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Precipitation Polymerization (precipitation + polymerization)
Selected AbstractsA Novel Macromolecular Complex: Fabrication of Monodisperse Colloidal Microspheres by Precipitation Polymerization of Imine Chains and Concomitant Transition Metal BindingADVANCED MATERIALS, Issue 17 2003H. Houjou A series of monodisperse colloidal microspheres has been fabricated by precipitation polymerization of imine chains and concomitant transition metal binding. The resulting metal-bound polyimine microspheres (M-PIMSs, M = Co, Ni, Cu, or Zn, see Figure, which shows Zn-PIMSs) have characteristic diameters in the range from 0.5 to 1.4 ,m, depending on the metal used, and are of interest for applications in photonic devices. [source] Fully Crosslinked Poly[cyclotriphosphazene- co -(4,4,-sulfonyldiphenol)] Microspheres via Precipitation Polymerization and Their Superior Thermal PropertiesMACROMOLECULAR REACTION ENGINEERING, Issue 1 2007Lu Zhu Abstract Fully crosslinked, stable poly[cyclotriphosphazene- co -(4,4,-sulfonyldiphenol)] (PZS) microspheres have been prepared via the polycondensation between hexachlorocyclotriphosphazene and 4,4,-sulfonyldiphenol by precipitation polymerization. The diameter of the PZS microspheres ranged from 0.6 to 1.0 µm with the specific surface area of the microspheres ranging from 11.7 to 10.1 m2,·,g,1. The formation of the non-porous microspheres was observed to obey an oligomeric species absorbing mechanism. The fully crosslinked chemical structure of the PZS microspheres were determined by IR, CP/MAS NMR, XRD, and EDX. No glass-transition temperature was observed and the onset of the thermal-degradation temperature was 542,°C. Thermal stability of the PZS microspheres by the precipitation polycondensation was significantly improved as compared with crosslinked microspheres produced by addition polymerizations. [source] Microspheres Sensor Based on Molecularly Imprinted Polymer Synthesized by Precipitation PolymerizationCHINESE JOURNAL OF CHEMISTRY, Issue 5 2003Zhang Zhao-Hui Abstract A new biomimetic bulk acoustic wave sensor based on molecularly imprinted microspheres (MIM) technique was described. The sensing materials were synthesized by precipitation polymerization. By using the Scatchard analysis, the equilibrium dissociation constant KD and the apparent maximum number Qmax of the binding sites were calculated to be 3.70 mmol·L,1 and 9.11 ,mol·g,1, respectively. The sensor exhibited a sensitive response to the template compound (dipyridamole) in liquid phase with a detection limit of 2 × 10,9 mol· L,1. The recoveries of the sensor were 95.1%-105.4%. Studies presented in this paper show that the stability of this sensor is excellent. The sensor has been applied successfully to the determination of dipyridamole in human urine. [source] Precipitation polymerization of acrylamide with quaternary ammonium cationic monomer in potassium carbonate solution initiated by plasmaJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2007Yangang He Abstract Precipitation polymerization of 2-(methacryloyloxyethyl) trimethyl ammonium chloride (DMC)- co -acrylamide (AM) [poly(AM-DMC)] has been successfully performed in potassium carbonate (K2CO3)-water media by plasma initiation. K2CO3 solution was selected because not only the higher solubility of AM and DMC comparing with that of poly(AM-DMC), but the higher intrinsic viscosity of poly(AM-DMC) could be obtained. A set of experiments was performed using different K2CO3 concentration (from 50 down to 10% (w/w)), thus the precipitation architecture was not obtained below 20% (w/w). And particles size, particles size distribution (7,120 ,m), and intrinsic viscosity of poly(AM-DMC) (ranging up to 455 cm3/g) were also summarized in this article. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 4060,4067, 2007 [source] A Biomimetic Potentiometric Sensor Using Molecularly Imprinted Polymer for the Cetirizine Assay in Tablets and Biological FluidsELECTROANALYSIS, Issue 18 2008Mehran Javanbakht Abstract Despite the increasing number of applications of molecularly imprinted polymers (MIPs) in analytical chemistry, the construction of a biomimetic potentiometric sensor remains still challenging. In this work, a biomimetic potentiometric sensor, based on a non-covalent imprinted polymer was fabricated for the recognition and determination of cetirizine. The MIP was synthesized by precipitation polymerization, using cetirizine dihydrochloride as a template molecule, methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as a cross linking agent. The sensor showed high selectivity and a sensitive response to the template in aqueous system. The MIP-modified electrode exhibited Nernstian response (28.0±0.9 mV/decade) in a wide concentration range of 1.0×10,6 to 1.0×10,2 M with a lower detection limit of 7.0×10,7 M. The electrode has response time of ca. 20,s, high performance, high sensitivity, and good long term stability (more than 5,months). The method was satisfactory and used to the cetirizine assay in tablets and biological fluids. [source] A Novel Macromolecular Complex: Fabrication of Monodisperse Colloidal Microspheres by Precipitation Polymerization of Imine Chains and Concomitant Transition Metal BindingADVANCED MATERIALS, Issue 17 2003H. Houjou A series of monodisperse colloidal microspheres has been fabricated by precipitation polymerization of imine chains and concomitant transition metal binding. The resulting metal-bound polyimine microspheres (M-PIMSs, M = Co, Ni, Cu, or Zn, see Figure, which shows Zn-PIMSs) have characteristic diameters in the range from 0.5 to 1.4 ,m, depending on the metal used, and are of interest for applications in photonic devices. [source] Novel bioactive scaffolds with fibronectin recognition nanosites based on molecular imprinting technologyJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Elisabetta Rosellini Abstract Biomimetic materials for application in the field of tissue engineering are usually obtained through covalent bonding between the polymer backbone and the bioactive molecules. A totally new approach, proposed for the first time by our research group, for the creation of advanced synthetic support structures for cell adhesion and proliferation is represented by molecular imprinting (MI) technology. In this article, we describe the synthesis and characterization of molecularly imprinted polymers with recognition properties toward a fibronectin peptide sequence and their application as functionalization structures. Polymers, in the form of densely fused microgel particles, were obtained by precipitation polymerization. The imprinted particles showed good performance in terms of recognition capacity and quantitative rebinding; moreover, the epitope effect was observed, with the particles able to recognize and rebind not only the specific peptide sequence but also a larger fibronectin fragment. The cytotoxicity tests showed normal vitality in C2C12 myoblasts cultured in a medium that was put in contact with the imprinted particles. Therefore, imprinted particles were used to functionalize synthetic polymeric films by deposition on their surface. The deposition of the imprinted particles did not alter their specific recognition and rebinding behavior. The most remarkable result was obtained by the biological characterization: in fact, the functionalized materials appeared able to promote cell adhesion and proliferation. These results are very promising and suggest that MI can be used as an innovative functionalization technique to prepare bioactive scaffolds with an effective capacity for improving tissue regeneration. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Synthesis and characterization of PNIPAM/PS core/shell particlesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010Li Zhang Abstract Crosslinked, monodisperse PNIPAM particles were synthesized by precipitation polymerization. The particle size was measured by dynamic light scattering (DLS), capillary hydrodynamic fractionation (CHDF), and transmission electron microscopy (TEM). Two different polymerization methods were used to prepare PNIPAM/PS core/shell particles, both above and below the volume phase transition temperature (VPPT) using either a semibatch or seeded semibatch polymerization process. In both processes, uniform "raspberry" structures were obtained in which polystyrene formed small domains on the surface of the PNIPAM particles. The resulting core and shell structure was confirmed by temperature-dependent particle size and density gradient experiments. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Dispersion polymerization of methyl methacrylate: Effect of stabilizer concentrationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2008Sheng Jiang Abstract In dispersion polymerizations of methyl methacrylate (MMA), little difference was found in the polymerization kinetics with varying stabilizer (PVP K-30) concentration, indicating that in contrast to emulsion polymerization, the kinetics of these dispersion polymerizations are independent of the number of particles. Comparing MMA precipitation and dispersion polymerizations revealed that nuclei formation in the latter results from precipitation polymerization occurring in the continuous phase, which can contribute significantly to the kinetics, and especially to the molecular weight distributions. No change was found in the molecular weight distribution of the PVP during a dispersion polymerization, nor was there any measurable difference between using fresh and recycled stabilizer. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] One-pot synthesis of surface-functionalized molecularly imprinted polymer microspheres by iniferter-induced "living" radical precipitation polymerizationJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2010Junyi Li Abstract This article describes for the first time the development of a new polymerization technique by introducing iniferter-induced "living" radical polymerization mechanism into precipitation polymerization and its application in the molecular imprinting field. The resulting iniferter-induced "living" radical precipitation polymerization (ILRPP) has proven to be an effective approach for generating not only narrow disperse poly(ethylene glycol dimethacrylate) microspheres but also molecularly imprinted polymer (MIP) microspheres with obvious molecular imprinting effects towards the template (a herbicide 2,4-dichlorophenoxyacetic acid (2,4-D)), rather fast template rebinding kinetics, and appreciable selectivity over structurally related compounds. The binding association constant Ka and apparent maximum number Nmax for the high-affinity sites of the 2,4-D imprinted polymer were determined by Scatchard analysis and found to be 1.18 × 104 M,1 and 4.37 ,mol/g, respectively. In addition, the general applicability of ILRPP in molecular imprinting was also confirmed by the successful preparation of MIP microspheres with another template (2-chloromandelic acid). In particular, the living nature of ILRPP makes it highly useful for the facile one-pot synthesis of functional polymer/MIP microspheres with surface-bound iniferter groups, which allows their direct controlled surface modification via surface-initiated iniferter polymerization and is thus of great potential in preparing advanced polymer/MIP materials. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3217,3228, 2010 [source] Preparation of molecularly imprinted polymer microspheres via atom transfer radical precipitation polymerizationJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 13 2009Baiyi Zu Abstract The first combined use of atom transfer radical polymerization (ATRP) and precipitation polymerization in the molecular imprinting field is described. The utilized polymerization technique, namely atom transfer radical precipitation polymerization (ATRPP), provides MIP microspheres with obvious molecular imprinting effects towards the template, fast template binding kinetics and an appreciable selectivity over structurally related compounds. The living chain propagation mechanism in ATRPP results in MIP spherical particles with diameters (number-average diameter Dn , 3 ,m) much larger than those prepared via traditional radical precipitation polymerization (TRPP). In addition, the MIP microspheres prepared via ATRPP have also proven to show significantly higher high-affinity binding site densities on their surfaces than the MIP generated via TRPP, while the binding association constants Ka and apparent maximum numbers Nmax of the high-affinity sites as well as the specific template bindings are almost the same in the two cases. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3257,3270, 2009 [source] Stable poly(methyl methacrylate- co -divinylbenzene) microspheres via precipitation polymerizationJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 6 2005Sunhye Yang Stable poly(MMA- co -DVB) microspheres were prepared by precipitation polymerization using acetonitrile as the main medium under various polymerization conditions including monomer and initiator concentrations. [source] Potential of combining of liquid membranes and molecularly imprinted polymers in extraction of 17,-estradiol from aqueous samplesJOURNAL OF SEPARATION SCIENCE, JSS, Issue 11 2009Olga Nemulenzi Abstract The potential of combination of liquid membranes (microporous membrane liquid,liquid extraction) and molecularly imprinted polymers (MIPs) was performed using 17,-estradiol (E2) as model compound. The model compound was extracted from aqueous sample through a hydrophobic porous membrane that was impregnated with hexane/ethyl acetate (3:2), which also formed part of the acceptor phase. In the acceptor phase, the compound was bound onto MIP particles that were also part of the organic phase. The potential of such combination was optimised for the type and amount of MIP particles in the organic acceptor phase, the extraction time, and the type of organic acceptor solvent. Ultrasound assisted binding of E2 onto MIP particles was also investigated. MIPs prepared by precipitation polymerization were found to be superior to those prepared by bulk polymerization. Increase in the extraction time and the amount of MIP particles in the acceptor phase led to more E2 binding onto the MIP particles. Hexane/ethyl acetate (3:2) as an organic acceptor was found to give higher E2 binding onto MIP particles compared to toluene, diethyl ether, and hexane. Ultrasound was furthermore found to increase the binding of E2 onto MIP particles. The selectivity of the technique was demonstrated by extracting wastewater and where clean chromatograms were obtained compared to liquid membrane extractions (SLMs) alone. [source] Preparation and Properties of Cyclodextrin/PNIPAm MicrogelsMACROMOLECULAR BIOSCIENCE, Issue 5 2009Yu-Yang Liu Abstract A two-stage precipitation polymerization in aqueous solution was used to prepare , -cyclodextrin/poly(N -isopropylacrylamide) (, -CD/PNIPAm) core,shell microgels. At the first stage, core microgels with CD moieties were synthesized by precipitation copolymerization of N -isopropylacrylamide (NIPAm) with a monovinyl , -CD monomer. At the second stage, using the core particles as seeds, PNIPAm shell were further added onto the seeds by NIPAm polymerization. The microgels were characterized by means of Zetasizer Nano-ZS dynamic light scattering, TEM, IR, NMR, DSC, and TGA measurements. Using paeonol as a model drug molecule, the release behaviors of the microgels were investigated. The result indicates that the core,shell microgels could respond to change in temperature. Furthermore, the release of paeonol was related to supramolecular inclusion behavior of , -CD and temperature sensitivity of PNIPAm. [source] Synthesis of Composite Polystyrene/Silica Nanoparticles via Precipitation and Emulsion Polymerization MethodsMACROMOLECULAR REACTION ENGINEERING, Issue 5 2010Katerina Kotti Abstract Polystyrene/silica composite nanoparticles were synthesized via precipitation and emulsion polymerization methods, in the presence of a basic co-monomer (e.g., 4-VP and 1-VID), and a colloidal aqueous silica solution. The effects of key process parameters, that is, solvent type, monomer/co-monomer volume ratio and total monomers concentration for precipitation polymerization, and reaction temperature, pH value, initial silica-sol concentration and initial monomer/co-monomer molar ratio for emulsifier-free emulsion polymerization on the particle morphology, silica content, and particle size distribution of the composite nanoparticles were experimentally investigated. Stable, spherical, and uniform in size composite nanoparticles were synthesized by both techniques. The average particle diameter varied from 108 to 182,nm for the emulsifier-free emulsion polymerization and from 400 to 800,nm for the precipitation polymerization, while the silica content was as high as 38.3,wt.-% for the former method and up to 15.5,wt.-% for the later. The synthesized composite polymer/silica particles were then electrolytically co-deposited with zinc on steel plates to improve the corrosion resistance of the metal's surface. [source] Fully Crosslinked Poly[cyclotriphosphazene- co -(4,4,-sulfonyldiphenol)] Microspheres via Precipitation Polymerization and Their Superior Thermal PropertiesMACROMOLECULAR REACTION ENGINEERING, Issue 1 2007Lu Zhu Abstract Fully crosslinked, stable poly[cyclotriphosphazene- co -(4,4,-sulfonyldiphenol)] (PZS) microspheres have been prepared via the polycondensation between hexachlorocyclotriphosphazene and 4,4,-sulfonyldiphenol by precipitation polymerization. The diameter of the PZS microspheres ranged from 0.6 to 1.0 µm with the specific surface area of the microspheres ranging from 11.7 to 10.1 m2,·,g,1. The formation of the non-porous microspheres was observed to obey an oligomeric species absorbing mechanism. The fully crosslinked chemical structure of the PZS microspheres were determined by IR, CP/MAS NMR, XRD, and EDX. No glass-transition temperature was observed and the onset of the thermal-degradation temperature was 542,°C. Thermal stability of the PZS microspheres by the precipitation polycondensation was significantly improved as compared with crosslinked microspheres produced by addition polymerizations. [source] Preparation of monodisperse hydrophilic polymer microspheres with N,N,-methylenediacrylamide as crosslinker by distillation precipitation polymerizationPOLYMER INTERNATIONAL, Issue 7 2007Guangyu Liu Abstract Highly crosslinked cauliflower-like poly(N,N,-methylenebisacrylamide) particles were prepared by distillation precipitation polymerization in neat acetonitrile with 2,2,-azobisisobutyronitrile as initiator. Monodisperse hydrophilic polymer microspheres with various functional groups, such as amide, pyrrolidone and carboxylic acid, with a spherical shape and smooth surface in the size range 120,600 nm were prepared by distillation precipitation copolymerizations of functional comonomers including N -isopropylacrylamide, N -vinylpyrrolidone, methacrylic acid with N,N,-methylenebisacrylamide as crosslinker. The polymer particles were formed and precipitated out from the reaction medium during the distillation of the solvent from the reaction system through an entropic precipitation manner. The effects of the solvent and the degree of crosslinking on the morphology and the loading capacity of the functional groups of the resultant polymer particles were investigated. The resulting polymer particles were characterized with scanning electron microscopy, transmission electron microscopy, dynamic light scattering and Fourier transform infrared spectroscopy. Copyright © 2007 Society of Chemical Industry [source] Rapid and Effective Adsorption of Lead Ions on Fine Poly(phenylenediamine) MicroparticlesCHEMISTRY - A EUROPEAN JOURNAL, Issue 16 2006Mei-Rong Huang Prof. Abstract Fine microparticles of poly(p -phenylenediamine) (PpPD) and poly(m -phenylenediamine) (PmPD) were directly synthesized by a facile oxidative precipitation polymerization and their strong ability to adsorb lead ions from aqueous solution was examined. It was found that the degree of adsorption of the lead ions depends on the pH, concentration, and temperature of the lead ion solution, as well as the contact time and microparticle dose. The adsorption data fit the Langmuir isotherm and the process obeyed pseudo-second-order kinetics. According to the Langmuir equation, the maximum adsorption capacities of lead ions onto PpPD and PmPD microparticles at 30,°C are 253.2 and 242.7 mg,g,1, respectively. The highest adsorptivity of lead ions is up to 99.8,%. The adsorption is very rapid with a loading half-time of only 2 min as well as initial adsorption rates of 95.24 and 83.06 mg,g,1 min,1 on PpPD and PmPD particles, respectively. A series of batch experiment results showed that the PpPD microparticles possess an even stronger capability to adsorb lead ions than the PmPD microparticles, but the PmPD microparticles, with a more-quinoid-like structure, show a stronger dependence of lead-ion adsorption on the pH and temperature of the lead-ion solution. A possible adsorption mechanism through complexation between Pb2+ ions and N groups on the macromolecular chains has been proposed. The powerful lead-ion adsorption on the microparticles makes them promising adsorbents for wastewater cleanup. [source] Microspheres Sensor Based on Molecularly Imprinted Polymer Synthesized by Precipitation PolymerizationCHINESE JOURNAL OF CHEMISTRY, Issue 5 2003Zhang Zhao-Hui Abstract A new biomimetic bulk acoustic wave sensor based on molecularly imprinted microspheres (MIM) technique was described. The sensing materials were synthesized by precipitation polymerization. By using the Scatchard analysis, the equilibrium dissociation constant KD and the apparent maximum number Qmax of the binding sites were calculated to be 3.70 mmol·L,1 and 9.11 ,mol·g,1, respectively. The sensor exhibited a sensitive response to the template compound (dipyridamole) in liquid phase with a detection limit of 2 × 10,9 mol· L,1. The recoveries of the sensor were 95.1%-105.4%. Studies presented in this paper show that the stability of this sensor is excellent. The sensor has been applied successfully to the determination of dipyridamole in human urine. [source] | |||||||||||||