首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 421 毫秒
1.
Synthesis and properties of the new aromatic tetrafunctional methacrylate monomer 1,3‐di(2‐hydroxy‐3‐methacryloyloxypropoxy)benzene are presented. This monomer was applied for the synthesis of porous microspheres. It was copolymerized with trimethylolpropane trimethacrylate in the presence of pore‐forming diluents, decan‐1‐ol and chlorobenzene. Influence of diluents composition on their porous structures was studied. Thermal resistance and tendency to swell in different organic diluents for a chosen sample were also determined. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3190–3201, 2009  相似文献   

2.
Fully crosslinked, stable poly(styrene‐co‐divinylbenzene) microspheres, which are composed of various concentrations of divilylbenzene from 5 to 75 mol % based on styrene monomer, were prepared without a significant particle coagulation by the precipitation polymerization. The number‐average particle diameter ranged from 3.5 to 2.8 μm and decreased with an increasing concentration of divinylbenzene in monomer. In addition, the coefficient of variation of the microspheres was slightly reduced with the increasing concentration of divinylbenzene. The circularity and the measured specific surface area indicated that lesser particles are coagulated because of the improved stability of individual particles at a high divinylbenzene concentration and that the resulting particles have a smooth surface without micropores. The glass‐transition temperature was not observed for all microspheres formed from the range of divinylbenzene concentrations. In addition, the onset of the thermal‐degradation temperature was increased from 339.8 to 376.9 °C upon higher contents of divinylbenzene. On the basis of the DSC and thermogravimetric data, the polymer microspheres prepared by the precipitation polymerization possessed a fully crosslinked structure and highly enhanced thermal stability. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 835–845, 2004  相似文献   

3.
A “continuous” emulsifier‐free emulsion copolymerization (CEFEP) of styrene and divinylbenzene (DVB) or methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDMA) has been devised to produce uniform polymeric microspheres of narrow size distribution from 74 nm to 2 μm, depending on reaction time. Monomer and crosslinker vapors were fed continuously into a small reactor. We suggest that after initial nucleation, subsequent CEFEP proceeds near the surfaces of growing particles in a monomer‐swollen outer shell. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3181–3187, 2000  相似文献   

4.
The facile and efficient one‐pot synthesis of monodisperse, highly crosslinked, and “living” functional copolymer microspheres by the ambient temperature iniferter‐induced “living” radical precipitation polymerization (ILRPP) is described for the first time. The simple introduction of iniferter‐induced “living” radical polymerization (ILRP) mechanism into precipitation polymerization system, together with the use of ethanol solvent, allows the direct generation of such uniform functional copolymer microspheres. The polymerization parameters (including monomer loading, iniferter concentration, molar ratio of crosslinker to monovinyl comonomer, and polymerization time and scale) showed much influence on the morphologies of the resulting copolymer microspheres, thus permitting the convenient tailoring of the particle sizes by easily tuning the reaction conditions. In particular, monodisperse poly(4‐vinylpyridine‐co‐ethylene glycol dimethacrylate) microspheres were prepared by the ambient temperature ILRPP even at a high monomer loading of 18 vol %. The general applicability of the ambient temperature ILRPP was confirmed by the preparation of uniform copolymer microspheres with incorporated glycidyl methacrylate. Moreover, the “livingness” of the resulting polymer microspheres was verified by their direct grafting of hydrophilic polymer brushes via surface‐initiated ILRP. Furthermore, a “grafting from” particle growth mechanism was proposed for ILRPP, which is considerably different from the “grafting to” particle growth mechanism in the traditional precipitation polymerization. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013  相似文献   

5.
A novel microphase‐inversion method was proposed for the preparation of TiO2–SiO2/poly(methyl methacrylate) core–shell nanocomposite particles. The inorganic–polymer nanocomposites were first synthesized via a free‐radical copolymerization in a tetrahydrofuran solution, and the poor solvent was added slowly to induce the microphase separation of the nanocomposite and result in the formation of nanoparticles. The average particle sizes of the microspheres ranged from 70 to 1000 nm, depending on the reaction conditions. Transmission electron microscopy and scanning electron microscopy indicated a core–shell morphology for the obtained microspheres. Thermogravimetric analysis and X‐ray photoelectron spectroscopy measurements confirmed that the surface of the nanocomposite microspheres was polymer‐rich, and this was consistent with the core–shell morphology. The influence of the synthetic conditions, such as the inorganic composition and the content of the crosslinking monomer, on the particle properties was studied in detail. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3911–3920, 2006  相似文献   

6.
Amphiphilic polymer conetworks consisting of hydrophilic poly[2‐(dimethylamino)ethyl methacrylate], poly(N‐isopropylacrylamide), or poly(N,N‐dimethylacrylamide) and hydrophobic polyisobutylene chains were synthesized with a novel two‐step procedure. In the first step, a methacrylate‐multifunctional polyisobutylene crosslinker was prepared by the cationic copolymerization of isobutylene with 3‐isopropenyl‐α,α‐dimethylbenzyl isocyanate. In the second step, the methacrylate‐multifunctional polyisobutylene crosslinker, with a number‐average molecular weight of 8200 and an average functionality of approximately 4 per chain, was copolymerized radically with 2‐(dimethylamino)ethyl methacrylate, N‐isopropylacrylamide, or N,N‐dimethylacrylamide into transparent amphiphilic conetworks containing 42–47 mol % hydrophilic monomer. The synthesized conetworks were characterized with solid‐state 13C NMR spectroscopy and differential scanning calorimetry. The amphiphilic nature of the conetworks was proved by swelling in both water and n‐heptane. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6378–6384, 2006  相似文献   

7.
We herein report a facile method to prepare the submicron‐sized raspberry‐like polystyrene/polyacrylonitrile particles with anisotropic properties and controllable structure via γ‐radiation‐induced seeded emulsion polymerization under ambient pressure and at room temperature, in which the monodisperse crosslinked styrene‐divinylbenzene‐acrylic acid terpolymer (P(S‐DVB‐AA)) particles were used as seed particles and acrylonitrile (AN) as the second monomer. The influence of the weight ratio of polymer/monomer, the absorbed dose rate, the absorbed dose, and the dispersion medium on the morphology of the as‐prepared particles was investigated. The final products were thoroughly characterized by Fourier transform infrared spectroscopy (FTIR), field‐emission scanning electron microscopy, and transmission electron microscopy. The results showed that the raspberry‐like particles could be fabricated in high yield. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010  相似文献   

8.
Synthesis and properties of the new difunctional methacrylate monomer 2‐hydroxy‐3‐methacryloyloxypropoxybenzene are presented. This monomer was applied for the synthesis of porous microspheres. It was copolymerized with trimethylolpropane trimethacrylate in the presence of two pairs of pore‐forming diluents dodecane and toluene, and n‐decanol and toluene. Influence of diluents composition on their porous structures was studied. Thermal resistance and tendency to swell in different organic diluents for a chosen sample were also determined. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6165–6174, 2008  相似文献   

9.
The formation of monodisperse, crosslinked, thermally inscribed core‐shell microspheres by free radical precipitation copolymerization of chloromethylstyrene and divinylbenzene in acetonitrile is reported. The radial density profiles of these microspheres match the thermal profiles used during copolymerization: stepping down the polymerization temperature from 75 °C to 65 °C several hours into the copolymerization led to core‐shell microspheres with porous cores and denser shells, while stepping up the polymerization temperature from 68 °C to 78 °C during the polymerization led to formation of microspheres with denser cores and more swellable shells. Microsphere size distributions and internal morphologies were studied using optical and transmission electron microscopy. The change in network swellability with temperature was compared with model studies of aggregation of corresponding nanogels, both in acetonitrile and in related solvent systems, as a function of temperature, indicating the theta‐temperature for this copolymer/solvent system to be around 30 °C. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1159–1166  相似文献   

10.
A novel high oil‐absorbing crosslinked gel was synthesized by copolymerization of butyl methacrylate (BMA) with a small amount of pentaerythritol triacrylate (PETA) crosslinker using single electron transfer‐living radical polymerization (SET–LRP) initiated with carbon tetrachloride (CCl4) and catalyzed by Cu(0)/hexamethylenetetramine (HMTA) in N, N‐dimethylformamide (DMF). The polymerization followed first‐order kinetics as indicated by linear increase of monomer concentration with reaction time. Effects of reaction temperature, crosslinker, initiator, and catalyst on the oil‐absorbing properties of the crosslinked gel were investigated in detail. The oil absorptions of the crosslinked gel to chloroform, toluene could reach 51.9, 34.5 g/g, respectively. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012  相似文献   

11.
Polystyrene template microspheres of narrow size distribution were prepared by dispersion polymerization of styrene in a mixture of ethanol and 2‐methoxy ethanol. Spherical and hemispherical polystyrene/poly(glycidyl methacrylate) microspheres of narrow size distribution were prepared by a single‐step swelling of the polystyrene template microspheres with the swelling solvent monomer glycidyl methacylate, followed by polymerization of the monomer within the swollen template microspheres at 73 °C. Uniform polystyrene/poly(glycidyl methacylate‐ethylene glycol dimethacrylate) polyepoxide composite microspheres were synthesized similarly, substituting glycidyl methacylate for glycidyl methacylate and ethylene glycol dimethacrylate. Uniform crosslinked poly(glycidyl methacylate‐ethylene glycol dimethacrylate) polyepoxide microspheres have been prepared by dissolution of the PS template polymer of the former composite microspheres. Particles with different properties, for example size, size distribution, shape, surface morphology, surface area, and so forth, were prepared by changing various parameters belonging to the swelling and/or polymerization steps, for example, volume of the swelling monomer/s and/or the swelling solvent dibutyl phthalate. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4612–4622, 2007  相似文献   

12.
A variety of polymer microspheres were successfully synthesized by the surface‐initiated atom transfer radical polymerization (SI‐ATRP) of monomers by using monodisperse polymer microsphere having benzyl halide moiety as a multifunctional polymeric initiator. First, a series of monodisperse polymer microsphere having benzyl chloride with variable monomer ratio (P(St‐DVB‐VBC)) were synthesized by the precipitation polymerization of styrene (St), divinylbenzene (DVB), and 4‐vinylbenzyl chloride (VBC). Next, hairy polymer microspheres were synthesized by the surface‐initiated ATRP of various monomers with P(St‐DVB‐VBC) microsphere as a multifunctional polymeric initiator. The hair length determined by the SEC analysis of free polymer was increased with the increase of M/I. These hairy polymer microspheres were characterized by SEM, FT‐IR, and Cl content measurements. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1296–1304  相似文献   

13.
Novel and well‐defined dendrimer‐star, block‐comb polymers were successfully achieved by the combination of living ring‐opening polymerization and atom transfer radical polymerization on the basis of a dendrimer polyester. Star‐shaped dendrimer poly(?‐caprolactone)s were synthesized by the bulk polymerization of ?‐caprolactone with a dendrimer initiator and tin 2‐ethylhexanoate as a catalyst. The molecular weights of the dendrimer poly(?‐caprolactone)s increased linearly with an increase in the monomer. The dendrimer poly(?‐caprolactone)s were converted into macroinitiators via esterification with 2‐bromopropionyl bromide. The star‐block copolymer dendrimer poly(?‐caprolactone)‐block‐poly(2‐hydroxyethyl methacrylate) was obtained by the atom transfer radical polymerization of 2‐hydroxyethyl methacrylate. The molecular weights of these copolymers were adjusted by the variation of the monomer conversion. Then, dendrimer‐star, block‐comb copolymers were prepared with poly(L ‐lactide) blocks grafted from poly(2‐hydroxyethyl methacrylate) blocks by the ring‐opening polymerization of L ‐lactide. The unique and well‐defined structure of these copolymers presented thermal properties that were different from those of linear poly(?‐caprolactone). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6575–6586, 2006  相似文献   

14.
Polystyrene template microspheres of 1.4 ± 0.1 μm were prepared by dispersion polymerization of styrene in a mixture of ethanol and 2‐methoxy ethanol. These template particles were then swelled at room temperature in a single step with emulsion that was prepared in sodium dodecyl sulfate aqueous solution from a swelling solvent (dibutyl phthalate) containing the initiator (benzoyl peroxide) and monomer(s) (chlormethylstyrene, divinylbenzene, or ethylene dimethacrylate). Composite uniform particles composed of the template polystyrene and noncrosslinked or crosslinked polychloromethylstyrene were prepared by polymerizing the monomer(s) within the swelled particles at 73 °C. Crosslinked uniform polychloromethylstyrene particles of higher surface area were formed by dissolving the template polystyrene polymer of the composite particles. The influence of various reaction parameters, such as dibuthyl phthalate concentration, chloromethylstyrene concentration, crosslinker type and concentration, and so forth on the molecular weight, size, size distribution, shape, morphology, surface area, and decomposition temperature of the particles was investigated. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1342–1352, 2002  相似文献   

15.
Highly crosslinked copolymers of 1‐vinyl‐2‐pyrrolidone (VP) were obtained in the form of microspheres by combined suspension–emulsion polymerization. The porous structure of the copolymers was created by the use of proper diluents. The main parameters of porous structure were established in the dry and wet states. Three methods: inverse size‐exclusion chromatography (ISEC), nitrogen adsorption, and small X‐ray scattering (SAXS) were used in porous structure investigations. It was shown that the determined parameters strongly depend on the chosen method and the microspheres can be used as packing materials in chromatography. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

16.
Statistical copolymers of 2‐hydroxyethyl methacrylate (HEMA) and 2‐diethylaminoethyl methacrylate (DEA) were synthesized at 50 °C by free‐radical copolymerization in bulk and in a 3 mol L?1 N,N′‐dimethylformamide solution with 2,2′‐azobisisobutyronitrile as an initiator. The solvent effect on the apparent monomer reactivity ratios was attributed to the different aggregation states of HEMA monomer in the different solvents. The copolymers obtained were water‐insoluble at a neutral pH but soluble in an acidic medium when the molar fraction of the DEA content was higher than 0.5. The quaternization of DEA residues increased the hydrophilic character of the copolymers, and they became water‐soluble at a neutral pH when the HEMA content was lower than 0.25. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2427–2434, 2002  相似文献   

17.
We report on the synthesis of snowman‐like magnetic/nonmagnetic nanocomposite asymmetric particles (SMNAPs) via seeded emulsion polymerization initiated by γ‐ray radiation. In situ formation of magnetite in the presence of the emulsified poly(styrene‐divinylbenzene‐acrylic acid) microspheres affords raspberry‐like magnetic nanocomposite particles, which are used as seeds for further seeded emulsion polymerization induced by γ‐ray radiation. We study the effect of the kind of surfactant, the kind and content of second monomer, and the content of swelling agent on the morphologies of the final nanocomposite particles. It is found that SMNAPs can be fabricated in high yield using 12‐acryloxy‐9‐octadecenoic acid as the surfactant and styrene as the second monomer with the addition of 2‐butanone (a swelling agent). The as‐synthesized SMNAPs may serve as magnetically controllable solid surfactants to stabilize O/W immiscible mixtures, which preferentially orientated at the interface. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012  相似文献   

18.
2,2′‐Azobis[N‐(2‐propenyl)‐2‐methylpropionamide] (APMPA) with two carbon–carbon double bonds and an azo group was copolymerized with vinyl benzoate (VBz) at 60 °C, resulting in azo groups containing VBz/APMPA prepolymers and crosslinked polymers as soluble and insoluble polymeric azo initiators, respectively. The polymerization characteristics of APMPA as a novel diallyl monomer were clarified with the rate and degree of polymerization and the monomer reactivity ratios. The gelation behaviors in VBz/APMPA crosslinking copolymerizations were examined in detail with a comparison of the actual gel point and the theoretical gel point calculated according to Stockmayer's equation with the tentative assumption of equal reactivity for both vinyl groups belonging to VBz and APMPA. The effectiveness of the resulting branched or crosslinked poly(VBz‐co‐APMPA)s as soluble or insoluble polymeric azo initiators, respectively, at providing graft polymers through the cleavage of azo groups at an elevated temperature was examined by the polymerization of allyl benzoate at 120 °C. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 317–325, 2002  相似文献   

19.
4‐Chloro‐3‐methyl phenyl methacrylate (CMPM) and 8‐quinolinyl methacrylate (8‐QMA) were synthesized through the reaction of 4‐chloro‐3‐methyl phenol and 8‐hydroxy quinoline, respectively, with methacryloyl chloride. The homopolymers and copolymers were prepared by free‐radical polymerization with azobisisobutyronitrile as the initiator at 70 °C. Copolymers of CMPM and 8‐QMA of different compositions were prepared. The monomers were characterized with IR spectroscopy and 1H NMR techniques. The copolymers were characterized with IR spectroscopy. UV spectroscopy was used to obtain the compositions of the copolymers. The monomer reactivity ratios were calculated with the Fineman–Ross method. The molecular weights and polydispersity values of the copolymers were determined with gel permeation chromatography. The thermal stability of the polymers was evaluated with thermogravimetric analysis under a nitrogen atmosphere. The homopolymers and copolymers were tested for their antimicrobial activity againstbacteria, fungi, and yeast. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 157–167, 2005  相似文献   

20.
《先进技术聚合物》2018,29(7):2042-2049
Highly cross‐linked porous copolymers of 1‐vinyl‐2‐pyrrolidone with divinylbenzene were obtained in the form of microspheres by the free‐radical cross‐linking copolymerization. The porous structure of the copolymers was created by the use of adequate diluents and stabilizers. The main parameters of the porous structure were determined by nitrogen adsorption/desorption method and positronium annihilation lifetime spectroscopy. It was shown that the determined parameters strongly depend on the chosen approach.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号