Methacrylate Solution Research Articles

IMPROVEMENT OF POLY(METHYL METHACRYLATE) ELECTROSPUN FIBER UNIFORMITY BY ADDITION OF POLY(ESTER AMINE)

Linear and hyperbranched poly(ester amine)s (PEAs) were used as additives in electrospinning of low concentration poly( methyl methacrylate) solutions to eliminate beads and improve the fiber uniformity. With only 1 wt% PEA,no matter linear or hyperbranched,the electrospinnability was all improved,and uniform fibers without beads were obtained. Compared to linear PEA,hyperbrchched PEA has better ability in improving the fiber uniformity. The average fiber diameter decreases significantly ( from 1. 9 μm to 1. 0 μm) compared to those obtained at high concentration without PEA. The principle of the improvement in electrospinnability was investigated by measuring the solution properties ( viscosity,conductivity and surface tension),and it was attributed to the significant increase in solution conductivity. The solution viscosity and surface tension only change slightly,while solution conductivity increases greatly with the addition of 1 wt% PEA (including linear and hyperbranched). The hyperbranched PEAs have higher conductivity than the linear PEA because they have more polar end-groups resulted from the multiple branches,and therefore the hyperbranched PEAs have better performance than the linear PEA in improving the electrospinnability of low concentration PMMA solutions. The method reported in this paper could be generalized and provides a good alternative to the existing methods.

Convenient fabrication of carbon-doped titania nanofibres by electrospinning

Carbon-doped titania nanofibres have been fabricated by the electrospinning technique using polymethyl methacrylate (PMMA) solution and a titania non-aqueous sol followed by calcination. PMMA was used as a base polymer in the electrospinning solution to assist the formation of nanofibres and subsequently removed by the thermal treatment. The nanofibres were characterised using various techniques. The diameter of the titania nanofibres is in the range of 200–300 nm according to scanning electron microscopy observation. X-ray photoelectron spectroscopy results demonstrate that the carbon doping into titania nanofibres is achieved via calcining the PMMA/titania hybrid nanofibres at 400°C. The carbon-doped titania nanofibres exhibit good photocatalytic activity under visible light irradiation.

Absorption of carbon dioxide into glycidyl methacrylate solution with quaternary onium salts

Carbon dioxide was absorbed into organic solutions of glycidyl methacrylate (GMA) in a semi-batch stirred tank with a plane gas-liquid interface at 101.3 kPa to measure absorption rates of carbon dioxide, from which the reaction kinetics between carbon dioxide and GMA with quaternary onium salts as catalysts was obtained. The reaction rate constants were estimated by the mass transfer mechanism accompanied by the pseudo-first-order reaction method. An empirical correlation formula between the reaction rate constants and the solubility parameters of solvents such as toluene, N-methyl-2-pirrolidinone, and dimethyl sulfoxide was presented.

Fabrication of a biodegradable polysaccharide hydrogel with riboflavin, vitamin B2, as a photo‐initiator and L‐arginine as coinitiator upon UV irradiation

The objective of this study is to develop a completely natural material based photo-initiation system for fabricating biologically compatible hydrogels, that is, free of any synthetic materials like conventional synthetic photo-initiators. The resulting biodegradable hydrogels would be completely free of conventional toxic synthetic substances. Dextran-based precursor was used as a model system for this study. The natural material based photo-initiation system used riboflavin (vitamin B2) as photo-initiator and L-arginine as a coinitiator. Dextran-methacrylate precursor was prepared to introduce photosensitive unsaturated moieties into dextran for subsequent photo-induced gel formation. Riboflavin alone could not initiate the photo-crosslinking reaction of the dextran methacrylate solution upon UV irradiation. L-arginine, which can act as an electron donor in the photo-initiation process, was used as a coinitiator. The optimum gel formulation conditions in terms of the concentrations of riboflavin and L-arginine as well as different pH media were extensively investigated. The dextran-methacrylate hydrogels were formed well and fast at low riboflavin concentration range (0.2-1 wt %), and L-arginine promoted the photo-initiation at all concentrations. The gelation was promoted most in the neutral pH and the least in the alkaline pH. The turbidity of the dextran-methacrylate hydrogel precursor solution affected the polymerization because UV penetration was significantly hindered as the opacity of the solution increased. The swelling property and structural visualization of the prepared hydrogels were also investigated.

Absorption of carbon dioxide into glycidyl methacrylate solution containing the triethylamine immobilized ionic liquid on MCM-41 catalyst

An ionic liquid (TEA-MS41), triethylamine-immobilized on chloropropyl-functionalized MCM-41, was synthesized by a grafting technique through a co-condensation method and used as a catalyst in the reaction of carbon dioxide with glycidyl methacrylate (GMA). CO2 was absorbed into the heterogeneous system of the GMA solution and dispersed with solid particles of the catalyst in a batch stirred tank with a plane gas-liquid interface at 101.3 kPa. The absorption of CO2 was analyzed by using mass transfer accompanied by chemical reactions based on film theory. The proposed model fits the measured data of the enhancement factor to obtain the reaction rate constants. Solvents such as N,N-dimethylacetamide, N-methyl-2-pyrrolidinone, and dimethyl sulfoxide influenced the reaction rate constants.

Surface treatment of phosphate glass fibers using 2‐hydroxyethyl methacrylate: Fabrication of poly(caprolactone)‐based composites

Abstract2‐Hydroxyethyl methacrylate (HEMA) solution (1–10 wt %) was prepared in methanol and phosphate glass fibers were immersed in that solution for 5 min before being cured (irradiation time: 30 min) under UV radiation. Maximum polymer loading (HEMA content) was found for the 5 wt % HEMA solution. Degradation tests of the fibers in aqueous medium at 37°C suggested that the degradation of the HEMA‐treated fibers was lower than that of the untreated fibers. X‐ray photoelectron spectroscopy revealed that HEMA was present on the surface of the fibers. Using 5 wt % HEMA‐treated fibers, poly(caprolactone) matrix unidirectional composites were fabricated by in situ polymerization and compression molding. For in situ polymerization, it was found that 5 wt % HEMA‐treated fiber‐based composites had higher bending strength (13.8% greater) and modulus (14.0% greater) than those of the control composites. For compression molded composites, the bending strength and modulus values for the HEMA‐treated samples were found to be 27.0 and 31.5% higher, respectively, than the control samples. The tensile strength, tensile modulus, and impact strength of the HEMA composites found significant improvement than that of the untreated composites. The composites were investigated by scanning electron microscopy after 6 weeks of degradation in water at 37°C. It was found that HEMA‐treated fibers inside the composite retained much of their original integrity while the control samples degraded significantly. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Flexural Behavior of Polymer Mortar Permanent Forms Using Methyl Methacrylate Solution of Waste Expanded Polystyrene

This experimental study examines the applicability of polymer mortar permanent forms using a methyl methacrylate (MMA) solution of waste expanded polystyrene (EPS) to develop effective recycling processes for the EPS, referring to the flexural behavior of a polymer-impregnated mortar permanent form with almost the same performance as commercial products. An MMA solution of EPS is prepared by dissolving EPS in MMA, and unreinforced and steel fiber-reinforced polymer mortars are mixed using the EPS-MMA-based solution as a liquid resin or binder. Polymer mortar permanent forms (PMPFs) using the EPS-MMA-based polymer mortars without and with steel fiber and crimped wire cloth reinforcements and steel fiber-reinforced polymer-impregnated mortar permanent form (PIMPF) are prepared on trial, and tested for flexural behavior under four-point (third-point) loading. The EPS-MMAbased PMPFs are more ductile than the PIMPF, and have a high load-bearing capacity. Consequently, they can replace PIMPF in practical applications.

Viscosity of moderately concentrated solutions of polymethyl‐methacrylate in methyl‐methacrylate

AbstractA Haake® viscometer with the NV cup‐and‐bob sensor is used to measure the viscosity, η, of polymethyl methacrylate (PMMA) solutions in methyl methacrylate (MMA) at several polymer concentrations, weight‐average molecular weights, and temperatures, and under nonreacting conditions. Six polymer samples having different average molecular weights are prepared by polymerizing MMA in a 1‐L batch reactor using 2,2′‐azoisobutyronitrile (AIBN) as the initiator. Our earlier experimental data (at moderate concentrations of the polymer) on the viscosity of PMMA solutions in MMA under reacting conditions is also used. Two general correlations are developed between $ {\eta \over \eta_{\rm sol}} $ and CpolyM with the parameters obtained using genetic algorithm. The tuned correlations for viscosity can be used over an extended range of monomer conversions for model‐based state estimation and on‐line optimal control of the bulk polymerization of MMA. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Reaction kinetic for poly(styrene- co-vinylbenzyl chloride)-supported catalyst containing pendant tetraethylammonium chloride in the reaction of glycidyl methacrylate with carbon dioxide

A soluble copolymer-supported catalyst containing pendant triethylammonium chloride was synthesized by the radical copolymerization of p-chloromethylated styrene with styrene followed by the addition reaction of the resulting copolymer with triethylamine. Initial absorption rate of carbon dioxide into glycidyl methacrylate (GMA) solutions containing the catalyst was measured in a semi-batch stirred tank with a plane gas–liquid interface at 101.3 kPa. The reaction rate constants of the reaction between carbon dioxide and GMA were evaluated from analysis of the mass transfer mechanism accompanied by the elementary reactions based on the film theory. Solvents such as toluene, N-methyl-2-pirrolidinone, and dimethyl sulfoxide influenced on the reaction rate constants. Furthermore, this catalyst was compared to the monomeric tetraethylammonium chloride under the same reaction conditions.

Kinetic parameters using an immobilized tetrahexylammonium chloride catalyst in glycidyl methacrylate reaction with carbon dioxide

A soluble copolymer-supported catalyst containing pendant tetrahexylammonium chloride was synthesized by the radical copolymerization of p-chloromethylated styrene with styrene followed by the addition reaction of the resulting copolymer with trihexylamine. Initial absorption rate of carbon dioxide into glycidyl methacrylate (GMA) solutions containing the catalyst was measured in a semi-batch stirred tank with a plane gas-liquid interface at 101.3 kPa. The reaction rate constants of the elementary reaction between carbon dioxide and GMA were evaluated from analysis of the mass transfer mechanism accompanied by the elementary reactions based on film theory. Solvents such as toluene, N-methyl-2-pirrolidinone, and dimethyl sulfoxide influenced the reaction rate constants. Furthermore, this catalyst was compared to monomeric tetrahexylammonium chloride under the same reaction conditions.

Electrical Properties of Electrospun Fibers of PANI-PMMA Composites

Electrospinning is one of the simplest techniques for obtaining polymer nano fibers. Nanofibers have large surface area to volume ratio and hence have excellent application potential in sensors, filter design etc. Polyaniline (PANI) is the well-known and widely studied conducting polymer, which however, is insoluble in many common organic solvents and hence difficult to process. PANI in its base form is non conductive but it can be made conducting by protonating with an acids such as hydrochloric acid (HCl) or camphor sulphonic acid (CSA). However, it is difficult to electrospin PANI by itself since we need preferably the polymer in solution form. In this study we have formed nanofibers of PANI (CSA) dispersed in Poly Methyl Methacrylate (PMMA) solution in chloroform. The morphology of the electrospun conducting PMMA-PANI composite fibers is studied using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The DC and AC conductivities of these fibers are measured and the results are discussed.

Reaction kinetics of carbon dioxide with glycidyl methacrylate using immobilized trioctylamine supported on poly(styrene-CO-vinylbenzyl chloride) as a catalyst

A soluble polymer-supprted catalyst containing pendant trioctylammonium chloride was synthesized by the radical copolymerization of p-chloromethylated styrene with styrene followed by the addition reaction of the resulting copolymer with trioctylamine. Absorption rate of carbon dioxide into glycidyl methacrylate (GMA) solutions containing the catalyst was measured using a semi-batch stirred tank with a plane gas-liquid interface at 101.3 kPa. The reaction kinetics of the reaction between carbon dioxide and GMA was evaluated using the absorption rate and the mass transfer mechanism of carbon dioxide. Solvents such as toluene, N-methyl-2-pyrrolidinone, and dimethyl sulfoxide influenced the reaction rate constants. Furthermore, this catalyst was compared to the monomeric tetraoctylammonium chloride under the same reaction conditions.

Chemical kinetics of carbon dioxide with glycidyl methacrylate using immobilized tributylamine supported on poly(styrene-co-vinylbenzyl chloride) as a catalyst

A soluble copolymer-supported catalyst containing pendant tributylammonium chloride was synthesized by the radical copolymerization of p-chloromethylated styrene followed by the addition reaction of the resulting copolymer with tributylamine. The absorption rate of carbon dioxide was measured from the absorption experiment into glycidyl methacrylate (GMA) solutions containing the catalyst in a semi-batch stirred tank with a plane gas–liquid interface at 0.1013 MPa. The reaction rate constants of the reaction between carbon dioxide and GMA were obtained by the analysis of the mass transfer mechanism accompanied by chemical reactions based on the film theory.Solvents such as toluene, N-methyl-2-pirrolidinone, and dimethyl sulfoxide influenced the reaction rate constants. Furthermore, this catalyst was compared to the monomeric tetrabutyl-ammonium chloride under the same reaction conditions.

Antioxidation Study of Sm(Co, Cu, Fe, Zr) z-Sintered Permanent Magnets by Metal Injection Molding

Antioxidation effects on Sm(Co, Cu, Fe, Zr) z -sintered magnets treated by different methods were studied through TGA and DTA. Microstructure of Sm(Co, Cu, Fe, Zr) z -sintered magnets was analyzed through SEM and EDS. The results indicate that the antioxidation effect of the alloy powder treated in silane solution is better than that of the other methods. The alloy powders treated in stearic acid (SA) solution and polymethyl methacrylate (PMMA) solution can prevent powders from oxidation for a short period of time. Silane solution is not suitable for metal injection molding (MIM) because it severely damages the magnetic properties and microstructure of Sm(Co, Cu, Fe, Zr) z -sintered magnets. SA solution can not only prevent powders from oxidizing in MIM, but also does not damage magnetic properties and microstructure of Sm(Co, Cu, Fe, Zr) z magnets. The oxygen content of Sm(Co, Cu, Fe, Zr) z -sintered magnets by MIM is 3300 μg·g −1.

CONTROL OF A CONTINUOUS POLYMERIZATION REACTOR BY WIENER INPUT/OUTPUT DATA-BASED PREDICTIVE CONTROLLER WITH DIRECT INVERSE IDENTIFICATION

ABSTRACT This article reports an experimental study for the identification and predictive control of a continuous methyl methacrylate (MMA) solution polymerization reactor. The Wiener model was introduced to identify the polymerization reactor in a more efficient manner than the conventional methods of Wiener model identification. In particular, the method of subspace identification was employed and the inverse of the nonlinear part was directly identified. The input variables in this work were the jacket inlet temperature and the feed flow rate, while the monomer conversion and the weight average molecular weight were selected as the output variables. On the basis of the identified model a Wiener-type input/output data-based predictive controller was designed and applied to the property control of polymer product in the continuous MMA polymerization reactor by conducting an on-line digital control experiment with online densitometer and viscometer. Despite the complex and nonlinear characteristics of the polymerization reactor, the proposed controller was found to perform satisfactorily for property control in the multiple-input multiple-output system with input constraints for both set-point tracking and disturbance rejection. This was also confirmed by simulation results.

Reaction rate of carbon dioxide in glycidyl methacrylate solution using tricaprylylmethylammonium chloride as a catalyst

Carbon dioxide was absorbed into organic solutions of glycidyl methacrylate (GMA) in a semi-batch stirred tank with a plane gas-liquid interface at 101.3 kPa to measure absorption rates of carbon dioxide, from which the reaction kinetics between carbon dioxide and GMA were studied by using tricaprylylmethylammonium chloride catalyst. The reaction rate constants of the reaction were estimated by using the mass transfer mechanism accompanied by the pseudo-first-order reaction. An empirical correlation formula between the reaction rate constants and the solubility parameters of solvents such as toluene,N-methyl-2-pirrolidinone, and dimethyl sulfoxide was presented.

Chemical Absorption of Carbon Dioxide into Glycidyl Methacrylate Solution with Tetrabutylammonium Bromide

Absorption of carbon dioxide was carried out in a semi‐batch stirred tank of glycidyl methacrylate solution with tetrabutylammonium bromide as a catalyst at 101.3 kPa. The measured rate of absorption of carbon dioxide was used to obtain the reaction kinetics by the mass transfer mechanism accompanied by the chemical reaction, which was consisted of two elementary reactions. An empirical correlation formula between the reaction rate constants and the solubility parameters of the solvents, such as toluene, N‐methyl‐2‐pirrolidinone, and dimethyl sulfoxide, was presented.

Polymer Bonded Anisotropic Thick Hard Films for Micromotors/Microgenerators

Hard magnetic films are very promising elements for the production of MEMS, due to the optimum scaling properties of magnetic interactions. These elements are specially well suited for the development of micromotors and microgenerators. A magnetization multipolar structure is required on the material to be used in such applications. In order to generate this multipolar structure, a well defined magnetic anisotropy is required, this anisotropy being directed in many cases in the direction perpendicular to the film plane. The maximum torque obtainable from a micromotor depends mainly on the mass of magnetic material (i.e. the film thickness). Anisotropic hard magnetic films with thicknesses on the order of tenths of millimetres can not be prepared by any of the common thin film deposition techniques available nowadays. Though some preparation techniques have been developed that can be used to prepare hard magnetic films with the desired thicknesses, they are not able to produce materials with a well defined anisotropy along the direction perpendicular to the film plane. In this work, we describe a method to prepare anisotropic hard magnetic films with thicknesses of tenths of millimetres by dispersing NdFeB anisotropic microparticles on a polymethyl methacrylate (PMMA) solution at room temperature under low intensity magnetic fields. Large macrospic anisotropics have been reached for magnetic fields as low as 150 Oe applied during the deposition, with room temperature coercivities in excess of 1.2 T and maximum energy products up to 9 MGOe. The analysis of the temperature dependence of the magnetic properties indicates that a columnar arrangement of the particles on the direction parallel to the field applied during the preparation is the reason of the observed macroscopic anisotropy. The films can be easily deposited onto different substrates and mechanised in order to obtain a smooth surface with the desired shape. Their use in micromotors/microgenerators has been tested.

The electrochemical detection of Ru(II) in a methyl methacrylate solution

This article describes the voltammetric behaviour of RuCl 2(PPh 3) 3 in a methyl methacrylate (MMA) solution. Acquiring this type of information is only possible when the ohmic resistance can be kept sufficiently low. Therefore, the conductivity study of pure methyl methacrylate and a tetrabutylammonium tetrafluoroborate (TBABF 4) methyl methacrylate solution has been described as well. Impedance measurements show an increase in conductivity by adding TBABF 4, while a conductometric curve illustrates the presence of ion pairs, triple ions and quadrupoles depending on the TBABF 4 concentration. The conductivity of a 0.1 mol L −1 TBABF 4–MMA solution (formation of charged triple ions) was high enough to perform electrochemical experiments and a calibration curve could be obtained. The ability of obtaining relevant electrochemical data in low conducting media opens up new perspectives, especially for electroanalytical purposes used to monitor polymer reactions, more specific atom transfer radical polymerization (ATRP) reactions. This method employs a redox process with transition metal complexes in which a halogen ion is transferred reversibly between the transition metal and the polymer chain end. The dynamic equilibrium can be monitored by measuring the ruthenium concentration.

Fast prototyping of hydrophobic disposable polymer support arrays for matrix‐assisted laser desorption/ionization‐time of flight‐mass spectrometry of proteins by atmospheric molding

A fast protocol for prototyping hydrophobic disposable poly(alkyl methacrylate-co-methyl methacrylate) copolymer sample support arrays for matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) of proteins by atmospheric molding is introduced. The sample support arrays were replicated by molding prepolymer alkyl methacrylate solutions into sandwich molds containing a micromachined silicon master, an aluminum spacer, and glass cover plates, followed by UV-initiated in situ polymerization under atmospheric pressure. The fabrication procedure enables a simultaneous fabrication/modification of single-use polymer arrays by a targeted selection of functional groups of the copolymerized monomers during molding. The one-step modification during the fabrication is demonstrated for enhanced protein adsorption to the modified materials by introduction of hydrophobic butyl-, dodecyl-, and octadecyl groups to the polymer backbone without a need for additional surface coating or derivatization. The MALDI-MS performance of the new polymer chips was tested for spectral measurements of bovine pancreas insulin, horse heart myoglobin, and bovine serum albumin. The protein adsorption to the new hydrophobic copolymer chips was studied for bovine pancreas trypsinogen; the sample desalting parameters, such as time and volume, were optimized for myoglobin as model proteins. A significant signal increase was achieved after efficient desalting of an insect Delta11-desaturase membrane protein fragment from a complex elution buffer (100 mM phosphate, 10 mM tris(hydroxyethyl)aminomethane, 0.5 M NaCl, and 10 mM ethylenediamine tetraacetic acid) on the poly(butyl methacrylate-co-methyl methacrylate) copolymer chip (monomer ratio 8:2 v/v) by simply washing the target zones. The new chips offer reduced sample manipulation and device fabrication times as well as simple operation.