Polymer Chemistry
·
2020
·Vol. 12
·期 4
·545-553
·
IF 5.342
Lingjuan Hu,Qianqian Hao,Linan Wang,Zhe Cui,Peng Fu,Minying Liu,Xiaoguang Qiao,Xinchang Pang
We report the first example of in situ polymer brush growth on the surface of upconversion nanoparticles (UCNPs) in a one-pot near-infrared (NIR) light mediated reversible addition–fragmentation chain transfer (RAFT) polymerization. In the process of polymerization, the surface growth of polymer brushes was realized through an efficient in situ ligand exchange between a photo-activated chain transfer agent (CTA) and the ligand groups on the surface of UCNPs. BF4− was found to be the most efficient ligand in comparison with oleic acid and pyridine. The 980 nm NIR-mediated RAFT polymerization exhibits good temporal control with a low dispersity (Mw/Mn < 1.30), and the thickness of the polymer brushes can be easily adjusted by changing the polymer molecular weight and light exposure time. Moreover, the growth of polymer brushes can proceed even if there is a barrier (e.g. chicken skin) outside the reactor due to the excellent penetration ability of the NIR light.
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ACS Applied Materials & Interfaces
·
2020
·
IF 8.758
Qi Wang,Lingjuan Hu,Zhe Cui,Peng Fu,Minying Liu,Xiaoguang Qiao,Xinchang Pang
Silicon quantum dots (SiQDs) are explored for the first time as an efficient photocatalyst for visible-light-regulated reversible addition-fragmentation chain transfer (RAFT) polymerization. The fluorescence quenching confirmed the photoinduced electron transfer (PET) between SiQDs and RAFT reagents. Besides all features of controlled radical polymerization, the SiQDs catalyzed PET-RAFT polymerization also exhibit good temporal control, high chain-end fidelity, and versatility with diverse monomers. Moreover, amino-functionalized SiQDs can be easily coated on the surface of substrates (silicon wafer) owing to the electrostatic interaction, and play a dual role of polymer–substrate connector and photocatalyst for the surface-initiated PET-RAFT polymerization. The SiQD-coated wafer was also proved to be an efficient recycle photocatalyst for PET-RAFT polymerization.
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Polymer Chemistry
·
2012
·Vol. 3
·期 9
·2656-2664
·
IF 5.321
Chunlei Zhang,Miao Miao,Xueteng Cao,Zesheng An
The arm-first approach is well accepted for the synthesis of core cross-linked star (CCS) polymers, which typically involves two separate steps, i.e., the initial synthesis and purification of the arm polymers followed by a second step synthesis of CCS. We report here a one-pot approach for the RAFT synthesis of a well-defined CCS in water without the separation and purification of the arm polymers. This novel approach consists of a homogeneous polymerization step to prepare the arm polymer, polyPEGMA, and a heterogeneous polymerization step to assemble the arm polymers into CCS polymers. Various parameters affecting the formation of the CCS were studied, including the type of cross-linker, spacing monomer, arm polymer concentration and arm polymer molecular weight. Cross-linkers of longer length provided the flexibility required to form high-quality CCS polymers. The use of spacing monomers in conjugation with cross-linkers reduced the stress during cross-linking and also provided enhanced driving force to produce well-defined CCS polymers. High-quality CCS polymers were prepared at relatively high polymer concentration (≥10%). The higher molecular weight arm polymer exhibited increased steric hindrance for CCS formation. Overall, this one-pot approach is highly efficient, environmentally benign and amenable to a variety of reaction conditions.
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Polymers
·
2017
·Vol. 9
·期 3
·89
·
IF 3.364
Fangjun Yao,Qingqing Liu,Zhengbiao Zhang,Xiulin Zhu
The impacts of hydrogen bonding on polymerization behavior has been of interest for a long time; however, universality and in-depth understanding are still lacking. For the first time, the effect of hydrogen bonding on the classical alternating-type copolymerization of styrene and maleimide was explored.N-phenylmaleimide (N-PMI)/styrene was chosen as a model monomer pair in the presence of hydrogen bonding donor solvent 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), which interacted with N-PMI via hydrogen bonding. Reversible addition-fragmentation chain transfer polymerization (RAFT) technique was used to guarantee the “living” polymerization and thus the homogeneity of chain compositions. In comparison with the polymerization in non-hydrogen bonding donor solvent (toluene), the copolymerization in HFIP exhibited a high rate and a slight deviation from alternating copolymerization tendency. The reactivity ratios of N-PMI and St were revealed to be 0.078 and 0.068, respectively, while the reactivity ratios in toluene were 0.026 and 0.050. These interesting results were reasonably explained by using computer simulations, wherein the steric repulsion and electron induction by the hydrogen bonding between HFIP and N-PMI were revealed. This work first elucidated the hydrogen bonding interaction in the classical alternating-type copolymerization, which will enrich the research on hydrogen bonding-induced polymerizations.Keywords:alternating copolymerization;hydrogen bonding;N-phenylmaleimide;fluoroalcohol;reversible addition-fragmentation chain transfer (RAFT) copolymerization
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·Vol. 141
·期 14
·e55198
·
IF 2.7
Junjie Zhang,Shuiliang Yan,Xinyuan Li,Peng Xiao,Meifei Niu,Yanfu Pi,Jun Xu
The precipitation and deposition of waxes in high waxy crude oil often result in the low throughput and clogging of pipeline. Adding polymers is a practical approach to solve these problems. In this study, poly(styrene-co-docosyl maleate)s (PSDMs) were synthesized by reversible addition-fragmentation chain transfer polymerization. The chemical structure and molecular weight of copolymers were characterized using Fourier infrared spectroscopy, 1 H nuclear magnetic resonance spectroscopy, and gel permeation chromatography. The ratio of phenyl to aliphatic branches varies from 10:8 to 25:8. The crystallization and morphology of waxes in model oil were investigated by x-ray diffraction, differential scanning calorimetry, and polarized light microscopy. The cold flow behaviors of crude oil were evaluated by rheological methods. With the increase of the ratio of phenyl to aliphatic branches, the crystallinity, viscosity, and yield stress of crude oil first increase and then decrease. In the presence of PSDM-2, the crystallinity and enthalpy of phase transition (Δ H ) are reduced by 44.2% and 48.9%. Thus, the pour point, viscosity, and yield stress of crude oil are reduced by 6.0°C, 76.8% and 77.4%, respectively. Therefore, well-defined PSDMs are promising to be remarkable flow improvers for waxy crude oils.
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EUROPEAN POLYMER JOURNAL
·
2024
·
IF 5.8
Lingshan Li,Qian Zhou,Jingyi Zhao,Yuangong Zhang,Zhaolei Jia,Xuan Liu,Hailei Zhang,Xinwu Ba,Libin Bai
Multiblock copolymer macrochain-transfer agents (MBP-CTAs) can be used to synthesize MBPs in one pot via reversible addition-fragmentation chain-transfer (RAFT) polymerization. MBP-CTAs can be efficiently synthesized via a copper-catalyzed azide-alkyne cycloaddition reaction. However, traditional purification methods cannot sufficiently purify MBP-CTAs, resulting in the failure of RAFT. In this study, it was discovered that using a supported catalytic system, namely, Cu@A-HNTs, inhibited the connection between Cu and S. The residual Cu content in the MBP-CTA was successfully reduced to a low level (7.88 µg/mg). Then, hydrophilic and hydrophobic MBPs were synthesized through RAFT polymerization using the MBP-CTAs. Subsequently, multiblock copoly(methyl methacrylate-b-butyl methacrylate-CTA)s (PMMA-b-PBMA-c-CTA)s were successfully prepared. The MBP-CTAs and MBPs were characterized using ultraviolet–visible spectroscopy, 1 H nuclear magnetic resonance, size-exclusion chromatography, matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry, differential scanning calorimetry measurements and uniaxial tensile tests. The results of performance testing of PMMA-b-PBMA-c-CTAs demonstrated that their fracture stress and strain significantly increased comparing with that of PMMA-b-CTAs.
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Scientific Reports
·
2017
·Vol. 7
·期 1
·1-8
·
IF 4.259
Chen Qijing,Shi Ting,Han Fei,Li Zihan,Lin Chao,Zhao Peng
A hydrophobic CCS polymer of poly(benzyl methacrylate) (PBzMA) was prepared in toluene by reversible addition-fragmentation chain transfer (RAFT)-mediated dispersion polymerization. The CCS polymer, with poly(benzyl methacrylate) as the arm and crosslinked N , N ′-bis(acryloyl)cystamine (BAC) as the core, was confirmed by characterization with gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR) spectroscopy. Three kinds of oils (toluene, anisole and styrene) were chosen to study the emulsification properties of PBzMA CCS polymer. The oils can be emulsified by CCS polymer to form water-in-oil (w/o) emulsions. Moreover, w/o high internal phase emulsions (HIPEs) can be obtained with the increase of toluene and styrene volume fractions from 75% to 80%. Porous polystyrene monolith and microparticles were prepared from the emulsion templates and characterized by the scanning electronic microscopy (SEM). With the internal phase volume fraction increased, open-pore porous monolith was obtained.
研究领域:
材料科学
·
化学工程
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Analytical Methods
·
2020
·Vol. 13
·期 3
·426-435
·
IF 2.596
Shicong Jia,Yanqiang Zhou,Jianmin Li,Bolin Gong,Shujuan Ma,Junjie Ou
Restricted access media magnetic molecularly imprinted polymers (RAM-MMIPs) were prepared as magnetic solid phase extraction (M-SPE) material by reversible addition fragmentation chain transfer (RAFT) technique. The resulting RAM-MMIPs had a uniform, imprinted, hydrophilic layer (63 nm), good binding capacity (34.85 mg g−1) and satisfactory selectivity. In addition, these RAM-MMIPs had a robust ability to eliminate the interference of protein macromolecules. These RAM-MMIPs were then coupled with HPLC/UV to identify imazethapyr (IM) residues in untreated milk samples. Several major factors would affect M-SPE extraction efficiency, such as the amount of RAM-MMIPs, pH, extraction time of the sample solution, and the volume ratio of the elution solvent. Under the optimal conditions, the developed method had good linearity (R2 > 0.9993), low detection limit (2.13 μg L−1), and low quantitative limit (7.15 μg L−1). These results indicated this proposed approach is an efficient method for direct enrichment and detection of IM herbicides in milk and other biological samples.
研究领域:
分析化学
·
食品科学
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RSC Advances
·
2016
·Vol. 6
·期 17
·14120-14127
·
IF 3.289
Haicun Yang,Sheng Xue,Ji Pan,Fanghong Gong,Hongting Pu
Nanoclay attapulgite (ATP) was first activated with hydrochloric acid to enhance the surface reactivity, and was then allowed to react with a synthetic aromatic tertiary amine coupling agent to introduce electron-donor groups. Subsequently, the surface-initiated reversible addition–fragmentation chain transfer (SI-RAFT) polymerization of methyl methacrylate (MMA) was carried out in the presence of a free RAFT agent cyanoisopropyl dithiobenzoate (CPDB) initiated by a redox pair made up of benzoyl peroxide (BPO) and aromatic tertiary amine functionalized ATP (ATP-ATA). The grafting process was verified by 1H nuclear magnetic resonance, UV-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, thermo gravimetric analysis, transmission electron microscopy and gel permeation chromatography. Kinetic behavior indicated that polymerization using this redox initiation system displayed a living/controlled nature. Both the grafted and free polymers were grown in a controlled manner, and the RAFT polymerization proceeded with 37.6% monomer conversion achieved within 10 h at 50 °C, yielding about 47.4% grafting ratio of polymer relative to hybrid particles with high affinity to organic media.
研究领域:
材料科学
·
高分子化学
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ACS Applied Materials & Interfaces
·
2014
·
IF 5.9
Yonghuan He,Yanyan Huang,Yulong Jin,Xiangjun Liu,Guoquan Liu,Rui Zhao
The construction of molecularly imprinted polymers on magnetic nanoparticles gives access to smart materials with dual functions of target recognition and magnetic separation. In this study, the superparamagnetic surface-molecularly imprinted nanoparticles were prepared via surface-initiated reversible addition–fragmentation chain transfer (RAFT) polymerization using ofloxacin (OFX) as template for the separation of fluoroquinolones (FQs). Benefiting from the living/controlled nature of RAFT reaction, distinct core–shell structure was successfully constructed. The highly uniform nanoscale MIP layer was homogeneously grafted on the surface of RAFT agent TTCA modified Fe3O4@SiO2 nanoparticles, which favors the fast mass transfer and rapid binding kinetics. The target binding assays demonstrate the desirable adsorption capacity and imprinting efficiency of Fe3O4@MIP. High selectivity of Fe3O4@MIP toward FQs (ofloxacin, pefloxacin, enrofloxacin, norfloxacin, and gatifloxacin) was exhibited by competitive binding assay. The Fe3O4@MIP nanoparticles were successfully applied for the direct enrichment of five FQs from human urine. The spiked human urine samples were determined and the recoveries ranging from 83.1 to 103.1% were obtained with RSD of 0.8–8.2% (n = 3). This work provides a versatile approach for the fabrication of well-defined MIP on nanomaterials for the analysis of complicated biosystems.
研究领域:
分析化学
·
材料科学
·
药物分析
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EUROPEAN POLYMER JOURNAL
·
2026
·
IF 6.8
Xuewen Wu,Lingfeng Xia,Haican Liu,Xiaoqin Hu,Hongyan Zeng,Haitao Wang,Yan Xiong
The controlled synthesis of anisotropic polymer particles with precisely tunable morphologies remains a significant challenge in polymer science. Here, we report a straightforward and scalable strategy for the synthesis of Janus-like polymer particles via oxygen-tolerant photo-mediated reversible addition-fragmentation chain transfer (RAFT) Pickering emulsion polymerization. This method eliminates the need for prior deoxygenation, inert gas protection, or additives, offering a green and operationally simple approach to functional polymer particles. Key particle properties—including wettability, size, rigidity, and flexibility—can be precisely tuned by modulating the monomer-to-crosslinker ratio, introducing a third monomer, and varying the size of the calcium carbonate nanoparticle Pickering stabilizer. Notably, using 50-nm calcium carbonate nanoparticles enables the systematic evolution of particle morphology from spherical to fragmented, compositionally anisotropic Janus-like architectures. The resulting Janus-like polymer particles exhibit superior performance as solid emulsifiers for oil-in-water cinnamaldehyde (CA) emulsions, achieving exceptional stability and a sustained release profile (85% over 20 days, following the Weibull model). These emulsions demonstrate enhanced and sustained antibacterial activity against both E. coli and S. aureus , outperforming free CA. In a practical food preservation application, the Pickering emulsion reduces banana weight loss from 12.24% (blank control) to 8.97% and significantly delays peel browning over seven days. This work establishes a novel and green synthetic methodology for the controlled preparation of functional Janus-like polymer particles, with promising implications for polymer-based delivery systems in pharmaceutical and agricultural applications.
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DYES AND PIGMENTS
·
2018
·
IF 3.767
Yanzhu Liu,Liucheng Mao,Saijiao Yang,Meiying Liu,Hongye Huang,Yuanqing Wen,Fengjie Deng,Yongxiu Li,Xiaoyong Zhang,Yen Wei
In recent years, florescent polymeric nanoparticles (FPNs) containing aggregation-induced emission (AIE) fluorogens have received great intention for their potential applications in biological imaging and theranostic nanomedicine . Herein, we have developed AIE-active FPNs through a combination of reversible addition-fragmentation chain transfer (RAFT) polymerization and post-polymerization modification strategies. The salicylaldehyde (SA) containing zwitterionic copolymers are fabricated via RAFT polymerization and further modified by benzophenone hydrazone (BPH) via Schiff base reaction. The obtained AIE-active amphiphilic copolymers BPH-poly(FHMA- co -MPC) can self-assemble in aqueous solution with the hydrophobic fluorogens aggregating together to form the core and the hydrophilic chains to form the protective shell. BPH-poly(FHMA- co -MPC) and the resulting FPNs are characterized by 1 H nuclear magnetic resonance spectroscopy , Fourier transform infrared spectroscopy, transmission electron microscopy and fluorescence spectroscopy . Results demonstrate that BPH-poly(FHMA- co -MPC) are successfully synthesized and as-prepared BPH-poly(FHMA- co -MPC) FPNs exhibit desirable morphology and size, good dispersibility , high brightness, remarkable photostability and large Stokes shifts . More importantly, through cytotoxicity test and cell uptake behavior, these BPH-poly(FHMA- co -MPC) FPNs show low toxicity and excellent cell dyeing behavior. Taken together, we have developed a facile and effective method for the fabrication of AIE-active FPNs, which display great potential for biomedical applications .
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