OXIDATIVE POLYMERIZATION BEHAVIOR OF 2,6-DIMETHYLPHENOL IN AQUEOUS MEDIA WITH POTASSIUM FERRICYANIDE

The effects of potassium ferricyanide,sodium n-dodecyl sulfate,sodium hydroxide and temperature on the molecular weight and the yield of poly(2,6-dimethyl-1,4-phenylene oxide)(PPO) synthesized in an aqueous medium were studied.It was found that oxygen in air had little influence on the oxidative polymerization of 2,6-dimethylphenol(DMP) in the aqueous medium,and potassium ferricyanide was only an oxidant during the oxidative polymerization of DMP.Sodium n-dodecyl sulfate could stabilize polymer particles an...

Emitting stability of poly(9,9-dialkylfluorene-co-N-butylcarbazole) by solid-state oxidative coupling polymerization

Dihexylfluorene and N-butylcarbazole were copolymerized by solid-state oxidative coupling polymerization in the presence of anhydrous FeCl3 at room temperature. The solid-state films of the copolymers emitted blue light after beating at 150 ℃ in air for 24 h, no red-shifted emission was observed by fluorescence spectroscopy.

Green Light-Emitting Region-Regular Poly(9,9-Dihexylfluorene-co-Fluorenone) Prepared from Solvent-Free Oxidative Coupling Polymerization

Soluble green light-emitting poly（9,9-dihexylfluorene- co-fluorenone） was synthesized by solvent-free oxidative coupling polymerization of 9,9-dihexylfluorene in a facile one-step reaction. The polymers were characterized by FT-IR, ^1H NMR, ^13C NMR, UV-Vis and fluorescence spectroscopy. The region-regular structure of the polymer linking at 2, 7＇-position on the fluorene moieties was obtained. The FT-IR spectra of the polymers showed fluorenone vibration. The fluorescence spectra of the solid thin film of the polymers displayed green light-emitting, which was emitted from fluorenone moieties produced in the polymerization process.

Study of lithium/polypyrrole secondary batteries with Lithium as cathode and polypyrrole anode

Lithium/polypyrrole （Li/PPy） batteries were fabricated using lithium sheet as cathode, PPy as anode, microporous membrane polypropylene/polyethylene/polypropylene （PP/PE/PP） composite as separator and LiPF6/ethylene carbonate-dimethyl carbonate-methyl ethyl carbonate （EC-DMC-EMC） as electrolyte. Polypyrrole was prepared by chemical polymerization. Certain fundamental electrochemical performances were investigated. Properties of the batteries were characterized and tested by SEM, galvanostatic charge/discharge tests, cyclic voltammetry （CV）, and a.c. impedance spectroscopy. The influences of separator, morphology, and conductivity of PPy anode, cold-molded pressure, and electric current on the performances of the batteries were studied. Using PP/PE/PP membranes as separator, the battery showed good storage stability and cycling property. The conductivity of materials rather than morphology affected the behavior of the battery. The higher the conductivity, the better performances the cells had. Proper cold-molded pressure 20 MPa of the anode pellet would make the properties of the cells good and the fitted charge/discharge current was 0.1 mA. The cells showed excellent performance with 97%-100% coulombic efficiency. The highest discharge capacity of 95.2 mAh/g was obtained.

NOVEL SYNTHESIS OF POLYARYLENESULFONIUM CATIONS THROUGH A MULTI-ELECTRON TRANSFER PROCESS

The oxidative polymerization of aryl sulfoxides provides a novel polysulfo-nium compound, poly(methylsulfonio-1,4-phenylenethio-1,4-phenylene cation) in quantita-tive yield. The polymerization proceeds efficiently in an acidic solution under atmosphericconditions. Oxygen, chemical and electrochemical oxidations are available. Vanadyl acety-lacetonate and cerium ammonium nitrate act as an effective catalyst for the oxygen ox-idative polymerization. The polymerization mechanism involves multielectron oxidation ofthe sulfides followed by successive electrophilic substitution. The resulting polyarylenesul-fonium cations are useful as a soluble precursor for the synthesis of high molecular weight(M_w>10~5) poly(thio arylne)s.

Composition Dependence of the Thermal Behavior,Morphology and Properties of Biodegradable PBS/PTMO Segment Block Copolymer

A series of aliphatic biodegradable poly（ether-ester）s based on poly（butylene succinate）（PBS）as hard segment and poly（tetramethylene oxide）（PTMO,M_n=1 000 g/mol） as soft segment were synthesized.The composition dependence of thermal behavior,morphology and mechanical properties was investigated by differential scanning calorimetry（DSC）,atomic force microscopy（AFM）,and tensile testing.The crystallization temperature（T_c） and melting temperature（T_m） of the PBS block within poly（ether-ester）s decrease steadily at first,but decrease sharply with PTMO content above 50 wt%.Two crystallization peaks were detected for PTMO in PBSPTMO60 sample,suggesting the occurrence of fractionated crystallization.The crystallization enthalpies（△H_c） and melting enthalpies（△H_m） of PBS block decrease at first,then increase as PTMO content increases further.AFM has demonstrated that phase-separated morphology transforms from a phase of continuous hard matrix to one of continuous soft matrix containing isolated hard domain as PTMO content is increased.Finally,the results of tensile testing show that the poly（ether-ester）s present the behavior of plastics when PTMO content is below 40 wt%,and of thermoplastic elastomers with PTMO content above 50 wt%.By varying the composition of copolymer,the aliphatic poly（ether-ester）s plastics,or especially biodegradable aliphatic poly（ether-ester）s thermoplastic elastomers can be obtained.

SYNTHESIS OF CONDUCTIVE POLYANILINE VIA OXIDATION BY MnO_2

A unique process of chemical oxidation polymerization of aniline using manganese dioxide (MnO2) as the oxidizing agent in an aqueous medium is described. The reaction between aniline and MnO2 follows a mechanism by which the organic monomer is oxidized while the metal oxide undergoes reductive dissolution. The effects of the amount of oxidizing agent and aniline, pH and temperature of the reactive system, type of acid on the yield and conductivity of polyaniline are discussed. The resulting polyaniline was characterized by IR and UV-Vis spectrometry. Polyaniline with a conductivity of 12.5 S/cm was obtained using 0.033 mol of aniline oxidized by 0.023 mol MnO2 in the presence of 100 mL of 2.7 mol/L HCl at 25degreesC for 4 h.

Poly(imine-amide)Hybrid Covalent Adaptable Networks via in situ Oxidation Polymerization

Polyimine represents a rapidly emerging class of readily accessible and affordable covalent adaptable networks(CANs)that have been extensively studied in the past few years.While being highly malleable and recyclable,the pioneering polyimine materials are relatively soft and not suitable for certain applications that require high mechanical performance.Recent studies have demonstrated the possibility of significantly improving polyimine properties by varying its monomer building blocks,but such component variations are usually not straightforward and can be potentially challenging and costly.Herein,we report an in situ oxidation polymerization strategy for preparation of mechanically strong poly(imine-amide)(PIA)hybrid CANs from simple amine and aldehyde monomers.By converting a portion of reversible imine bonds into high-strength amide linkages in situ,the obtained hybrid materials exhibit gradually improved Young’s modulus and ultimate tensile strength as the oxidation level increased.Meanwhile,the PIAs remain reprocessable and can be depolymerized into small molecules and oligomers similar as polyimine.This work demonstrates the great potential of the in situ transformation strategy as a new approach for development of various mechanically tunable CANs from the same starting building blocks.

Thiophene-based conjugated microporous polymers:synthesis,characterization and efficient gas storage

A series of thiophene-based conjugated microporous polymers(ThPOPs) have been synthesized on the basis of ferric chloride-catalyzed oxidative coupling polymerization of multi-thienyl monomers. The structures of ThPOPs were confirmed via solid-state 13 C CP/MAS NMR spectroscopy and Fourier-transform infrared spectroscopy. The ThPOPs possess high porosities and their high Brunauer-Emmett-Teller specific surface area results vary between 350 and 1320 m^2 g^(-1). The presence of abundant ultra-micropores at 0.50–0.63 nm allows ThPOPs efficient gas(carbon dioxide, methane, and hydrogen) adsorption.

SYNTHESIS AND CHARACTERIZATION OF A NEW DYESTUFF POLYMER SOLUBLE IN ALKALINE AQUEOUS MEDIA

Novel dyestuff polymers were successfully obtained through oxidative polymerization technique. The synthesized Schiff base and its polymer were soluble in alkaline＇aqueous medium and they have various colors in different solutions. Also, it can be said that the synthesized compounds are suitable as coloring agent （dyestuff） for textile applications. Fluorescence properties of the compounds were determined in DMF with different concentrations （mg/L）. Poly-tris（4- aminophenyl）methanol （P-TAPM） has quite high emission and excitation intensity values. Optical and electrochemical band gaps of the polymers were lower than those of the monomers indicating the more conjugated structure of the polymers. The oxidized states of the novel dyestuff compounds were examined by cyclic voltammetry （CV） technique. The solid state conductivity measurements showed that the synthesized polymers were semiconductors when exposed to the iodine vapour their conductivities could be increased. P-TAPM had the highest undoped conductivity. Thermal characterizations of the synthesized compounds were carried out by TG-DTA and DSC methods.

Improving the electroconductivity and mechanical properties of cellulosic paper with multi-walled carbon nanotube/polyaniline nanocomposites

Cellulose is the most abundant renewable polymer in the nature,and cellulosic paper is widely used in our daily life.Conferring electroconductivity to cellulosic paper would allow this conventional material to hold great promise for a wide range of energy-related applications.In the present work,multi-walled carbon nanotube(MWCNT)/polyaniline(PANI)nanocomposites were synthesized via in situ oxidation polymerization process and characterized by FT-IR and TEM.Subsequently,the application of the synthesized MWCNT/PANI nanocomposites as a wet-end filler for the production of electro-conductive paper was demonstrated/developed.Results showed that the cellulosic paper was imparted with an electro-conductivity of up to 0.14 S·m^(-1) while exhibiting a pronounced improvement in mechanical properties as a function of the added MWCNT/PANI nanocomposites.

NaV3O8/poly(3,4-ethylenedioxythiophene) composites as high-rate and long-lifespan cathode materials for reversible sodium storage

Sodium-ion batteries have received a surge of interests for the alternatives to lithium-ion batteries due to their abundant reserves and low cost.The quest of reliable and high-performance cathode materials is crucial to future Na storage technologies.Herein,poly(3,4-ethylenedioxythiophene)(PEDOT)was successfully introduced to NaV3O8 via in situ oxidation polymerization,which can effectively enhance electron conductivity and ionic diffusion of NaV3O8 material.As a result,these NaV3O8@-PEDOT composites exhibit a significantly improved electrochemical performance including cycle stability and rate performance.In particular,NaV3O8@20 wt%PEDOT composite demonstrates better dispersibility and lower charge transfer resistance compared with bare NaV3O8,which delivers the first discharge capacity of 142 mAh-g-1and holds about 128.7 mAh·g-1 after 300 cycles at a current density of 120 mA·g-1.Even at a high current density of 300 mA·g-1,a high reversible capacity of 99.6 mAh·g-1 is revealed.All these consequences suggest that NaV3O8@20 wt%PEDOT composite may be a promising candidate to serve as a high-rate and long-lifespan cathode material for sodium-ion batteries.

Polystyrene-graphene oxide modified glassy carbon electrode as a new class of polymeric nanosensors for electrochemical determination of histamine

A simple and rapid protocol for the synthesis of polystyrene-graphene oxide nanocomposite （PS/GONC） was achieved for first time using an in situ polymerization method. PS/GONC modified glassy carbon electrode （PS/GONC/GCE） has been employed as an efficient nanosensor for the electrooxidation of histamine. The PS/GONC/GCE is used as an electrochemical nanosensors for monitoring histamine using differential pulse voltammetry techniques （detection limit 0.03 μmol/L）. In addition, the prepared nanosensor was successfully applied to determine histamine in fish samples, yielding satisfactory results. The spiked recoveries were in the range of 98.2%-103.1%.

Self-healing Supramolecular Polymer Composites by Hydrogen Bonding Interactions between Hyperbranched Polymer and Graphene Oxide

A self-healing supramolecular polymer composite（HSP-GO） was designed and prepared via incorporation of modified graphene oxide to hyperbranched polymer by hydrogen-bonding interactions. The polymer matrix based on amino-terminated hyperbranched polymer（HSP-NH_2） was synthesized by carboxylation, Curtius rearrangement, and amination of hydroxyl-terminated hyperbranched polyester（HP-OH）, while the modified graphene oxide was prepared by transformation of hydroxyl to isocyanate and further to carbamate ester. Spectroscopic methods were utilized to characterize the obtained polymer composites. Stress-strain test was selected to carefully study the self-healing property of HSP-GO. It is found that a small amount of modified graphene oxide（up to 2 wt%） improves the glass transition temperature（T_g）, tensile strength, Young＇s modulus, and self-healing efficiency of the polymer composites. After healed at room temperature for 10 min, the addition of modified graphene oxide improves the self-healing efficiency to 37% of its original tensile strength. The experiment result shows that the self-healing efficiency is related to the density of hydrogen bonding site and the molecular movement.

Synthesis, Characterization and Electrochemical Study of Graphene Oxide-Multi Walled Carbon Nanotube-Manganese Oxide-Polyaniline Electrode as Supercapacitor

The synthesis of graphene oxide-multi walled carbon nanotube-manganese oxide-polyaniline namely （GMMP） nanocomposite for application in supercapacitor devices was investigated. Morphology of the nanocomposites was studied by X-ray diffraction （XRD）, Fourier transform infrared （FT-IR） spectrosco- py, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and energy dispersive X-ray micmanalysis （EDX）. The electrochemical properties of nanocomposite based electrodes were in- vestigated by cyclic voltammetry （CV）, galvanostatic charge-discharge and electrochemical impedance spectroscopy （EIS） techniques in 0.5 mol/L Na2SO4. The specific capacitances of 173.00, 127.85, 87.50, 58.65 and 12.00 （mF cm^-2） were obtained for GMMP, GMP （GO-MWCNT-PANI）, GMM （GO-MWCNT-MnO2）, GM （GO-MWCNT） and G （GO） at a scan rate of 10 mV s^-1, respectively. Also, GMMP nanocomposite re- tained 90% initial capacitance after 200 cycle of charge-discharge. The good electrochemical response of this nanocomposite is due to the combination of the electrical double layer capacitance of GO and MWCNT and the gradual introduction of pseudo-capacitance through the redox processes of PANI, -COOH, -OH （in MWCNT-COOH, GO-COOH and GO-OH） and MnO2. This revealed the synergistic effect of PANI, MnO2, -OH -COOH on the carbon based support.

Flexible,robust and highly efficient broadband nonlinear optical materials based on graphene oxide impregnated polymer sheets

We report a simple solution-processed method for the fabrication of low-cost,flexible optical limiting materials based on graphene oxide(GO) impregnated polyvinyl alcohol(PVA) sheets.Such GO–PVA composite sheets display highly efficient broadband optical limiting activities for femtosecond laser pulses at 400,800,and 1400 nm with very low limiting thresholds.Femtosecond pump–probe measurement results revealed that nonlinear absorption played an important role for the observed optical limiting activities.High flexibility and efficient optical limiting activities of these materials allow these composite sheets to be attached to nonplanar optical sensors in order to protect them from light-induced damage.