Redox active polymer metal chelates for use in flexible symmetrical supercapacitors:Cobalt-containing poly(acrylic acid)polymer electrolytes

The novel polymer metal chelate electrolytes(polychelates)were prepared by incorporation of cobalt sulfate(Co)into poly(acrylic acid)(PAA)host matrix.Quasi-solid state supercapacitor devices were fabricated using polychelates,PAA-Co X(X:3,5,7,and 10)where X represents the doping fraction(w/w)of Co in PAA.All polymer metal electrolytes were showed excellent bending-stretching properties,thermal stability and electrochemical durability with an optimum ionic conductivity of 3.15×10^(-4) S cm^(-1).Hierarchically porous activated carbon and nano-sized conductive carbon were used to form carbon composite symmetrical device electrodes.The electric double-layer capacitor(EDLC)and redox reactions of Co-incorporated polychelates at the interfaces of porous activated carbon provided an optimum specific capacitance of 341.33 F g^(-1) with a device of PAA-Co7,which is at least 15 times enhancement compared to the device of pristine PAA.The PAA-Co7 device also provided energy density of 21.25 Wh kg^(-1) at a power density of 117.69 W kg^(-1).A prolonged cyclic stability of the device exhibited superior capacitive performance after 10,000 charge-discharge cycles and the maintained 90%of its initial performance.In addition,the supercapacitor with a dimension of 1.5 cm×3 cm containing PAA-Co7 successfully operated the red-blue-green(RGB)LED light.

CONFORMATIONAL CHARACTERISTICS OF POLY(ACRYLIC ACID) AND POLY(METHACRYLIC ACID)

A full-relaxation optimization of molecule and the Dreiding force field are employed to obtain the geometry parameters and the conformational energy surfaces of meso or racemic dyad of poly(acrylic acid) (PAA) and poly(methacrylic acid) (PMAA). Three different carbonyl-bond orientations of side-groups resulted in the differences in depth of potential wells in their energetic contours for a meso or a racemic dyad. These discrepancies are interpreted as a result of various fine structures corresponding to grid search conformations as well as thereby different interactions. The analysis on the most stable conformations of PMAA confirmed that the ester groups are nearly perpendicular to the plane defined by the two adjacent skeletal bonds but may possibly change their relative orientations to meet the requirement of lower energy during the conformational state transition. For each polymer, two global energy maps of a meso and a racemic dyad were finally constructed from the superposition of energy data for the three kinds of side-group orientations by the Boltzmann factors. From an ensemble average, the proposed scheme with three rotational isomeric states (RIS) allowed us to access the experimentally unperturbed dimensions of PAA chain via the configurational statistical mechanics. Although the calculation was based on the short-range, local interactions, it was interested to note that the experimental characteristic ratios just fell within the range calculated for atactic chains.

PREPARATION OF POLY(ETHYLENEGLYCOL-co-ACRYLIC ACID) MICROSPHERES WITH DIVINYLBENZNE AS CROSSLINKER BY DISTILLATION-PRECIPITATION POLYMERIZATION

Monodisperse poly（poly（ethyleneglycol） methyl ether acrylate-co-acrylic acid） （poly（PEGMA-co-AA）） microspheres were prepared by distillation-precipitation polymerization with divinylbenzene （DVB） as crosslinker with 2,2＇- azobisisobutyronitrile （AIBN） as initiator in neat acetonitrile without stirring. Under various reaction conditions, four distinct morphologies including the sol, microemulsion, microgels and microspheres were formed during the distillation of the solvent from the reaction system. A 2D morphological map was established as a function of crosslinker concentration and the polar monomer AA concentration, in comonomer feed in the transition between the morphology domains. The effect of the covalent crosslinker DVB on the morphology of the polymer network was investigated in detail at AA fraction of 40 vol%. The ratios of acid to ethylene oxide units presenting in the comonomers dramatically affected the polymer-polymer interaction and hence the morphology of the resultant polymer network. The covalent crosslinking by DVB and the hydrogen bonding crosslinking between two acid units as well as between the acid and ethylene oxide unit played key roles in the formation of monodisperse polymer microspheres.

Graft Polymerization of Acrylic Acid on a Polytetrafluoroethylene Panel by an Inductively Coupled Plasma

Surface modification on a polytetrafluoroethylene （PTFE） panel was performed with sequential nitrogen plasma treatments and surface-initiated polymerization. By introducing COO- groups to the surface of the PTFE panel through grafting polymerization of acrylic acid （AA）, a transparent poly （acrylic acid） （PAA） membrane was achieved from acrylic acid solution. Grafting polymerization initiating from the active group5 was achieved on the PTFE panel surface after the nitrogen plasma treatment. Utilizing the acrylic acid as monomers, with COO- groups as cross link sites to form reticulation structure, a transparent poly （acrylic acid） membrane with arborescent macromolecular structure was formed on the PTFE panel surface. Analysis meth- ods, such as fourier transform infrared spectroscopy （FTIR）, microscopy and X-ray photoelectron spectroscopy （XPS）, were utilized to characterize the structures of the macromolecule membrane on the PTFE panel surface. A contact angle measurement was performed to characterize the modified PTFE panels. The surface hydrophilicities of modified PTFE panels were significantly enhanced after the plasma treatment. It was shown that the grafting rate is related to the treating time and the power of plasma.

Poly (Acrylamide-co-Acrylic Acid) Hydrogel Induced by Glow-Discharge Electrolysis Plasma and Its Adsorption Properties for Cationic Dyes

In this paper, poly （acrylamide-co-acrylic acid） （P（AM-co-AA）） hydrogel was pre- pared in an aqueous solution by using glow-discharge electrolysis plasma （GDEP） induced copoly- merization of acrylamide （AM） and acrylic acid （AA）, in which N,N＇-methylenebisacrylamide （MBA） was used as a crosslinker. A mechanism for the synthesis of P（AM-co-AA） hydrogel was proposed. To optimize the synthesis condition, the following parameters were examined in detail： the discharge voltage, discharge time, the content of the crosslinker, and the mass ratio of AM to AA. The results showed that the optimum pH range for cationic dyes removal was found to be 5.0-10.0. The P（AM-co-AA） hydrogel exhibits a very high adsorption potential and the ex- perimental adsorption capacities for Crystal violet （CV） and Methylene blue （MB） were 2974.3 mg/g and 2303.6 mg/g, respectively. The adsorption process follows a pseudo-second-order kinetic model. In addition, the adsorption mechanism of P（AM-co-AA） hydrogel for cationic dyes was also discussed.

Molecular Imprinting Fibrous Membranes of Poly(acrylonitrile-co-acrylic acid) Prepared by Electrospinning

IntroductionOver the past few decades, molecular imprinting has been described as a technology for preparing ＂molecular doors＂ which can be matched to ＂template keys＂. It has been found to be a simple and effective approach to introduce specific recognition sites into synthetic polymers, namely, to create molecular imprinting polymers Remarkable features such as stability, ease of preparation and low cost, have made molecular imprinting polymers particularly attractive in chemical sensors, catalysis, drug delivery, and dedicated separations. Practical applications of molecular imprinting polymers require accessible sites, fast mass transfer, and quick binding. However, present techniques used to prepare molecular imprinting polymers most often result in materials exhibiting a high affinity and selectivity but a low capacity and poor site accessibility for the target molecules. It is also very difficult to remove the imprinted molecules located in these molecular imprinting polymers because the highly cross-linked structures do not allow the templates to move freely. To some extent, combining molecular imprinting technology with membrane separation and surface imprinting can overcome the shortcomings, such as mass transfer limitations and non-quantitative recovery of the template molecules seen for imprinted materials fabricated by conventional bulk methods. In that ease, it appears to us that molecular imprinting polymers with high surface area to volume ratios are particularly desirable for largescale applications. Eleetrospun nano and ultrafine fibrous membranes are the most suitable materials due to advantages such as： （1） large specific surfaces, providing relatively high imprinting sites per unit mass; （2） fine porous structures, resulting in the accessibility of imprinting sites and low diffusion resistance necessary for high efficiency; and （3） easy recoverability from practical operation or applicability for continuous usages. Therefore, in this work, we prepared a unique kind of imprinted material--molecularly imprinted fibrous membranes of poly （ acrylonitrile-co-acrylic acid） fabricated by means of an electrospinning process.

Synthesis and Properties of IPN Hydrogels Based on Konjac Glucomannan and Poly(acrylic acid)

Novel interpenetrating polymer network （IPN） hydrogels based on konjac glucomannan （KGM） and poly（acrylic acid） （PAA） were prepared by polymerization and cross-linking of acrylic acid （AA） in the pre-fabricated KGM gel. The IPN gel was analyzed by FF-IR. The studies on the equilibrium swelling ratio of IPN hydrogels revealed their sensitive response to environmental pH value. The results of in vitro degradation showed that the IPN hydrogels retain the enzymatic degradation character of KGM.

Preparation and Properties of Carrageenan-g-Poly(Acrylic Acid)/Bentonite Superabsorbent Composite

A novel biopolymer-based superabsorbent hydrogel composite based on kappa-carrageenan (κC) have been prepared via graft copolymerization of acrylic acid (AA) in the presence of bentonite powder using methylenebisacrylamide (MBA) as a crosslinking agent and ammonium persulfate (APS) as an initiator. The hydrogel structure was confirmed using FTIR spectroscopy and the morphology of the samples was examined by scanning electron microscopy (SEM). The affecting variables onto graft polymerization (i.e. AA, MBA and APS concentration, as well as the bentonite amount) were systematically optimized to achieve a hydrogel with swelling capacity as high as possible. The results of Brunauer–Emmett–Teller (BET) analysis showed that the average pore diameter of the synthesized hydrogel was 11.5 nm. The effect of various salt media and solutions with different pHs on the swelling of the superabsorbent was also studied.

Synthesis and application of a novel star-hyperbranched poly(acrylic acid) for improved dental restoratives

A new star-hyperbranched poly(acrylic acid) has been synthesized and incorporated into dental glassionomer cement for enhanced mechanical strengths. The effects of arm number and branching on viscosity of the polymer aqueous solution and mechanical strengths of the formed experimental cement were evaluated. It was found that the higher the arm number and the more the branching, the lower the viscosity of the polymer solution as well as the mechanical strengths of the formed cement. It was also found that the experimental cement exhibited significantly higher mechanical strengths than commercial Fuji II LC. The experimental cement was 51% in CS, 55% in compressive modulus, 118% in DTS, 82% in FS, 18% in FT and 85% in KHN higher than Fuji II LC. The experimental cement was only 6.7% of abrasive and 10% of attritional wear depths of Fuji II LC in each wear cycle. It appears that this novel experimental cement is a clinically attractive dental restorative and may potentially be used for high-wear and high-stress-bearing site restorations.

Studies on Micellization of a Polystyrene-b-poly(acrylic acid) Copolymer in Aqueous Media by Pyrene Fluorescence

Pyrene probe and TEM have been employed to investigate the behavior of a polystyrene-b-poly(acrylic acid) (PS-b-PAA) copolymer in aqueous solution. A significant annealing temperature effect on the I1/I3 ratio of pyrene was observed and was interpreted in terms of the morphological change of micellar cores. Annealing at a temperature higher than the glass transition temperature (Tg) of PS leads to densification of the hydrophobic core.

Swelling Behaviors of Polyaniline-Poly(Acrylic Acid) Hydrogels

Using poly(acrylic acid) (PAA) aqueous solution, NaOH aqueous solution, aniline(An) and ammonium persulfate(APS), PAn-PAA hydrogels with a semi-interpenetrating structure connected by physical interlocks, chemical ion bonds and hydrogen bonds were prepared. The swelling properties of the hydrogels in solutions of different pH values (adjusted by adding NaOH or HCl) were studied. All the hydrogels prepared have similar swelling curves (the curves of equilibrium swelling ratio vs. pH value) and reach their maximum swelling at pH of 810. The maximum swelling ratio of the hydrogels is dependent on composition, including molecular weight of PAA, polymer content of the hydrogel, and molar ratios of AA to An, APS to An, and NaOH to AA. And the compositional dependence of the swelling capacity of PAn-PAA hydrogels was also studied.

Poly(Acrylamide-Co-Acrylic Acid)-Zinc Acetate Polymer Electrolytes: Studies Based on Structural and Morphology and Electrical Spectroscopy

Solid polymer electrolytes (SPEs) of polyacrylamide-co-acrylic acid (PAA) as the polymer host and zinc acetate (ZnA) as an ionic dopant were prepared using a single solvent by the solution casting technique. The amorphous and crystalline structures of film were investigated by X-ray diffraction (XRD). The surface morphology of samples was examined by scanning electron microscopy (SEM). The composition and complex formation of films were characterized by Fourier transform infrared (FTIR) spectroscopy. The conductivity of the PAA-ZnA films was determined by electrochemical impedance spectroscopy. According to the XRD and FTIR analyses, all electrolyte films were in amorphous state and the existence of interaction between Zn2+ cations and the PAA structure confirms that the film was successfully prepared. The SEM observations reveal that the electrolyte films appeared to be rough and flat with irregularly shaped surfaces. The highest ionic conductivity (σ) of 1.82 × 10-5 Scm-1 was achieved at room temperature (303 K) for the sample containing 10 wt % ZnA.

Studies on interacting Blends of Acrylated Epoxy resin based Poly(Ester-Amide)s and Vinyl EsterResin

Epoxy resin based Unsaturated poly(ester-amide) resins (UPEAs) can be prepared by many methods but here these were prepared by reported method [1]. These UPEAs were then treated with acrylotl chloride to afford acrylated UPEAs resin (i.e. AUPEAs). Interacting blends of equal proportional AUPEAs and vinyl ester epoxy (VE) resin were prepared. APEAs and AUPEAs were characterized by elemental analysis, molecular weight determined by vapour pressure osmometer and by IR spectral study and by thermogravimetry. The curing of interacting blends was monitored on differential scanning calorimeter (DSC). Based on DSC data in situ glass reinforced composites of the resultant blends have been prepared and characterized for mechanical, electrical and chemical properties. Unreinforced blends were characterized by thermogravimetry (TGA).

Self-healing poly(acrylic acid) hydrogels fabricated by hydrogen bonding and Fe^(3+) ion cross-linking for cartilage tissue engineering

Autonomous self-healing hydrogels were achieved through a dynamic combination of hydrogen bonding and ferric ion(Fe^(3+))migration.N,N′-methylenebis(acrylamide)(MBA),a cross-linking agent,was added in this study.Poly(acrylic acid)(PAA)/Fe^(3+)and PAA–MBA/Fe^(3+)hydrogels were prepared by introducing Fe^(3+)into the PAA hydrogel network.The ionic bonds were formed between Fe^(3+)ions and carboxyl groups.The microstructure,mechanical properties,and composition of hydrogels were characterized by field emission scanning electron microscopy and Fourier transform infrared spectroscopy.The experimental results showed that PAA/Fe^(3+)and PAA–MBA/Fe^(3+)hydrogels healed themselves without external stimuli.The PAA/Fe^(3+)hydrogel exhibited good mechanical properties,i.e.,the tensile strength of 50 kPa,the breaking elongation of 750%,and the self-healing efficiency of 82%.Meanwhile,the PAA–MBA/Fe^(3+)hydrogel had a tensile strength of 120 kPa.These fabricated hydrogels are biocompatible,which may have promising applications in cartilage tissue engineering.

HYDROLYSIS TRANSFORMATION OF A POLYSTYRENE-b-POLY(tert-BUTYL ACRYLATE) COPOLYMER AND MICELLIZATION PROPERTIES OF THE HYDROLYZED COPOLYMER

A very mild and extremely efficient hydrolysis method for transformation of polystyrene-b-poly(tert-butyl acrylate) (PS-b-PtBA) to polystyrene-b-poly(acrylic acid) (PS-b-PAA) was designed and carried out using more convenient and inexpensive chlorotrimethylsilane/sodium iodide as reagents. The hydrolysis product can self-assemble in aqueous media to give regular micelles with PS block forming the core and PAA block forming the corona, or in tetrahydrofuran (THF) to give reverse micelles with the hydrophilic block in the core.

3D打印工艺参数对PLA/PTW共混物力学性能影响的研究

采用3D打印中的熔融沉积成型(FDM)工艺制备了聚乳酸/乙烯-丙烯酸丁酯-甲基丙烯酸缩水甘油酯共聚物(PLA/PTW),通过单因素实验探究了3D打印工艺参数(喷头温度、打印平台温度和打印速度)对PLA/PTW共混物力学性能的影响,并在此基础上设计了三因素三水平正交实验,优化了3D打印的工艺参数。结果表明,共混物的冲击强度和拉伸强度均随喷头温度的增加呈现先上升后下降、均随打印平台温度的增加而增加、均随打印速度的增加出现下降的趋势。各工艺参数对PLA/PTW共混物综合力学性能的影响从大到小依次为:喷头温度、打印速度、打印平台温度,且当喷头温度为210℃、打印平台温度为80℃以及打印速度为40 mm/s时,打印出的PLA/PTW共混物的综合力学性能最佳。

PAAS高吸水树脂对重金属离子盐溶液的吸液及吸附性能

用聚丙烯酸高吸水树脂（PAAS）研究了单一和混合重金属离子硝酸盐溶液中的吸液和吸附性能。在Pb^2＋、Ni^2＋、Cd^2＋、Zn^2＋、Mn^2＋和Cu^2＋的一、二元溶液中,PAAS的吸液倍率随时间延长而增加,约50min达吸液平衡,一元金属离子溶液中平衡吸液倍率为160～190g/g,而对Cr^3＋溶液,最大为120g/g;二元金属离子混合溶液中平衡吸液倍率都在150～180g/g之间,有Cr^3＋存在时平衡吸液倍率最小。对上述单一金属离子的吸附量随时间延长而增加,约180min达吸附平衡,平衡吸附量顺序为：Pb^2＋〉Cd^2＋〉Ni^2＋〉Cu^2＋〉Zn^2＋〉Mn^2＋〉Cr^3＋。对二元混合金属离子溶液,吸附量随时间增加而增加,30min后逐渐变慢,约70min后达吸附平衡。

PAAM高吸水树脂的土壤保水性能

以不同河砂/泥土比例混配不同质地土壤,研究了聚(丙烯酸-丙烯酰胺)高吸水树脂(PAAM)用量在自来水和0.9%NaCl溶液中对土壤保水能力的影响。发现自然蒸发条件下,PAAM树脂施用量为5g/kg时,使河砂/泥土=10∶0,5∶5,3∶7,0∶10四种质地土壤在自来水中保水率降至30%的时间与对照组相(无PAAM)比分别延长了560,445,360,350h;使河砂/泥土=10∶0,7∶3,5∶5,3∶7,0∶10五种质地土壤在自来水中饱和含水率分别提高4.5,2.6,2.2,1.6,1.2倍。该树脂临界用量为5g/kg能显著改善土壤团粒结构,满足实际使用要求;在0.9%NaCl溶液中吸液倍率明显降低,在盐碱地区施用后对土壤保水和蓄水能力提高不大,更适合施用于砂质土壤中而不适用于在高盐碱地区使用。

PAA-AANa/PVA高吸水纤维的制备及性能测试

以部分中和的丙烯酸（AA）为单体，在聚乙烯醇（PVA）水溶液中共聚，由聚合液进行溶液纺丝制备高吸水纤维。DSC测试结果表明，PAA—AANa／PVA共混纤维具有两个Tg，均随热处理时间延长而升高。PVA／PAA—AANa纤维受热后发生化学交联的温度区间是130℃～230℃。TG测试表明，PAA—AANa／PVA共混体系内PAA—AANa与PVA侧基官能团间作用使PVA热稳定性增加。溶胀后初生纤维干凝胶的微观形貌显示出大量沿纤维轴向取向的层片，层间大量孔洞说明纤维曾经吸收过大量的水。

pH值敏感介孔纳米复合材料SBA-15/PAA的制备与性能研究

通过浸渍吸附的方法将pH值敏感的功能单体-丙烯酸引入到介孔二氧化硅SBA-15的孔道内,经自由基聚合使丙烯酸(AA)在孔道内聚合,成功合成了pH值敏感的SBA-15/聚丙烯酸(PAA)纳米复合材料。所得纳米复合材料的结构通过XRD、TEM、氮气吸附/脱附、TG、FT-IR等手段进行了表征,并进行了pH敏感性能研究。结果表明,当聚合物(PAA)的量达到20%左右时,复合材料仍然具有较大的孔体积0.5203cm3/g和较高的比表面积334.5m2/g。聚合反应的发生没有破坏SBA-15的有序介孔结构,这种纳米复合材料初步显示出了pH敏感性。这种具有高比表面的pH值响应介孔纳米复合材料,有望在药物缓释领域得到应用。