CARBOHYDRATE POLYMERS
·
2014
·
IF 3.916
Yadong Liu,Xiaosa Jin,Xiaosa Zhang,Miaomiao Han,Shengxiang Ji
Three amphiphilic poly( N -acryloyl- l -amino acid) grafted celluloses were prepared by RAFT polymerization of N -acryloyl- l -amino acid, where amino acid is alanine, proline or glutamic acid, onto cellulose backbones. The chemical structure and solution properties of the brush copolymers were characterized with FTIR, NMR and wide angle X-ray diffraction (WAXD). The thermal stability of the brush copolymers was estimated by thermal gravimetric analysis (TGA). Circular dichroism (CD) and specific rotation measurements confirmed that these grafted celluloses had characteristic chiroptical properties. The amphiphilic brush copolymers self-assembled into micelles in the aqueous solution as confirmed by transmission electron microscopy (TEM) and dynamic light scattering (DLS) analyses. The micellar aggregates showed a tunable pH-responsive property and disaggregated to form unimolecular micelles at higher pH in diluted solutions. The brush copolymers have potential applications in controlled drug release and high-performance liquid chromatography, and so forth.
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高影响因子
Polymer Chemistry
·
2014
·Vol. 5
·期 21
·6244-6255
·
IF 5.368
Yuanyuan Xu,Youcheng Li,Xueteng Cao,Qijing Chen,Zesheng An
Reversible addition–fragmentation chain transfer (RAFT) dispersion polymerization in cononsolvents of poly(N-isopropylacrylamide) (PNIPAM) was developed as a versatile strategy for the synthesis of thermoresponsive nanogels with controlled composition, functionality and architecture. Cononsolvents composed of mixtures of methanol, ethanol and isopropanol with water were first screened for their suitability as the media for dispersion polymerization of NIPAM, and water–ethanol (75 : 25, v : v) solution was selected due to good RAFT control, efficient formation of nanogels and low toxicity. RAFT dispersion polymerization of NIPAM in the cononsolvent using poly(N,N-dimethylacrylamide) (PDMA) as the macromolecular chain transfer agent (Macro-CTA) showed good control over the molecular weight, polydispersity and pseudo linear polymerization kinetics, as characterized by gel permeation chromatography (GPC) and 1H NMR. The effect of the molecular weight of Macro-CTA, the degree of polymerization of PNIPAM, the molar ratio of [crosslinker] : [Macro-CTA] and the solid content on the formation and size of nanogels was investigated. The thermal profiles of nanogels were characterized by dynamic light scattering (DLS) both in cononsolvents and water. This cononsolvency strategy for dispersion polymerization was shown to be compatible with the incorporation of hydrophilic comonomers of N-(2-hydroxyethyl)acrylamide (HEAM) and diacetone acrylamide (DAAM). The nanogel containing DAAM was demonstrated for postpolymerization modification using ketone–alkoxyamine chemistry. More importantly, dispersion polymerization in cononsolvents allowed various hydrophobic components, e.g. butyl acrylate (BA), fluorescein O-acrylate (FLA), and 1,6-hexanediol diacrylate (HDDA), to be reliably copolymerized with NIPAM, showing well controlled polymerization, composition, nanogel size and colloidal stability. Finally, an amphiphilic block copolymer PDMA-b-PBA was used as a Macro-CTA to produce the PDMA-b-PBA-b-PNIPAM triblock copolymer and triple-layered nanogel, taking advantage of the solubility of PDMA-b-PBA and the insolubility of PNIPAM in the water–ethanol solution at the polymerization temperature.
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Polymer Chemistry
·
2014
·Vol. 5
·期 14
·4277-4284
·
IF 5.368
Xueteng Cao,Chunlei Zhang,Songbai Wu,Zesheng An
We have developed a highly efficient, one-step approach for the synthesis of core cross-linked star (CCS) polymers using commercial macromonomers (polyethylene glycol methyl ether methacrylates) as the arms via RAFT-mediated emulsion polymerization in aqueous media. This approach employs a small molecular chain transfer agent (CTA), commercial macromonomer, hydrophobic cross-linker, and optional hydrophobic spacing monomer as the polymerization recipe to synthesize CCS polymers via direct one-step polymerization in aqueous buffer solution. Various polymerization parameters, including buffer concentration and molar ratio of macromonomer/cross-linker/spacing monomer relative to CTA, were investigated. CCS polymers of high yield and low dispersity were obtained within 4 h under a wide range of conditions. Analysis of polymerization kinetics and macromolecular parameters of the generated polymeric species during the polymerization process led to insights into the mechanistic aspects of the CCS formation process, which was proposed to involve three stages, i.e., polymer chain growth, cross-linking to form CCS, and CCS growth. Finally, synthesis of CCS polymers using macromonomers of different molecular weights pointed to the necessity for optimization of the polymerization conditions for each macromonomer, possibly due to different polymerization rates and steric hindrance.
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Polymer Chemistry
·
2016
·Vol. 7
·期 20
·3423-3433
·
IF 5.687
Ke Wang,Zefeng Song,Chonggao Liu,Wangqing Zhang
The thermo- and pH/CO2-responsive poly[N-[2-(dialkylamino)ethyl]acrylamide]s containing a polyacrylamide backbone but different N-substitutes of dialkylamine were synthesized and their solution properties were comparatively checked. A controllable RAFT synthesis of poly[N-[2-(dialkylamino)ethyl]acrylamide]s was achieved when a typical trithiocarbonate containing an easily cleavable R group was employed. The RAFT polymerization rate decreases with the increasing C-number in the N-substitutes. The thermo- and pH/CO2-responsive property of poly[N-[2-(dialkylamino)ethyl]acrylamide]s is firmly correlative to the N-substitutes. With the C-number in the R-substitute increasing, the solution properties of poly(N-[2-(dialkylamino)ethyl]acrylamide)s undergo a soluble-to-thermoresponsive-to-insoluble evolution, and the critical pH of poly[N-[2-(dialkylamino)ethyl]acrylamide]s gradually decreases. The dialkylamine moieties in the poly[N-[2-(dialkylamino)ethyl]acrylamide]s lead to a characteristic CO2-response during CO2/N2 bubbling. The present study reveals the structure-dependent solution properties of the thermo- and pH/CO2-responsive poly[N-[2-(dialkylamino)ethyl]acrylamide]s, and these multistimuli-responsive polymers are believed to be very useful due to the controllable RAFT synthesis and tunable solution properties.
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PROGRESS IN ORGANIC COATINGS
·
2016
·
IF 2.632
Jiahui Su,Xiaoxuan Liu,Chengjing Xiong,Hong Huang,Yanyan Cui
In this study, we prepared a novel triblock copolymer, PDMS- b -(PMAEBB- co -PDMAEMA) 2 ( tri -PI) bearing side-chain benzophenone (BP) and coinitiator amine, as a macro-photoinitiator via reversible addition-fragmentation chain transfer (RAFT) copolymerization of the polymerizable photoinitiator 2-(methacryloyloxy)ethyl-2-benzoylbenzoate (MAEBB) and the unsaturated coinitiator amine 2-(dimethylamino)ethyl methacrylate (DMAEMA) with a bifunctional polydimethylsiloxane (PDMS) macro-chain transfer agent (macro-CTA). The structure of synthesized copolymer was confirmed by Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance ( 1 H NMR), differential scanning calorimetry (DSC), and gel permeation chromatography (GPC). The effects of the photoinitiator/coinitiator ratio, concentration, and photoinitiator systems on the photopolymerization kinetics of tri(propylene glycol) diacrylate (TPGDA) were investigated by real-time FT-IR. The mobility of the tri -PI chain segments was proven by X-ray photoelectron spectroscopy (XPS), and the surface morphology of TPGDA curing coatings was studied by scanning electron microscopy (SEM). Results showed that tri-PI strongly suppressed the effect of oxygen inhibition on the photopolymerization system. Tri-PI was also used in the curing of UV-curable waterborne polyurethane acrylate (UV-WPUA) resin to determine its versatility.
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Veterinary Sciences
·
2025
·Vol. 12
·期 3
·233
·
IF 2.3
Yang Yang,Xin Zhang,Jin Yang,Ziyan Wu,Junpeng Li,Ruilong Song,Chuang Meng,Guoqiang Zhu
Simple SummaryQuorum sensing (QS) not only regulates bacterial virulence through signaling molecules, but is also capable of causing direct damage to host cells. Previous studies have found a high correlation between N-acyl homoserine lactone (AHL) of the QS in the piglet intestine and piglet health. In a mouse model, AHL signaling N-(3-oxododecanoyl)-homoserine lactone (OdDHL) induced apoptosis of intestinal cells and damage to intestinal barrier. In a porcine intestinal epithelial cell model, OdDHL also was confirmed to induce apoptosis. The direct role and mechanism of OdDHL in the digestive tract of porcine animal models have not been elucidated. For the first time in a piglet model, we have verified that AHL induces apoptosis and disrupts the intestinal barrier, and we have also verified the protective effect of QS inhibitors. The present study also investigates the central role of cellular lipid rafts in the critical phase in which OdDHL adheres to cells and exerts functions. In cells where lipid rafts were eliminated, the ability of OdDHL adherence to cell surface was significantly reduced, and apoptosis induction was similarly impaired. This result indicates an important role for lipid rafts in relevant processes. This study provides basic data for the antimicrobial application of QSI in pig farming.Quorum sensing (QS) is a process by which bacteria sense their population density and regulate behavior accordingly. QS not only regulates bacterial virulence but also directly influences host cells. Previous studies have shown that QS is strongly associated with piglet intestinal health, but the mechanism is not yet clear. For the first time, we have confirmed in a piglet animal model that OdDHL directly damages intestinal cells in weaned piglets, disrupting the intestinal barrier. We also provide a preliminary exploration of the underlying mechanism of these effects. TUNEL assays confirmed that damage to the piglet intestinal barrier coincided temporally and spatially with dysregulated apoptosis. Lipid rafts, key components of the cell membrane, are involved in many biological processes, including the activation of apoptosis-related proteins. Following the disruption of the lipid raft structure in IPEC-J2 cells, the apoptosis rate under OdDHL stimulation decreased by 50%. These data demonstrate that lipid rafts mediate the attachment of OdDHL to porcine intestinal cells; then, OdDHL induces apoptosis in porcine intestinal cells through the mitochondrial and death receptor pathways, thereby compromising the integrity of the porcine intestinal barrier. This study provides foundational insights into the role of QS in piglet intestinal diseases.
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高影响因子
Soft Matter
·
2011
·Vol. 7
·期 11
·5348-5352
·
IF 4.457
Yin Wang,Guohua Jiang,Ming Zhang,Lina Wang,Rijing Wang,Xinke Sun
A series of novel shell cross-linked nanocapsules were facilely fabricated in an inverse miniemulsion reversible addition–fragmentation chain transfer (RAFT) system, in which poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) acted as a stabilizer and macroinitiator. The as-prepared nanocapsules with PDMAEMA cores and poly(methylacrylic acid) (PMAA) shells, had a size of 220 nm and can be used as a carrier for the encapsulation of hydrophilic components such as inorganic salts.
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ADVANCED MATERIALS
·
2025
·
IF 26.8
Xiaoxi Li,Ni Yao,Ming Yang,Yucheng Tian,Xiaobao Gong,Xiaoyan Liu,Jianyong Yu,Shichao Zhang,Bin Ding
Airborne particulate matter (PM) is a major global safety concern, significantly straining the ecological environment, human health, and economy. Filtration membranes, essential for PM removal, are challenging in achieving both high efficiency and low air resistance, resulting in a high pressure drop during efficient filtration. Herein, inspired by bubble rafts, an ultrathinnanofibrous network membrane is fabricated by transforming a liquid film of polysulfonesolution on electrospun fibrous scaffold into a single-layer network via nonsolvent-induced phase separation. Tailoring of the polysulfone concentration in the liquid film supported by the scaffold and of the phase separation process induced by flowing nonsolvent allows the construction of the single-layer network with interconnected nanofibers (diameter of ≈40 nm). Benefiting from the single-layer network, the membrane exhibits a small pore size (≈270 nm) at a high porosity of 90.3% and ultrathin thickness of ≈800 nm. Consequently, the membrane shows high efficiency (99.8% removal of PM 0.3 ) at an ultralow pressure drop (<40 Pa). Moreover, the membrane exhibits high transparency (>83%) and allows the light breeze (wind speed of 3.2 m s −1 ) to pass through easily, enabling energy-efficient applications, such as window screens. This work provides new insights into designing membranes for efficient and low-resistance filtration and separation.
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CARBON
·
2019
·
IF 7.466
Fangyan Liu,Zixing Wang,Haitao Zhang,Long Jin,Xiang Chu,Bingni Gu,Haichao Huang,Weiqing Yang
The O-N-S co-doped hierarchical porous carbons are prepared by direct pyrolysis of kraft lignin which is the byproduct from papermaking black liquor . The proposed preparation method is extremely facile, green-environmental, and low-cost without any additional activating agents, additives or templates. The kraft lignin-derived carbon materials possess large specific surface areas (338−1307 m 2 g −1 ), hierarchical porous structures and abundant multi-heteroatoms co-doping (9.84–19.91 wt%). Benefiting from above synergistic advantages, the as-fabricated symmetric supercapacitor in aqueous electrolyte delivers a high specific capacitance of 244.5 F g −1 at 0.2 A g −1 , excellent rate-capability (81.8% retention of initial capacitance at 40.0 A g −1 ), and outstanding cycling stability (91.6% retention over 10000 cycles). Importantly, this device in aqueous electrolyte delivers an energy density of 8.5 W h kg −1 at a power density of 100 W kg −1 . Furthermore, a remarkable energy density of 66.8 W h kg −1 at a power density of 1.75 kW kg −1 has been achieved and 32.2 W h kg −1 is still maintained even at an ultrahigh power density of 40.0 kW kg −1 when ionic liquid serves as electrolyte. This study demonstrates the successful conversion of low-valued natural biomass derivative into sustainable high-performance supercapacitor electrode materials with a simple, low-cost, and green-environmental production process.
研究领域:
材料科学
·
能源科学
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高影响因子
POLYMER JOURNAL
·
2020
·Vol. 52
·期 12
·1323-1331
·
IF 2.826
Xia Lei,Zhang Ze,You Ye-Zi
Ring-opening polymerization of lactones has served as one of the most resourceful and versatile methods for the production of polyesters. However, the photocontrolled ring-opening polymerization of lactones with the advantages of being inexpensive, green, and noninvasive, is still rarely reported. In this work, we developed a series of composite photoacid generators containing a common photocatalyst and an onium salt to induce the living/controlled cationic ring-opening polymerization of lactones using benzyl alcohol or butyl alcohol as an initiator under visible light. The wavelength of the light could be easily adjustable by applying different photocatalysts. Moreover, radical species are generated concurrently during the electron transfer processes; as a result, simultaneous living/controlled cationic ring-opening polymerization of lactones and reversible addition–fragmentation chain transfer radical (RAFT) polymerization can be performed using hydroxy group capped trithiocarbonate to produce hybrid block copolymers.
研究领域:
高分子化学
·
材料科学
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高影响因子
EUROPEAN POLYMER JOURNAL
·
2024
·
IF 5.8
Weiwei Liu,Tengfei Liu,Xiaofei Wang,Yuan Gao,Pingye Deng,Tao Zou,Zhi Luo,Shuangkun Zhang
Development of high-performance fluorescent materials is crucial for fluorescence imaging technology. Herein, well-defined fluorescent star poly-N-isopropylacrylamide (Flu-PNIPAM) was prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization in a continuous-flow microreactor. A tetrafunctional RAFT agent and the functional monomer fluorescein undecylenoyl (Flu-UE) were synthesized, and then pumped into a microreactor with NIPAM monomer together for RAFT polymerization. The microreactor process parameters for the RAFT polymerization were optimized to obtain well-defined Flu-PNIPAM. The NIPAM and Flu-UE units endow Flu-PNIPAM with temperature and pH responsiveness, respectively. Transmission electron microscopy and dynamic light scattering analyses revealed that Flu-PNIPAM self-assembled into nanoparticles with uniform size in an aqueous solution at 37 °C. Moreover, Flu-PNIPAM exhibited good fluorescence and biocompatibility, rendering it highly promising for cell imaging.
研究领域:
高分子化学
·
生物医学工程
·
材料科学
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高影响因子
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2016
·Vol. 54
·期 15
·2413-2420
·
IF 3.114
Ye Sha,Qing Zhu,Yuanxin Wan,Linling Li,Xiaoliang Wang,Gi Xue,Dongshan Zhou
A new type of chain transfer agent used in reversible addition fragmentation chain transfer (RAFT) polymerization named 9-anthracenylmethyl (4-cyano-4-( N -carbazylcarbodithioate) pentanoate) (ACCP) was synthesized with a total yield over 75% by the incorporation of both fluorescent donor and acceptor chromophores. Polymerization of heterotelechelic α,ω end-labeled dye-functionalized polystyrene (PS), poly(methyl methacrylate) (PMMA), and poly( n -butyl methacrylate) (PBMA) with adjustable molecular weights and narrow polydispersity could be conducted by a one-pot procedure through RAFT polymerization with this bischromophore chain transfer agent. The polymerizations demonstrated “living” controlled characteristics. By taking advantage of the characteristic fluorescence resonance energy transfer (FRET) response between the polymer chain terminals, the variation of chain dimensions in solution from the dilute region to the semidilute region can be monitored by changes in the ratio of the fluorescence intensities of the carbazolyl group to the anthryl group, which lends itself to potential applications in characterizing chain dimensions in solutions for thermodynamic or dynamic studies. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54 , 2413–2420
研究领域:
高分子化学
·
物理化学
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