COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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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.
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高影响因子
POLYMER ENGINEERING AND SCIENCE
·
2022
·Vol. 62
·期 9
·2769-2778
·
IF 2.573
Xiaodong Chen,Xinde Tang,Cuizhen Zhang,Xiao Lu,Haichao Guo,Xuefan Li,Laixue Pang,Yong Yang,Fuying Dong
Polycarboxylate ether superplasticizers (PCEs) with comb-shaped molecular structures have attracted considerable attention in the area of admixtures for construction engineering. However, there are some contradictions in studying the relationship between the molecular structure and property of PCE due to its random structure based on traditional free radical polymerization, which is confused for designing and developing novel PCEs. In this article, a series of reversible addition fragmentation chain transfer (RAFT) polymerization-based polycarboxylate ether superplasticizers (RPCs) were prepared by the copolymerization of acrylic acid (AA) and ethylene-glycol monovinyl polyethylene glycol (EPEG). The chemical structure and composition of RPCs were characterized and their adsorption behavior and dispersion properties were conducted. The results demonstrate that the molecular weights of RPCs do not vary significantly with prolonging reaction time, and the actual monomer ratio in RPCs displays a significant change to the feed one due to the monomer reactivity and conversion at higher reaction temperature, which is different from conventional free radical polymerization. The dispersion and adsorption properties of RPCs to cement were evaluated by slurry fluidity tests and total organic carbon (TOC) experiments. The effect of polymerization temperature and time on the dispersion ability has been systematically studied. The results indicate that the dispersion ability and adsorption capacity of RPCs are closely related to their molecular structures. The dispersion ability of RPCs were enhanced with increasing carboxyl group density in a certain range of monomer molar ratios (≤6:1). This study will provide a new platform for designing and developing high-performance and rational cost-effective superplasticizers with well-defined structure and controlled molecular weight.
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 139
·期 43
·e53061
·
IF 3.057
Binglun Gao,Lianwei Sun,Xin Chen,Xiaobo Zhai,Junchi Zheng,Xin Ye,Jianmin Lu,Anchao Feng,Liqun Zhang
The focus of this paper is to report the quantitative synthesis of bis-epoxy end functionalized polyisoprene (BETPI) macromonomers by anionic polymerization and reversible addition fragmentation chain transfer (RAFT) polymerization. For anionic polymerization, more stable and sterically hindered living anions polyisoprene (Li + -PIp-Li + ) react with epichlorohydrin (ECH) for the synthesis of well-defined BETPI. For the high-pressure RAFT polymerization, a novel bis-epoxy end functionalized trithiocarbonate (BODAAT) is designed as RAFT agent for the polymerization of isoprene monomer to obtain well-defined BETPI. The functionalities of the resulting BETPI are analyzed by Fourier transform infrared spectroscopy (FT-IR), NMR, and size exclusion chromatography (SEC). Through two polymerization methods, the BETPI with 600–1000 Da of molecular weight and over 75% of epoxy end capping rate is obtained, which can be further utilized as highly reactive liquid macromonomers.
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FIBERS AND POLYMERS
·
2021
·Vol. 23
·期 2
·396-403
·
IF 2.153
Meng Xu,Dong Yanyan,Arias Manuel J. Lis,Mu Song,Liang Liping
For the actual courses of surroundings conservation, segregation of oily water mixtures is increasingly desired. The hydrophobic/oleophilic cotton fabric as a system for removing oil from a water phase was prepared by reversible addition fragmentation chain transfer (RAFT) reaction technology. A piece of fabric was modified with the RAFT chain transfer agent S-1-Dodecyl-S′-(α′,α″-dimethyl-α″-acetic acid) trithiocarbonate (CTA), then hydrophobic/oleophilic interface was fabricated on the CTA modified fabric by grafting the octadecyl methacrylate. The chemical structures, surface topographies and surface properties were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and contact angle experiments, respectively. The ability of as-prepared fabric with a separation efficiency was better than 97.0 % on average for various types of oil/water mixtures demonstrated the hydrophobic/oleophilic property. We believe that the work will extend the applications of fabric in the oil/water separation and provide a new design in practical applications.
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高影响因子
ANALYTICAL CHEMISTRY
·
2021
·
IF 6.986
Qiong Hu,Luofeng Su,Zhuohua Chen,Yanyu Huang,Dongdong Qin,Li Niu
Trypsin is a key proteolytic enzyme in the digestive system and its abnormal levels are indicative of some pancreatic diseases. Taking advantage of the coenzyme-mediated electrografting of ferrocenyl polymers as a novel strategy for signal amplification, herein, a signal-on cleavage-based electrochemical biosensor is reported for the highly selective interrogation of trypsin activity at ultralow levels. The construction of the trypsin biosensor involves (i) the immobilization of peptide substrates (without free carboxyl groups) via the N-terminus, (ii) the tryptic cleavage of peptide substrates, (iii) the site-specific labeling of the reversible addition–fragmentation chain transfer (RAFT) agents, and (iv) the grafting of ferrocenyl polymers through the electro-RAFT (eRAFT) polymerization, which is mediated by potentiostatic reduction of nicotinamide adenine dinucleotide (NAD+) coenzymes. Through the NAD+-mediated eRAFT (NAD+-eRAFT) polymerization of ferrocenylmethyl methacrylate (FcMMA), the presence of a few tryptic cleavage events can eventually result in the recruitment of a considerable amount of ferrocene redox tags. Obviously, the NAD+-eRAFT polymerization is low-cost and easy to operate as a highly efficient strategy for signal amplification. As expected, the as-constructed biosensor is highly selective and sensitive toward the signal-on interrogation of trypsin activity. Under optimal conditions, the detection limit can be as low as 18.2 μU/mL (∼72.8 pg/mL). The results also demonstrate that the as-constructed electrochemical trypsin biosensor is applicable to inhibitor screening and the interrogation of enzyme activity in the presence of complex sample matrices. Moreover, it is low-cost, less susceptible to false-positive results, and relatively easy to fabricate, thus holding great potential in diagnostic and therapeutic applications.
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PubMed
高影响因子
Polymers
·
2017
·Vol. 9
·期 12
·681
·
IF 3.364
Jianbo Tan,Xueliang Li,Jun He,Qin Xu,Yuxuan Zhang,Xiaocong Dai,Liangliang Yu,Ruiming Zeng,Li Zhang
Herein, we report a photoinitiated reversible addition-fragmentation chain transfer (RAFT) dispersion copolymerization of methyl methacrylate (MMA) and methyl methacrylic (MAA) for the preparation of highly monodisperse carboxyl-functionalized polymeric microspheres. High rates of polymerization were observed, with more than 90% particle yields being achieved within 3 h of UV irradiation. Effects of reaction parameters (e.g., MAA concentration, RAFT agent concentration, photoinitiator concentration, and solvent composition) were studied in detail, and highly monodisperse polymeric microspheres were obtained in most cases. Finally, silver (Ag) composite microspheres were prepared by in situ reduction of AgNO3using the carboxyl-functionalized polymeric microspheres as the template. The obtained Ag composite microspheres were able to catalyze the reduction of methylene blue (MB) with NaBH4as a reductant.Keywords:carboxyl-functionalized microspheres;RAFT polymerization;photoinitiated dispersion polymerization
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高影响因子
Polymer Chemistry
·
2021
·Vol. 13
·期 7
·914-921
·
IF 5.582
Fei Deng,Menglin Yang,Yanli Zhang,Xiaohui Wu,Rujiang Ma,Feihe Ma,Linqi Shi
Refolding a denatured protein into its native form and stabilizing its structure are significant in the production and storage of protein products. The self-assembled mixed-shell polymeric micelle (MSPM) based nanochaperones closely mimic natural molecular chaperones in terms of structure and function and have been widely used to regulate the (re)folding of denatured proteins. However, the traditional manufacturing method of MSPM based nanochaperones is inconvenient with a very low concentration, which greatly restricts its large-scale applicability in practice. Here, we developed a one-pot strategy to synthesize high-concentration MSPMs for the mass preparation of nanochaperones to refold bulk denatured proteins and stabilize the structure of native proteins. The high-concentration MSPM is synthesized using two macro-RAFT agents to induce the polymerization and cross-linking of hydrophobic monomers. Through this one pot synthesis method, MSPMs with a concentration of 36.8 mg ml−1 are obtained, which is much higher than that obtained through the traditional method (0.5 mg ml−1). Moreover, the obtained MSPMs provide a good renaturation efficiency for the refolding of bulk denatured proteins and can stabilize native proteins for long-term storage. This strategy provides a simple method for the mass preparation of functional nanochaperones, which will promote its applications in practice.
研究领域:
生物化学
·
分子生物学
·
纳米医学
·
药物递送
·
蛋白质工程
·
高分子科学
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高影响因子
JOURNAL OF CONTROLLED RELEASE
·
2026
·
IF 12.4
Yingzi Li,Yanxia Yang,Wenxin Zhao,Zhen Ren,Ningbo Zhang,Xiaoxu Cao,Qian Dong,Mingcan Bao,Zouyixing Lv,Ziyang Li,Changwei Lin,Ding Ding,Zhuo Chen
Current gastroesophageal reflux disease (GERD) therapies either systemically suppress gastric acid, risking physiological disruption, or rely on antacid rafts that offer transient, non-responsive neutralization. We address this with a chemistry-centered strategy that spatially localizes proton conversion around the self-positioning raft at the gastric interface. The dynamic H + conversion equilibrium system (DH + -CES) integrates a CO 2 -generating calcium alginate raft which physically impedes reflux via its bubble-stabilized architecture for rapid interfacial self-positioning, with an engineered Lactococcus lactis expressing acid urease. Under acidic challenge, urease catalysis consumes protons locally. As pH normalizes, feedback-regulated enzymatic attenuation constrains the reaction zone, preventing bulk alkalization. DH + -CES elevates interfacial pH from 2.0 to ∼5.0 within 5 min, sustains this zone for hours while modulating only 5.38% of total fluid volume, and reduces reflux-like surge height by 38%. In an acute rat GERD model, it inhibits esophageal injury by 93.95%, downregulates key inflammatory mediators, and shows favorable biocompatibility. These findings establish DH + -CES as a proof-of-concept interface-resident chemical gatekeeper for localized, self-limiting, and physiologically respectful pH control.
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PubMed
高影响因子
TALANTA
·
2019
·
IF 4.916
Qiong Hu,Jinming Kong,Dongxue Han,Yu Bao,Xueji Zhang,Yuwei Zhang,Li Niu
Since the oversecretion of protein kinases is indicative of multiple human diseases, the screening of their activities is quite important to clinical diagnosis and targeted therapy. In this work, an ultrasensitive peptide-based electrochemical biosensor was presented for the detection of protein kinase activity by using the reversible addition-fragmentation chain transfer (RAFT) polymerization technique as a signal amplification strategy. First, the substrate peptides were tethered to a gold electrode surface via the thiol terminals. After the phosphorylation of substrate peptides by protein kinases, the carboxyl group-containing dithiobenzoates were labeled to the phosphorylated sites via the robust phosphate-Zr 4+ -carboxylate linkages. Finally, the RAFT polymerization was initiated using ferrocenylmethyl methacrylates (FcMMAs) and dithiobenzoates as the monomers and the RAFT agents, respectively. The grafting of ferrocenyl polymer chains efficiently recruits a great number of electro-active Fc probes to each phosphorylated site, leading to a drastic amplification of the electrochemical signal. With PKA (protein kinase A) as the target, the detection limit of the peptide-based biosensor can be as low as 1.05 mU mL −1 . Moreover, it can selectively differentiate the target from other interferents and is applicable for the screening of potential inhibitors as well as the detection of protein kinase activity in complex cell lysates. Therefore, the peptide-based biosensor shows great promise as a universal tool for protein kinase activity detection and inhibitor screening.
研究领域:
生物化学
·
分析化学
·
生物医学工程
·
分子生物学
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PubMed
高影响因子
MACROMOLECULES
·
2022
·
IF 6.057
Bowen Zhao,Jiajia Li,Yuan Xiu,Xiangqiang Pan,Zhengbiao Zhang,Jian Zhu
Three-dimensional (3D) printing based on photoinduced reversible addition–fragmentation chain transfer (RAFT) polymerization is emerging as a versatile and powerful method to prepare “living” 3D objects, which can be postmodified with various functionalities. However, an additional photoinitiator or photocatalyst is necessary in these systems, which is toxic and will cause negative effects on the properties of the prepared materials. Here, we report oxygen-tolerant and rapid living 3D printing based on photoiniferter RAFT polymerization, which does not need additional photoinitiators or photocatalysts. A xanthate, O-ethyl-S-2-ethyl propionate, was chosen as both the photoinitiator and RAFT agent in this process. Various monomers and RAFT agents were screened in this system. Materials with different properties were prepared utilizing the postfunctionalization of the printed living objects. Furthermore, a polymer welding method was proposed by painting fresh monomers between two living objects for post-photocuring. This photoiniferter RAFT polymerization-based living 3D printing method was also successfully applied to a commercial digital light processing technique-based 3D printer, offering a facile method to fabricate living 3D materials with different shapes.
研究领域:
材料科学
·
聚合物化学
·
3D打印
·
光聚合
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高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2023
·Vol. 41
·期 12
·1856-1867
·
IF 4.3
Zhang Yan-Xin,Chen Dong,Hu Gao-Fei,Ma Yu-Hong,Yang Wan-Tai
The alternating copolymerization of hydroxyalkyl vinyl ethers and dialkyl maleates is investigated by conventional radical polymerization and reversible addition-fragmentation chain transfer polymerization (RAFT). The influence of comonomer structure, comonomer feeding ratios, and monomer concentrations on the copolymerization and the copolymer structure have been investigated systematically. With 2-hydroxyethyl vinyl ether (HEVE) and dimethyl maleates (DMM) as comonomers, a well-defined alternating copolymer is prepared with M n =3400 and M w / M n =1.93 up to 71.6% monomer. The alternating sequential chain structure of the copolymers has been proved by both NMR and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The experimental reactivity ratios and theoretical calculated highest occupied molecular orbital and the lowest unoccupied molecular orbital of vinyl ethers and alkyl maleates support that these monomer pairs have tendency to form alternating copolymers. With 2-cyanopropan-2-yl N -methyl- N -(pyridin-4-yl)carbamodithioate as the RAFT agent, the molecular weight of HEVE and DMM copolymer increases with the monomer conversion, demonstrating a controlled radical polymerization feature with well-controlled molecular weight and relatively narrower molecular weight distribution. With alternating copolymer of HEVE and DMM as macro-CTA ( M n =5200 and M w / M n =1.46), both the chain extension with HEVE and DMM ( M n =10400 and M w / M n =1.72) and block copolymerization with vinyl acetate have been successfully achieved ( M n =8500 and M w / M n =1.52).
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高影响因子
CARBOHYDRATE POLYMERS
·
2022
·
IF 10.723
Zhiqiang Wang,Lujun Zhang,Jiajun Feng,Pengfei Tang,Shuaishuai Chen,Hanqing Yu,Yueyao Hu,Zhongkai Wang,Feng Jiang
In this work, a chitin-based macromolecular chain transfer agent (Chitin-CTA) was designed to graft polymers from chitin at the molecular level. Homogeneous reversible addition-fragmentation chain transfer (RAFT) polymerization was performed to prepare branched MA elastomers , chitin- graft -poly(methyl acrylate) (Chitin- g -PMA) copolymers , which were thermally stable and showed tunable glass transition temperatures . These ultra-stretchable branched MA elastomers exhibit unique strain-hardening behavior and significantly enhanced mechanical properties. Mechanical tests indicate that the chitin backbones in branched MA elastomers can act as cross-linking points to improve the tensile strength , toughness, and elasticity simultaneously. The macroscopic performance of branched MA elastomers c be further promoted by introducing hydrogen bonding as non-covalent interaction to form an additional reversible physical network. This robust and versatile grafting strategy can provide new opportunities to prepare chitin-based branched MA elastomers with extraordinary mechanical properties.
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高影响因子
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