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In-Situ Synthesized Myoglobin Imprinted Poly(N-Isopropylacrylamide)/Silica Nanocomposite Gels by Using the Molecular Imprinting Method 被引量:1
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作者 Burcu Meshur Eylem Turan Nursel Dilsiz 《Advances in Materials Physics and Chemistry》 2014年第1期1-5,共5页
Temperature sensitive imprinted poly(N-isopropylacrylamide) nanocomposite gels were syntheses via in-situ, free radical crosslinking polymerization of corresponding monomer in nano-sized silica and five different conc... Temperature sensitive imprinted poly(N-isopropylacrylamide) nanocomposite gels were syntheses via in-situ, free radical crosslinking polymerization of corresponding monomer in nano-sized silica and five different concentrations of myoglobin solution by using the molecular imprinting method. Mb adsorption from five different concentrations of Mb solutions was investigated by two types of nanocomposite gel systems prepared by non-imprinted and imprinted methods. Nanocomposite gels imprinted with Mb showed higher adsorption capacity and specificity for Mb than nanocomposite gels prepared by the usual procedure. The highest Mb adsorption was observed via the imprinted nanocomposite gels with 12.5% Mb. In addition, selectivity studies were also performed by using two reference molecules as fibrinogen and hemoglobin. The imprinted nanocomposite gels had higher adsorption capacity for Mb than the non-imprinted gels and also exhibited good selectivity for Mb and high adsorption rate depending on the number of Mb sized cavities. 展开更多
关键词 Nanocomposite gels poly(n-isopropylacrylamide) Temperature Sensitive Myglobin Free Radical Crosslinking polymerization Adsorption Imprinted
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Synthesis and Properties of Poly (N-isopropylacrylamide) and Poly (N-isopropylacrylamide-co-acrylamide) Hydrogels
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作者 裴勇 陈捷 +2 位作者 杨黎明 施丽莉 罗浩杰 《Journal of Shanghai University(English Edition)》 CAS 2005年第5期466-470,共5页
The thermosensitive poly ( N-isopropylacrylamide ) (PNIPAAm) and poly (N-isopropylacrylamide-co-acrylamide) [ poly (NIPAAm-co-AAm) ] hydrogels with different acrylamide molar percentage are prepared by radiati... The thermosensitive poly ( N-isopropylacrylamide ) (PNIPAAm) and poly (N-isopropylacrylamide-co-acrylamide) [ poly (NIPAAm-co-AAm) ] hydrogels with different acrylamide molar percentage are prepared by radiation polymerization using Co^60 γ-ray. Their swelling equilibrium data in the media of deionized water, NaCl aqueous solutions and different pH buffer solutions are determined. It appears that lower critical solution temperature (LCST) of the hydrogels will drop with the increase of ionic strength and increase with the rising of acrylamide content, A semi-empirical formula is set up with the experimental results. Moreover, it also indicates that this copolymer is pH-sensitive, which is similar to the homopolymer of PNIPAAm. 展开更多
关键词 hydrogel lower critical solution temperature (LCST) poly (n-isopropylacrylamide poly (n-isopropylacrylamide-co-acrylamide) ionic strength pH sensitive.
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Temperature-pH Sensitive IPN Hydrogels Composed of Silk Sericin and Poly(N-isopropylacrylamide)
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作者 Wen WU Wen Jing LI +2 位作者 Li Qun WANG Ke Hua TU Wei Lin SUN 《Chinese Chemical Letters》 SCIE CAS CSCD 2006年第3期403-406,共4页
Interpenetrating polymer network (IPN) composed of silk sericin (SS) and poly(N-isopropylacrylamide) (PNIPAAm) was prepared. The morphology of the IPNs, in which the SS phase was stained with ammonium cuprate,... Interpenetrating polymer network (IPN) composed of silk sericin (SS) and poly(N-isopropylacrylamide) (PNIPAAm) was prepared. The morphology of the IPNs, in which the SS phase was stained with ammonium cuprate, was examined with TEM and a relative homogeneous distribution of the two polymers was exhibited. The swelling behavior of the IPN hydrogels showed both temperature and pH dependences. 展开更多
关键词 Silk sericin poly(n-isopropylacrylamide interpenetrating polymer network.
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Poly(N-isopropylacrylamide)-based Vertically Sandwich-typed Hydrogel with Fast Temperature-response Speed and Its Controlled-release Characteristics
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作者 卢程 肖新才 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2012年第2期280-284,共5页
A novel poly(N-isopropylacrylamide)-based sandwich-typed hydrogel, which was featured with both ends of linear poly(N-isopropylaerylamide) (PNIPAM) chains being grafted onto cross-linked PNIPAM chains, was succe... A novel poly(N-isopropylacrylamide)-based sandwich-typed hydrogel, which was featured with both ends of linear poly(N-isopropylaerylamide) (PNIPAM) chains being grafted onto cross-linked PNIPAM chains, was successfully prepared in a three-step process by a method of sequential synthesis. The proposed hydrogel displays faster and hydration/dehydration dynamic response to temperature cycling owing to linear PNIPAM chains to form big-pore structure. This work may lead to high attraction for targeting drug delivery systems, polymeric pump, sensors and so on. 展开更多
关键词 sandwich-typed hydrogels microstructure poly(n-isopropylacrylamide gels
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Microwave-assisted Preparation of Temperature Sensitive Poly(N-isopropylacrylamide) Hydrogel with Improved Responsive Properties
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作者 Shao Hua SHI Li Jian LIU 《Chinese Chemical Letters》 SCIE CAS CSCD 2006年第3期361-364,共4页
Poly(N-isopropylacrylamide)-based hydrogel was prepared under microwave irradiation The hydrogel thus prepared, comparing with that prepared by thermal heating method, exhibits faster swelling and shrinking kinetics... Poly(N-isopropylacrylamide)-based hydrogel was prepared under microwave irradiation The hydrogel thus prepared, comparing with that prepared by thermal heating method, exhibits faster swelling and shrinking kinetics. The improved responsive properties are due to the more heterogeneous and porous networks formed under microwave irradiation. 展开更多
关键词 MICROWAVE poly(n-isopropylacrylamide HYDROgel fast response.
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Laterally Sandwich-typed Hydrogel Columns with Liner Poly(N-isopropylacrylamide) Layer:Preparation, Swelling/deswelling Kinetics and Drug Delivery Characteristics
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作者 LI Ying XIAO Xincai 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2012年第1期115-119,共5页
A novel thermo-responsive hydrogel column, featured with both ends of linear poly(N- isopropylacrylarnide) (PNIPAM) chains being grafted onto cross-linked PNIPAM chains, was reported. The laterally sandwich-typed ... A novel thermo-responsive hydrogel column, featured with both ends of linear poly(N- isopropylacrylarnide) (PNIPAM) chains being grafted onto cross-linked PNIPAM chains, was reported. The laterally sandwich-typed hydrogel columns were fabricated by radical polymerization in a three-step process using a method of ice-melting synthesis. The initiating path, morphology and thermoresponsive characteristics of the prepared hydrogel columns were experimentally studied. The results show that the hydrogel column obtained by the initiator inside part has more quick swelling and deswelling rates responsing to temperature cycling than other hydrogels owing to linear PNIPAM chains to form supermacroporous structure. The proposed hydrogel structure provide a new mode of the phase transition behavior for thermo-sensitive "smart" or "intelligent" monodisperse micro-actuators, which is highly attractive for targeting drug delivery systems, chemical separations, and sensors and so on. 展开更多
关键词 ice-melting synthesis laterally sandwich-typed hydrogel columns swelling/de-swellingrates poly(n-isopropylacrylamide
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Preparation of Hollow Silica Microspheres via Poly(N-isopropylacrylamide) 被引量:2
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作者 汪谟贞 陈宇晨 +1 位作者 葛学平 葛学武 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2012年第1期120-124,I0004,共6页
Core-shell structured SiO2/poly(N-isopropylacrylamide) (SiO2/PNIPAM) microspheres were successfully fabricated through hydrolysis and condensation reaction of tertraethyl orthosilicate (TEOS) on the surface of P... Core-shell structured SiO2/poly(N-isopropylacrylamide) (SiO2/PNIPAM) microspheres were successfully fabricated through hydrolysis and condensation reaction of tertraethyl orthosilicate (TEOS) on the surface of PNIPAM template at 50 ~C. The PNIPAM template can be easily removed by water at room temperature so that SiO2 hollow microspheres were finally obtained. The transmission electron microscope and scanning electron microscope observations indicated that SiO2 hollow microspheres with an average diameter of 150 nm can be formed only if there are enough concentration of PNIPAM and TEOS, and the hy- drolysis time of TEOS. FTIR analysis showed that part of PNIPAM remained on the wall of SiO2 because of the strong interaction between PNIPAM and silica. This work provides a clean and efficient way to prepare hollow microspheres. 展开更多
关键词 SiO2 hollow microsphere poly(n-isopropylacrylamide Tertraethyl orthosilicate Soft template
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Rheological behavior of ZnO suspension with thermosensitive poly(N-isopropylacrylamide) for colloidal processing of ceramics
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作者 孙月花 彭超群 +3 位作者 王小锋 王日初 冯艳 王乃光 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第11期2930-2938,共9页
Novel colloidal processing using thermosensitive poly(N-isopropylacrylamide) (PNIPAM) as a coagulating agent has beendeveloped to prepare complex-shaped ceramic components. In this work, the properties of PNIPAM a... Novel colloidal processing using thermosensitive poly(N-isopropylacrylamide) (PNIPAM) as a coagulating agent has beendeveloped to prepare complex-shaped ceramic components. In this work, the properties of PNIPAM aqueous solutions and therheological behavior of ZnO suspensions with PNIPAM were investigated. The results show that the PNIPAM solutions exhibitobvious thermosensitivity and its transition temperature is around 32℃. When the temperature is above 40℃ (Tc, the criticaltransition temperature of thermosensitive suspension), the 50% ZnO (volume fraction) suspension with 8 mg/mL PNIPAM has asharp increase in viscosity and reaches up to 11.49 Pa·s at 50℃, displaying strong elasticity. The main reasons are the increase ofeffective volume fraction attributed to precipitation of PNIPAM segments and the flocculation between ZnO powder particles. Inaddition, the maximum solid loading (volume fraction) at 20 ℃ is higher than that at 40℃, which proves that the phase transition ofPNIPAM can induce the flocculation of suspension. 展开更多
关键词 rheological behavior ZNO poly(n-isopropylacrylamide colloidal processing THERMOSENSITIVITY effective volumefraction
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Effect of Graft Yield on the Thermo-Responsive Permeability Through Porous Membranes with Plasma-Grafted Poly(N-isopropylacrylamide)Gates 被引量:6
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作者 褚良银 朱家骅 +3 位作者 陈文梅 NIITSUMA Takuya YAMAGUCHI Takeo NAKAO Shin-ichi 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2003年第3期269-275,共7页
The effect of graft yield on both the thermo-responsive hydraulicpermeability and the therrno-responsive diffusional permeability through porous membranes withplasma-grafted poly(N-isopropylacrylamide) (PNIPAM) gates ... The effect of graft yield on both the thermo-responsive hydraulicpermeability and the therrno-responsive diffusional permeability through porous membranes withplasma-grafted poly(N-isopropylacrylamide) (PNIPAM) gates was investigated. Both thermo-responsiveflat membranes and core-shell microcapsule membranes with a wide range of graft yield of PNIPAM wereprepared using a plasma-graft pore-filling polymerization method. The grafted PNIPAM was formedhomogeneously throughout the entire thickness of both the flat polyethylene membranes and themicrocapsule polyamide membranes. Both the hydraulic permeability and the diffusional permeabilitywere heavily dependent on the PNIPAM graft yield. With increasing the graft yield, the hydraulicpermeability (water flux) decreases rapidly at 25℃ because of the decrease of the pore size;however, the water flux at 40℃ increases firstly to a peak because of the increase ofhydrophobicity of the pore surface, and then decreases and finally tends to zero because of the poresize becoming smaller and smaller. For the diffusional permeability, the temperature showsdifferent effects on the diffusional permeability coefficients of solutes across the membranes. Whenthe graft yield was low, the diffusional coefficient of solute across the membrane was higher attemperature above the lower critical solution temperature (LCST) than that below the LCST; however,when the graft yield was high, the diffusional coefficient was lower at temperature above the LCSTthan that below the LCST. It is very important to choose or design a proper graft yield of PNIPAMfor obtaining a desired thermo-responsive 'on/off' hydraulic or diffusional permeability. 展开更多
关键词 thermo-responsive membrane poly(n-isopropylacrylamide) plasma-graftpore-filling polymerization graft yield hydraulic permeability diffusional permeability
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The Swelling Equilibria of N-isopropylacrylamide Based Hydrogel in Aqueous Solution of Ethanol 被引量:3
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作者 许小平 HüTHER Andreas MAURER Gerd 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2003年第3期264-268,共5页
N-isopropylacrylamide (NIPAAm) was used to synthesize NIPAAm homopolymer (nonionized) and NIPAAm-sodium methacrylate copolymer (ionized). The swelling equilibria for both gels were obtained in aqueous solution of etha... N-isopropylacrylamide (NIPAAm) was used to synthesize NIPAAm homopolymer (nonionized) and NIPAAm-sodium methacrylate copolymer (ionized). The swelling equilibria for both gels were obtained in aqueous solution of ethanol with concentration ranging from 0 to 100%(by mass) at 25℃. The swollen gel in water shrank first with the addition of a small amount of ethanol and then reswelled with further addition of ethanol showing not only a discontinuous volume phase transition but also a typical reentrant phenomenon. A thermodynamic model based on the UNIQUAC with the 'free-volume' contribution was applied to correlate and predict the swelling behavior of the poly(NIPAAM)-gels in ethanol-water mixture. 展开更多
关键词 HYDROgel SWELLING poly(n-isopropylacrylamide) model
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Y-shaped block copolymers of poly(ethylene glycol) and poly(N-isopropylacrylamide) synthesized by ATRP 被引量:2
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作者 Xin De Tang Xiao Chao Liang Nian Feng Han 《Chinese Chemical Letters》 SCIE CAS CSCD 2009年第11期1353-1356,共4页
Novel Y-shaped block copolymers of poly(ethylene glycol) and poly(N-isopropylacrylamide), PEG-b-(PNIPAM)2, were successfully synthesized through atom transfer radical polymerization (ATRP). A difunctional macr... Novel Y-shaped block copolymers of poly(ethylene glycol) and poly(N-isopropylacrylamide), PEG-b-(PNIPAM)2, were successfully synthesized through atom transfer radical polymerization (ATRP). A difunctional macroinitiator was prepared by esterification of 2,2-dichloroacetyl chloride with poly(ethylene glycol) monomethyl ether (PEG). The copolymers were obtained via the ATRP ofN-isopropylacrylamide (NIPAM) at 30℃ with CuCl/Me6TREN as a catalyst system and DMF/H2O (v/v = 3:1) mixture as solvent. The resulting copolymers were characterized by gel permeation chromatography (GPC) and ^1H NMR. These block copolymers show controllable molecular weights and narrow molecular weight distributions (PDI 〈 1.15). Their phase transition temperatures and the corresponding enthalpy changes in aqueous solution were measured by differential scanning calorimetry (DSC). As a result, the phase transition temperature of PEG45-b-(PNIPAM55)2 is higher than that of PNIPAM, however, the corresponding enthalpy change is much lower, indicating the significant influence of the macromolecular composition and architecture on the phase transition. 展开更多
关键词 Y-shaped Block copolymer poly(ethylene glycol) poly(n-isopropylacrylamide Atom transfer radical polymerization (ATRP)
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Self-Oscillating Structural Polymer Gels 被引量:1
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作者 Srinivasa R. Pullela Qingsheng Wang Zhengdong Cheng 《Advances in Nanoparticles》 2013年第2期94-98,共5页
self-oscillating polymer gel has become a distinguished class of smart soft materials. Here we fabricated and demonstrated a self-oscillating structural gel network with the incorporation of the Belousov-Zhabotinsky (... self-oscillating polymer gel has become a distinguished class of smart soft materials. Here we fabricated and demonstrated a self-oscillating structural gel network with the incorporation of the Belousov-Zhabotinsky (BZ) reaction. The structural polymer gel oscillates at a macroscopic level with remarkably faster kinetics compared to a normal gel of similar chemical compositions. The structural polymer gel also displays larger oscillating amplitude compared to the normal gel because of the increased diffusion of fluids surrounding the gel particles. This type of structural polymer gels can be harnessed to provide novel and feasible applications in a wide variety of fields, such as drug delivery, nanopatterning, chemical and biosensing, and photonic crystals. 展开更多
关键词 STRUCTURAL gel Belousov-Zhabotinsky Reaction SELF-OSCILLATION poly-(n-isopropylacrylamide) Fast Response
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THERMAL-SENSITIVE BETA-CYCLODEXTRIN-CONTAINING POLY(NISOPROPYLACRYLAMIDE)HYDROGELS CROSSLINKED BY Si—O—Si BONDS—SYNTHESIS,CHARACTERIZATION AND PROLONGING IN VITRO RELEASE OF 5-FLUOROURACIL
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作者 Jian-tao Zhang Shi-wen Huang +2 位作者 Ya-nan Xue Ji Liu and Ren-xi Zhuo Key Laboratory of Biomedical Polymers,Ministry of Education Department of Chemistry,Wuhan University,Wuhan 430072,China 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2005年第5期513-519,共7页
A series of novel p(N-isopropylacrylamide) (PNIPAM) hydrogels were synthesized by radical copolymerization of N-isopropylacrylamide (NIPAM) and 3-methacryloxypropyltrimethoxysilane (MPTMS). The copolymers were... A series of novel p(N-isopropylacrylamide) (PNIPAM) hydrogels were synthesized by radical copolymerization of N-isopropylacrylamide (NIPAM) and 3-methacryloxypropyltrimethoxysilane (MPTMS). The copolymers were then crosslinked through hydrolysis of the siloxane in acetic acid/water mixed solvent. Beta-cyclodextrin (Beta-CD) was introduced into the polymeric networks by condensation of 3-glycidoxypropyltrimethoxysilane derived beta-cyclodextrin (KH560-beta-CD) with MPTMS under acidic condition. These gels were heterogeneous, porous and exhibited fast deswelling kinetics when the temperature was elevated to above lower critical solution temperature (LCST). The swelling ratios of the gels containing beta-CD at room temperature were higher than that of the normal PNIPAM hydrogel, which was caused by the lower crosslinking density in beta-CD contained gels. In comparison to that of the normal PNIPAM gel, the amount of loaded-drug in the hydrogel containing beta-CD was higher, and the release time of 5-fluorouracil (5-Fu) was prolonged, which was attributed to the formation of inclusion compounds between 5-Fu and beta-CD in gel network. 展开更多
关键词 Hydrogel Thermal-sensitive poly(n-isopropylacrylamide BETA-CYCLODEXTRIN Fast responsive.
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THE ADSORPTION OF LINEAR POLY(N-ISOPROPYLACRYLAMIDE)CHAINS ON SURFACTANT-FREE POLYSTYRENE NANOPARTICLES
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作者 吴奇 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1999年第6期595-601,共7页
The adsorption of linear poly(N-isopropylacrylamide) (PNIPAM) chains on surfactant-free polystyrene (PS) nanoparticles was used as a model system to study the hydrophobic adsorption of polymer on the surface, because ... The adsorption of linear poly(N-isopropylacrylamide) (PNIPAM) chains on surfactant-free polystyrene (PS) nanoparticles was used as a model system to study the hydrophobic adsorption of polymer on the surface, because the hydrophobility of PNIPAM can be continuously varied by a small temperature change. The adsorption was investigated by a combination of static and dynamic laser light scattering (LLS) measurements. In static LLS, the absolute excess scattered light intensity led to the amount of PNIPAM adsorbed on the surface. In dynamic LLS, the hydrodynamic thickness of the adsorbed PNIPAM layer was accurately measured. For a given particle concentration, the adsorption increases as the PNIPAM concentration and the incubation temperature increase. The average density of the adsorbed PNIPAM layer is reciprocally proportional to the number of the PNIPAM chains on the surface, revealing a simple scaling of the chain density distribution. The adsorption follows the Langmuir's isotherm. The enthalpy change estimated from the adsorption at 25 degrees C and 30 degrees C is slightly positive, indicating that the adsorption involves the coil-to-globule transition of the chains on the surface. 展开更多
关键词 poly(n-isopropylacrylamide) polystyrene nanoparticles surface adsorption of polymers light scattering
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New Insights into Folding Kinetics of α,ω Dye-Functionalized Poly(N-isopropylacrylamide)
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作者 Xiao-yan Wang Hai-yan Fan +2 位作者 Xiao-dong Ye Shi-lin Liu Guang-zhao Zhang 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2018年第6期789-798,733,734,共12页
Two narrowly-distributed poly(N-isopropylacrylamide)(PNIPAM) samples were prepared via atom transfer radical polymerization (ATRP) with a novel dansyl functionalized initiator. The other end of the PNIPAM was function... Two narrowly-distributed poly(N-isopropylacrylamide)(PNIPAM) samples were prepared via atom transfer radical polymerization (ATRP) with a novel dansyl functionalized initiator. The other end of the PNIPAM was functionalized by dabcyl group via click reaction. From the static fluorescence measurements, the fluorescence intensity of dansyl group and energy transfer efficiency between dansyl and dabcyl groups increased when the temperature increased from 36 °C to 45 °C, indicating that the microenvironment surrounding dansyl became hydrophobic and the distance between dansyl and dabcyl decreased. The kinetics of the conformational change of the dye-labeled PNIPAM was studied by a home-made laser-induced temperature jump device with fluorescent measurement. Our results revealed that the characteristic transition time was 3.8 and 5.8 ms for PNIPAM with degrees of polymerization of 85 and 142, respectively, indicating that the characteristic transition time was related to the chain length. Besides, characteristic transition time for the change of the energy transfer efficiency was 2.9 ms for PNIPAM with the degree of polymerization of 85, suggesting that the energy transfer efficiency change was faster than the fluorescence intensity change of dansyl group. 展开更多
关键词 FLUORESCENCE Laser-induced temperature jump Phase transition poly(n-isopropylacrylamide)
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Thermo-Responsive Electrospun Nanofibers from Poly( N-isopropylacrylamide )/Polyvinyl Pyrrolidone Blends
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作者 吕瑶 吴焕岭 +2 位作者 李赫宇 潘琪霞 朱利民 《Journal of Donghua University(English Edition)》 EI CAS 2017年第1期152-158,共7页
A novel nanofiber composite poly(N-isopropylacrylamide)(PNIPAAm)/polyvinyl pyrrolidone(PVP)was successfully prepared by electrospinning.Analogous medicated fibers loaded with ketoprofen(KET)as a model drug were prepar... A novel nanofiber composite poly(N-isopropylacrylamide)(PNIPAAm)/polyvinyl pyrrolidone(PVP)was successfully prepared by electrospinning.Analogous medicated fibers loaded with ketoprofen(KET)as a model drug were prepared.X-ray diffraction(XRD)demonstrated that the drug was presented in the fibers with an amorphous form.Both scanning and transmission electron microscopy showed that the fibers had an even diameter and smooth surface,and no phase separation was observed.The KET loaded nanofibers did not affect the morphology of the fibers,and no drug aggregation was separated from the polymer fibers.Water contact angle measurements proved that the PNIPAAm/PVP fibers switched from hydrophilic to hydrophobic when the temperature increased the lower critical solution temperature of 32℃.In vitro drug release studies were also undertaken and the result indicated that the PNIPAAm/PVP blend nanofiber presented the properties of the two polymers,having temperature-sensitive systems with sustained release properties.In addition,MTT assay demonstrated that the nanofiber film was non-toxic and suitable for cell growth.Thus,the nanofiber can be used as thermoresponsive carriers for sustained release of poor water soluble drugs. 展开更多
关键词 poly(n-isopropylacrylamide)(PNIPAAm) polyvinyl pyrrolidone(PVP) ELECTROSPINNING drug release
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Thermal Stability Improvement and Structural Change of Oil Gels Formed by Styrene-Butadiene-Styrene Triblock Copolymer Induced by Adding Poly(phenylene ether)
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作者 Kouichi Kato Yuki Tsukamoto +2 位作者 Eri Hirai Yasuhiro Matsuda Shigeru Tasaka 《Open Journal of Organic Polymer Materials》 2014年第4期65-73,共9页
The thermal stability of oil gels formed by styrene-butadiene-styrene triblock copolymer (SBS) was improved by adding a small amount of poly(phenylene ether) (PPE), which has a higher glass transition temperature (Tg)... The thermal stability of oil gels formed by styrene-butadiene-styrene triblock copolymer (SBS) was improved by adding a small amount of poly(phenylene ether) (PPE), which has a higher glass transition temperature (Tg). In naphthenic oil which is a good solvent for the butadiene blocks, but a non-solvent for the styrene blocks and PPE, PPE was selectively included into styrene blocks in SBS, and induced the increase of the Tg of these blocks. The melting temperature determined by viscoelastic measurements and softening temperature of the gels were elevated by adding PPE, while no significant change was detected by adding polystyrene. The gel became opaque by adding PPE, and partially separated phases were observed by field emission scanning electron microscopy (FE-SEM). The dependence of the viscoelastic behavior on the PPE concentration can be explained by the structural change observed by FE-SEM. 展开更多
关键词 Styrene-Butadiene-Styrene TRIBLOCK Copolymer poly(phenylene ether) (PPE) OIL gel Naphthenic OIL
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Thermotolerant and fireproof gel polymer electrolyte toward high-performance and safe lithium-ion battery 被引量:8
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作者 Man-Cheng Long Ting Wang +4 位作者 Ping-Hui Duan You Gao Xiu-Li Wang Gang Wu Yu-Zhong Wang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2022年第2期9-18,共10页
Poly(ethylene oxide)(PEO)and its derivatives based gel polymer electrolytes(GPEs)are severely limited in advanced and safe lithium-ion batteries(LIBs)owing to the intrinsically high flammability of liquid electrolytes... Poly(ethylene oxide)(PEO)and its derivatives based gel polymer electrolytes(GPEs)are severely limited in advanced and safe lithium-ion batteries(LIBs)owing to the intrinsically high flammability of liquid electrolytes and PEO.Directly adding flame retardants to the GPEs can suppress their flammability and thus improve the safety of LIBs,but results in deteriorative electrochemical performance.Herein,a novel GPE with chemically bonded flame retardant(i.e.diethyl vinylphosphonate)in cross-linked polyethylene glycol diacrylate matrix,featuring both high-safety and high-performance,is designed.This as-prepared GPE storing the commercial 1 mol L^(-1) LiPF6 electrolyte resists high temperature of 200℃and cannot be ignited as well as possesses a high ionic conductivity(0.60 m S cm^(-1))and good compatibility with lithium.Notably,the LiFePO_(4)/Li battery with this GPE delivers a satisfactory capacity of 142.2 m A h g^(-1) and a superior cycling performance with a capacity retention of 96.3%and a coulombic efficiency of close to 100%for 350 cycles at 0.2 C under ambient temperature.Furthermore,the battery can achieve steady charge–discharge for 100 cycles with a coulombic efficiency of 99.5%at 1 C under 80℃and run normally even at a high temperature of 150℃or under the exposure to butane flame.Differential scanning calorimetry manifests significantly improved battery safety compared to commercial battery systems.This work provides a new pathway for developing next-generation advanced LIBs with enhanced performance and high safety. 展开更多
关键词 gel polymer electrolyte poly(ethylene oxide) Flame retardant Vinylphosphonate Lithium-ion batteries
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Molecular weight determination of a newly synthesized guanidinylated disulfide-containing poly(amido amine) by gel permeation chromatography 被引量:3
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作者 Haonan Xing Mei Lu +4 位作者 Lei Xian Jinmin Zhang Tianzhi Yang Li Yang Pingtian Ding 《Asian Journal of Pharmaceutical Sciences》 SCIE CAS 2017年第3期292-298,共7页
A cationic gene delivery vector, guanidinylated disulfide-containing poly(amido amine)(CARCBA), was synthesized by Michael addition reaction between N,N′-cystaminebisacrylamide(CBA) and guanidine hydrochloride(CAR). ... A cationic gene delivery vector, guanidinylated disulfide-containing poly(amido amine)(CARCBA), was synthesized by Michael addition reaction between N,N′-cystaminebisacrylamide(CBA) and guanidine hydrochloride(CAR). Gel permeation chromatography(GPC) was used to evaluate the molecular weight of synthesized CAR-CBA. Polyethyleneimine(PEI) with molecular weight of 25 kDa was adopted as a reference, and polyethylene glycols(PEG) with different molecular weights were used to establish a standard curve for determining the molecular weight of CAR-CBA. The effects of two critical factors, namely columns and eluents,on the molecular weight measurement of CAR-CBA were investigated to optimize the GPC quantitative method. The results showed that Ultrahydrogel columns(120, 250) and HAc–NaAc(0.5 M, pH 4.5) buffer solution were the optimal column and GPC eluent, respectively.The molecular weight of the synthesized CAR-CBA was analyzed by the optimized GPC method and determined to be 24.66 kDa. 展开更多
关键词 Guanidinylated disulfide-containing poly(amido amine) Synthesis Cationic gene delivery vector Molecular weight determination gel PERMEATION chromatography
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Novel Method to Monitor the De-Swelling of PNIPAAm Hydrogels of Different Cross-Link Density 被引量:1
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作者 Noémi Karnok Csaba Németh Viktória Vargha 《American Journal of Analytical Chemistry》 2016年第3期306-317,共12页
The effect of cross-linker (methylene-bis-acrylamide) (MBA) on the volume phase transition, mechanical properties and de-swelling of Poly(N-isopropyl acrylamide-co-methylene-bis-acrylamide) hydrogel (PNIPAAm/MBA hydro... The effect of cross-linker (methylene-bis-acrylamide) (MBA) on the volume phase transition, mechanical properties and de-swelling of Poly(N-isopropyl acrylamide-co-methylene-bis-acrylamide) hydrogel (PNIPAAm/MBA hydrogel) was investigated. A new method, namely isothermal thermo-gravimetry was developed for monitoring de-swelling of PNIPAAm/MBA hydrogel. Monomer/ Cross-linker ratio of the initial monomer composition R = moleNIPAAm/moleMBA was introduced. It has been proven earlier that initial monomer composition is close to the copolymer composition;hence R values may be used to express cross-link density. Hydrogels from R10 to R150 were investigated. The results of DSC analysis revealed that the less the cross-linker ratio in the gel (from R10 to R150) the more sharp the temperature range of volume phase transition and the higher its enthalpy. Cross-link density, namely increasing cross-linker content in the copolymer (R from 150 to 10) does not significantly affect the temperature range of volume phase transition. It sets on at 33&deg;C - 34&deg;C, and ends between 35?C and 38?C. Cross-link density has significant effect on compression modulus. By decreasing the ratio of cross-linker (by increasing R from 10 to 150), the compression modulus increases, goes through a maximum, and then decreases. The highest compression modulus was measured for PNIPAAm/MBA hydrogel R20. Hydrogels with cross-linker content between R100 and 30 are strong enough and have their thermoresponsivity. Isothermal thermograms of de-swelling are of similar character for all the gels with different cross-linker content. During the initial stage of de-swelling for gels with higher cross-linker content (R10 - R15) the solute release is quicker than for gels R20 - 150 and the thermograms are drawn out. In the initial stage of de-swelling, i.e. during the first 40 minutes the rate of solute release is the highest for gels R70 - 150. The cross-linker content effects solute release, especially for gels with high cross-linker content. It is noteworthy that gels R10 - 15 release solute quicker than gels R30 - 50 and their rate of de-swelling is comparable to that of gels R100 - 150. The novel thermogravimetric method enables the selection of gels based on the rate of solute release and it can also be applied for other cross-linked gels. 展开更多
关键词 Intelligent gel poly(N-isopropyl Aceylamide) PNIPAAm De-Swelling THERMOGRAVIMETRY
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