COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2020
·
IF 3.99
Xichen Zhang,Yutian Su,Liling Lei,Shishan Wu,Jian Shen
Graphene oxide (GO) nanosheets own a large specific surface area and excellent mechanical properties. GO sheets can be dispersed in water to form nano dispersoid, and are easy to composite with cement-based materials. However, the dispersity of GO in alkaline cement slurry is inferior, which causes severe agglomeration, so that the enhancement effect of GO cannot be fully utilized. In this paper, GO-g-PPOE (GE) and GO-g-PPOE- b -PAA (GEA) were synthesized via RAFT polymerization on GO surface. The growth models of poly(poly(ethylene glycol) methyl ether methacrylate) (PPOE) and poly(poly(ethylene glycol) methyl ether methacrylate) -co- acrylic acid) (poly(POE-co-AA)) from GO surface were predicted by TEM and SEM. The result of Zeta potential proved that both GE and GEA effectively improved the dispersity of graphene oxide in cement pore solution. Due to the improvement of dispersity and the adsorption of metal ions in cement paste, GE and GEA promoted cement hydration, thereby reinforcing cement composites.
研究领域:
材料科学
·
化学工程
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DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2024
·
IF 4.9
Lin Zhou,Yangcheng Lu
Polystyrene-based magnetic composite nanoparticles with well-defined core-shell morphology, customizable surface functionalization , and adjustable magnetic properties are promising catalyst support materials. In this work, chloromethylated magnetic polystyrene composite nanoparticles are successfully prepared through RAFT-mediated surfactant-free emulsion polymerization . A comprehensive investigation is carried out to explore the influence of copolymer monomer ratios and polymerization degrees on emulsion polymerization conversion and encapsulation efficiency. The results unveil the critical importance of moderately adjusting the hydrophobic/hydrophilic properties of the macroRAFT agents in achieving an effective encapsulation process. Excessive monomer addition is found to disrupt the conditions necessary for emulsion polymerization by causing the detachment of macroRAFT agents from the surface of the modified Fe 3 O 4 nanoclusters . These results are instructive for the future rational design and synthesis of high-performance catalysts.
研究领域:
材料科学
·
化学工程
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产品关联
DOI
高影响因子
COLLOIDS AND SURFACES B-BIOINTERFACES
·
2019
·
IF 3.973
Jianhua Zhou,Yannan Li,Hong Li,Hongtao Yao
Cellulose nanocrystals/fluorinated polyacrylate soap-free emulsion was successfully synthesized via RAFT-assisted Pickering emulsion process using modified cellulose nanocrystals as particle stabilizers. The cellulose nanocrystals were organically modified by linear triblock copolymer poly(2-(dimethylamino) ethyl methacrylate) -b- poly(glycidyl methacrylate) -b- poly(2,2,3,4,4,4-Hexafluorobutyl acrylate) (PDMAEMA -b- PGMA -b- PHFBA) with reactive trithiocarbonate group. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analyses showed that modified cellulose nanocrystals were armored on the surface of spherical particles. The morphology and particle size of the resulting products depended on the pH value of particle dispersion. When the value of pH increased from 1.06 to 2.97, the spherical-like particles size decreased from 763 nm to 253 nm. However, with pH value increasing to 6.85, the particle size increased to 394 nm. Furthermore, a possible mechanism for the formation of the cellulose nanocrystals/fluorinated polyacrylate nanoparticles with core-shell structure was proposed.
研究领域:
材料科学
·
化学工程
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产品关联
DOI
PubMed
高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
·
2014
·Vol. 25
·期 6
·684-688
·
IF 1.964
Chang Peng,Wu Pan,Lin Bao,Shu Chen,Yi Chen,Mingsong Han,Yuanqin Xiong,Weijian Xu
We report a facile method that combined sol–gel reaction, reversible addition–fragmentation chain transfer (RAFT)/macromolecular design via interchange of the xanthates process and thiol-ene click reaction to prepare monodisperse silica core-poly( N -vinylimidazole) (PVim) shell microspheres of 200 nm in average diameters. First, silica with C = C double bonds was prepared by the sol–gel reaction of 3-(trimethoxysilyl)propyl methacrylates (MPS) with tetraethoxysilane in ethanol; SiO 2 @PVim were subsequently prepared by grafting PVim chain (Mn = 9800 g/mol, polydispersity index = 1.22) to MPS-SiO 2 via the thiol-ene click chemisty. The obtained SiO 2 @PVim microspheres show higher catalytic activity toward the hydrolysis of p -nitrophenyl acetate compared with the PVim homopolymers. The as-prepared composites have been characterized by scanning electron microscopy, transmission electron microscopy, thermal gravimetric analysis and Fourier transform infrared spectrometry analysis. Copyright © 2014 John Wiley & Sons, Ltd.
研究领域:
材料科学
·
化学
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产品关联
DOI
高影响因子
Polymer Chemistry
·
2017
·Vol. 8
·期 47
·7390-7399
·
IF 5.375
Ruming Jiang,Meiying Liu,Qiang Huang,Hongye Huang,Qing Wan,Yuanqing Wen,Jianwen Tian,Qian-yong Cao,Xiaoyong Zhang,Yen Wei
Fluorescent organic nanoparticles (FONs) based on an aggregation-induced emission (AIE) dye have recently received increasing interest owing to their unique optical properties, water dispersibility and biocompatibility. However, fabrication of multifunctional AIE-active FONs through a facile controlled free radical polymerization method has not been reported thus far. In this work, a novel photo-initiated reversible addition–fragmentation chain-transfer (RAFT) polymerization has been developed for the fabrication of AIE-active FONs for the first time. During this procedure, a new tetraphenylethene based dye (named TPE-DETC) was conjugated to a chain transfer agent, which could serve as the fluorescence signal and catalyst for RAFT polymerization. Styrene (SE) and itaconic acid (IA) were selected as the monomers to construct the final fluorescent copolymers (TPE-SE-IA). Due to the amphiphilicity and AIE properties of TPE-DETC, the TPE-SE-IA copolymers tend to self-assemble and form FONs. The physicochemical properties, drug loading and release behavior of TPE-SE-IA FONs towards cisplatin (CDDP), their biocompatibility as well as cell uptake behavior have been investigated in detail. The results verified that TPE-SE-IA FONs possess strong fluorescence, high water dispersibility, distinguished biocompatibility and highly efficient drug loading capability, making them promising candidates for biomedical applications. More importantly, the in situ photo-initiated RAFT polymerization strategy is an ideal method to be used for the preparation of functional polymeric materials owing to its fascinating features, such as environmental friendliness, mild reaction conditions, being catalyst-free and cost effectiveness.
研究领域:
材料科学
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生物医学工程
·
化学
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产品关联
DOI
高影响因子
Polymer Chemistry
·
2010
·Vol. 1
·期 10
·1638-1643
·
IF 0
Yin Wang,Guohua Jiang,Xinke Sun,Miaojun Ding,Hongyuan Hu,Wenxing Chen
Shell cross-linked polymeric nanoparticles were prepared through an interfacially confined copolymerization of styrene and disulfide cross-linker in a reversible addition-fragmentation chain transfer (RAFT) miniemulsion system using poly(2-(dimethylamino) ethyl methacrylate) (PDMAEMA) as stabilizer and macroinitiator. 1H NMR, FT-IR, and FE-SEM have been applied to investigate the structures and morphologies of the resultant nanoparticles. Fluorescent spectra results show that the as-prepared samples have fluorescent properties, which may be used as a fluorescent carrier for control release of guest molecules.
研究领域:
高分子化学
·
纳米医学
·
药物递送
·
生物材料
·
聚合物科学
✓ 已验证
DOI
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.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
Polymer Chemistry
·
2013
·Vol. 4
·期 16
·4450-4460
·
IF 5.231
Sipei Li,Chao Gao
Multifunctional dendritic molecular brushes (DMBs) with pendent poly(glycidyl methacrylate) (PGMA) chains were synthesized via a sequential reversible addition–fragmentation chain transfer (RAFT) polymerization approach. By controlling the kinetics of the polymerization, DMBs with a high number-averaged molecular weight (Mn) of ∼1.4 × 106 g mol−1 and narrow polydispersity index (PDI) of 1.50 were obtained. DMBs were reacted with sodium azide, giving rise to giant macromolecules with a high density of hydroxyl and azide bifunctional groups. Pyrene moieties (with a conventional chromophore) were efficiently attached to the DMBs by esterification, affording solution-emissive blue-light DMBs. Ultrahigh excimer emission at 475 nm was achieved for these fluorescent DMBs at a very low concentration of pyrene (∼10−7 mol L−1). Alternatively, tetraphenylethylene (TPE, with an aggregation-induced emission (AIE) chromophore) units were attached to DBMs with a conversion of 100% by copper-catalyzed alkyne–azide click chemistry. The solid-state-emissive blue-light TPE-functionalized DMBs exhibited typical AIE (rather than aggregation enhanced emission, AEE) effect which was rarely observed for dendritic scaffolds and its quantum yield at aggregated state is two times higher than that of fluorophore monomer. Such topology-induced unusual emission phenomena were attributed to the cage effect of DMBs.
研究领域:
高分子化学
·
材料科学
·
光化学
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产品关联
DOI
高影响因子
MACROMOLECULAR RAPID COMMUNICATIONS
·
2021
·Vol. 43
·期 1
·2100559
·
IF 5.734
Bolei Yuan,Tingting Huang,Xinghuo Wang,Yi Ding,Lin Jiang,Yunhe Zhang,Jun Tang
An enzyme cascade system including glucose oxidase (GOx) and iron porphyrin (DhHP-6) is encapsulated in a metal–organic framework called zeolitic imidazolate framework-8 (ZIF-8) through one-step facile synthesis. The composite (GOx&DhHP-6@ZIF-8) is then used to initiate oxygen-tolerant reversible addition-fragmentation chain-transfer polymerization for different methacrylate monomers, such as 2-diethylaminoethyl methacrylate, 2-hydroxyethyl methacrylate, and poly(ethylene glycol) methyl ether methacrylate ( M n = 500 g mol −1 ). The composite shows the robustness toward solvent and temperatures, all polymerizations using above monomers and catalyzing by GOx&DhHP-6@ZIF-8 exhibits high monomer conversion (>85%) and narrow molar mass dispersity (<1.3). Besides, acrylic and acrylamide monomers such as 2-hydroxyethyl acrylate and N,N-dimethylacrylamide are also carried to demonstrate the broad applicability. Proton nuclear magnetic resonance characterization and chain extension experiments confirm the retaining end groups of the resultant polymers, which is a significant feature of living polymerization. More importantly, the process of recycling the composite through a centrifuge is simplistic, and the composite still maintains similar activity compared to the original composites after five times. This low-cost and easily separated composite catalyst represents a versatile strategy to synthesize well-defined functional polymers suitable for industrial-scale production.
研究领域:
材料科学
·
生物化学
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DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2014
·
IF 2.129
Liang Cui,Rui Wang,Xuqiang Ji,Ming Hu,Bin Wang,Jingquan Liu
The preparation of pH responsive, biodegradable, biocompatible and cross-linked polymer capsules for controlled drug release is presented. These capsules were prepared using silica particles as templates for surface grafting of poly (acrylic acid) (PAA) and PAA-co-poly(polyethylene glycol) acrylate) (PAA-PPEGA) block copolymer via reversible addition fragmentation chain transfer (RAFT) polymerization directly from silica particles, followed by cross-linking with cystamine dihydrochloride and removal of the silica template in the presence of hydrofluoric acid, respectively. The resultant polymer capsules were water soluble, biocompatible with a mean diameter of approximately 260 ± 10 nm, and non-toxic to human cells at low concentration, which are favorable to be utilized as drug carriers for pH responsive and biodegradation controlled drug release. Doxorubicin hydrochloride (DOX) was chosen as a model drug to test the drug loading and releasing properties of the polymer capsules. It was found that the DOX could be effectively loaded into the PAA and PAA-PPEGA capsules with a loading capacity up to 52.24% and 36.74%, respectively. The pH and biodegradation controlled release behaviors of DOX loaded PAA-PPEGA capsules were also explored. The results imply that both PAA and PAA-PPEGA capsules are promising platforms for pH and biodegradation controlled drug delivery systems, while the PAA-PPEGA capsules exhibit less cytotoxicity.
研究领域:
材料科学
·
药学
·
生物医学工程
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产品关联
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 72
·58393-58402
·
IF 3.84
Yuanyuan Xu,Jinming Sun,Hou Chen,Liangjiu Bai
This study describes reversible addition–fragmentation chain-transfer (RAFT) polymerization initiated by cobalt(III) acetylacetonate (Co(acac)3). With Co(acac)3 as the initiator, RAFT polymerization of acrylonitrile was achieved at 90 °C mediated by 2-cyanoprop-2-yl dithionaphthalenoate. The polymerization exhibited “living”/controlled characteristics with a molar mass distribution as low as 1.25. Homogeneous polyacrylonitrile nanofibers (PAN-nFs) were produced via the electrospinning technique. FTIR, SEM and TGA analyses revealed aminated-PAN-nFs (APAN-nFs) were successfully obtained via ethylenediamine grafting onto the surface of PAN-nFs. The adsorption interaction between methyl orange (MO) dye and APAN-nFs is discussed in detail. The maximum saturation adsorption capacity was 102 mg g−1. The adsorption kinetics followed a pseudo-second-order model. The Langmuir model was better for interpreting the isothermal process for MO and APAN-nFs. The Dubinin–Radushkevich isothermal model indicated that the adsorption proceeded chemically. Intraparticle diffusion was not the only rate-limiting step. The thermodynamics properties indicated the adsorption process was exothermic and spontaneous in nature. The MO dye adsorbed by APAN-nFs could be reversibly desorbed by an aqueous solution of pH = 1. APAN-nFs could be recycled efficiently.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
Polymer Chemistry
·
2013
·Vol. 4
·期 6
·1921-1931
·
IF 5.231
Wei Zhou,Weijun Yu,Zesheng An
Core cross-linked star (CCS) polymers of poly(N,N-dimethylacrylamide) (PDMA) were prepared and explored as macromolecular chain transfer agents (Macro-CTAs) in the emulsion polymerization of styrene. The mass ratio of styrene : CCS and the solid content were systematically varied to elucidate their effect on the size and morphology of the particles. Control experiments using linear PDMA as a Macro-CTA were also performed in order to understand the mechanistic difference in CCS-mediated emulsion polymerization. While a two-phase process was typical of emulsion polymerization using linear Macro-CTAs, the CCS polymers functioned as “seeds” for the emulsion polymerization of styrene and exhibited a much higher polymerization rate. Significant clustering of spherical particles was observed when the mass ratio of styrene : CCS was increased while maintaining the solid content. On the other hand, linear and branched fibers were observed when the solid content was increased while maintaining the mass ratio of styrene : CCS. This morphology transformation is unique to CCS-mediated emulsion polymerization, and a protrusion mechanism caused by the cross-links in the core of the CCS was proposed to account for the aggregation of spherical particles into clusters or fibers.
研究领域:
材料科学
·
高分子化学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）