Trimethylolpropane Trimethylacrylate Research Articles

In-situ constructing efficient gel polymer electrolyte with fluoride-rich interface enabling high-capacity, long-cycling sodium metal batteries

Sodium metal batteries (SMBs) are considered feasible candidate for large-scale energy systems. However, complicated reactions between the electrode and electrolyte in liquid electrolyte system lead to poor performance and significant safety issues. Therefore, constructing stable electrode-electrolyte interface is necessary to enhance the comprehensive performance of cells. Utilizing gel polymer electrolytes (GPEs) by in-situ polymerization and moderate additive can effectively address these problems. Herein, a series of fluoroethylene carbonate (FEC) modified GPEs have been successfully prepared by one-step in-situ polymerization, in which trimethylolpropane trimethyl acrylate (TMPTMA) and 1,6-hexanediol diacrylate (HDDA) were used as polymer monomers. As a result, the as-optimized electrolyte, THDP-FEC-2%, exhibited high ionic conductivity (3.77 × 10−3 S cm−1) at 25 °C, high Na+ migration number (0.41), and broad electrochemical window (4.6 V). Encouragingly, the NVP|THDP-FEC-2%|Na cell even exhibited ultra-long cycling stability at high rate (95.31% capacity retention at 5C after 1000 cycles). Such excellent electrochemical performances are attributed to the successful establishment of uniform and dense NaF-rich solid electrolyte interface protection layer. This work is expected to offer interface soft protection layer tuned strategy to construct the ideal interface for high-performance SMBs.

In‐plane actuation performance of graphene oxide filled VHB 4910 dielectric elastomer

AbstractThe effects of solid fillers on optical, electrical, mechanical, and electromechanical actuation behavior of VHB 4910 elastomer is inadequate, possibly due to readiness as a foam tape that makes the filler reinforcement a challenging work. VHB 4910 is modified by filling graphene oxide (GO) particles to realize the influences on material behavior towards actuator applications. The elastomer samples are ultrasonicated, swollen then thermochemically cured in GO dispersed; deionized‐water, trimethylolpropane trimethylacrylate (TMPTMA) and toluene to prepare three different filled‐elastomers. Material modification is confirmed by analyzing optical micrograph, and FTIR spectra. Whereas, dielectric constant and Young's modulus are assessed to ensure the feasibility of modified elastomers for electromechanical actuation strain. Amongst the three, GO‐TMPTMA filled‐elastomer samples are considered to test electromechanical actuation using an in‐house designed diaphragm actuator. Results showed enhanced in‐plane actuation performance and electrical breakdown strength, dependent on the curing time and prestrain. This work may strengthen the future strategies of making VHB 4910‐composite for dielectric elastomer actuator based electromechanical devices.

A novel gel polymer electrolyte based on trimethylolpropane trimethylacrylate/ionic liquid via in situ thermal polymerization for lithium-ion batteries

Gel polymer electrolytes (GPEs) based on trimethylolpropane trimethylacrylate (TMPTMA) are in situ polymerized using lithium bis(trifluoromethane)sulfonimide (LiTFSI), dimethylcarbonate (DMC) and ionic liquid (IL)-tributylmethylammonium bis(trifluoromethanesulfonyl) imide (N1,4,4,4TFSI). The GPEs presented both the liquid-like ionic transport and solid-like features. The N1,4,4,4TFSI can effectively dissociate the lithium salts to boost ionic transport, and thus delivers a high ionic conductivity of 6.15 × 10−3 S cm−1 at 25 °C. The interfacial resistance between ionic liquid and lithium metals was reduced, resulting in the benign interfacial contact with Li metal electrode. Lithium ion batteries are assembled based on TMPTMA-based cross-linked gel polymer electrolytes (with LiCoO2 as positive electrode and lithium as negative electrode). The results suggest that the GPEs modified with ionic liquid presented improved cycling performance (with a discharge capacity of 111.1 mA h g−1 after 100 cycles) and good capacity retention of 80%. Also, the GPEs hold favorable compatibility with the LiNi0.8Co0.1Mn0.1O2 positive electrode, exhibiting an initial discharge capacity of 183.1 mA h g−1 as well as a stable capacity of beyond 149 mA h g−1 after 100 cycles. The GPEs enable the assembled LiCoO2/Li and Li1.2Ni0.8Co0.1Mn0.1O2/Li batteries for well operating within a wide C rate range (0.1–2.0 C). The improved cycling behaviors can be attributed to the suppressed growth of the cell impedance and stable interface compatibility toward lithium metal negative electrode .

Study of self-assembly system of norfloxacin molecularly imprinted polymers based on simulated design

To rationally design molecularly imprinted polymers (MIPs) of norfloxacin (NOR), functional monomers, cross-linking agents, and solvents were screened by using the LC-WPBE/6-31G(d,p) method. The nature of the interaction between NOR imprinted molecules and trifluoromethylacrylic acid (TFMAA) functional monomers is discussed. The functional monomers were screened based on the interaction ratio, the number of bonds, and the binding energy of the stable complexes between NOR and 4-vinylpyridine, methacrylic acid, TFMAA, and 2-vinyl-4,6-diamino-1,3,5-triazine. The selection of cross-linking agent was carried out based on the binding energy when the molar ratio of cross-linking agent TFMAA was 1:1. The solvent was optimized by calculating the solvation energy of the NOR–TFMAA stable complex (1:1) using different solvents. The nature of imprinting was obtained by the topological analysis of electron density of stable complexes of NOR and TFMAA based on the atom in molecule theory. On the basis of computational results, TFMAA, trimethylolpropane trimethylacrylate, and toluene were selected as the functional monomer, cross-linking agent, and solvent, respectively. When the molar ratio of NOR:TFMAA was 1:7, the complex that was formed had the lowest binding energy and highest number of hydrogen bonds. In addition, the O and H atoms on the quinoline ring and the N and H atoms on the piperazine ring of NOR interacted with TFMAA and formed ordered complexes matching each other in chemical groups and steric configuration via hydrogen bonding. Therefore, this study can provide a theoretical basis and reference for the design and preparation of NOR–MIPs.

Theoretical Design and Adsorption Properties of Molecularly Imprinted Polymers Obtained from Chloramphenicol and Acrylamide

Molecular simulations are widely used to model molecularly imprinted polymers(MIPs) in order to enhance their adsorption and selectivity. In this study, chloramphenicol(CAP) and acrylamide(AM) were used as the template and functional monomer, respectively, and pentaerythritol triacrylate(PETA), ethylene glycol dimethacrylate (EGDMA), and trimethylolpropane trimethylacrylate(TRIM) were used as cross-linking agents. The ωB97XD/6-31G(d,p) density functional theory method was employed to simulate binding sites, binding energy, the number of hydrogen bonds, the imprinted molar ratio, which produced the most stable complex, and the interaction mechanism. The cross-linking agent was optimized based on the binding energy. The atoms in molecules theory were used to study the nature of the imprinting effects. The theoretical calculations revealed that CAP and AM formed ordered complexes via hydrogen bonding interactions when the molar ratio between CAP and AM was 1:7 using TRIM as the cross-linking agent. The CAP-AM complex(molar ratio 1:7) had the most stable structure, the largest number of hydrogen bonds, and the smallest ΔE. The experimental results indicate that the CAP-MIPs formed perfect microspheres with an average particle size of 314 nm. Scatchard plot analysis showed that the CAP-MIPs had only one type of binding site over the studied concentration ranges. The dissociation equilibrium constant and maximum apparent adsorption capacities were 1887.35 mg/L(5.84 mmol/L) and 155.56 mg/g(0.482 mmol/g), respectively.

Theoretical and experimental research on self-assembly system of molecularly imprinted polymers formed via chloramphenicol and methacrylic acid.

Chloramphenicol was chosen as the imprinting molecule and the methacrylic acid was chosen as the functional monomer to prepare molecularly imprinted polymers. Ethylene glycol dimethacrylate, pentaerythritol triacrylate, and trimethylolpropane trimethylacrylate were used as the cross-linking agents, respectively. The interaction processes between chloramphenicol and methacrylic acid were simulated by using the ωB97XD/6-31G (d,p) method. The self-assembled configuration, bonding sites, binding number, binding energy, and interaction principle of stable complex formed by chloramphenicol and methacrylic acid with different molar ratios have been studied. The selectivity of the most stable complex formed from chloramphenicol and methacrylic acid was discussed with the thiamphenicol and florfenicol as the analogues of chloramphenicol. The results showed that chloramphenicol and methacrylic acid were interacted through the hydrogen bonds. When the molar ratio was 1:10 and pentaerythritol triacrylate as the cross-linking agent, the ordered complex formed by chloramphenicol and methacrylic acid has the largest amount of hydrogen bonds and the lowest binding energy. Scatchard analysis showed that the maximum apparent adsorption capacity was 173.3mg/g (0.536mol/g), and the selection factor of florfenicol was the largest. This study provides a reliable theoretical and experimental basis for the design, preparation, and characterization of chloramphenicol molecularly imprinted polymers.

Study on Dicyandiamide-Imprinted Polymers with Computer-Aided Design.

With the aid of theoretical calculations, a series of molecularly imprinted polymers (MIPs) were designed and prepared for the recognition of dicyandiamide (DCD) via precipitation polymerization using acetonitrile as the solvent at 333 K. On the basis of the long-range correction method of M062X/6-31G(d,p), we simulated the bonding sites, bonding situations, binding energies, imprinted molar ratios, and the mechanisms of interaction between DCD and the functional monomers. Among acrylamide (AM), N,N’-methylenebisacrylamide (MBA), itaconic acid (IA), and methacrylic acid (MAA), MAA was confirmed as the best functional monomer, because the strongest interaction (the maximum number of hydrogen bonds and the lowest binding energy) occurs between DCD and MAA, when the optimal molar ratios for DCD to the functional monomers were used, respectively. Additionally, pentaerythritol triacrylate (PETA) was confirmed to be the best cross-linker among divinylbenzene (DVB), ethylene glycol dimethacrylate (EGDMA), trimethylolpropane trimethylacrylate (TRIM), and PETA. This is due to the facts that the weakest interaction (the highest binding energy) occurs between PETA and DCD, and the strongest interaction (the lowest binding energy) occurs between PETA and MAA. Depending on the results of theoretical calculations, a series of MIPs were prepared. Among them, the ones prepared using DCD, MAA, and PETA as the template, the functional monomer, and the cross-linker, respectively, exhibited the highest adsorption capacity for DCD. The apparent maximum absorption quantity of DCD on the MIP was 17.45 mg/g.

Composite Polymer Electrolytes for Lithium Ion Batteries

Polymer electrolytes are expected to be the alternative electrolytes to satisfy the needs for power storage device because of several important factors, such as high ionic conductivities, reliable safety, easy fabrication, appropriate mechanical properties along with important technological issues related to electrochemical stability. Solid polymer electrolytes prepared by dissolving the salt into the polymer framework are still found to present low ionic conductivities at ambient temperature and dependence of temperature. The ionic conductivities can be enhanced by dissolving polymer matrices and lithium salts in organic solvents. However, liquid electrolytes will deteriorate mechanical properties. Here we have prepared a series of polymer electrolytes with excellent thermostability,well mechanical property, wide electrochemical window and high ionic conductivity, including trimethylolpropane trimethylacrylate (TMPTMA) based, triethylene glycol diacetate-2-propenoic acid butyl ester (TEGDA-BA) based, polyimide (PI) based and polyacrylonitrile (PAN) based polymer electrolytes using in situ thermal polymerization or polymer casting method [1-8]. The as prepared polymer electrolytes exhibit high ionic conductivities, electrochemical stability and excellent charge/discharge cycling performance. The excellent properties of polymer electrolytes make them significant potential materials for next generation lithium ion batteries.

The Effect of Ethylene Copolymers on the Properties of Crosslinking Polyolefin Composites Modified with Trimethylolpropane Trimethacrylate

An investigation was made of the effect of copolymers of ethylene with vinyl acetate (CEVA) on the thermodynamic stability and structural and mechanical properties of cured composites based on low-density polyethylene (LDPE) and dicumyl peroxide with crosslinking coagent trimethylolpropane trimethylacrylate (TMPTMA). It was shown that, in the presence of CEVA, thermodynamic compatibility of LDPE with TMPTMA is ensured, and the chemical network density is increased significantly.

Theoretical research on self-assembly system of molecularly imprinted polymers formed by melamine and trifluoromethacrylic acid

The long-range correction method (WB97XD) was applied to simulate the self-assembly system of the molecularly imprinted polymers via Gaussian 09 software. Melamine (MAM) was taken as the template molecule and trifluoromethacrylic acid (TFMAA) was taken as the functional monomer. The ethylene glycol dimethacrylate, divinylbenzene, pentaerythritol triacrylate, and trimethylolpropane trimethylacrylate were chosen as the cross-linking agents, respectively. The acetonitrile, methanol, dichloromethane, chloroform, toluene, ethanol, and dimethylsulfoxide were taken as solvents, respectively. The bonding situation, the geometry optimization of the different imprinting ratios, the binding energy, the molecular imprinting mechanism between MAM and TFMAA, and the influence of cross-linking agent as well as solvent have been studied. The detailed topological property was also applied to discuss the nature of the imprinting effect. The results indicate that MAM and TFMAA can form ordered compounds via hydrogen bond interaction. The melamine-molecularly imprinted polymers with a molar ratio of 1:6 have the lowest binding energy, the largest amount of hydrogen bonds, and the stable structure in toluene solvent. Divinylbenzene is the best cross-linking agent for the melamine-molecularly imprinted polymers in comparison with others. The study can provide a theoretical reference for the synthesis of the high selectivity melamine-molecularly imprinted polymers.

Preparation of melamine molecularly imprinted polymer by computer-aided design.

Melamine was chosen as template, methacrylic acid was chosen as functional monomer, and divinylbenzene, ethylene glycol dimethacrylate, trimethylolpropane trimethylacrylate were chosen as cross-linking agents, respectively. The WB97XD/6-31G(d, p) method was used to calculate the geometry optimization of the different imprinting ratios, the action sites, the bonding situation, and the optimization of the cross-linking agents. The nature of the imprinting effect was also studied by the atoms in molecules theory. The theoretical results showed that melamine interacts with methacrylic acid by hydrogen bonding, and the melamine molecularly imprinted polymers with a molar ratio of 1:6 have the most hydrogen bonds and the most stable structure. Divinylbenzene is the best cross-linking agent for the melamine molecularly imprinted polymers. The melamine molecularly imprinted polymers were synthesized by precipitation polymerization. The results showed that the maximum adsorption capacity for molecularly imprinted polymers towards melamine is 19.84 mg/g, and the adsorption quantity of the polymers to melamine is obviously higher than that of cyromazine, cyanuric acid, and trithiocyanuric in milk. This study could provide theoretical and experimental references for the screening of the imprinting ratio and the cross-linking agent for the given template and monomer system.

Electron-Beam Irradiation of Halogen Free Flame Retardant Polymers for Wire and Cable Applications

Effect of addition different polymers and fillers with electron beam irradiation on changes of physical, electrical and flammability properties of low density polyethylene (LDPE) / trimethylol propane trimethylacrylate (TMPTMA) / Irganox/ zinc borate (ZB) have been investigated. Results of measured gel content (GC), tensile strength (TS), elongation at break (EL), hot set (HS) tests, melt index (MFI), dielectric strength (DS), volume resistivity (VR), flammability and limiting oxygen index (LOI) have confirmed positive effects of adding maleic anhydride grafted LDPE (LDPEgMAH), ethylene vinyl acetate (EVA) and CS whereas effect of ATH to blends drastically had negative effects on improvement of physical properties of blends. Meanwhile, presence of TMPTMA and enhancing irradiation could improve properties seriously. Keywords Halogen free; polymers; irradiation; wires and cables

Research on Composite Quasi-Solid Polymer Electrolytes

Lithium-ion batteries are dominated the fields of power sources for future electrochemical device attribute to their high energy density, high working voltage, high efficiency, long life and memory-effect-free [1]. Solid-state polymer have been employed to develop rechargeable lithium-ion batteries which have little security problems caused by liquid electrolyte leakage. In recent years, Soft matter ionic conductors such as gel polymer electrolytes (GPEs) have been emerging as a suitable class of materials due to their ability to deliver substantially higher Li+ transport number [2]. In general, conventional GPEs are prepared using a predesigned frame via solution casting of liquid state mixtures (i.e., lithium salt and polymers dissolved in organic solvents), followed by solvent evaporation for solidification. However, the cumbersome preparation processes, and low lithium transport numbers are usually inadequate for practical application. To relieve the preparation problem, in situ synthesis process has been increasingly attracted extensive attention in the preparation of GPEs. The as prepared GPEs are also known as composite polymer electrolytes, because they combine the cohesive features typical of solid systems with liquid-like transport properties. The composite quasi-solid polymer electrolytes were prepared by in situ thermal polymerization using trimethylolpropane trimethylacrylate (TMPTMA) [3, 4] or triethylene glycol diacetate-2-propenoic acid butyl ester copolymer (TEGDA-BA) [5, 6] as monomer. The preparation processes, electrochemical performance and interfacial properties of polymer electrolytes were studied.TMPTMA-based gel polymer electrolytes were prepared by using TMPTMA as a monomer, lauroyl peroxide (LPO) as a thermal initiator, 1M LiFP6 / (EC:DMC:EMC =1:1:1, V/V/V) liquid electrolyte solvent and plastic crystal electrolyte (containing 4 mol% LiTFSI in the succinonitrile) as plasticizer, respectively.The influencing factors of the electrochemical performance, such as polymerization temperature, liquid electrolyte content and initiator content, were systematically discussed and the process parameters were optimized. The high ionic conduction (>10-3 S cm-1) of gel polymer electrolytes was mainly due to the liquid electrolyte trapped in the pores highly dispersed in the polymer framework.The homogeneous and stable liquid state electrolyte was obtained by magnetic stirring the precursors. After the gel reaction, the precursor liquid electrolyte became a viscous gel and showed little flow even tipping the vial at a certain angle.The polymer electrolytes has a wider electrochemical voltage window was stable approximately up to 5 V versus Li/Li+ without an irreversible oxidation.The discharge capacity vs. the cycle number had been studied employing LiCoO2, Li[Li1/6Ni1/4Mn7/12]O2, LiFePO4 as the active cathode material and lithium metal as the anode. The Li/GPEs/ LiCoO2 display a high initial discharge capacity of 134.1 mAh g-1, as well as an excellent rate capability (83% remaining capacity after 100 cycles).TMPTMA-based and TEGDA-BA-based composite polymer electrolytes have been successfully prepared in situ thermal polymerization. The polymer electrolytes have higher ionic conductivities, electrochemical stability and excellent charge/discharge galvanostatic cycling performance at room-temperature. The excellent properties of polymer electrolytes make it significant potential material for next generation lithium ion batteries.Acknowledgements This work was supported by the 973 project (2013CB934001), NSF of China (51172024, 51372022)References[1] L.Z. Fan, Y.S. Hu, J. Maier. Adv. Funct. Mater., 2007, 17, 2800.[2] E.H. Kil , K.H. Choi. K.Y. Cho, S.Y. Lee. Adv. Mater., 2013, 25, 1395.[3] D. Zhou, L.Z. Fan, H.H. Fan, Q. Shi. Electrochim. Acta, 2013, 89, 334.[4] Q.J. Wang, H.H. Fan, L.Z. Fan, Q. Shi. Electrochim. Acta, 2013, In press.[5] H.H. Fan, H.X. Li, L.Z. Fan. J. Power Sources, 2013, Accepted.[6] Q.J. Wang, H.F. Ni, W.L. Song, L.Z. Fan. J. Power Sources, 2013,in press.

Preparation and performance of a non-ionic plastic crystal electrolyte with the addition of polymer for lithium ion batteries

A soft matter solid electrolyte was prepared by polymerizing a monomer trimethylolpropane trimethylacrylate (TMPTMA) using in situ thermal polymerization into a non-ionic plastic crystal electrolyte, which is consisted of 5mol% lithium bis-trifluoromethanesulfonimide dissolved in succinonitrile (SN). X-ray diffraction, differential scanning calorimetry and conductivity measurements are used to investigate the structural and electrochemical performance of the polymer electrolyte films. It exhibits high ionic conductivities, wide electrochemical window and excellent mechanical strength. The solid electrolyte with 7.5wt% TMPTMA displays a high initial discharge capacity of 160.3mAhg−1 at 0.1C when combined with a LiFePO4 cathode and excellent capacity retention. With their beneficial properties, the polymer electrolytes are considered to have significant potential applications for lithium ion batteries.

The Effect of TMPTMA Addition on Electron-beam Irradiated LDPE, EVA and Blend Properties

Abstract In this work low density polyethylene (LDPE) and ethylene vinyl acetate (EVA) were blended in the presence of trimethylol propane trimethylacrylate (TMPTMA) (0 to 6 phr). The resultant blends were irradiated with a 3 MeV electron-beam resulting in dosages of 0 to 240 kGy using a rhodotron accelerator system. The effect of radiation exposure on the LDPE/EVA/TMPTMA blend properties were investigated with respect to gel content, tensile strength and elongation up to breakage of the blends. The findings indicate that increasing EVA and TMPTMA content yield tighter network structures through enhanced blend crosslinking, which is a direct consequence of irradiation. For pure EVA significant tensile strength improvements are evident as irradiation increases up to 210 kGy. Irradiated blends exhibit improved tensile strength and elongation at breakage with respect to pure LDPE and EVA. Volume resistivity (VR) and dielectric constant (DC) of the blends were also studied as a function of EVA content, TMPTMA content and radiation dosage. Increasing EVA and TMPTMA content enhances DC and VR values, whereas, increasing irradiation dosage only effects VR values of the blends. The maximum VR value attained in this work corresponds to a radiation dosage of 170 kGy and a blend comprising of 30 wt% of EVA.

Thermal and anti-dripping properties of γ-irradiated PA6 fiber with the presence of sensitizers

Abstract PA6 fiber with the presence of sensitizers trimethallyl isocyanurate (TMAIC) and trimethylolpropane trimethylacrylate (TMPTMA) has been prepared using the melt spinning method and then irradiated by γ-rays. Radiation-induced crosslinking was efficiently promoted by sensitizers revealed by the increase in percentage of gel content. Owing to the formation of three-dimensional network, the melt viscosity of PA6 fiber became higher at time of burning and the amount of non-volatile residue at 600 °C increased which contributed to the improvement of anti-dripping performance. Thermal gravimetric analysis showed that the onset temperature of degradation of PA6 fiber fell and the rate of maximum mass loss decreased after irradiation.

Controlled Synthesis of Bulk Polymer Nanocomposites with Tunable Second Order Nonlinear Optical Properties

The transparent bulk polymer nanocomposites blended with rare earth nanoparticles are prepared through the radical polymerization of trimethylolpropane trimethylacrylate (TMPTMA). These materials produce continuously tunable second harmonic (SH) radiation under illumination of a wide spectral range of fundamental waves (750-850 nm). The SHG efficiency can be controlled well by altering the Tb(3+) doping content in the nanoparticles.

Preparation of a Crosslinked Bioimprinted Lipase for Enrichment of Polyunsaturated Fatty Acids from Fish Processing Waste

Geotrichum sp. lipase modified with a combined method composed of crosslinking and bioimprinting was employed to selectively hydrolyze waste fish oil for enrichment of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in glycerides. Crosslinked polymerization by monomer (polyethylene glycol 400 dimethyl acrylate), crosslinker (trimethylolpropane trimethylacrylate), and photoinitiator (benzoin methyl ether) coupled to bioimprinting using palmitic acid as imprint molecule, resulted in much more effective enzyme preparation used in aqueous hydrolysis reaction. Since the crosslinked polymerization modification maintained bioimprinted property and gave good dispersion of enzyme in reaction mixture, the crosslinked bioimprinted enzyme exhibited higher hydrolysis temperature, enhanced specific activity, shorter hydrolysis time, and better operational stability compared to free lipase. Crude fish oil was treated at 45 degrees C with this crosslinked bioimprinted lipase for 8 h, and 46% hydrolysis degree resulted in the production of glycerides containing 41% of EPA and DHA (EPA+DHA), achieving 85.7% recovery of initial EPA and DHA. The results suggested that bioimprinted enzymes did not lose their induced property in aqueous environment when prepared according to the described crosslinking-bioimprinting method. It could also be seen that the crosslinked bioimprinted lipase was effective in producing glycerides that contained a higher concentration of polyunsaturated fatty acid with better yield.

Hydrophilic modification of polyethersulfone porous membranes via a thermal-induced surface crosslinking approach

A thermal-induced surface crosslinking process was employed to perform a hydrophilic surface modification of PES porous membranes. Difunctional poly(ethylene glycol) diacrylate (PEGDA) was used as the main crosslinking modifier. The addition of trifunctional trimethylolpropane trimethylacrylate (TMPTMA) into the reaction solutions accelerated the crosslinking progress of PEGDA on PES membranes. The membrane surface morphology and chemical composition were characterized by scanning electron microscopy (SEM) and FTIR-ATR spectroscopy. The mass gains (MG) of the modified membranes could be conveniently modulated by varying the PEGDA concentration and crosslinking time. The measurements of water contact angle showed that the hydrophilicity of PES membranes was remarkably enhanced by the coating of crosslinked PEGDA layer. When a moderate mass gain of about 150 μg/cm 2 was reached, both the permeability and anti-fouling ability of PES membranes could be significantly improved. Excessive mass gain not only contributed little to the anti-fouling ability, but also brought a deteriorated permeability to PES membranes.

Synthesis and characterization of molecularly imprinted polymers for recognition of ciprofloxacin

A molecularly imprinted polymer (MIP), with special molecule recognition properties of ciprofloxacin (CIP), was prepared by thermal polymerization in which ciprofloxacin acted as template molecule, α-methacrylic acid (MAA) acted as functional monomer and trimethylolpropane trimethylacrylate (TRIM) acted as crosslinker. The optimized ratio was determined to be n(CIP): n (MMA):n(TRIM)51:6:16 by investigation of the effects of different concentrations of functional monomer and the crosslinker on the MIP’s recognition properties. Equilibrium binding experiment was used to investigate the adsorption dynamics, the binding ability to template molecule and the substrate selectivity. Scatchard analysis was used to study the MIP’s binding characteristic to template molecule. The results indicated that MIP has higher adsorption ability and selectivity. The equilibrium distribution coefficient KD was 41.64 and the separation factor α was 1.62. Scatchard analysis showed that two different kinds of binding sites were produced in the polymer matrix and their dissociation constants were calculated to be Kd1 = 5.249 × 10−5 mol·L−1, Kd2 = 2.237 × 10−3 mol·L−1.