ENERGY & FUELS
·
2024
·
IF 5.2
Dong Wang,Malcolm A. Kelland,Ying Xu,Xin Wang,Ping Lu,Jian Dong
Rapid formation of natural gas clathrate hydrates has been a significant hazard in off-shore natural gas drilling and gas transport. During operation, polymer inhibitors can serve as low-dosage kinetic inhibitors to prevent the formation of gas hydrates. A comprehensive consideration of the multiple factors involved in the actions of kinetic hydrate inhibitors (KHIs) can elucidate the inhibiting behavior of polymers. Here, amphiphilic poly(N-isopropylmethacrylamide) (PNIPMAm) (or poly(N-isopropylacrylamide)) are found to achieve weak to strong inhibition by the variable superimposed effect of the polymer’s amide group and hydrophobic effect of the polymer’s alkyl groups on the aqueous phase. The interfacial and bulk water mobility and hydrogen bonding energy in the polymer solutions are compared by low-temperature nuclear magnetic resonance (NMR) relaxometry. The mobility of the water is found to be sensitive to the hydrophobic α-methyl side group in PNIPMAm and its molecular weight when a guest molecule tetrahydrofuran is present. The water hydrogen bonding energies measured from NMR are also associated with the nonfreezable bound water amount revealed by differential scanning calorimetry. The α-methyl side group leads to a significant reduction of the water mobility, an increase in the hydrogen bonding energies of the interfacial water, and a decrease of the hydrate growth rate constants by 2 to 3 orders of magnitude. The retarded reaction kinetics of heterogeneous hydrate growth can be related to the hydrophobic effect of the polymer’s α-methyl side group and bound water properties (mobility and amount) in the interface.
研究领域:
化学工程
·
材料科学
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产品关联
DOI
高影响因子
POLYMER
·
2020
·
IF 4.231
Chandra Sekhar Biswas,Arpan Biswas,Massimillano Galluzzi,Mehdihasan I. Shekh,Qiao Wang,Biswajit Ray,Pralay Maiti,Florian J. Stadler
The synthesis of amphiphilic block-copolymers of poly( N -isopropylacrylamide) (PNIPAM) and poly( N -acryloyl- l -phenylalanine methyl ester) (PNALPA) by RAFT polymerization is reported. The polymers were characterized by proton NMR ( 1 H NMR), gel permeation chromatography (GPC), powder X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) to understand their structure-property relationships. All synthesized polymers show pH triggered release at acidic (pH 5) and biological pH (pH 7.4). Critical micellar concentration also varied systematically depending on the amphiphilic nature of the polymers. Biocompatibilities of the polymers are also determined to check their suitability for biomedical applications.
研究领域:
材料科学
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生物医学工程
·
高分子化学
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2019
·
IF 2.298
Zhen Liu,Gui Chen,Fa Zhou,Jianhan Huang
Herein, imidazolium salt incorporated poly(N-vinylimidazole-co-ethylene glycol dimethacrylate) was developed for adsorption of Congo Red (CR) and Hg2+ from aqueous solution. By the introduction of N-vinylimidazole and p-dichloroxylene on the skeletons, this polymer contained not only ionized imidazole moieties but also plenty of mesopores, endowing the polymer with excellent adsorption of CR and Hg2+. The maximum capacity at 298 K reached 503.0 and 240.0 mg/g, respectively. The Langmuir model described the equilibrium data well, and a chemical interaction in forms of electrostatic interaction, hydrogen bonding, and chelating interaction was involved in the adsorption with adsorption enthalpies of 9.99 and 17.28 kJ/mol, respectively. The adsorption was a fast process, and less than 20 min was sufficient to attain the equilibrium with pseudo-second-order rate constants of 4.003 × 10–3 and 9.830 × 10–4 g/(mg·min), respectively.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2025
·
IF 4.5
Xiaoqiang Xue,Yangjing Chen,Xuepei Miao,Jian Liu,Yi Ding,Yuheng Zhang,Yunkai Sun,Wenyan Huang,Qimin Jiang,Hongting Pu
Environmentally sensitive polymer materials exhibit diverse properties due to their ability to respond to external environmental changes such as light, temperature, pH, and et al. These responses lead to corresponding alterations in their structure or state, resulting in unexpected performance. In this study, azo pyridine groups were introduced into the end groups and side chains of PNIPAM to synthesize two distinct polymer structures (PNIPAM-AZO and P (NIPAM- co -PAZO- co -OEGMA). This integration enables the polymers to respond to multiple stimuli, including temperature, light, pH, and gas (CO 2 ). A comprehensive investigation of the properties of these multi-responsive polymer materials was conducted. The findings reveal that the presence of azo pyridine units enables both polymers to modulate the (lower critical solution temperature) LCST of PNIPAM through UV, pH, and CO 2 , with a maximum temperature adjustment of 13 °C when CO 2 is introduced. This modulation range is influenced by the azo pyridine content in the polymer. Notably, when azo pyridine is present only at the polymer end group, the maximum LCST regulation range is limited to 3 °C. Moreover, the LCST of the two polymers can also be adjusted by pH. In the presence of carbonate ions, the protonation of azo pyridine by carbonic acid increases the solubility of the polymer and enhances the LCST. Introducing argon gas removes CO 2 , thereby restoring the polymer's solubility and LCST to their neutral condition levels. By alternately introducing CO 2 and argon gas, the LCST of the polymer exhibits cyclic changes.
研究领域:
材料科学
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高分子化学
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2017
·Vol. 9
·期 7
·301
·
IF 3.364
Xiaoyan Tu,Chao Meng,Zhe Liu,Lu Sun,Xianshuo Zhang,Mingkui Zhang,Mingrui Sun,Liwei Ma,Mingzhu Liu,Hua Wei
Polymers with advanced topological architectures are promising materials for wide applications due to their structure-generated unique properties different from that of the linear analogues. The elegant integration of stimuli-responsive polymers with such advanced architectures can create novel materials with virtues from both moieties, are thus a hot subject of research for both fundamental and practical investigations. To fabricate cyclic brush polymer-based intelligent materials for biomedical applications, herein, we designed and synthesized thermo-sensitive cyclic brush polymers with poly(N-isopropylacrylamide) (PNIPAAm) brushes by controlled living radical polymerization using cyclic multimacroinitiator. The thermo-induced phase transition behaviors of the resultant cyclic brush polymers with different compositions were investigated in detail by temperature-dependent optical transmittance measurements, and compared with the properties of bottlebrush and linear counterparts. Interestingly, the cloud point transition temperature (Tcp) of cyclic brush PNIPAAm could be regulated by the chain length of PNIPAAm brush. Although the bottlebrush polymers with the same composition exhibited similarly structurally dependentTcps behaviors to the cyclic brush polymers, the cyclic brush PNIPAAm did show higher critical aggregation concentration (CAC) and enhanced stability against dilution than the bottlebrush counterpart. The readily tailorableTcps together with the ability to form highly stable nanoparticles makes thermo-sensitive cyclic brush PNIPAAm a promising candidate for controlled drug delivery.Keywords:cyclic brush polymer;thermo-sensitivity;poly(N-isopropylacrylamide)
研究领域:
材料科学
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生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2012
·
IF 2.236
Xue-Wen Liu,Shen Zhu,Sheng-Rong Wu,Pu Wang,Guo-Zhi Han
A type of poly( N -isopropylacrylamide) (PNIPAM) hydrogel with specific ion-sensitivity originating from crown ether unit is synthesized. The impacts of crown ether unit on temperature-sensitivity and ion-sensitivity of hydrogel are investigated. The result showed that crown ether units in the hydrogel network contributed to the ion response though they would reduce temperature-sensitivity of the hydrogel compared with traditional PNIPAM. Furthermore, the thermo-sensitivity and ion-recognition behaviors of the hydrogel are detailedly demonstrated which showed its potential as a promising candidate material for environment inspection, sensors and drug delivery systems.
研究领域:
材料科学
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生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
Coatings
·
2021
·Vol. 11
·期 6
·632
·
IF 2.881
Jia Li,Bo-Xiang Wang,De-Hong Cheng,Zhi-Mei Liu,Li-Hua Lv,Jing Guo,Yan-Hua Lu
There is a significant interest in developing environmentally responsive or stimuli-responsive smart materials. The purpose of this study was to investigate multi-function responsive cotton fabrics with surface modification on the nanoscale. Three technologies including electrospinning technology, interpenetrating polymer network technology, and cross-linking technology were applied to prepare the multi-function sericin/poly(N-isopropylacrylamide)/Poly(ethylene oxide) nanofibers, which were then grafted onto the surfaces of cotton textiles to endow the cotton textiles with outstanding stimuli-responsive functionalities. The multi-function responsive properties were evaluated via SEM, DSC, the pH-responsive swelling behavior test and contact angle measurements. The results demonstrate that with this method, multi-function responsive, including thermo- and pH-responsiveness, cotton fabrics were fast formed, and the stimuli-responsiveness of the materials was well controlled. In addition, the antimicrobial testing reveals efficient activity of cotton fabrics with the sericin/PNIPAM/PEO nanofiber treatments against Gram-positive bacteria and Gram-negative bacteria such asStaphylococcus aureusandEscherichia coli. The research shows that the presented strategy demonstrated the great potential of multi-function responsive cotton fabrics fabricated using our method.Keywords:sericin;poly(N-isopropylacrylamide);cotton fabrics;electrospinning
研究领域:
材料科学
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纺织工程
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2020
·
IF 7.183
Liang Cheng,Mengxiao Zhang,Chuanjie Fang,Weilin Feng,Liping Zhu,Youyi Xu
Loose nanofiltration (NF) membrane with pore radius approaching 1 nm and positive charges can be valuable alternative to commercial available negatively charged polyamide NF membrane in specific applications, such as removal of hardness and heavy metal ions and selective separation of dyes/salts mixture. In this work, positively charged poly( N -vinyl imidazole) (PVI) gel-filled loose NF membranes were developed by asymmetric gel-filling upon an asymmetric ultrafiltration (UF) support via UV-initiated surface grafting polymerization and post-quaternization. Compared to the polyamide NF membranes, these membranes displayed a comparable salt rejection ability due to their stronger Donnan exclusion effect. A rigorous three-parameter transport model (TPM) considering steric, Donnan and dielectric exclusion on ions partitioning via effective pore radius ( r p ), membrane charge density ( X d ) and averaged pore dielectric constant ( ε p ), was used to analyze the membrane parameters. Then the gel conformation model (GM) treating confined gel as semi-dilute polymer solution with a characteristic correlation length ( ξ ) was applied to analyze these gel composites. The results suggest that the gel polymer volume fraction ( φ ) is decisive in the gel mesh size (viewed as membrane pore size) and gel permeability. Surface porosity of the asymmetric UF base is a limiting factor in membrane permeability. The joint modelling analysis can clarify the membrane structure-properties relationship, performance limits and potentials of the gel-filled NF membrane and hence facilitate structure design and optimization.
研究领域:
化学工程
·
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2019
·
IF 3.131
Chuanbo Hu,Ying Li,Tingzhen Li,Yongquan Qing,Jianting Tang,Huawei Yin,Lei Hu,Lei Zhang,Yongsheng Xie,Kangning Ren
In this investigation, a comparative study on the anticorrosion properties of poly( N -methylaniline) (PNMA) coating, as well as PNMA-ZnO and PNMA/SiC-ZnO bilayer coatings, was carried out. The polymeric materials (PNMA and PNMA/SiC composite) were synthesized by emulsion polymerization method. The structures of the obtained polymeric materials were determined by different optic techniques, and the electrochemical activity and stability were examined by cyclic voltammetry . Subsequently, PNMA was spread on the surfaces of carbon steel and ZnO coating by chemical deposition method, and PNMA/SiC was spread on the surface of ZnO coating, which led to obtaining PNMA coating, PNMA-ZnO and PNMA/SiC-ZnO bilayer coatings. The structures of ZnO coating were characterized by X-ray diffraction and energy dispersive spectrometer, and the surface morphologies of all the coatings were also studied by field emission scanning electron microscopy . The anticorrosion properties of all the coatings were evaluated by electrochemical corrosion and accelerated immersion in the presence of a 3.5% NaCl solution. The results demonstrated that the polymeric materials-ZnO bilayer coatings had excellent corrosion protection ability, and in specific, for the carbon steel protected by PNMA/SiC-ZnO bilayer coatings it was higher than PNMA-ZnO bilayer coatings, with a corrosion rate of 0.004 mm/year and the protection efficiency was up to 97.43%. Overall, this study proves that the rough ZnO coating is beneficial to the embedding and pinning of polymeric materials, and the formed PNMA/SiC-ZnO bilayer coatings possess a strong adsorption ability and wide coverage area to the carbon steel substrate, which facilitates the external PNMA/SiC film to develop its unique barrier and passivation effects to prevent carbon steel from being corroded. The protection mechanism conferred by polymeric materials-ZnO bilayer coatings has also been discussed.
研究领域:
材料科学
·
腐蚀与防护
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2015
·
IF 5.056
Liang Cheng,Pei-Bin Zhang,Yi-Fan Zhao,Li-Ping Zhu,Bao-Ku Zhu,You-Yi Xu
Poly (N-vinyl imidazole) (PVI) gel-filled nanofiltration (NF) membranes were synthesized by UV-initiated graft polymerization of N-vinyl imidazole (VI) monomer , with and without crosslinker N,Nʹ-methylenbisacrylamide (MBAA) on/in a polysulfone (PSf) ultrafiltration (UF) substrate. A comprehensive characterization of the resulting composite membranes was conducted in terms of surface chemical composition (ATR-FTIR, XPS), surface morphology (SEM), surface charge (zeta potential), surface wettability (water contact angle) and barrier properties (water permeance, neutral solute/ions rejection and membrane stability). From rejection data of neutral solutes, including Vitamin B 12 and PEGs , the average pore sizes and pore size distributions of membranes were further determined. These results confirmed the prepared membranes as stable, defect-free, smooth, hydrophilic NF membranes with effective pore size between ~1.5 and 2 nm and water permeance between ~0.5 and 10 L m −2 h −1 bar −1 . Moreover, owing to the weak polybase characteristic of the incorporated PVI gel, the membranes would carry slight positive charge in neutral or slightly acidic solution. The small pore size membranes displayed high salt rejections in the order of MgCl 2 >NaCl≈MgSO 4 >NaSO 4 at near-neutral condition (pH 5.9±0.3).This testified their NF separation capability based on size exclusion, facilitated by Donnan repulsion. At last, by comparison with another reported type of gel-filled NF membranes with microporous substrate, and by applying a gel model, we delivered a qualitative description of the underlying fundamental parameters controlling the performance of such gel-filled membranes. Overall, these novel weak polybase gel-filled NF membranes with desirable nanometers-size pores and potentially tunable charge characteristics could offer great versatility for molecular-level separations.
研究领域:
材料科学
·
膜技术
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
TEXTILE RESEARCH JOURNAL
·
2016
·
IF 1.299
Jindan Wu,Yuelin Jiang,Ju He,Sufang Zhao,Guoqiang Cai,Jiping Wang
Thermo-responsive textile is newly developed and has wide application potentials in various fields. As the most commonly used textile, polyester has advantages in easy care, great durability and low cost. Since it has no reactive groups in fiber for surface functionalization, amino groups were generated by aminolysis in this study. By applying alkali deweighting during the aminolysis process, more -NH2 was produced. Poly(N-isopropylacrylamide) (PNIPAAm) was then grafted onto the surface via surface-initiated atom transfer radical polymerization. Infrared and X-ray photoelectron scanning measurements confirmed the success of PNIPAAm grafting. The thermo-switchable surface wettability was then explored by the test of surface wettability and fiber swelling–deswelling behavior. When the temperature rose, the surface switched from hydrophilic to hydrophobic as the contact angle transited from 0° to 120° reversely. This work established a feasible way and provided a new insight for preparing thermo-responsive polyester fabrics with smart cleaning and smart comfort properties.
研究领域:
材料科学
·
纺织工程
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2020
·
IF 7.489
Hui Xue,Ziqing Zhao,Rui Chen,John L. Brash,Hong Chen
Hypothesis : Poly( N -isopropylacrylamide) microgels are used extensively in the design of drug carriers, surfaces for control of cell adhesion, and optical devices . Particle size is a key factor and has a significant influence in many areas. Experiments : In this work, precise control of the particle size of poly( N -isopropylacrylamide) microgels was achieved by controlling the separation distance of the poly( N -isopropylacrylamide) chains. Dibromoalkanes of different size were used as an adjustable “molecular ruler” to measure molecular dimensions in poly( N -isopropylacrylamide) nanoaggregates at the critical crosslinking temperature. Findings : We find that the chain separation distance decreases as the temperature increases with a sharp decrease over the 55-to-65 °C interval. Based on the observed relationships between chain separation and crosslinker, the particle size of poly( N -isopropylacrylamide) microgels can be regulated by changing the length of the “molecular ruler” (crosslinker) at the same temperature. Furthermore, for partly crosslinked poly( N -isopropylacrylamide) microgels that contain free crosslinkable sites, the particle size can be reduced still more by further crosslinking (“re-crosslinking”) with crosslinkers of different size. It is shown that the particle size can be regulated by adjusting the length of “molecular ruler” and the degree of crosslinking. This work provides a “molecular level” method for precise control of poly( N -isopropylacrylamide) microgel particle size.
研究领域:
材料科学
·
生物医学工程
·
纳米技术
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）