a novel potentiometric device where molecularly imprinted polymers (MIPs) were used as ionophores. The host-tailored sites were imprinted on a polymeric network assembled by radical polymerization of methacrylic acid (MAA) and trimethylpropane trimethacrylate (TRIM). Non-imprinted polymers (NIPs) were produced as control by removing the template from the reaction media. The selective membrane was prepared by dispersing MIP or NIP particles in plasticizer and poly(vinyl chloride), PVC, and casting this mixture over a solid contact support made of graphite.The composition of the selective membrane was investigated with regard to kind/amount of sensory material (MIP or NIP), and the need for a lipophilic additive. Overall, MIP sensors with additive exhibited the best performance, with near-Nernstian response down to ~1×10−4molL−1, at pH5, and a detection limitof ~8×10−5molL−1. Suitable selectivity was found for all membranes, assessed by the matched potential method against some of the most common species in urine (urea, sodium, creatinine, sulfate, fructose and hemoglobin). CRT selective membranes including MIP materials were applied successfully to the potentiometric determination of CRT in urine samples.

Quercetin nanocomposite as novel anticancer therapeutic: Improved efficiency and reduced toxicity

A three-functional nanocomposite was prepared by radical polymerization of methacrylic acid around carbon nanotubes in the presence of Quercetin as biologically active molecule and proposed as new anticancer therapeutic. The so-obtained hybrid material was characterized by FT-IR, Raman, SEM, TEM analyses, while the functionalization degree of 2.33mg of Quercetin per g of composite was assessed by Folin–Ciocalteu test. Antioxidant test (DPPH and ABTS) showed that the covalent coupling did not interfere with the antioxidant properties of the flavonoid, while the anticancer activity was greatly enhanced with a recorded IC50 value much lower than free Quercetin. Cell viability tests on healthy cells demonstrated no-toxicity of the conjugate

Nitroxide-Mediated Photo-Controlled/Living Radical Polymerization of Methacrylic Acid

The photo-controlled/living radical polymerization of methacrylic acid (MAA) was performed at room temperature by irradiation with a high-pressure mercury lamp using azo initiators and 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl as the mediator in the presence of (4-tert-butylphenyl)diphenylsulfonium triflate (tBuS) as the accelerator. Whereas the bulk polymerization yielded polymers with a bimodal molecular weight distribution in both the absence and presence of tBuS, the solution polymerization in methanol produced unimodal polymers with the molecular weight distribution of 2.0 - 2.3 in the presence of tBuS. The molecular weight distribution of the resulting poly (MAA) decreased with an in- crease in tBuS. The dilution of the monomer concentration also reduced the molecular weight distribution. The use of the initiator with a low 10-h half-life temperature also effectively controlled the molecular weight. The livingness of the polymerization was confirmed by obtaining linear increases in the first-order conversion versus time, the molecular weight versus the conversion, and the molecular weight versus the reciprocal of the initiator concentration.

Synthesis of syndiotactic poly(methacrylic acid) by free‐radical polymerization of the pseudo‐divinyl monomer formed with methacrylic acid and catechol

AbstractSyndiotactic poly(methacrylic acid) (Syn‐PMAA, r diad = 91 mol %) was synthesized by free radical polymerization of methacrylic acid (MAA) with catechol. The pseudo‐divinyl monomer was formed with one catechol and two MAA molecules by the hydrogen bonding between OH groups of catechol and COOH group of MAA. When the free radical polymerization of the pseudo‐divinyl monomer was carried out, intra‐ and intermolecular addition proceeded with racemic addition. The hydrogen bonding was the driving force to control tacticity. We discussed the effects of solvent, temperature, and the concentrations of MAA and catechol on the pseudo‐divinyl monomer formation. The highly syndiotactic PMAA was successfully obtained. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Synthesis and characterization of comb polycarboxylic acid dispersants for coatings

AbstractComb polycarboxylic acid dispersants (CPCADs) graft acrylic copolymers which consist of hanging methoxy polyethylene glycol chains and carboxylic acid groups on main acrylic chain. The CPCADs have been synthesized by radical polymerization of methacrylic acid and methoxy polyethylene glycol methacrylate as a nonionic unsaturated hydrophilic macromonomer. The CPCADs are polymeric surfactants that can be used as anionic dispersant. Methoxy polyethylene glycol methacrylate has been synthesized by esterification of methacrylic acid and methoxy polyethylene glycol in the presence of methanesulfonic acid as catalyst. These have been characterized with 1H‐NMR and GPC. Acid values of CPCA dispersants have been determined. The dispersion of CPCA dispersants depends on their molecular weights, length mPEG, and acid values. Dispersion of titanium dioxide in typical solvent‐based paint formulation has been investigated. The physicochemical and mechanical properties of surface coatings having CPCADs such as gloss, hardness, and contrast ratio have been investigated. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Polymer Brush Controlled Bioinspired Calcium Phosphate Mineralization and Bone Cell Growth

Polymer brushes on thiol-modified gold surfaces were synthesized by using terminal thiol groups for the surface-initiated free radical polymerization of methacrylic acid and dimethylaminoethyl methacrylate, respectively. Atomic force microscopy shows that the resulting poly(methacrylic acid) (PMAA) and poly(dimethylaminoethyl methacrylate) (PDMAEMA) brushes are homogeneous. Contact angle measurements show that the brushes are pH-responsive and can reversibly be protonated and deprotonated. Mineralization of the brushes with calcium phosphate at different pH yields homogeneously mineralized surfaces, and preosteoblastic cells proliferate on both the nonmineralized and mineralized surfaces. The number of living cells on the mineralized hybrid surfaces is ca. 3 times (PDMAEMA) and 10 times (PMAA) higher than on the corresponding nonmineralized brushes.

Synthesis and Evaluation of pH Responsive Silica-Polymer Hybrid Nano Capsules

The construction of pH responsive silica-polymer hybrid nano capsules is demonstrated here. Eleven to 12 nm sized gold nano particles (GNPs) were used as template to build the nanoshell. GNPs were coated with a layer of silica and over that a polymer coating was done using free radical polymerization of methacrylic acid. The gold core of the nano particle was leached out using the cyanide chemistry to form hybrid nano shells. The different stages of the formation of the silica layer, polymer layer, and the etching away of the gold core were followed by UV-Visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM). A model compound Rhodamine B isothiocyanate was loaded into the shells to demonstrate the ability of the shells to modulate the release in response to external pH. At pH 1.98, the shells nearly stopped the release of the drug while at pH 7.0, 90% of the cargo was released. We monitored the stability of the guest loaded shells at pH 1.98 and found that even after several weeks the shells were intact. Our results show that the smart hybrid nano shells possess the ability to protect the entrapped molecules from the hostile pH of stomach and are suitable vehicles for the delivery of delicate drugs such as peptides through oral routes.

Synthesis, Characterization, and Swelling Studies of Gum Arabic–Grafted Methacrylic Acid Polymeric Network

Gum arabic–based copolymer has been synthesized by free radical polymerization of methacrylic acid (MAA) onto gum arabic in the presence of potassium persulfate (KPS). Hexamethylene tetramine (HMTA) was used to give the copolymer a three-dimensional cross-linked structure. The reaction has been carried out under vacuum in order to prevent hindrance caused by air in the reaction. Various reaction parameters like reaction time, temperature, pH, KPS concentration, MAA concentration, HMTA concentration, vacuum, and amount of solvent have been optimized to achieve maximum percentage grafting. The characterization was carried out using FT-IR, SEM, and TGA/DTA/DTG techniques, which confirmed the grafting of MAA onto gum arabic. Various swelling studies have been carried out with the copolymer at room temperature, at elevated temperatures, in different salt solutions, and in different pH media. The results showed that MAA concentration, temperature, and pH affect the percentage swelling of graft copolymer to a reasonable extent. The copolymer swelled in different salt solutions but to a lesser extent than in distilled water.

Preparation and Characterization of Superporous Hydrogels as pH-Sensitive Drug Delivery System for Pantoprazole Sodium

The objective of the present study is to develop Superporous Hydrogel (SPH) and SPH composites (SPHC) as pH-sensitive drug delivery system for Pantaprazole sodium. In this investigation, Superporous hydrogels containing poly(methacrylic acid-co-acrylamide) with interconnected pores of several hundreds of micrometer were prepared using radical polymerization of methacrylic acid and acrylamide in the presence of N,N-methylene-bis-acrylamide as crosslinking agent. A gas blowing method using bicarbonate as a foaming agent was applied to introduce the porous structure. SPH composite polymers were made in the same way, except for using Ac-Di-Sol as a stabilizer. The structures of the SPH and SPH composites were characterized by FT-IR and Scanning electron microscopy (SEM). Apparent density and swelling ratio studies were also carried out. The swelling properties and mechanical strength of SPHs were affected by the addition of the mechanical stabilizer, Ac-Di-Sol. Results indicated that SPH polymers have more pores and higher swelling ratio but less mechanical stability compared to SPH composite polymers, which have less pores and lower swelling ratio but a higher mechanical stability. With a change in pH from acidic to basic, a considerable increase in swelling was observed for all the formulations. Since the prepared SPH and SPHC swell only in the basic pH, it may be concluded that SPH and SPHC can be used as pH-sensitive drug delivery systems for Pantoprazole sodium.

Electrochemically Induced Free Radical Polymerization of Methacrylic Acid and Fabrication of Amperometric Glucose Biosensor

Electrochemically Induced Free Radical Polymerization of Methacrylic Acid and Fabrication of Amperometric Glucose Biosensor

PH-Responsive Drug Release from Polymer-Coated Mesoporous Silica Spheres

A novel method was proposed to coat poly(methacrylic acid-co-vinyl triethoxylsilane) (PMV) on mesoporous silica spheres (MSSs) to obtain a core−shell pH-responsive drug-carrier (MSS/PMV). PMV was prepared by free radical polymerization of methacrylic acid (MAA) and vinyl triethoxylsilane (VTES), in which MAA acted as the pH-sensitive monomer and VTES acted as the siloxane-containing monomer to provide an anchoring effect with the MSS surface. The micrographs of MSSs before and after coating were investigated by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). It was found that the PMV shell with a thickness of 20 nm had been coated successfully on MSS particles. To confirm the pH-sensitivity of the PMV shell, we investigated the pH-response difference between MSS/PMV and MSS/PMV-H (acidified MSS/PMV) in NH4NO3/C2H5OH solution. It was found that the PMV shell of MSS/PMV was loose (“open” state) and allowed template molecules to penetrate it easily. By contrast, the PMV shell of MSS/PMV-H was compact (“closed” state) and confined template molecules effectively inside MSS pores. These results indicated that the PMV shell played the role of molecular switch that could control the transport of molecules via a pH-dependent “open−close” mechanism. In a test of in vitro drug release, MSS/PMV showed high response to the pH of a drug solution. At high pH (pH = 7.5), ibuprofen (IBU) that loaded in MSS/PMV released rapidly and completely (within 2 h); at low pH (pH = 4.0 or 5.0), only a small part of the IBU (15 wt %) was slowly released from the MSS/PMV, and most of the IBU was effectively confined in MSS pores.

Use of acrylic acid in the synthesis of molecularly imprinted polymers for the analysis of cyproheptadine

The synthesis and comparative characterization of molecularly imprinted polymers (MIP s) with cyproheptadine (CYP), using two different monomers, acrylic acid (AA) and methacrylic acid (MAA), are described. Polyacids (PA) [poly(methacrylic acid) (PMAA) and poly(acrylic acid) (PAA)] were obtained by the radical polymerization of MAA and AA, respectively, in dichloromethane as the porogen solvent-imprinted medium. The non-covalent imprinting process was performed via thermal decomposition of an azo-initiator at 60 °C, using ethylene glycol dimethacrylate as the cross-linker and 2,2′-azobis(2-methylpropionitrile) as the initiator. The selectivities of MIP s and NIP s particles were evaluated in binding experiments of the four synthesized polymeric materials (MIP aa, MIP maa, NIP maa and NIP aa) with CYP. The effects of monomers on: a) the surface morphology, b) the binding capacity and c) the swelling properties of imprinted and non-imprinted polymers were studied and are presented here. Polymer material morphology was assessed with scanning electron microscopy (SEM). This revealed differences in monomer function, depending on which one was employed, as well as differences in function when polymerization occurred in the presence of template or without it. Non-specific retention of the template to NIP s was higher for NIP s-PAA polymers than for NIP s-PMAA materials. In terms of specific binding (Δ Q = Q MIP − Q NIP), MIP maa showed the greatest value (53.47%) in comparison with MIP aa (50.07%).

Dynamic swelling and <i> in vitro</i> release of insulin from semiinterpenetrating polymer networks of poly(vinyl alcohol) and poly(methacrylic acid)

Semi-interpenetrating polymer networks of poly(vinyl alcohol) and poly(methacrylic acid) were prepared by free radical polymerization of methacrylic acid in presence of poly(vinyl alcohol) using N,N-methylenebisacrylamide as cross linking agent. The dynamic swelling behavior of the semi-interpenetrating polymer networks was studied to determine the water transport mechanism. The effect of cross linking agent and methacrylic acid concentration on the swelling and insulin release characteristics were evaluated. Swelling ratio and water diffusion coefficients were used to characterize the water uptake process. Swelling rates correlated well with the polymer composition, the slowest rate of water uptake was observed in hydrogel samples containing large quantities of N,N-methylenebisacrylamide and maximum swelling was observed with hydrogels containing higher methacrylic acid content. The mechanism of water transport in these semi-interpenetrating polymer network hydrogels was significantly affected by the pH of the swelling medium. At pH 2.0 mechanism was Fickian (diffusion controlled) and became case II (relaxation controlled) at pH 7.4. Insulin was incorporated by active loading technique and the insulin incorporated in the semi-interpenetrating polymer network hydrogels was in the range of 28-35%. The formulations showed decreased insulin release in pH 2.0, while complete release was observed in pH 7.4 pH buffer. The diffusion coefficient of insulin through the hydrogels was in the range of 3.84×10 -6 to 5.59×10 -6 cm 2 /min in pH 2.0 buffer and in pH 7.4 buffer it was in the range of 7.55×10 -6 to 21.636×10 -6 cm 2 /min.