Polymerization Of Methacrylic Acid Research Articles

Selective photooxidation of chlorophenols with molecularly imprinted polymers containing a photosensitizer

Molecularly imprinted polymers containing a photosensitizer, rose bengal (RB), were synthesized via a polymerization of methacrylic acid (MAA) as a functional monomer and chlorophenols as template molecules. The polymeric sensitizers promote selective oxidation of target chlorophenol in water with molecular oxygen under visible light irradiation (λ > 530 nm). This is due to the selective attraction of the target substrate onto the molecular recognition site on the polymer followed by efficient oxidation of the substrate by a singlet oxygen produced by the photoexcited RB units located in the vicinity of the recognition site.

Adsorption Behavior and Mechanism of Grafted PMAA-HEMA/NVP Microspheres toward Lysozyme

采用反相悬浮聚合法制备了甲基丙烯酸羟乙酯（HEMA）与N-乙烯基吡咯烷酮（NVP）的交联共聚微球HEMA/NVP,然后采用＂接出＂法,实施了甲基丙烯酸（MAA）在交联微球表面的接枝聚合,制得了接枝微球PMAA-HEMA/NVP.以溶菌酶（LYZ）为模型碱性蛋白,深入研究了接枝微球PMAA-HEMA/NVP对碱性蛋白的吸附性能与吸附机理.测定了微球PMAA-HEMA/NVP的zeta电位,考察了PMAA接枝度、介质pH值及离子强度等因素对体系吸附性能的影响.结果表明,在较大的pH范围内,接枝微球PMAA-HEMA/NVP的zeta电位为绝对值较大的负值,即其表面携带有高密度的负电荷.在强静电相互作用的驱动下,接枝微球PMAA-HEMA/NVP对溶菌酶表现出很强的吸附能力.随介质pH值的增高,接枝微球对溶菌酶的吸附容量呈现先增大后减小的变化趋势,在与溶菌酶等电点接近的pH值处（pH=9）,具有最大的吸附容量（90mg.g^-1） 离子强度对接枝微球的吸附能力也有较大的影响,当pH〈9时,溶菌酶吸附容量随NaCl浓度的增高而减小 当pH〉9时,吸附容量随NaCl浓度的增高而增大.

Selective solid-phase extraction of dibutyl phthalate from soybean milk using molecular imprinted polymers

An analysis method is reported for dibutyl phthalate and related compounds with high selectivity and sensitivity by using the selective molecularly imprinted solid-phase extraction (MISPE) technique. In this report, dibutyl phthalate (DBP) is employed as the template molecule, and the molecularly imprinted polymers (MIPs) are synthesized through the bulk polymerization of methacrylic acid (MAA). The Scatchard plot suggests that the template–polymer system has two-site binding behavior with the dissociation constants of 0.5187 and 0.01898 mmol L −1, respectively. The rebinding test, based on the MISPE column technique, shows the recoveries of soybean milk samples spiked with 5 phthalates are in the range of 75.8–107.5% with the relative standard deviations of 1.80–10.08%, indicating the feasibility of the prepared MIPs for phthalates extraction. Finally, the method is used to analyze the trace level of phthalates in commercial soybean milk.

Dual Responsive Methacrylic Acid and Oligo(2-ethyl-2-oxazoline) Containing Graft Copolymers

Graft copolymers containing a poly(methacrylic acid) (PMAA) backbone and oligo(2-ethyl-2-oxazoline) (OEtOx) side chains were synthesized by reversible addition−fragmentation chain transfer (RAFT) polymerization of methacrylic acid (MAA) and OEtOx methacrylate macromonomers. In order to achieve a constant backbone length of the graft copolymer, living OEtOx chains were also directly grafted onto a deprotonated PMAA backbone in grafting densities from 7% to 92%. Both methods resulted in graft copolymers which were characterized by SEC (Mn = 5500 to 18 700 g mol−1, PDI < 1.3), 1H NMR spectroscopy, and acid/base titrations. The solubility behavior of the graft copolymers in aqueous media was investigated using turbidity measurements revealing a lower critical solution temperature (LCST) behavior of the polymers with a grafting density above 35%. The cloud points of the solutions can be varied in a temperature range from 8 to 90 °C by adjustment of the polymer composition and the pH of the solution. 1H NMR measurements in D2O at varying temperatures revealed a collapse of the polymer backbone above the cloud point of the solution whereas parts of the OEtOx side chains remained mobile.

Graft polymerization of methacrylic acid onto polyethersulfone for potential pH-responsive membrane materials

Facile graft polymerization of methacrylic acid (MAA) onto polyethersulfone (PES) using benzoyl peroxide (BPO) as chemical initiator had been developed. The polymerization was carried out in a heterogeneous polymer–monomer reaction system using water as reaction medium. The crucial parameters affecting the graft yield, such as monomer concentration, reaction time and temperature, were studied. The amount of grafted PMAA on PES was increased with increasing monomer concentration and reaction time. The optimum temperature for the grafting was around 75 °C. The graft polymers produced herein were cast into ultrafiltration membranes via phase inversion process. The cross-sectional morphology and surface composition of the membranes were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. Remarkable surface enrichment of the hydrophilic MAA segment in the membrane was revealed by XPS analysis. Due to the pH-induced conformational transition of the PMAA chains, the permeability of the membranes cast from the grafted polymers displayed pronounced pH dependence, which was large under low pH values and small under high pH values.

Photografting of methacrylic acid onto hydroxyapatite particles surfaces

The unsaturated functional groups (CC) were introduced onto hydroxypatite (HAP) particles surfaces by esterification reaction between hydroxyl groups on the HAP surface and methacrylic acid (MAA). Then, graft polymerization of MAA onto the esterified HAP particles surfaces was carried out by ultraviolet light (UV) initiation. The structure of the surface-esterified and grafted HAP was studied by ESCA, FTIR, Scanning Electron microscopy, laser particle sizes analyze, esterification, and graft degrees tests. The results show that poly(methyl acrylic acid) (PMAA) is successfully inserted onto HAP particles surfaces by covalent bond linkage. The esterification degree between MAA and HAP particles increases with reaction temperature and time, and tends to level off at about 6 h under 90°C. The graft degree of MAA onto HAP particles with 1.14% esterification degree and its average particle sizes increase with UV initiation polymerization time, and to reach a maximum at 25 min under 40°C, then decrease as irradiation time further increases. The surfaces of the grafted HAP particles become rough and loose. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

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.

Synthesis of pH-sensitive hollow polymer microspheres with movable magnetic core

The pH-sensitive hollow poly( N, N′-methylenebisacrylamide- co-methacrylic acid) (P(MBAAm- co-MAA)) microspheres with movable magnetic/silica (Fe 3O 4/SiO 2) cores were prepared by the selective removal of poly(methacrylic acid) (PMAA) layer in ethanol/water from the corresponding Fe 3O 4/SiO 2/PMAA/P(MBAAm- co-MAA) tetra-layer microspheres, which were synthesized by the distillation precipitation copolymerization of N, N′-methylenebisacrylamide (MBAAm) and methacrylic acid (MAA) in the presence of Fe 3O 4/SiO 2/PMAA tri-layer microspheres as seeds in acetonitrile with 2,2′-azobisisobutyronitrile (AIBN) as the initiator. The Fe 3O 4/SiO 2/PMAA tri-layer microspheres were afforded by the distillation precipitation polymerization of MAA with 3-(methacryloxy)propyl trimethoxysilane (MPS)-modified Fe 3O 4/SiO 2 core–shell particles as the seeds. The functional multi-layer inorganic/polymer microspheres and the corresponding hollow polymer microspheres with movable magnetic cores were characterized with transmission electron microscopy (TEM), Fourier-transform infrared (FT-IR) spectra, dynamic light scattering (DLS), and vibrating sample magnetometer (VSM).

Mechanistic Studies on Template Polymerization in Porous Isotactic Poly(methyl methacrylate) Thin Films by Radical Polymerization and Postpolymerization of Methacrylate Derivatives

The postpolymerization of various vinyl monomers was applied for mechanistic studies of the template polymerization of methacrylic acid (MAA) in porous isotactic (it-) poly(methyl methacrylate) (PM...

High Molecular Weight Poly(methacrylic acid) with Narrow Polydispersity by RAFT Polymerization

Poly(methacrylic acid) is an adaptable macromolecule that offers many benefits in the development of new materials for a host of applications. Herein we report the reversible addition−fragmentation chain transfer (RAFT) polymerization of methacrylic acid (MAA) under a range of synthesis conditions by adjusting the ratio of reactants and the type of solvent employed. The RAFT system was composed of 4,4-azobis(cyanopentanoic acid) and 4-cyanopentanoic acid dithiobenzoate as the radical initiator (I) and chain transfer agent (CTA), respectively. This system was previously applied to synthesize MAA oligomers, but high molecular weight MAA homopolymers, to our knowledge, have yet to be reported. Three distinct [MAA]0:[I]0:[CTA]0 ratios (150:0.25:1, 250:0.25:1, and 150:0.1:1), in addition to two solvents (methanol and water/1,4-dioxane), initial monomer concentration and pH were evaluated and contrasted. It was determined that the polymerization evolved in a controlled fashion particularly in methanol. In addit...

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%).

Dopamine-Imprinted Polymers: Template-Monomer Interactions, Analysis of Template Removal and Application to Solid Phase Extraction

A dopamine-imprinted polymer (MIP) was prepared in aqueous methanol solution at 60(o)C by free-radical cross-linking polymerization of methacrylic acid in the presence of ethylene glycol dimethacrylate as the cross-linker and dopamine hydrochloride as the template molecule. Its ability to isolate dopamine was evaluated as the basis of a solid phase extraction procedure and compared with that of a non-imprinted polymer(NIP). The binding of dopamine was 84.1% and 29.1% for MIP and NIP, respectively. Various reported post-polymerization treatments to reduce template bleeding were examined. In our case the lowest bleeding was achieved after applying a combined procedure: continuous extraction in a Soxhlet apparatus (CE), followed by microwave-assisted extraction (ME) to a level of 0.061 microg/mL. A simplified model of the template-monomer complexes allowed rationalization of monomer choice based on the heats of complex formation at a PM3 level of theory.

Surgical suture materials with antimicrobial properties

Methods and manufacturing conditions were developed for giving ion-exchange properties to PCA fibres by graft polymerization of methacrylic acid to PCA fibres and styrene to PP fibres followed by sulfurization of the graft polystyrene. Antimicrobial surgical suture materials with fixation of antibiotics on the modified sutures by the ion-exchange mechanism were obtained. It was found that the duration and effectiveness of the antimicrobial action of the sutures are determined by the amount of antibiotic sorbed and the ionic bond strength of the latter with the ion-exchange groups in the sutures. The effect of the conditions of modification and methods of sterilization on the physicomechanical properties of the sutures was investigated. Antimicrobial surgical PCA sutures with the gentamycin Caprogent are recommended for use in general clinical practice and are being manufactured.

Nitroxide-Mediated Copolymerization of Methacrylic Acid and Styrene To Form Amphiphilic Diblock Copolymers

The controlled free-radical polymerization of methacrylic acid was performed at 73 and 83 °C using a methacrylic acid-based alkoxyamine and the nitroxide SG1 as a mediator in the presence of a small concentration of styrene, without protection of the carboxylic acid groups. The solvent was 1,4-dioxane or ethanol, and no chain transfer to the solvent could be detected. Because of the presence of styrene, the polymerization exhibited the characteristics of a living one. In particular, the polymers could be chain-extended and were used as efficient macroinitiators in the polymerization of styrene, allowing well-defined, amphiphilic diblock copolymers to be synthesized.

Separation of l-lysine from dilute aqueous solution using molecular imprinting technique

In the present study, separation of l-lysine from dilute aqueous solution by solid-phase extraction based on molecular imprinting technique using a polar porogen was investigated. l-Lysine imprinted polymer (LLIP) was prepared by free radical solution polymerization of methacrylic acid and ethylene glycol dimethacrylate as functional and cross-linking monomers, in the presence of l-lysine as an imprint molecule, mixture of water and methanol as solvent and AIBN as an initiator. Non-imprinted polymer (NIP) as control was also prepared by the same procedure in the absence of template molecules. LLIP particles were applied to determine the optimum operational condition for l-lysine separation from dilute aqueous solution. In adsorption step, optimum pH and retention time were 7.8 and 90 min, while corresponding values in extraction step were 12 and 50 min, respectively. l and d-Lysine recovery by LLIP at optimum condition were found to be 96 and 58% with corresponding distribution coefficients of 8000 and 460, respectively. The retention capacity of LLIP was 27.26 mg l-lys/g of polymer at optimum condition.

Propagation Kinetics of Free‐Radical Methacrylic Acid Polymerization in Aqueous Solution. The Effect of Concentration and Degree of Ionization

AbstractPropagation rate coefficients, kp, of free‐radical methacrylic acid (MAA) polymerization in aqueous solution are presented and discussed. The data has been obtained via the pulsed laser polymerization – size‐exclusion chromatography (PLP‐SEC) technique within extended ranges of both monomer concentration, from dilute solution up to bulk MAA polymerization, and of degree of ionic dissociation, from non‐ionized to fully ionized MAA. A significant decrease of kp, by about one order of magnitude, has been observed upon increasing monomer concentration in the polymerization of non‐ionized MAA. Approximately the same decrease of kp occurs upon varying the degree of MAA ionization, α, at low MAA concentration from α = 0 to α = 1. With partially ionized MAA, the decrease of kp upon increasing MAA concentration is distinctly weaker. For fully ionized MAA, the propagation rate coefficient even increases toward higher MAA concentration. The changes of kp measured as a function of monomer concentration and degree of ionization may be consistently interpreted via transition state theory. The effects on kp are essentially changes of the Arrhenius pre‐exponential factor, which reflects internal rotational mobility of the transition state (TS) structure for propagation. Friction of internal rotation of the TS structure is induced by ionic and/or hydrogen‐bonded intermolecular interaction of the activated state with the molecular environment.

6-Chloro-N,N-diethyl-1,3,5-triazine-2,4-diamine (CAT) Sensor Based on Biomimetic Recognition Utilizing a Molecularly Imprinted Artificial Receptor

We aimed to develop a 6-chloro-N,N-diethyl-1,3,5-triazine-2,4-diamine (CAT)-sensing system based on a biomimetic receptor of a molecularly imprinted polymer for CAT and electrochemical determination of CAT. A molecularly imprinted polymer for CAT was prepared by the polymerization of methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylate (EDMA) as a cross-linker with a template molecule (CAT) in dimethyl formamide (DMF). The polymer prepared with the ratio of these monomers (CAT:MAA:EDMA = 1:7.5:20) showed the most selective rebinding to CAT, and the obtained polymer was recognized as a CAT-imprinted polymer (CAT-MIP). The effect of the specific imprinting sites of CAT-MIP was demonstrated by Scatchard analysis. In an aqueous solution of CAT, CAT-MIP showed the maximum binding of CAT in a 0.05 M phosphate buffer (PB), pH 5.0. The binding amount of CAT to CAT-MIP was 24% more than atrazine and 72% more than propazine. The CAT-sensing system was composed of a column of CAT-MIP particles and a voltammetry analyzer. The reductive current of CAT depended on the concentration of CAT up to 30 microM with the system.

Critically evaluated rate coefficients for free-radical polymerization Part 6: Propagation rate coefficient of methacrylic acid in aqueous solution (IUPAC Technical Report)

Abstract Critically evaluated propagation rate coefficients, k p, for free-radical polymerization of methacrylic acid, MAA, in aqueous solution are presented. The underlying k p values are from two independent sources, which both used the IUPAC-recommended technique of pulsed-laser-initiated polymerization (PLP) in conjunction with molar mass distribution (MMD) analysis of the resulting polymer by size-exclusion chromatography (SEC). Different methods of measuring the MMD of the poly(MAA) samples have, however, been used: (i) direct analysis via aqueous-phase SEC and (ii) standard SEC with tetrahydrofuran as the eluent carried out on poly(methyl methacrylate) samples obtained by methylation of the poly(MAA) samples from PLP. Benchmark k p values for aqueous solutions containing 15 mass % MAA are presented for temperatures between 18 and 89 °C. The Arrhenius pre-exponential and activation energy of k p at 15 mass % MAA are 1.54 × 106 L mol-1 s-1 and 15.0 kJ mol-1, respectively. Also reported are critically evaluated k p values for 25 °C over the entire MAA concentration range from dilute aqueous solution to bulk polymerization.