pCEC coupling with ESI‐MS for the analysis of β2‐agonists and narcotics using a poly‐(1‐hexadecene‐co‐TMPTMA) monolithic column

A pressure‐assisted CEC with ESI‐MS based on poly(1‐hexadecene‐co‐trimethylolpropane trimethacrylate) monolithic column for rapid analysis of two β₂‐agonists and three narcotics was established in this article. After the organic polymer‐based monolithic column was prepared by an in‐situ polymerization procedure, a systematic investigation of the pressure‐assisted CEC separation and ESI‐MS detection parameters was performed. Baseline separation of the studied analytes could be obtained using the solution containing 75% ACN v/v and 20 mmol/L ammonium acetate with pH 8.0 as running buffer, when applying separation voltage of 20 kV and assisted pressure of 5 bar. Under the optimized conditions, two β₂‐agonists and three narcotics could be completely resolved and accurately determined within 15 min. Finally, the proposed method was successfully used for real urine samples detection.     

Preparation and spectroscopic characterization of surface‐enriched (with active sites) polymer‐supported phase‐transfer catalysts and their efficiency in organic addition reactions: A kinetic study

We prepared two batches of surface‐enriched (with active sites) polymer‐supported phase‐transfer catalysts (SE‐PSPTC) by fixing the crosslinking monomer divinylbenzene (DVB) at 2% (first batch) and 6% (second batch) through a free‐radical suspension copolymerization method with vinylbenzyl chloride (VBC; 25%) as a functionality and with styrene (St) as a supporting monomer, followed by the quaternization of the resulting terpolymer beads with triethylamine. The enrichment of the active sites on the surfaces of the beads was accomplished by a surface‐grafting technique through the delayed addition of the functional monomer (VBC) to the partially polymerized copolymer beads of poly(St/DVB). To bring the active sites fully onto the surfaces, we prepared six different types of terpolymer beads in each batch by varying the partial polymerization time (PPT) of St/DVB—0 h [0 VBC (conventional)], 3 h (3 VBC), 6 h (6 VBC), 9 h (9 VBC), 12 h (12 VBC), and 15 h (15 VBC)—and then gradually adding the functional monomer (VBC) to the partially polymerized poly(St/DVB) system. The resulting terpolymer beads, containing different concentrations of pendant benzyl chloride (? CH₂Cl) on the surface in each batch, underwent facile quaternization [? CH₂N⁺(C₂H₅)₃Cl^?] with an increase in the PPT of St/DVB and remained constant at 12 VBC and 15 VBC. To asses the superiority of the catalysts according to the surface enrichment of the active sites, particularly between conventional (0 VBC) catalysts and other PPT‐based SE‐PSPTCs, we characterized all the catalysts by estimating the chloride‐ion concentration, by using Fourier transform infrared (FTIR), scanning electron microscopy (SEM), EDAX, and ESCA, and by carrying out the dichlorocarbene addition to olefins. The chloride‐ion concentration by the Volhard method and the peak intensity of the C? N stretching absorbance concentration, that is, the quaternary onium group in the FTIR spectra of both batches, increased with the PPT of St/DVB in both batches of catalysts. In particular, the chloride concentration of a first‐batch catalyst of a representative mesh size (?120 + 140) had a twofold enhancement between the conventional catalyst (0 VBC; 1.88 m equiv g^?1) and 9 VBC/SE‐PSPTC (3.74 m equiv g^?1), although the same amount of the functional monomer was added in both preparations. These results showed the higher enrichment of the active site on the surface of 9 VBC, and the same trend was also maintained for second‐batch catalysts, regardless of the catalyst mesh size. SEM images of both batches showed that there was a higher concentration of nodules [due to the grafting of poly(VBC)] on the surfaces of the beads of 9 VBC/SE‐PSPTC and the aforementioned PPT catalysts than on the surfaces of the conventional catalysts (0 VBCs), which exhibited smooth surfaces (because of the simultaneous addition of all three monomers). This observation confirmed the enrichment of active sites on the surfaces. In the EDAX analysis, up to a depth of 0.5–1 μm, the surface chloride concentration increased from 0 VBC to 9 VBC/SE‐PSPTC and remained constant in 12 VBC and 15 VBC, first‐batch catalysts of a representative mesh size (?120 + 140). The same trend was also observed in second‐batch catalysts, indicating the enrichment of the onium group more on the surface in 9 VBC/SE‐PSPTCs. The ESCA analysis, to a depth of about 20–30Å, proved that the concentration of covalent chloride on the surface had increased from 0 VBC (15%) to 9 VBC/SE‐PSPTCs (29%) and remained constant thereafter in first‐batch catalyst; the trend was the same for second‐batch catalysts, also confirming the strong evidence of surface enrichment of the active sites. Similarly, the rate constants of different olefin addition reactions catalyzed by both batches of catalysts also increased from 0 VBC to 9 VBC and remained constant with 12 VBC and 15 VBC catalysts. The twofold increase of the rate constants, regardless of the olefins, for conventional catalysts to 9 VBC/SE‐PSPTCs confirmed the enrichment of the active sites on the surfaces. All these experimental observations proved that 50% of the active sites were successfully brought out from inside the poly(St/DVB) networks to the exterior surfaces, although same amount of VBC was added for the preparation of all the catalyst types. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 347–364, 2003     

Syntheses,antitumor activities,and antiangiogenesis of exo‐3,6‐epoxy‐1,2,3,6‐tetrahydrophthalimidoethanoyl‐ 5‐fluorouracil and its polymers

A new monomer, exo‐3,6‐epoxy‐1,2,3,6‐tetrahydrophthalimidoethanoyl‐5‐fluorouracil (ETFU), was synthesized by the reaction of exo‐3,6‐epoxy‐1,2,3,6‐tetrahydrophthalimidoethanoyl chloride (ETPC) and 5‐fluorouracil (5‐FU). The homopolymer of ETFU and its copolymers with acrylic acid (AA) and vinyl acetate (VAc) were prepared via photopolymerizations with 2,2‐dimethoxy‐2‐phenylacetophenone at 25 °C for 48 h. The structures of the synthesized monomer and polymers were identified by Fourier transform infrared, ¹H NMR, and ¹³C NMR spectroscopy and elemental analysis. The ETFU contents in poly(ETFU‐co‐AA) and poly(ETFU‐co‐VAc) were 26 mol % and 26 mol %, respectively. The number‐average molecular weights of the polymers, as determined by gel permeation chromatography, ranged from 5600 to 17,000. The in vitro cytotoxicities of 5‐FU and the synthesized samples against mouse mammary carcinoma and human histiocytic lymphoma cancer cell lines increased in the following order: ETFU > 5‐FU > poly(ETFU‐co‐AA) > poly(ETFU) > poly(ETFU‐co‐VAc). The in vivo antitumor activities of the polymers against Balb/C mice bearing the sarcoma 180 tumor cells were greater than those of 5‐FU at all doses tested. The inhibitions of the samples for SV40 DNA replication and antiangiogenesis were much greater than the inhibition of the control. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4272–4281, 2000     

Sulfoalkylbetaine‐based monolithic column with mixed‐mode of hydrophilic interaction and strong anion‐exchange stationary phase for capillary electrochromatography

A novel monolithic stationary phase with mixed mode of hydrophilic and strong anion exchange (SAX) interactions based on in situ copolymerization of pentaerythritol triacrylate (PETA), N,N‐dimethyl‐N‐methacryloxyethyl N‐(3‐sulfopropyl) ammonium betaine (DMMSA) and a selected quaternary amine acrylic monomer was designed as a multifunctional separation column for CEC. Although the zwitterionic functionalities of DMMSA and hydroxy groups of PETA on the surface of the monolithic stationary phase functioned as the hydrophilic interaction (HI) sites, the quaternary amine acrylic monomer was introduced to control the magnitude of the EOF and provide the SAX sites at the same time. Three different quaternary amine acrylic monomers were tested to achieve maximum EOF velocity and highest plate count. The fabrication of the zwitterionic monolith (designated as HI and SAX stationary phase) was carried out when [2‐(acryloyloxy)ethyl]trimethylammonium methylsulfate was used as the quaternary amine acrylic monomer. The separation mechanism of the monolithic column was discussed in detail. For charged analytes, a mixed mode of HI and SAX was observed by studying the influence of mobile phase pH and salt concentration on their retentions on the poly(PETA‐co‐DMMSA‐co‐[2‐(acryloyloxy)ethyl]trimethylammonium methylsulfate) monolithic column. The optimized monolith showed good separation performance for a range of polar analytes including nucleotides, nucleic acid bases and nucleosides, phenols, estrogens and small peptides. The column efficiencies greater than 192 000 theoretical plates/m for estriol and 135 000 theoretical plates/m for charged cytidine were obtained.     

Fast fabrication of a hybrid monolithic column containing cyclic and aliphatic hydrophobic ligands via photo‐initiated thiol‐ene polymerization

Three monomers, octakis (3‐mercaptopropyl) octasilsesquioxane, 1,2,4‐trivinylcyclohexane and isophytol were employed to synthesize a novel monolithic stationary phase via photo‐initiated thiol‐ene click polymerization for reversed‐phase liquid chromatography. Several factors such as porogenic system, reaction time and the molar ratio of functional groups were investigated in detail. The resulting poly(POSS‐co‐TVCH‐co‐isophytol) monolithic column exhibited suitable permeability for fast separation and outstanding thermal stability. Five alkylbenzenes were employed to evaluate the ability of chromatographic separation of the resulting monolithic columns at different flow rates, and showed the highest column efficiencies of 90,200–93,100 N/m (corresponding to 10.4–10.6 μm of plate height) at a velocity of 0.41 mm/s. The baseline separations of five anilines and eight phenols further proved the applicability of poly(POSS‐co‐TVCH‐co‐isophytol) monolithic column in the separation of small molecules.     

Magnetic solid-phase extraction using magnetic hypercrosslinked polymer for rapid determination of illegal drugs in urine

A novel magnetic material Fe₃O₄/SiO₂/P(MAA‐co‐VBC‐co‐DVB) was prepared via the hypercrosslinking of its precursor which was produced via precipitation polymerization of methacrylic acid (MAA), vinylbenzyl chloride (VBC), and divinylbenzene (DVB) in the presence of Fe₃O₄/SiO₂ submicrospheres with the surface containing abundant reactive double bonds. The resultant sorbent was characterized by scan electron microscopy, N₂ adsorption, and Fourier transform infrared spectroscopy. It was found that this material had remarkable features such as large surface area (500 m²/g) and pore volume (0.32 cm³/g), as well as desirable chemical composition (including hydrophobic and ion‐exchange moieties). Taking advantages of the Fe₃O₄/SiO₂/P(MAA‐co‐VBC‐co‐DVB), a magnetic SPE (MSPE) coupled with capillary electrophoresis (CE) method was developed for the determination of illegal drugs in urine samples. The extraction time could be clearly shortened up to 3 min. The recoveries of these drug compounds were in the range of 84.0–123% with relative standard deviations ranging between 1.7 and 10.5%; the limit of detection was in the range of 4.0–6.0 μg/L. The proposed method is simple, effective, and low‐cost, and provides an accurate and sensitive detection platform for abused drug analysis.     

Hairy polymeric nanocapsules with ph‐responsive shell and thermoresponsive brushes: Tunable permeability for controlled release of water‐soluble drugs

The hairy poly(methacrylic acid‐co‐divinylbenzene)‐g‐poly(N‐isopropylacrylamide) (P(MAA‐co‐DVB)‐g‐PNIPAm) nanocapsules with pH‐responsive P(MAA‐co‐DVB) inner shell and temperature‐responsive PNIPAm brushes were prepared by combined distillation–precipitation copolymerization and surface thiol‐ene click grafting reaction using 3‐(trimethoxysilyl)propyl methacrylate‐modified silica (SiO₂‐MPS) nanospheres as a sacrificial core material. The well‐defined PNIPAm was synthesized by a reversible addition fragmentation chain transfer (RAFT) polymerization. The chain end was converted to a thiol by chemical reduction. The PNIPAm was integrated into the nanocapsules via thiol‐ene click reaction. The surface thiol‐ene click reaction conduced to tunable grafting density of PNIPAm brushes. The grafting densities decreased from 0.70 chains nm^?2 to 0.15 chains nm^?2 with increasing the molecular weight of grafted PNIPAm chains. Using water soluble doxorubicin hydrochloride (DOX·HCl) as a model molecular, the tunable shell permeability of the nanocapsule was investigated in detail. The permeability constant can be tuned by controlling the thickness of the P(MAA‐co‐DVB) inner shell, the grafting density of PNIPAm brushes, and the environmental pH and temperature. The tunable shell permeability of these nanocapsules results in the release of the loaded guest molecules with manipulable releasing kinetics. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2202–2216     

Poly(glycidyl methacrylate‐co‐N‐methylolacrylamide‐co‐ethylene dimethacrylate) monolith coupled to high‐performance liquid chromatography for the determination of adenosine phosphates in royal jelly

A polymer monolith microextraction method coupled with high‐performance liquid chromatography was developed for the determination of adenosine triphosphate, adenosine diphosphate, and adenosine monophosphate. The monolithic column was synthesized inside fused‐silica capillaries using thermal initiation free‐radical polymerization with glycidyl methacrylate as the monomer, ethylene dimethacrylate as the cross‐linker, cyclohexanol, and 1‐dodecanol as the porogen. N‐Methylolacrylamide, an important hydrophilic monomer, was incorporated into the polymerization mixture to enhance the hydrophilicity of the poly(glycidyl methacrylate‐co‐ethylene dimethacrylate) column. The obtained poly(glycidyl methacrylate‐co‐N‐methylolacrylamide‐co‐ethylene dimethacrylate) monolith was characterized by scanning electron microscopy, Fourier‐transform infrared spectra, and X‐ray photoelectron spectroscopy. Optimum conditions for the preconcentration and separation of the target adenosines were also investigated. Under the optimum conditions, we obtained acceptable linearities, low limits of detection, and good relative standard deviations. The developed polymer monolith microextraction with high‐performance liquid chromatography method exhibited a good performance with recovery values in the range of 76.9?104.7% when applied to the determination of the adenosines in five royal jelly samples.     

Poly(methacrylamide‐co‐2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid) hydrogels: Investigation of pH‐ and temperature‐dependent swelling characteristics and their characterization

Novel poly(methacrylamide‐co‐2‐acrylamido‐2‐methyl‐ 1‐propanesulfonic acid) (poly(MAAm‐co‐AMPS)) hydrogels were synthesized by free radical polymerization of methacrylamide (MAAm) and 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid (AMPS) in deionized water at 60 °C by using ammonium peroxydisulfate (APS), N,N′‐methylenebisacrylamide (MBAAm) and N,N,N′,N′‐tetramethylethylenediamine (TEMED) as initiator, crosslinker, and activator, respectively. To investigate the effects of feed content on the pH‐ and temperature‐dependent swelling behavior of poly(MAAm‐co‐AMPS), molar ratio of MAAm to AMPS in feed was varied from 90/10 to 10/90. Structural characterization of gels was performed by Fourier transform infrared (FTIR) spectroscopy using attenuated total reflectance (ATR) technique. Thermal and morphological characterizations of gels were performed by thermogravimetric analysis (TGA) and scanning electron microscopy (SEM), respectively. Although an apparent pH‐sensitivity was not observed for the poly(MAAm‐co‐AMPS) gels during the swelling in different buffer solutions, their temperature‐sensitivity became more evident with the increase in AMPS content of copolymer. Thermal stability of poly(MAAm‐co‐AMPS) gels increased with MAAm content. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010     

Syntheses and antitumor activities of polymers containing amino acid and 5‐fluorouracil moieties

The new monomer, 3,6‐endo‐methylene‐1,2,3,6‐tetrahydrophthalimidoethanoyl‐5‐fluorouracil (ETEFU), was synthesized from 5‐fluorouracil (5‐FU) and 3,6‐endo‐methylene‐1,2,3,6‐tetrahydophthalimidoethanoyl chloride (ETEC). Its homopolymer and copolymers with acrylic acid (AA) and vinyl acetate (VAc) were prepared by photopolymerization reactions using 2,2‐dimethoxy‐2‐phenylacetophenone (DMP) as the photoinitiator. The synthesized ETEFU and polymers were identified by FT‐IR, ¹H‐NMR, and ¹³C‐NMR spectra. The contents of ETEFU units in poly(ETEFU‐co‐AA) and poly(ETEFU‐co‐VAc) were 20 and 17 mol%, respectively. The number‐average molecular weights of the synthesized polymers determined by gel permeation chromatography (GPC) were 4,600 to 10,700 g mol⁻¹. In vitro cytotoxicities of samples were evaluated with cancer cell lines [mouse mammary carcinoma (FM3A), mouse leukemia (P388), and human histiocytic lymphoma (U937)] and a normal cell line [mouse liver cells (AC2F)]. Cytotoxicities of 5‐FU and synthesized samples against the cancer cell lines were ranked as follows: ETEFU > poly(ETEFU) > 5‐FU > poly(ETEFU‐co‐AA) > poly(ETEFU‐co‐VAc). The in vivo antitumor activities of poly(ETEFU) and poly(ETEFU‐co‐AA) against Balb/C mice bearing the sarcoma 180 tumor cells were greater than those of 5‐FU at all doses except for the activity of poly(ETEFU) at 0.8 mg/kg. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1589–1595, 1999     

Comparative evaluation of a one‐pot strategy for the preparation of β‐cyclodextrin‐functionalized monoliths: Effect of the degree of amino substitution of β‐cyclodextrin on the column performance

To further evaluate the feasibility and applicability of the one‐pot strategy in monolithic column preparation, two novel β‐cyclodextrin‐functionalized organic polymeric monoliths were prepared using two β‐cyclodextrin derivatives, i.e. mono(6‐amino‐6‐deoxy)‐β‐cyclodextrin and heptakis(6‐amino‐6‐deoxy)‐β‐cyclodextrin. In this improved method, mono(6‐amino‐6‐deoxy)‐β‐cyclodextrin or heptakis(6‐amino‐6‐deoxy)‐β‐cyclodextrin reacted with glycidyl methacrylate to generate the corresponding functional monomers and were subsequently copolymerized with ethylene dimethacrylate. The polymerization conditions for both monoliths were carefully optimized to obtain satisfactory column performance with respect to column efficiency, reproducibility, permeability, and stability. The obtained poly(glycidyl methacrylate‐mono(6‐amino‐6‐deoxy)‐β‐cyclodextrin‐co‐ethylene dimethacrylate) and poly(glycidyl methacrylate‐heptakis(6‐amino‐6‐deoxy)‐β‐cyclodextrin‐co‐ethylene dimethacrylate) monoliths exhibited a uniform structure, good permeability, and mechanical stability as indicated by scanning electron microscopy and micro‐high‐performance liquid chromatography experimental results. Because of the probable existence of multi‐glycidyl methacrylate linking spacers on the poly(glycidyl methacrylate‐heptakis(6‐amino‐6‐deoxy)‐β‐cyclodextrin‐co‐ethylene dimethacrylate) monolith, the effect of the ratio of glycidyl methacrylate/heptakis(6‐amino‐6‐deoxy)‐β‐cyclodextrin was especially studied, and satisfactory reproducibility could still be achieved by strictly controlling the composition of the polymerization mixture. To investigate the effect of the degree of amino substitution of β‐cyclodextrin on column performance, a detailed comparison of the two monoliths was also carried out using series of analytes including small peptides and chiral acids. It was found that the β‐cyclodextrin‐functionalized monolith with mono‐glycidyl methacrylate linking spacers demonstrated better chiral separation performance than that with multi‐glycidyl methacrylate linking spacers.     

Synthesis of poly[(2‐oxo‐1,3‐dioxolane‐4‐yl) methyl methacrylate‐co‐ethyl acrylate] by incorporation of carbon dioxide into epoxide polymer and the miscibility behavior of its blends with poly(methyl methacrylate) or poly(vinyl chloride)

This study was related to the investigation of the chemical fixation of carbon dioxide to a copolymer bearing epoxide and the application of the cyclic carbonate group containing copolymer‐to‐polymer blends. In the synthesis of poly[(2‐oxo‐1,3‐dioxolane‐4‐yl) methyl methacrylate‐co‐ethyl acrylate] [poly(DOMA‐co‐EA)] from poly(glycidyl methacrylate‐co‐ethyl acrylate) [poly(GMA‐co‐EA)] and CO₂, quaternary ammonium salts showed good catalytic activity. The films of poly(DOMA‐co‐EA) with poly(methyl methacrylate) (PMMA) or poly(vinyl chloride) (PVC) blends were cast from N,N′‐dimethylformamide solution. The miscibility of the blends of poly(DOMA‐co‐EA) with PMMA or PVC have been investigated both by DSC and visual inspection of the blends. The optical clarity test and DSC analysis showed that poly(DOMA‐co‐EA) containing blends were miscible over the whole composition range. The miscibility behaviors were discussed in terms of Fourier transform infrared spectra and interaction parameters based on the binary interaction model. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1472–1480, 2001     

Syntheses,antitumor activities,and antiangiogenesis of a monomer and its medium molecular weight polymers: Maleimidoethanoyl‐5‐fluorouracil and its polymers

A new monomer, maleimidoethanoyl‐5‐fluorouracil (MIEFU), was synthesized by the reaction of maleimidoethanoyl chloride and 5‐fluorouracil (5‐FU). The homopolymer of MIEFU and its copolymers with acrylic acid (AA) or vinyl acetate (VAc) were prepared by photopolymerizations with 2,2‐dimethoxy‐2‐phenylacetophenone as an initiator at 25 °C for 48 h. The structures of the synthesized monomer and polymers were identified by Fourier transform infrared, ¹H NMR, and ¹³C NMR spectroscopies and elemental analysis. The contents of the MIEFU units in poly(MIEFU‐co‐AA) and poly(MIEFU‐co‐VAc) were 18 and 30 mol %, respectively. The number‐average molecular weights of the synthesized polymers, as determined by gel permeation chromatography, ranged from 4900 to 9800. The in vitro cytotoxicities of the samples against mouse mammary carcinoma (FM3A), mouse leukemia (P388), and human histiocytic lymphoma (U937) cancer cell lines decreased in the following order: 5‐FU ≥ MIEFU > poly(MIEFU) > poly(MIEFU‐co‐AA) > poly(MIEFU‐co‐VAc). The in vivo antitumor activities of the polymers against Balb/C mice bearing the sarcoma 180 tumor cells were greater than those of 5‐FU at all the doses tested. The inhibitions of the SV40 DNA replication of the samples were much greater than that of the control. The synthesized monomer and polymers showed more antiangiogenesis activity than the control. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1247–1256, 2000     

Control of porosity in hierarchically porous polymers derived from hyper‐crosslinked block polymer precursors

We report an approach to control the pore characteristics of hierarchically porous polymers (HPPs) containing micropores in a well‐defined 3D continuous mesoporous framework, by the hyper‐crosslinking reaction of a crosslinked block polymer precursor polylactide‐b‐poly(vinylbenzyl chloride‐co‐styrene‐co‐divinylbenzene) (PLA‐b‐P(VBzCl‐co‐S‐co‐DVB)) consisting of bicontinuous PLA and P(VBzCl‐co‐S‐co‐DVB) microdomains. We investigated the hyper‐crosslinking reaction of P(VBzCl‐co‐S‐co‐DVB)s synthesized by reversible addition‐fragmentation chain transfer (RAFT) copolymerization, and then examined the effect of VBzCl, S, DVB, and polylactide macrochain transfer agent (PLA‐CTA) contents in the polymerization mixture on the pore characteristics of the HPPs. We demonstrate that while the VBzCl content responsible for the hyper‐crosslinking reaction primarily governs microporosity, the DVB content has a strong influence on the mesopore structure, as it determines the onset of the gelation of the polymerization mixture, which arrests the emerging disordered bicontinuous morphology induced by the polymerization‐induced microphase separation process. Because the PLA microdomains template the percolating mesoporous space, mesoporosity was mainly controlled by the PLA‐CTA contents. The synergistic combination of hyper‐crosslinking and block polymer self‐assembly in the HPP formation provided a highly reinforced mesoporous framework, stable against pore collapse, and interconnected mesopores. These facilitated diffusion to the microporous surfaces, suggesting its utility for advanced absorbents and catalytic supports. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 900–913     

Fast reversed‐phase liquid chromatographic separation of proteins by flow‐through poly(styrene‐co‐divinylbenzene) microspheres

With the explosive growth of the bioscience and biopharmaceuticals, the demand for high efficient analysis and separation of proteins is urgent. High‐performance liquid chromatography is an appropriate technology for this purpose, and the stationary phase is the kernel to the separation efficiency. In this study, flow‐through poly(styrene‐co‐divinylbenzene) microspheres characteristic of the binary pores, i.e. flow‐through pores and mesopores, were synthesized; this special porous structure would benefit the convective mass transfer while guarantee the high specific surface area. Owing to the hydrophobic nature, poly(styrene‐co‐divinylbenzene) microspheres were suitable as the reversed‐phase stationary phase for separation of proteins. For the high permeability of the poly(styrene‐co‐divinylbenzene) microspheres packed column, fast separation of the studied six proteins in ～2 min was achieved. The recoveries of studied proteins were acceptable in the range of 79.0–99.4%. The proposed column had good pH stability of 1–13 and repeatability. Moreover, the column was applied for egg white fast separation, further demonstrating its applicability for complex bio‐sample separation. The flow‐through poly(styrene‐co‐divinylbenzene) microspheres were promising for fast separation of large molecules.     

Synthesis and properties of the ionomer diblock copolymer poly(4‐vinylbenzyl triethyl ammonium bromide)‐b‐polyisobutene

A new amphiphilic diblock copolymer containing an ionomer segment, poly[(4‐vinylbenzyl triethyl ammonium bromide)‐co‐(4‐methylstyrene)‐co‐(4‐bromomethylstyrene)]‐b‐polyisobutene [poly(4‐VBTEAB)‐b‐PIB], was synthesized by the chemical modification of poly(4‐methylstyrene)‐b‐polyisobutene [poly(4‐MSt)‐b‐PIB]. First, the 4‐methylstyrene moiety in poly(4‐MSt)‐b‐PIB was brominated with azobisisobutyronitrile as an initiator at 60 °C in CCl₄, and then the highly reactive benzyl bromide groups were ionized by a reaction with triethylamine in a toluene/isopropyl alcohol (80/20 v/v) mixture at about 85 °C to produce the ionomer diblock copolymer poly(4‐VBTEAB)‐b‐PIB. The solubility of the ionomer block copolymer was quite different from that of the corresponding poly[(4‐methylstyrene)‐co‐(4‐bromomethylstyrene)]‐b‐polyisobutene {poly[(4‐MSt)‐co‐(4‐BrMSt)]‐b‐PIB}. Transmission electron microscopy observations demonstrated that all three diblock copolymers had microphase‐separation structures in which polyisobutene (PIB) domains existed in the continuous phase of the poly(4‐methylstyrene) segment or its derivative segment matrix. Dynamic mechanical thermal analysis measurements showed that poly[(4‐MSt)‐co‐(4‐BrMSt)]‐b‐PIB had two glass‐transition temperatures (T_g's), ?56 °C for the PIB segment and 62 °C for the poly[(4‐MSt)‐co‐(4‐BrMSt)] domain, whereas poly(4‐VBTEAB)‐b‐PIB showed one T_g at ?8 °C of the PIB domain; T_g of the poly[(4‐vinylbenzyl triethyl ammonium bromide)‐co‐(4‐methylstyrene)‐co‐(4‐bromomethylstyrene)] domain was not observable because of the strong ionic interactions resulting in a higher T_g and a retention of modulus up to 124 °C. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2755–2764, 2003     

Synthesis of Davankov‐type hypercrosslinked resins using different isomer compositions of vinylbenzyl chloride monomer,and application in the solid‐phase extraction of polar compounds

Two different gel‐type resins have been prepared by suspension polymerization using 2 wt % divinylbenzene (DVB) with either p‐vinylbenzyl chloride (pVBC) or a mixture of VBC isomers (～ 70% m‐; ～ 30% p‐). Significant difference in the chlorine content was observed, which was attributed to a more favored hydrolysis process when p‐VBC was used. The presence of hydroxyl groups has been confirmed by elemental microanalytical data and solid‐state ¹³C cross‐polarization/magic angle spinning (CP‐MAS) nuclear magnetic resonance (NMR) spectra. Hypercrosslinked resins were prepared from both gel‐type precursors by treatment with FeCl₃ in 1,2‐dichloroethane (DCE) at 80 °C. The resultant resins showed differences in specific surface area and degree of hydrophilicity. The performance of the hypercrosslinked resins was evaluated in solid‐phase extraction (SPE) of polar compounds, and better results were obtained for the hypercrosslinked resin prepared from p‐VBC that combines a relatively high specific surface area (908 m² g^?1) and somewhat higher oxygen content (3.96 wt % O). © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1718–1728, 2005     

Zwitterionic shell‐crosslinked micelles from block‐comb copolymer of PtBA‐b‐P(PEGMEMA‐co‐DMAEMA)

Through reversible addition‐fragmentation chain transfer (RAFT) polymerization of t‐butyl acrylate (tBA) and RAFT copolymerization of 2‐dimethylaminoethyl methacrylate (DMAEMA) with poly(ethylene glycol) methyl ether methacrylate (PEGMEMA), block‐comb copolymer of PtBA‐b‐P(PEGMEMA‐co‐DMAEMA) was prepared. After the self‐assembly of PtBA‐b‐P(PEGMEMA‐co‐DMAEMA) into core‐shell spherical micelles, P(PEGMEMA‐co‐DMAEMA) segments of the shell was crosslinked with 1,2‐bis(2‐iodoethoxy)ethane and the core of PtBA was selectively hydrolysized with trifluoroacetic acid. Thus, zwitterionic shell‐crosslinked micelles with positively charged outer shell and negatively charged inner core were obtained. Dynamic light scattering, transmission electron microscope, Zeta potential measurement, and nuclear magnetic resonance were used to confirm the formation of the zwitterionic shell‐crosslinked micelles. They showed the excellent resistance to the variation of pH value and possessed the positive values throughout the whole range of pH range even if the carboxylic groups of the micelles was much more than ammonium groups. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis and characterization of well‐defined poly(2‐hydroxyethyl methacrylate‐co‐styrene)‐graft‐poly(ε‐caprolactone) by sequential controlled polymerization

A new graft copolymer, poly(2‐hydroxyethyl methacrylate‐co‐styrene) ‐graft‐poly(?‐caprolactone), was prepared by combination of reversible addition‐fragmentation chain transfer polymerization (RAFT) with coordination‐insertion ring‐opening polymerization (ROP). The copolymerization of styrene (St) and 2‐hydroxyethyl methacrylate (HEMA) was carried out at 60 °C in the presence of 2‐phenylprop‐2‐yl dithiobenzoate (PPDTB) using AIBN as initiator. The molecular weight of poly (2‐hydroxyethyl methacrylate‐co‐styrene) [poly(HEMA‐co‐St)] increased with the monomer conversion, and the molecular weight distribution was in the range of 1.09 ～ 1.39. The ring‐opening polymerization (ROP) of ?‐caprolactone was then initiated by the hydroxyl groups of the poly(HEMA‐co‐St) precursors in the presence of stannous octoate (Sn(Oct)₂). GPC and ¹H‐NMR data demonstrated the polymerization courses are under control, and nearly all hydroxyl groups took part in the initiation. The efficiency of grafting was very high. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5523–5529, 2004     

Determination of Sudan dyes in chili pepper powder by online solid‐phase extraction with a butyl methacrylate monolithic column coupled to liquid chromatography with tandem mass spectrometry

A poly(butyl methacrylate‐co‐ethylene dimethacrylate) monolithic column was fabricated and used as a novel sorbent for online solid‐phase extraction coupled to liquid chromatography with tandem mass spectrometry for the simultaneous determination of Sudan I–IV in chili pepper powder. The prepared columns were characterized by scanning electron microscopy, nitrogen adsorption‐desorption, and pressure drop measurements. Online solid‐phase extraction was performed on the synthesized monolithic column using 10 mM ammonium acetate solution as the loading solution with the aid of an online cleanup chromatography system. The desorption of Sudan I–IV was achieved with acetonitrile as the eluting solution at the flow rate of 0.5 mL/min. The extracted analytes were subsequently eluted into a C₁₈ analytical column for chromatographic separation using a mixture of 10% acetonitrile/90% formic acid (0.5%) solution as the mobile phase. Under the optimized conditions, the developed method had linear range of 1.0–50 μg/kg, a detection limit of 0.3 μg/kg, and a quantification limit of 1.0 μg/kg for each analyte. The intraday and interday recoveries of Sudan I–IV in chili pepper powder samples ranged from 94.8 to 100.9% and 94.9 to 99.4%, respectively. The intraday and interday precision were between 3.37–7.01% and 5.01–7.68%, respectively.