PROGRESS IN ORGANIC COATINGS
·
2010
·
IF 1.669
Xiang-Chen Che,Yu-Zi Jin,Youn-Sik Lee
Stable nano-TiO 2 /polyurethane (PU) emulsions were prepared via in situ reversible addition-fragmentation chain transfer (RAFT) emulsion polymerization of 2-hydroxyethyl acrylate (HEA)-capped PU macromonomer, using azobisisobutyronitrile (AIBN) as a radical initiator and 2-{[(butylsulfanyl)carbonothioyl]sulfanyl} propanoic acid (BCSPA) anchored onto TiO 2 nanoparticles (TiO 2 -BCSPA) as a RAFT agent. When the molar ratio of AIBN to TiO 2 -BCSPA was changed from 1:3 to 1:10, the polydispersity index (PDI) of polymers in the emulsions decreased from 1.83 to 1.06, due to more effective RAFT polymerization in the emulsions. The TiO 2 nanofillers were well-dispersed throughout the polymer films . The tensile strengths of the nanocomposite films were significantly enhanced due to coordination bonding between the TiO 2 nanofillers and the –COOH end groups of the polymers, as evidenced by the FT-IR spectral data.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2022
·
IF 5.518
Shixian Zhang,Xinyu Ma,Yujie Zhu,Ruiwei Guo
A series of poly(acrylate polyether)s (RPA) was designed and synthesized by reversible addition-fragmentation chain transfer (RAFT) copolymerization , which were then used as dispersants for the dispersion copolymerization of styrene/acrylonitrile in polyethers in a semicontinuous approach to prepare graft polyether polyol (POP) with high solid content. The effects of structure, dosage, and feed ratio for macro-RAFT agent RPA on the stability, viscosity, and particle size of POP were examined and discussed. The dispersion polymerization process was also characterized by gradient elution polymer chromatography , and the results indicated that RPA was rapidly consumed and block-type stabilizer formed in the initial stage of polymerization. A portion of RPA added with monomer feeding provided better stability for the semicontinuous polymerization process.
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
CELLULOSE
·
2016
·Vol. 23
·期 6
·3717-3735
·
IF 3.195
Liu Ting,Xue Feng,Ding Enyong
Graft modification is an excellent way to prepare cellulose nanocrystals (CNCs) with various functions. In this work, different water-soluble macro reversible addition fragmentation chain transfer (macroRAFT) agents were used to mediate grafting of polyacrylamide with cellulose nanocrystals. Fourier-transform infrared spectroscopy, 13 C solid-state nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy, and elemental analysis were used to characterize the presence of polyacrylamide and quantify its content on the modified cellulose nanocrystals. The results show that two amphiphilic macroRAFTs, namely St 5 AA 14 RAFT and St 7 AA 14 RAFT, increased the weight ratio of polyacrylamide on the modified cellulose nanocrystals, whereas a corresponding hydrophilic macroRAFT (AA 14 RAFT) impeded growth of the polymer chains on the cellulose nanocrystals. Examination of the structure of the graft products and the cleaved polyacrylamide chains revealed that the amphiphilic macroRAFTs were involved in the graft reaction through effective chain transfer, thereby increasing the weight ratio of polyacrylamide on the modified CNCs.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
·
2020
·Vol. 32
·期 3
·1126-1134
·
IF 2.578
Xiangyun Mi,Xiuzhi Zhang,Mei Ding,Ming Zhang,Meishan Pei
Polycarboxylic acid dispersants (PCs) with comb-like molecular structure have become the focus of dispersants. However, there are many contradictions in the study of molecular structure of polycarboxylic acids. In this article, a series of PCs with different molecular structures were prepared from acrylic acid (AA) and methyl allyl alcohol polyoxyethylene ether (TPEG) by reversible addition fragmentation chain transfer (RAFT) polymerization. The structural characteristics of PCs were characterized by flourier transform infrared spectrometer (FT-IR), 1 H nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography (GPC). The dispersion performance of PCs to cement was measured by the fluidity and adsorbing capacity. The results show that the dispersion performance and adsorbing capacity of PCs are significantly related to its structure. The adsorption and dispersion properties increase with the increase of carboxyl content and molecular weight. However, this phenomenon is limited to a certain range that the acid ether ratio in this range is no greater than 5:1, and the molecular weight is no greater than PC-4 ( Mw = 82 125, Mn = 63 889).
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
JOURNAL OF POROUS MATERIALS
·
2019
·Vol. 27
·期 1
·95-105
·
IF 1.947
Xu Xiang,Zeng Yanning,Yu Caili,Zhang Faai
A series of mesoporous SBA-15 with various pore diameter (8, 15, 22 and 27 nm) were synthesized and used as “microreactor”. Reversible addition–fragmentation chain transfer (RAFT) polymerization of methyl methacrylate (MMA) was conducted in the channels of SBA-15 using azodiisobutyronitrile (AIBN) as initiator, ethyl xanthate ethyl propionate as chain transfer agent. The obtained PMMA/SBA-15 composites and neat PMMAs from composites were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption and desorption, Fourier transform infrared spectroscopy, thermogravimetry analysis, differential scanning calorimetry, hydrogen nuclear magnetic resonance. Results showed that compared with PMMA from conventional RAFT polymerization, PMMAs obtained from internal SBA-15 featured with narrower molecule weight distribution (1.34–1.55) and higher thermal stability due to confinement effects. With the increment of pore size of SBA-15, the molecular weight and glass transition temperature (T g ) of PMMA obtained from internal SBA-15 were distinctly improved whereas isotacticity of the PMMA decreased. The properties of the PMMA were managed with controllable RAFT polymerization by regulation the pore size of SBA-15.
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
TALANTA
·
2024
·
IF 5.6
Jianwen Wan,Mengge Wang,Songmin Chen,Xiyao Zhang,Wenhui Xu,Di Wu,Qiong Hu,Li Niu
The individualized administration and pharmacokinetics profiling are integral to the safe use of antibody drugs in immunotherapy. Here, we propose an electrochemical platform for the highly sensitive and selective detection of antibody drugs, taking advantage of the affinity capture by the peptide mimotopes together with the signal amplification by the biologically-driven RAFT polymerization (BDRP). Briefly, the BDRP-based platform involves the capture of antibody drugs by peptide mimotopes, the labeling of multiple reversible addition-fragmentation chain-transfer (RAFT) agents to the glycan chains of antibody drugs, and the BDRP-enabled controlled recruitment of numerous redox labels. The BDRP-based signal amplification relies on the reduction of RAFT agents by NADH coenzymes into the carbon-centered radicals, which can propagate efficiently into long polymer chains by reacting with the ferrocene-derivated monomers, recruiting numerous redox labels to the glycan chains of antibody drugs. The BDRP is conducted at the physiological temperature (i.e., 37 o C) and in the absence of external stimuli or radical sources, holding the advantages of biological compatibility and desirable simplicity over conventional RAFT polymerization approaches. The developed platform is highly selective and the detection limit in the presence of rituximab as the target was determined to be 0.14 ng/mL. Moreover, the applicability of the BDRP-based platform in the sensitive assay of antibody drugs in serum samples has been validated. In view of the biocompatibility, desirable simplicity, and cost-effectiveness, the BDRP-based platform shows great promise in the quantitative assay of antibody drugs.
研究领域:
分析化学
·
生物技术
·
药学
·
电化学
·
免疫疗法
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2023
·Vol. 30
·期 4
·1-8
·
IF 2.8
Li Dongxiang,Qian Xing,Huang Rui,Li Chunfang
Thermo-responsive poly( N -isopropylacrylamide) with terminal azobenzene group (PNIPAM-Azo) can show distinct property changes in response to temperature and light. In this paper, azobenzene-terminated trithiocarbonate (DDMAT-Azo) was synthesized as chain transfer agent, with which PNIPAM-Azo was prepared by reversible addition-fragmentation transfer (RAFT) polymerization of NIPAM in 1, 4-dioxane at 80 °C under N 2 atmosphere, azodiisobutyronitrile as initiator. The structure of DDMAT-Azo was characterized by nuclear magnetic resonance (NMR) and fourier transform infrared spectra, and PNIPAM-Azo was characterized by NMR spectra and Gel Permeation Chromatography (GPC). The result from GPC showed the numerical average molecular weight of PNIPAM-Azo was 3870 and its molecular weight distribution index was 1.31. Furthermore, thermo- and light-responsive hydrogel was obtained by introducing PNIPAM-Azo. Both PNIPAM-Azo and the hydrogel showed good light sensitivity and thermo sensitivity. Such double-stimuli sensitive hydrogel will be applied in biomaterials such as sensor, drug controlled release, information storage etc.
研究领域:
高分子化学
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材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2023
·
IF 5.2
Lijun Wang,Yangyang Zhang,Yanfei Wang,Shiding Zhang,Fang Wang,Haixiang Song,Hanyi Duan
An in-depth investigation of the ultrasonic response of mechanophores containing weak covalent bonds within nanosized aggregates is vital for ultrasound imaging, drug delivery, and sensors. In this work, well-defined amphiphilic block SP-[poly(methyl methacrylate- b -N-isopropylacrylamide)] 2 SP-[p(MMA- b -NIPAM)] 2 ( P1 ) and amphiphilic random, SP-[poly(methyl methacrylate- r -N-isopropylacrylamide)] 2 SP-[p(MMA- r -NIPAM)] 2 ( P2 ) copolymers with SP mechanophore embedded at midpoint polymer chain are prepared by RAFT (reversible addition-fragmentation chain transfer) polymerization using a pre-synthesized novel functional bi (trithiocarbonate) and spiropyran (SP)-based RAFT reagent. Both P1 and P2 copolymers self-assemble in spherical micelles in AcCN/water mixed solvents, and several assemblies with different water contents are fabricated. The structural differentiation between block P1 and random P2 dominates the inverse influence of water content on the aggregate sizes of micelles. Under ultrasound irradiation , the SP mechanophore is activated within both micelles, and the amount of activated SP mechanophore increases progressively with prolonged sonication time. For P1 , the mechanochemical reaction (mechanochromism) kinetics in an aggregated state and a single chain state are different, while that of P2 micelles and liner are similar, inferred to be associated with the structure difference between both micelles. The mechanoactivation of SP mechanophore within micelles in AcCN/water mixed solvents is higher than in dissolved state due to the micellization of P1 and P2 , entangling the hydrophobic PMMA segments and partially swelling in the micellar core. Moreover, an increase in the medium's dielectric constant around the core's SP is also observed, promoting the SP mechanoactivation. This approach may provide a new strategy for preparing novel mechanophore-centered amphiphilic copolymers with colorful structures and high hydrophilicity . These can self-aggregate into nanoparticles in aqueous or mixed solutions, exhibiting effective effects of ultrasonic responsiveness. We expect this work to push forward the in-depth studies on the ultrasonic responsive mechanism of assembly and help open new research avenues into the mechanochemical reactions within nanosized aggregates.
研究领域:
材料科学
·
高分子化学
·
纳米医学
✓ 已验证
产品关联
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2018
·
IF 5.158
Wenyan Wang,Yuanyuan Yu,Ping Wang,Qiang Wang,Yongqiang Li,Jiugang Yuan,Xuerong Fan
This study reports on eco-friendly graft polymerization approach for the modification of a cellulosic material via combination between enzymatic catalysis and reversible addition-fragmentation chain transfer polymerization (RAFT). Polyacrylamide (PAM) was polymerized on a cellulosic filter paper via horseradish peroxidase (HRP)-initiated RAFT polymerization. The results of grafting ratio, conversion, and pseudo-first-order kinetics were proved that the PAM graft polymerization on the filter paper followed RAFT rules. The results of Attenuated total reflection (ATR-FTIR), elemental analysis, and X-ray photoelectron spectroscopy (XPS) confirmed the presence of PAM in PAM-grafted filter paper. The results of water contact angle and Thermogravimetric analysis (TG) evidenced the change in the wetting properties and thermal performance, respectively of the treated filter paper. This work provides a new environmentally approach to graft polymerization on cellulosic materials.
研究领域:
材料科学
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2019
·Vol. 136
·期 24
·47653
·
IF 2.188
Jinsheng Zhou,Lin Ye,Yanming Lin,Ling Wang,Li Zhou,Huiyuan Hu,Qilong Zhang,Hui Yang,Zhongkuan Luo
To improve the antifouling property, polyvinyl alcohol hydrogel was successfully grafted with [2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide (MEDSAH) via photoinduced electron transfer–reversible addition–fragmentation chain transfer (PET-RAFT) polymerization under a 10 W blue (450–460 nm) light-emitting diodes. It is surprising that the reaction could be performed in the presence of oxygen, which meant that the reaction has a great prospect of industrialization. The highest grafting percentage (GP) was 55.77% by adding triethylamine and changed the MEDSAH usage in the absence of oxygen. Thermal gravimetric analysis exhibited that grafted MEDSAH affects the thermal property of PVA hydrogel. Also, there was no influence on the ultraviolet–visible transmittance, and the PVA-g-pMEDSAH hydrogel became hydrophilicity after grafting. Moreover, in vitro cytotoxicity of both PVA and PVA-g-pMEDSAH hydrogel was noncytotoxic according to ISO 10993-2009. The antifouling property of PVA-g-pMEDSAH hydrogel was increased about 53.05%. Thus, the PVA-g-pMEDSAH hydrogel can be an ideal optical biomaterial candidate. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47653.
研究领域:
材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL PAPERS
·
2023
·Vol. 77
·期 7
·3713-3726
·
IF 2.2
Xue Tao,Wei Yan,Yu Caili,Zhou Zhongqun,Zhang Faai
A series of mesoporous silica (MS) materials, including rod-like and spherical SBA-15, spherical MCM-41, and MCM-48, was successfully synthesized and modified by silane coupling agent γ-aminopropyltriethoxysilane. The modified MS was utilized as a microreactor for solution reversible addition–fragmentation transfer (RAFT) polymerization of methyl methacrylate (MMA) using xanthate as a chain transfer agent and azodiisobutyronitrile as an initiator. Notably, modified MS had a low specific surface area and pore volume while maintaining the original morphological structure. Given to the confinement effects, poly(methyl methacrylate) (PMMA) prepared from internal mesoporous channels had higher molecular weight and initial thermal decomposition temperature than those from conventional RAFT polymerization. Moreover, PMMA obtained from spherical SBA-15 and modified MCM-48 exhibited the highest molecular weight ( M n = 8.78 × 10 4 and M n = 7.43 × 10 4 , respectively). This work provided a novel approach in designing a polymer microstructure for a more comprehensive application, such as in drug release. Graphical abstract
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
ANALYTICAL CHEMISTRY
·
2022
·
IF 8.008
Qiong Hu,Luofeng Su,Yilin Luo,Xiaojing Cao,Shuhan Hu,Shiqi Li,Yiyi Liang,Sijie Liu,Wanjing Xu,Dongdong Qin,Li Niu
The assay of kinase activity with ultrahigh sensitivity is important to medical diagnostics and drug discovery. Herein, we report the biologically mediated RAFT polymerization (BMRP) and its potential use as an efficient amplification strategy in the ultrasensitive electrochemical sensing of kinase activity. In BMRP, the reversible addition–fragmentation chain-transfer (RAFT) process is initiated and sustained by the reduced form of coenzyme I (i.e., NADH), which can efficiently mediate the direct fragmentation of thiocarbonylthio (TCT) compounds (or the TCT-capped dormant chains) to produce an initiating/propagating radical under mild conditions. Due to the absence of exogenous radicals, the notorious radical termination in RAFT equilibrium can be greatly suppressed. For the sensing of kinase activity, the recognition peptides, without carboxyl groups, are immobilized via the Au–S self-assembly. After phosphorylation, TCT compounds (as RAFT agents) are tethered to the enzymatically generated phosphate groups via the carboxylate-Zr(IV)-phosphate (CZP) linkage. Subsequently, the BMRP of ferrocenylmethyl methacrylate (FcMMA) results in the labeling of each phosphate group with hundreds to thousands of Fc tags, thereby greatly amplifying the sensing signal. Obviously, the BMRP-based strategy is biologically friendly, highly efficient, uncomplicated, and quite low-cost. The detection limit of 1.85 mU/mL has been achieved toward the selective sensing of the cAMP-dependent protein kinase (PKA). Moreover, the proposed kinase sensor is applicable to inhibitor screening and kinase activity sensing in serum samples. By virtue of its low cost, high sensitivity and selectivity, and uncomplicated operation, the proposed kinase sensor holds great potential in medical diagnostics and drug discovery.
研究领域:
分析化学
·
生物化学
·
医学诊断
·
药物发现
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）