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1.
Submicron core‐shell polymer particles, with molecularly imprinted shells, were prepared by a two‐stage polymerization process. Particles of this type, prepared with a cholesterol‐imprinted ethyleneglycol dimethacrylate shell and in the absence of porogen, were found to be 76 nm in diameter with a surface area of 82 m2 g−1. Cholesterol uptake from a 1 mM solution in isohexane was measured at both 10 and 30 mg mL−1, with the imprinted polymer showing considerable binding (up to 57%). Imprinted but not hydrolyzed and hydrolyzed nonimprinted polymers showed very low uptakes (≤4.5%) and a phenol‐imprinted polymer showed reduced binding (36%) under the same conditions. Imprinted shells were also prepared over superparamagnetic polymer cores and over magnetite ferrocolloid alone. The cholesterol binding to magnetic particles was very similar to that of equivalent nonmagnetic materials. Magnetic particles could be sedimented in as little as 30 s in a magnetic field. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1851–1859, 2000  相似文献   

2.
Molecularly imprinted polymers (MIPs) were synthesized through solution polymerization using quercetin as the template molecule, N‐vinylpyrrolidone and acrylic acid as functional monomers, N,N′‐methylenebiacrylamide as crosslinker and the redox system L ‐ascorbic acid and hydrogen peroxide as initiator in the porogen of ethanol and water. During the optimization process an interference compound, genistein (5,7,4′‐trihydroxy isoflavone), which possesses the same skeleton and functional groups as quercetin, was adopted to optimize the preparation conditions, and the separation degree of the MIP to quercetin and genistein was chosen to optimize each factor. The synthesized MIP under optimal conditions showed a specific recognition of quercetin from a mixture of quercetin and genistein. Thereafter, the structure of the MIP was comparatively characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and Brunauer–Emmett–Teller analysis using non‐imprinted molecular polymers as control. In addition, the kinetics of the adsorption process were also studied, and Scatchard analysis revealed that heterogeneous binding sites were formed in the polymers. Copyright © 2012 Society of Chemical Industry  相似文献   

3.
Porous copolymer beads of 2,3‐epoxypropyl methacrylate (glycidyl methacrylate, GMA) crosslinked with 2‐ethyl‐2‐(hydroxymethyl)‐propan‐1,3‐diol trimethacrylate (trimethylolpropane trimethacrylate, TRIM) were prepared with toluene and octan‐2‐one as porogens by suspension polymerization. With an increase in the ratio of porogen to monomer, the total pore volume of poly(GMA‐co‐TRIM) increases significantly, whereas the surface area hardly changes. The total pore volume also depends on the nature of the porogen, exhibiting a maximum at the larger GMA contents in the monomer mixture of 50% v/v with octan‐2‐one and of 60% v/v with toluene, compared to that at the GMA content of 25% v/v with a 9/1 v/v mixture of cyclohexanol and dodecan‐1‐ol [Verweij, P. D.; Sherrington, D. C. J Mater Chem 1991, 1 (3), 371]. The surface area decreases significantly with an increase in the ratio of GMA to TRIM, almost regardless of the nature of the porogen. The porous properties of poly(GMA‐co‐TRIM) was well explained on the basis of phase separation, particularly taking into account not only the solubility parameters of the resulting polymer network and porogen but also the rigidity of TRIM. The porous poly(GMA‐co‐TRIM) may be a promising polymer matrix of novel materials for separation of boron isotopes. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2374–2381, 2002  相似文献   

4.
Molecularly imprinted polymer microspheres were prepared by precipitation polymerization using a sacrificial covalent bond. In the present model, cholesteryl (4‐vinyl)phenyl carbonate was used as a template monomer. The imprinted microspheres were prepared using ethylene glycol dimethacrylate (EDMA) and divinylbenzene (DVB) as crosslinker. The base‐labile carbonate ester bond was easily hydrolyzed to leave imprinted cavities in the resulting polymers. Radioligand binding analysis, elemental analysis, and scanning electron microscopy were used to characterize the imprinted materials. Imprinted microspheres prepared from DVB crosslinker had larger and more defined spherical shape, and displayed better imprinting effect than did the EDMA‐based microparticles. For comparison, imprinted bulk polymers were also prepared in the same reaction solvent as that used in precipitation polymerization. Elemental analysis results indicated that imprinted microspheres contained more template monomer units than bulk materials. The efficiency of template removal by hydrolysis treatment for microspheres was also higher than that for bulk polymers. For DVB‐based polymers, imprinted microspheres displayed higher specific cholesterol uptake than did the corresponding bulk polymer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1390–1398, 2006  相似文献   

5.
A novel method for the separation of berberine hydrochloride has been developed. Berberine hydrochloride molecularly imprinted polymers were prepared by suspension polymerization in the aqueous phase using berberine hydrochloride as the template, methyl acrylic acid as a functional monomer, and ethylene glycol maleic rosinate acrylate (which contains a phenanthrene ring skeleton) and ethylene glycol dimethacrylate as combinatorial crosslinkers. The imprinted polymers were successfully used as a selective stationary phase in high‐performance liquid chromatography. Separation performance of the chromatographic column was determined from the selectivity (evaluated by separation factor) and sorption selectivity (evaluated by imprinting factor) of the molecularly imprinted and non‐imprinted polymers towards the template. The optimum conditions to maximize separation and imprinting factors were investigated. Acetic acid–methanol solution (0.05% v/v) was selected as the optimum mobile phase, while 0.2 mL min?1 was chosen as the optimized flow rate for selective separation of berberine hydrochloride. The highest imprinting and separation factors obtained were 1.924 and 18.52, respectively. Simultaneously, the chromatographic column backpressure was stable and showed good permeability. The chromatographic column was used to separate effectively template molecules from coptis root extract and other analogues. Such chromatographic columns with high selectivity can be used to selectively separate berberine hydrochloride from other compounds. © 2014 Society of Chemical Industry  相似文献   

6.
The copolymers of 4‐vinylpyridine (4VP), styrene (St) and divinylbenzene (DVB) with varied compositions, P(4VP‐St‐DVB), were synthesized by suspension polymerization using 2,2′‐azobisisobutyronitrile (AIBN) as an initiator. The insoluble (crosslinked) pyridinium‐type polymers in benzyl–pyridinium bromide form, which possess various macromolecular chain compositions, were prepared by the reaction of each P(4VP‐St‐DVB) with benzyl bromide (BzBr), respectively. By using different halohydrocarbon RX in the quaternization of P(4VP‐St‐DVB), the insoluble pyridinium‐type polymers with various pyridinium group structures were obtained. The structures of P(4VP‐St‐DVB) and its quaternized product Q‐P(4VP‐St‐DVB) were identified by FTIR. The 4VP content in each copolymer P(4VP‐St‐DVB) was measured by nonaqueous titration; and the pyridinium group content (Cq) in each Q‐P(4VP‐St‐DVB) sample was determined by means of the back titration manner in argentometry and/or the elemental analysis method, respectively. In addition, the particle structure and the surface morphology of the thus‐prepared polymer were observed using SEM. According to a series of experimental results, the preparation and characterization of insoluble pyridinium‐type polymers are analyzed and discussed. This work can prepare the ground for a study on the antibacterial activity of insoluble pyridinium‐type polymers. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 668–675, 2000  相似文献   

7.
Two molecularly imprinted polymers (MIPs) were prepared using (S)‐ibuprofen as the template molecule as well as methacrylic acid (MAA) or 4‐vinylpyridine and ethylene glycol dimethacrylate (EGDMA) as the functional monomer and crosslinker, respectively. Free radical polymerization was carried out at 4°C under ultraviolet (UV) radiation. The MIPs thus obtained were ground into 25–44 μm, which were slurry packed into analytical columns. The template molecules were removed by acetic acid/methanol solution (1:9, v/v). high‐performance liquid chromatography (HPLC), with UV detection, was used to evaluate the binding performance of the MIP for the template. The selectivity of (S)‐ibuprofen and naproxen on the host–guest system were assessed using acetonitrile‐based mobile phases. The limits of detection of ibuprofen and naproxen were found to be 0.1844 mmol/L and 0.3264 mmol/L, while the limits of quantitation were 0.6262 mmol/L and 1.0909 mmol/L, respectively. The stationary phase was applied successfully to the commercial tablet analysis. Ibuprofen and naproxen were extracted from tablets with acetonitrile; analysis results showed a good relative standard deviation (RSD) of 0.81–1.24% and accuracy from ?4.01 to +2.98% for ibuprofen as well as an RSD of 0.59–0.86% and accuracy from ?4.01 to ?2.01% for naproxen. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2972–2979, 2006  相似文献   

8.
Tyrosine and phenylalanine imprinted Fe3O4/P(St‐DVB) composite beads with magnetic susceptibility were prepared by suspension polymerization using Fe3O4 as the magnetically susceptible component, methacrylic acid and acrylamide as functional monomers, styrene and divinylbenzene as polymeric matrix components, stearic acid as porogen, and poly(ethylene glycol) 4000 as dispersant. Scanning electron microscopy examination of the composite beads showed macropores on the surface of spherical beads. The diameters of the composite beads and the macropores were in the ranges ~ 400–450 and 4–20 μm, respectively. The average content of Fe3O4 inside the composite beads was 3.78%, and Fe3O4 was unevenly distributed. The mechanism of macropore formation and the concept of “intellectual cavity” of molecularly imprinted composite beads were proposed. The recognition selectivity of the composite beads was investigated using tyrosine and phenylalanine as both templates and comparative molecules. Tyrosine‐imprinted composite beads exhibited a good recognition selectivity for tyrosine, and the separation factor was up to 3.67. In contrast, phenylalanine‐imprinted composite beads had little recognition selectivity for phenylalanine and the separation factor was only 1.12. It was confirmed that the three‐site interaction between tyrosine and functional monomers was stronger than the two‐site interaction between phenylalanine and functional monomers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3790–3796, 2003  相似文献   

9.
A novel method for combinatorial synthesis and screening of uniform‐size molecularly imprinted microspheres using a microfluidic device is presented, in which a new microfluidic device containing twelve pairs of “” shape microchannels is designed to produce droplets and imprinted microspheres via controlled suspension polymerization. This technique combines molecular imprinting and microfluidic device with the combinatorial chemical approach, allowing rapid screening and optimization of uniform imprinted microspheres. On the example of chloramphenicol (CAP), the imprinted microspheres of CAP were prepared by a combinatorial approach using water with 1.5% polyvinyl alcohol as continuous phase, and ethyl acetate–chloroform (4:1, v/v) as porogenic solvents. Functional monomers methacrylic acid (MAA), 4‐vinylpyridine or acrylamide were screened, and the molar ratio of template molecule to functional monomer was optimized. The results indicate that MAA is the best functional monomer for imprinting of CAP, and when the molar ratio of CAP to MAA is 1:5, the imprinted microspheres exhibit the best imprinting performance, and have good monodispersity and selectivity. This combinatorial protocol is well suited for fast and efficient screening and optimization of synthesis for uniform imprinted microspheres because 12 kinds of imprinting conditions can be performed simultaneously in this microfluidic device. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers  相似文献   

10.
A series of xerogels based on sodium acrylate (SA), cationic comonomer trimethyl methacrylamidopropyl ammonium iodide (TMMAAI), and N,N‐methylene‐bis‐acrylamide (NMBA) were prepared by inverse suspension polymerization. The water absorbency and the swelling behavior for these highly absorbent polymers in deionized water and various saline solutions were investigated. Results indicated that the water absorbency increased when a small amount of TMMAAI monomer was introduced into the SA gel. The water absorbency decreased with increase in TMMAAI content, but the contrary result was observed for initial absorption rate. Moreover, with more crosslinking agent, the water absorbency was lower. Finally, the adsorption of copper ion by these gels was also investigated. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1749–1759, 2000  相似文献   

11.
Three molecularly imprinted polymers P(2‐AQ), P(3‐AQ), and P(8‐AQ) based on methacrylic acid (MAA)–ethylene glycol dimethacrylate were prepared using isomers 2‐aminoquinoline (2‐AQ), 3‐aminoquinoline (3‐AQ), and 8‐aminoquinoline (8‐AQ) as template, respectively, by non‐covalent bulk polymerization technique. Neither P(3‐AQ) nor P(8‐AQ) exhibited imprinting effect for 3‐AQ or 8‐AQ, whereas P(2‐AQ) showed significant imprinting effect for 2‐AQ. This indicates that the position of amino group on the quinoline ring has crucial influence on imprinting effect. The recognition mechanism of P(2‐AQ) was investigated extensively by such methods as selective experiments, comparative study with 2‐aminopyridine‐imprinted polymer, and effect of different kinds of mobile phases. It is confirmed that there are complementary cavities in P(2‐AQ) both in size and in the arrangement of functional groups to 2‐AQ, and MAA binds 2‐AQ via cyclic hydrogen bond. Furthermore, the influence of synthetic conditions on 2‐AQ‐imprinted polymers was explored. We found 2‐AQ‐imprinted polymer synthesized in acetonitrile porogen showed higher imprinting effect for 2‐AQ than that prepared in chloroform. It is deduced that the morphology of the former might be more favorable to 2‐AQ binding, which is also supported indirectly by the fluorimetric experiments estimating the interaction of 2‐AQ with MAA in these two porogens. Additionally, 2‐AQ‐imprinted polymers prepared using two different amounts of acetonitrile exhibited very different imprinting effects, which suggested that porogen amount used in the imprinting process exerted significant influence. In addition to the in‐depth elucidation of the recognition mechanism of 2‐AQ‐imprinted polymer, this article provides the basis for the separation and enrichment of bioactive 2‐AQ. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

12.
Molecularly imprinted polymer nanoparticles were prepared in supercritical carbon dioxide using a noncovalent imprinting approach. In the present work, propranolol was used as a model template, methacrylic acid as a functional monomer, and divinylbenzene as a crosslinker. Under a high dilution condition, the heterogeneous polymerization resulted in discrete crosslinked polymer nanoparticles. Compared with the nonimprinted polymers, the imprinted nanoparticles displayed much higher propranolol uptake in a low polarity organic solvent. The use of a single enantiomer (S)‐propranolol as the template clearly demonstrated that the imprinted binding sites are chiral‐selective, with a cross‐reactivity towards (R)‐propranolol of less than 5%. The overall binding performance of the imprinted nanoparticles was comparable to imprinted polymers prepared in conventional organic solvents. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2863–2867, 2006  相似文献   

13.
In this work, molecular crowding agent was first applied to the preparation of molecularly imprinted polymer (MIP)‐based drug release system. With S‐naproxen as template, the MIPs were prepared with methacrylic acid and ethylene glycol dimethacrylate, in the presence of polystyrene as molecular crowding by precipitation polymerization. Morphology and particle size of the resulting MIP sub‐micrometer microparticles were determined by scanning electron microcopy and dynamic light scattering. The influence of several parameters on the sustained release of the imprinted polymers was investigated, including the molar ratio of the imprint molecule to the functional monomers, the molar ratio of the functional monomers to the crosslinking monomers, and the type of the porogen. In addition, the release of the MIP was compared to that of the traditionally prepared imprinted polymers with other porogens. The transport mechanism of template was studied by fitting experiment data with different model equations and calculating the corresponding parameters. The novel MIPs prepared with molecular crowding were able to prolong S‐naproxen, in a phosphate buffers solution of pH 7.4, for more than 12 h, indicating better sustained release effect than that prepared with noncrowding agent. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers  相似文献   

14.
Porous polymethacrylic acid‐co‐triethylene glycol dimethacrylate (MAA‐co‐3G) and polyacrylic acid‐co‐triethylene glycol dimethacrylate (AA‐co‐3G) were prepared by four different polymerization techniques, namely, suspension, dispersion, seed, and microemulsion polymerization using an inert diluent (n‐hexane and polystyrene). The morphology and porosity of the obtained polymers were examined by means of a scanning electron microscope. The surface areas of the obtained polymers were determined colorimetrically. The copolymers were modified by hydroximation and chlorination using hydroxyl amine and thionyl chloride, respectively. The effect of polymerization type, surface area, modification, and pH on the protease enzyme immobilization over poly(MAA‐co‐3G) and poly(AA‐co‐3G) was examined. The enzyme activity was measured by means of a spectrophotometer. The reactivity ratios of the two monomers MAA and 3G were determined by means of the elemental analysis method. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 594–601, 2000  相似文献   

15.
Fluorinated and chlorofluorinated polyimides with high thermal stability and low optical absorption loss in the optical communication wavelengths of 1.3 and 1.55 μm were investigated for low‐loss passive waveguide applications. These polyimides were prepared from pyromellitic dianhydride (PMDA) with 1,4‐bis‐[4‐amino‐2‐(trifluoromethyl)phenoxy]tetrafluorobenzene (ATPT), 1,4‐bis‐[4‐amino‐2‐(trifluoromethyl)phenoxy]benzene (ATPB), and 1,3‐bis‐[4‐amino‐2‐(trifluoromethyl)phenoxy]‐4,6‐dichlorobenzene (ATPD). Control of the refractive indices of the polymers was achieved from 1.5397–1.5671 for TE polarization and 1.5239–1.5513 for TM polarization at 1.55 μm by copolymerization of PMDA/ATPT and PMDA/ATPB. As the amount of PMDA/ATPT was increased, the refractive indices of the polymers were decreased. Rib‐type optical waveguides were fabricated using these fluorinated polyimides. These waveguides exhibited a low propagation loss of less than 0.5 dB/cm at 1.55 μm. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2172–2177, 2000  相似文献   

16.
Two molecularly imprinted polymers (MIPs) – poly(methacrylic acid‐co‐TRIM) (TRIM, trimethylolpropanetrimethacrylate) and poly(acylamide‐co‐TRIM) – were synthesized in different solvents for the selective recovery of isovaleric acid (template) generated during the anaerobic digestion process. The chemical and structural characterizations of the synthetic adsorbent were carried out by Fourier transform infrared spectroscopy, TGA and porosimetry through N2 adsorption–desorption isotherms. The selective and adsorptive performances of the imprinted polymers were evaluated by kinetic, isothermal, thermodynamic and selectivity studies and by adsorbent reuse experiments. The poly(methacrylic acid‐co‐TRIM) synthesized with dimethyl sulfoxide:chloroform presented higher selectivity and adsorption capacity for isovaleric acid in the presence of six volatile fatty acids. The kinetic results were well adjusted to the pseudo‐nth order and intraparticle diffusion models, leading to k values of 10?4 and 6 × 10?5 for the best synthesis of MIPs and not‐imprinted polymers, respectively. Moreover, the Sips model best described the adsorption isotherm and generated a maximum adsorption capacity of ca 209 mg g?1 (at 25 °C). Cycles of MIP use–desorption–reuse indicated that the selective adsorbent performed better than commercial adsorbents, losing less than 3% of adsorption capacity after three cycles. © 2018 Society of Chemical Industry  相似文献   

17.
2‐Hydroxymethyl‐but‐1‐ene‐3‐one [α‐hydroxymethyl methyl vinyl ketone (HMVK)] was synthesized from methyl vinyl ketone using paraformaldehyde and a tertiary amine catalyst. Free‐radical polymerization of this monomer created transparent, tough polymers that were insoluble in organic solvents. HMVK was converted to trimethylsilyl, acetate, and chloride derivatives. When the hydroxyl group was thus protected or removed, all these monomers could be free radically polymerized in bulk to make soluble polymers. The chlorination reaction is complicated by the formation of 1,1‐bischloromethylacetone, which dehydrohalogenated unexpectedly to the desired α‐chloromethyl methyl vinyl ketone. HMVK will self‐condense to an ether dimer in the presence of a catalytic acid. This reagent is capable of crosslinking many alkene monomers through hydrolytically stable ether bonds. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 509–516, 2000  相似文献   

18.
Macroporous beads, poly(ethylene glycol dimethacrylate‐co‐acrylic acid) [poly(EGDMA‐co‐AAc)], and poly(ethylene glycol dimethacrylate‐co‐hydroxyethyl methacrylate) [poly(EGDMA‐co‐HEMA)] were prepared by the suspension polymerization technique in the presence of a porogen agent. Different experimental conditions such as amount of initiator, porogen type, and temperature were studied to optimize the polymerization systems. These hydrophilic copolymers were characterized by IR spectroscopy, scanning electron microscopy, specific surface area, and swelling in water. A new parameter, H, defined as the ratio between the equilibrium weight swelling ratio (qw) and equilibrium volume swelling ratio (qv), allowed to select the reaction conditions from which matrices with high capacity of water sorption and low stretching degree were reached. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 920–927, 2001  相似文献   

19.
BACKGROUND: There are few reports on erythromycin molecularly imprinted polymers (MIPs) used as HPLC stationary phase and solid phase extraction matrices. These imprinted polymers are prepared by bulk polymerization, which is tedious and time‐consuming, and they are irregular and possess poor reproducibility and low binding capacity. In this study, molecularly imprinted microspheres for erythromycin were prepared by aqueous suspension polymerization for the first time. RESULTS: Imprinted microspheres for erythromycin were prepared using suspension polymerization in which 1.5% PVA‐water solution is used as continuous phase, and chloroform solution containing erythromycin, methacrylic acid and crosslinker is used as disperse phase. The composition of disperse phase is optimized, and the optimum molar ratio of erythromycin to methacrylic acid was 1:5. Selectivity analysis revealed that the imprinted microspheres can specifically recognize erythromycin from its structure analogues. The binding mechanism between erythromycin and methacrylic acid was investigated by UV‐Vis spectrophotometry. Adsorption kinetics and the adsorption isotherm of the imprinted microspheres indicate that erythromycin can be adsorbed rapidly by the imprinted microspheres and the maximum theoretical static binding capacity is 128.6110 mg g?1. The imprinted microspheres were used to extract erythromycin from a milk sample and a high recovery rate was obtained. CONCLUSION: Molecularly imprinted microspheres for erythromycin were uniform and possess high adsorption capacity and excellent selectivity. They are therefore a promising extraction and chromatographic media. Copyright © 2011 Society of Chemical Industry  相似文献   

20.
In this study, we examined the rational preparation of molecularly imprinted polymers (MIPs) for the selective removal of quinoline from octane. Before the preparation, density functional theory, as one of the methods of quantum chemical calculation, was used for the simulation of a quinoline‐imprinted preassembly system. Methacrylic acid turned out to be the more suitable monomer for quinoline compared with acrylamide, and different template–monomer ratios, including 1:1, 1:2, and 1:3, were studied and are discussed. On the basis of the result of molecular simulation, quinoline‐imprinted polymers were prepared with a combination of surface imprinting and living polymerization. The prepared quinoline–MIPs were characterized and used as selective adsorbents for batch‐mode binding experiments. The fitting result of the adsorption data indicates that the adsorption kinetics and adsorption isotherms of the quinoline‐imprinted polymers fit well a pseudo‐second‐order kinetics model and the Freundlich model, respectively. A selective recognition ability was demonstrated by equilibrium binding analysis. This study will provide needful guidance and a theoretical basis for the preparation of imprinted materials in the field of industrial denitrification. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41730.  相似文献   

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