检索结果-南通市图书馆

Chinese Journal of Polymer Science 2012年第5期30卷 770-776页

作者： Guo-liang Yue Qian-ling Cui Yu-xi Zhang Er-jian Wang 吴飞鹏 Technical Institute of Physics and Chemistry Chinese Academy of SciencesBeijing100190China Graduate School of Chinese Academy of Sciences Beijing100049China

Therrno-responsive block copolymers poly（ethylene glycol）-block-poly（N-acryloyl-2,2-dimethyl-1,3-oxazolidine）, PEG-b-PADMO, based on linear PEG were prepared via a versatile reversible addition-fragmentation chain transfer （RAFT） polymerization, PEG22 （Mw = 1000） was used as the hydrophilic component, whose dehydration was the main driving force for the phase transition of these copolymers, as demonstrated by the tH-NMR spectra. Their lower critical solution temperatures （LCSTs） could be tuned in the range of 20℃ to 35℃, by adjusting the degree of polymerization （DP） of PADMO between 14-27. Furthermore, a sharp phase transition at ca. 33℃, close to the physiological temperature with minimal hysteresis, was observed for the PEGzz-b-PADMO14 copolymer. Moreover, excellent reversibility and reproducibility were displayed for the same copolymer over 10 cycles of repeated temperature change between 25℃ （below the LCST） and 40℃ （above the LCST）.

关键词： thermo-responsive Block copolymers Linear PEG Phase transitions.

thermo-responsive and Antifouling PVDF Nanocomposited Membranes Based on PNIPAAm Modified TiO_2 Nanoparticles

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2014年第7期32卷 892-905页

作者： Qing Zhou 李建华 Bang-feng Yan 吴东张其清 Institute of Biomedical and Pharmaceutical Technology and College of Chemistry and Chemical Engineering Fuzhou University School of Stomatology Affiliated Stomatological HospitalFujian Medical University

A novel hydrophilic nanocomposite additive （TiO2-g-PNIPAAm） was synthesized by the surface modification of titanium dioxide （TiO2） with N-isopropylacrylamide （NIPAAm） via ＂graft-from＂ technique. And the nanocomposite membrane of poly（vinylidene fluoride）（PVDF）/TiO2-g-PNIPAAm was fabricated by wet phase inversion. The graft degree was obtained by thermo-gravimetric analysis （TGA）. Fourier transform infrared attenuated reflection spectroscopy （FTIR-ATR） and X-ray photoelectronic spectroscopy （XPS） characterization results suggested that TiO2-g-PNIPAAm nanoparticles segregated on membrane surface during the phase separation process. Scanning electron microscopy （SEM） was conducted to investigate the surface and cross-section of the modified membranes. The water contact angle measurements confirmed that TiO2-g-PNIPAAm nanoparticles endowed PVDF membranes better hydrophlilicity and thermo-responsive properties compared with those of the pristine PVDF membrane. The water contact angle decreased from 92.8~ of the PVDF membrane to 61.2~ of the nanocompostie membrane. Bovine serum albumin （BSA） static and dynamic adsorption experiments suggested that excellent antifouling properties of membranes was acquired after adding TiO2-g- PNIPAAm. The maximum BSA adsorption at 40℃ was about 3 times than that at 23 ℃. The permeation experiments indicated the water flux recover ratio and BSA rejection ratio were improved at different temperatures.

关键词： PVDF membrane TiO2-g-PNIPAAm nanoparticle thermo-responsive Antifouling.

thermo-responsive stick-slip behavior of advancing water contact angle on the surfaces of poly(N-isopropylacrylamide)-grafted polypropylene membranes

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2010年第1期53卷 183-189,289页

作者： WAN LingShu,MENG XiangLin,YANG YunFeng,TIAN Jing & XU ZhiKang Key Laboratory of Macromolecular Synthesis and Functionalization,Ministry of Education Department of Polymer Science and Engineering,Zhejiang University,Hangzhou 310027,China 1. Key Laboratory of Macromolecular Synthesis and Functionalization Ministry of Education Department of Polymer Science and Engineering Zhejiang University Hangzhou 310027 China

Wettability of a solid surface is highly important to its practical application,especially for the surface that shows thermoresponsive *** this paper,we describe a thermo-responsive stick-slip behavior of water droplets on the surfaces of poly(N-isopropylacrylamide)(PNIPAM)-grafted polypropylene *** emission scanning electron microscope(FESEM) images elucidate that the morphology of PNIPAM-grafted membrane surface is thermo-responsive,i.e.,the surface becomes rougher above the lower critical solution temperature(LCST) of *** the surface of nascent polypropylene membranes,the water droplet shows a smooth motion resulting in advancing and receding water contact angles of 111° and ～65°,*** the PNIPAM-grafted membrane surfaces,the water droplet shows a stick-slip pattern above the LCST,whereas it advances smoothly below the *** phenomenon is reproducible and can be ascribed to the energy barriers enhanced by the shrink of PNIPAM chains above the *** also find that the slip contact angle decreases from 102° to 92° after several stick-slip *** decrease is attributed to the water adsorption on the grafted PNIPAM layer,which is confirmed by the continuous decrease of the receding water contact angle.

关键词： stick-slip behavior water contact angle thermo-responsive surface poly(N-isopropylacrylamide) polypropylene membrane

Synthesis and Characterization of Butyl Acrylate-based Graft Polymers with thermo-responsive Branching Sites via the Diels-Alder Reaction of Furan/Maleimide

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2018年第9期36卷 1011-1018页

作者： Lin Ye Shao-Feng Zhang Yi-Chao Lin Jia-Kang Min LI Ma Tao Tang State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 China University of the Chinese Academy of Sciences Beijing 100049 China

thermo-responsive butyl acrylate/furfuryl methacrylate copolymer-based （PBF backbone） graft （co）polymers with dynamic covalent linkages between their backbones and side chains via the Diels-Alder reaction of furardmaleimide were synthesized. Atom transfer radical polymerization （ATRP） was used to synthesize graft copolymers with thermo-responsive transformation from graft copolymers to linear polymers with bimodal or wide MWD. The NMR measurements indicated that the Diels-Alder reaction and retro- Diels-Alder reaction occurred, depending on the change of the temperature, meaning that the side chains could be cleaved and reformed according to the variation of the temperature. GPC measurements demonstrated that the molecular weights of the polymers were thermo- responsive. Furthermore, three graft copolymers with various branching chains （PBF-g-PBA, PBF-g-P（BMA-co-MA） and PBF-g-PBMA） were compared to study the influence of compatibility between the backbone and the branching chain on the efficiency of Diels-Alder reaction after the cleavage of the DA linkage. The results showed that the ability of the side chains to come back to the main chain was strongly affected by the compatibility between the backbone and the side chains and the flexibility of the polymer chains.

关键词： thermo-responsive Furan/maleimide ATRP Diels-Alder Acrylate

Hofmeister Effect on thermo-responsive Poly(N-isopropylacrylamide)Hydrogels Grafted on Macroporous Poly(vinyl alcohol) Formaldehyde Sponges

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2020年第3期38卷 257-267,I0006页

作者： Kai Shi Di Sha Jiu-Duo Xu Xu Yang Bao-Long Wang Yan-Xiong Pan Xiang-Ling Ji State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China University of Chinese Academy of Sciences Beijing 100049China

In this work,the Hofmeister effects of nine kinds of anions at different concentrations on the lower critical solution temperature(LCST)of the macroporous thermo-responsive poly(N-isopropylacrylamide)grafted poly(vinyl alcohol)formaldehyde(PVF-g-PNIPAM)hydrogels are investigated with differential scanning calorimetry(DSC).Four kinds of anions with strong hydration,including CO3^2–,SO4^2–,S2 O3^2–,and F^–,and four kinds of anions with weak hydration,including Br^–,NO3^–,I^–,and ClO4^–,and Cl^–as a medium anion are systematically studied and found to demonstrate the effects of the residual hydroxyl groups and network structure of PVF on the LCST values of PVF-g-PNIPAM hydrogels in comparison with that of neat *** the one hand,the existence of hydroxyl groups on PVF backbone promotes the solubility of grafted PNIPAM due to their hydrophilicity and hydrogen-bond interactions with *** the other hand,the network structure of as-prepared samples restricts free movements of grafted PNIPAM chains,which results in the increase of LCST *** addition,the difference of grafting percentage also influences the variation of LCST values of PVF-g-PNIPAM hydrogels under salt concentration.

关键词： Hofmeister effect thermo-responsive PVF-g-PNIPAM Hydroxyl groups Network structure

The Doubly thermo-responsive Triblock Copolymer Nanoparticles Prepared through Seeded RAFT Polymerization

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2017年第1期35卷 66-77页

作者： Quan-long Li Lei Li Hong-song Wang Rui Wang Wei Wang Yong-jing Jiang 田倩刘加平 State Key Laboratory of High Performance Civil Engineering Materials Jiangsu Research Institute of Building Science Nanjing 210008 China Jiangsu Sobute New Materials Co. Ltd. Nanjing 211103 China College of Materials Science and Engineering Southeast University Nanjing 211189 China

The doubly thermo-responsive triblock copolymer nanoparticles of polystyrene-block-poly（N- isopropylacrylamide）-block-poly[N,N-（dimethylamino） ethyl methacrylate] （PS-b-PNIPAM-b-PDMAEMA） are successfully prepared through the seeded RAFT polymerization in situ by using the PS-b-PNIPAM-TTC diblock copolymer nanoparticles as the seed. The seeded RAFT polymerization undergoes a pseudo-first-order kinetics procedure, and the molecular weight increases with the monomer conversion linearly. The hydrodynamic diameter （Dh） of the triblock copolymer nanoparticles increases with the extension of the PDMAEMA block. In addition, the double thermo-response behavior of the PS-b-PNIPAM-b-PDMAEMA nanoparticles is detected by turbidity analysis, temperature-dependent 1H-NMR analysis, and DLS analysis. The seeded RAFT polymerization is believed as a valid method to prepare triblock copolymer nanoparticles containing two thermo-responsive blocks.

关键词： thermo-responsive Seeded RAFT polymerization Block copolymers

Poly(N-isopropylacrylamide)-based thermo-responsive surfaces with controllable cell adhesion

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2014年第4期57卷 552-557页

作者： LIU HongLiang WANG ShuTao Institute of Chemistry Chinese Academy of Sciences

Poly(N-isopropylacrylamide)(PNIPAAm)-based thermo-responsive surfaces can switch their wettability(from wettable to non-wettable) and adhesion(from sticky to non-sticky) according to external temperature changes. These smart surfaces with switchable interfacial properties are playing increasingly important roles in a diverse range of biomedical applications; these controlling cell-adhesion behavior has shown great potential for tissue engineering and disease diagnostics. Herein we reviewed the recent progress of research on PNIPAAm-based thermo-responsive surfaces that can dynamically control cell adhesion behavior. The underlying response mechanisms and influencing factors for PNIPAAm-based surfaces to control cell adhesion are described first. Then, PNIPAAm-modified two-dimensional flat surfaces for cell-sheet engineering and PNIPAAm-modified three-dimensional nanostructured surfaces for diagnostics are summarized. We also provide a future perspective for the development of stimuli-responsive surfaces.

关键词： poly(N-isopropylacrylamide) (PNIPAAm) thermo-responsive smart surface cell adhesion nanostructure

One-step synthesis and self-assembly behavior of thermo-responsive star-shaped β-cyclodextrin-（P（M EO2MA-co-PEGMA））21 copolymers

在线全文

学校读者我要写书评

暂无评论

Frontiers of Materials Science 2017年第3期11卷 223-232页

作者： Lulu WEI Beibei LU Lei LI Jianning WU Zhiyong LIU Xuhong GUO School of Chemistry and Chemical Engineering Shihezi University/Key Laboratory of Materials-Oriented Chemical Engineering of Xinjiang Uygur Autonomous Region/Engineering Research Center of Materials-Oriented Chemical Engineering of Xinjiang Bingtuan Shihezi 832003 China State Key Laboratory of Chemical Engineering East China University of Science and Technology Shanghai 200237 China

A novel β-cyclodextrin-poly（2-（2-methoxyethoxy）ethyl methacrylate）-co- poly（ethylene glycol） methacrylate （abbreviated as： β-CD-（P（MEO2MA-co-PEGMA））21） was prepared by using the one-step strategy, and then the star-shaped copolymers were used in the atom transfer radical polymerization （ATRP）. The structure of star-shaped β- CD-（P（MEO2MA-co-PEGMA））21 copolymers were studied by FTIR, 1H NMR and gel permeation chromatography （GPC）. The star-shaped copolymers could self-assembled into micelles in aqueous solution owing to the outer amphiphilic β-CD as a core and the hydrophilic P（MEO2MA-co-PEGMA） segments as a shell. These thermo-responsive starshaped copolymers micelles exhibited lower critical solution temperature （LCST） in water, which could be finely tuned by changing the feed ratio of MEO2MA to PEGMA. The LCST of star-shaped β-CD-（P（MEO2MA-co-PEGMA））21 copolymer micelles were increased from 35℃ to 58℃ with the increasing content of PEGMA. The results were investigated by DLS and TEM. When the temperature was higher than corresponding LCSTs, the micelles started to associate and form spherical nanoparticles. Therefore, β- CD-（P（MEO2MA-co-PEGMA））21 star-shaped copolymer micelles could be potentially applied in nano-carrier, nano-reactor, smart materials and biomedical fields.

关键词： star-shaped copolymers thermo-responsive β-cyclodextrin (β-CD) self- assembly atom transfer radical polymerization (ATRP)

thermo-responsive graphene dispersions by liquid phase exfoliation of graphite aided by an alkylated Percec monodendron

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Materials 2017年第4期60卷 343-351页

作者： Keyang Yin College of Materials Science and Engineering Liaocheng University Liaocheng 252059 China State Key Laboratory of Solid Lubrication & Laboratory of Clean Energy Chemistry and Materials Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou 730000 China University of Chinese Academy of Sciences Beijing 100049 China

Large-scale production of graphene and sub- sequent sample engineering is the key for fully-realizing the potential applications proposed to this intriguing two-dimensional nanomaterial. Herein, smart graphene dispersions with low defects and thermo-responsive properties can be obtained by liquid phase exfoliation of graphite using an alkylated Percec monodendron （3,4,5-trioctadecy- loxybenzaldehyde, 1） as the stabilizing reagent. By simply changing the temperature, the dispersed graphene and 1 can be detached, leading to the recovery of both components. Besides noncovalent wrapping, the stabilizing reagent 1 can be also covalently attached to graphene through [3＋2] cycloaddition. The covalently functionalized graphene sheets show improved dispersibility in organic solvents compared to the pristine graphene, which opens the door for their applications in various polymer matrixes. The strategy demonstrated here provides a new methodology to get smart graphene dispersions with multiple functions.

关键词： graphene thermo-responsive liquid phase exfoliation alkylated cycloaddition

Rheological properties of novel thermo-responsive polycarbonates aqueous solutions

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2008年第S1期15卷 102-106页

作者：王月霞谭业邦黄晓玲 School of Chemistry and Chemical Engineering Shandong University Key Laboratory of Colloid and Interface Chemistry Ministry of EducationShandong University

thermo-responsive multiblock polycarbonates were facilely synthesized by covalently binding poly(ethylene glycol)(PEG) and poly(propylene glycol)(PPG) blocks,using triphosgene as coupling agent and pyridine as *** aqueous solutions of thermo-responsive polycarbonates were investigated by rheological ***-state shear measurements reveal that the polycarbonate solutions exhibit shear-thinning behavior and the hydrophilic content has a pronounced effect on the flow behavior of the polycarbonates aqueous *** shear viscosity decreases with increasing poly(ethylene oxide)(PEO) *** increase of viscosity with increasing concentration is probably attributed to the formation of stronger network owing to interchain entanglement of PEO block at higher *** the flow curves are fitted to the power law model,flow index is obtained to be less than 1,as exhibiting typical pesudoplastic *** viscoelastic properties of the system also show close dependence on the composition of *** sweep confirms that the multiblock polycarbonates exhibit thermo-responsive *** 7% aqueous solution of polycarbonate with composition ratio of EO to PO of 1/1,the sol-gel transition occurs at 37 ℃,which makes the system suitable as an injectable drug delivery system.

关键词： polycarbonates thermo-responsive rheological measurements viscosity gel