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.

Graft Polymerization of Acrylic Acid and Acrylamide onto BOPET Corona Films

The graft polymerization of acrylic acid(A) and acrylamide(B) was carried out onto bi-oriented polyester BOPET corona film.The influence of monomer concentration,reducer concentration and reaction time on the graft polymerization was investigated.The surface tension of the films increased with an increase of monomer concentration,till the concentration of monomer A reached 1.5×10^(-2)g/mL and the concentration of monomer B reached 4.0×10^(-2)g/mL.The surface tension of the films reached a maximum value at 7×10^(-4)M of reducer concentration and subsequently decreased with further increase in reducer concentration.The surface tension of the films increased with the increase of the reaction time apparently within 50min.The grafted corona BOPET films were characterized with IR and XPS.The presence of graft on the film surface was confirmed.The attenuation experiments on grafted corona BOPET films in air at 50℃ and in water were carried out to investigate the persistence of graft polymerization of acrylic acid and arylamide onto BOPET corona films.

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.

Reactivity Ratios of Diethyldiallylammonium Chloride with Acrylamide or Acrylic Acid

The compositions of copolymers of diethyldiallylammonium chloride （DEDAAC） with acrylamide （AM）, acrylic acid （AA） or sodium acrylic acid （NaAA） at low conversion were determined by elemental analysis, and the reactivity ratios of monomers in copolymerization were obtained by Kelen-Tudos method. The results showed that the reactivity ratios rDE and rAM are 0.31 and 5.27 for DEDAAC with AM, rDE and rAA are 0.28 and 5.15 for DEDAAC with AA, and roe and rNsAA are 0.40 and 3.97 for DEDAAC with NaAA, respectively. The copolymerizations for DEDAAC with AM, AA or NaAA are non-ideal copolymerization and the products are random copolymers.

IMMOBILIZATION OF Saccharomyces Cerevisiae USING POLY(ACRYLAMIDE)GEL FOR ASYMMETRIC SYNTHESIS OF R(-)-MANDELIC ACID

In this paper,the poly(acrylamide)hydrogel used to immobilize saccharomyces cerevisiae for asymmetric synthesis of R(-)-mandelic acid was prepared with free radical ploymerization in deionized water at room temperature under nitrogen atmosphere.The influence of the composition of hydrogel,loading amount of cells and culture conditions on the asymmetric synthesis was investigated.Results show that PAAm hydrogel is a feasible carrier for immobilization of cells which is a potential alternative method to prepare enantiomerically pure R(-)-mandelic acid.

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.

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.

Phase Transition Temperature Controllable Poly(acrylamide-co-acrylic acid) Nanocomposite Physical Hydrogels with High Strength

Poly（acrylamide-co-acrylic acid） nanocomposite physical （P（AAm-co-AAc）NCP） hydrogels have been prepared through the in situ free radical solution polymerization based on a ＂single network, dual cross-linkings＂ strategy. The P（AAm-co-AAc） NCP hydrogels are composed of nanobrushes of P（AAm-co-AAc） chains grafted on the surface of vinyl- hybrid silica nanoparticles （VSNPs）. In the hydrogel system, the VSNPs act as the ＂analogous chemical cross-linking points＂ once the hydrogen bonds formed between the P（AAm-co-AAc） chains of the nanobrushes, thus leading to the fabrication of high-strength P（AAm-co-AAc） NCP hydrogels. Compared with conventional thermosensitive P（AAm-co-AAc） hydrogels, the P（AAm-co-AAc） NCP hydrogels have a broader range of phase transition temperature, which can be adjusted by altering the monomer ratio, the VSNPs concentration, the addition of urea and N,N-dimethylacrylamide （DMAAm）. At the same time, the mechanical properties of the P（AAm-co-AAc） NCP hydrogels have been improved significantly by the introduction of VSNPs. Furthermore, both the phase transition and the tensile strength of the P（AAm-co-AAc） NCP hydrogels are largely influenced when Fe3＋ ions are introduced as the ionic crosslinkers into the hydrogel networks.

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。

PBT辐射接枝改性对血小板功能影响的研究

目的研究聚对苯二甲酸丁二醇酯(PBT)接枝不同单体[丙烯酸(AA)、丙烯酰胺(AM)、苯乙烯磺酸钠(SSS)、AA+AM、AA+SSS]对血小板黏附及功能的影响。方法采用γ射线辐照将单体[丙烯酸(AA)、丙烯酰胺(AM)、苯乙烯磺酸钠(SSS)、AA+AM、AA+SSS]接枝到PBT表面,依据傅里叶变换红外光谱(FTIR)和润湿时间等指标表征接枝后的PBT;利用扫描电镜(SEM)观察接枝不同单体的PBT对血小板的活化、聚集情况,同时测定通过接枝不同单体的PBT的血小板浓度、最大聚集能力、CD62p阳性表达率、血小板低渗休克率(HSR),考察其对血小板粘附及功能的影响。结果FTIR上出现了AA、AM、SSS的特征吸收峰,且接枝后的材料亲水性明显改善,表明单体接枝成功;SEM结果显示,PBT原样导致的血小板活化聚集程度明显高于改性后的PBT;滤过PBT原样的血小板与血小板原样相比:血小板浓度为(533.00±4.58 vs 672.00±3.61)×10^(9)/L,血小板最大聚集率为(48.80±0.96 vs 58.60±1.37)%,CD62p阳性表达率为(45.35±0.58 vs 39.90±0.52)%,血小板HSR为(48.74±0.46 vs 51.86±0.93)%(P<0.05)。与PBT原样相比,接枝不同单体后的PBT材料导致的血小板损失和血小板功能损伤都明显下降(P<0.05),其中PBT-(AA+AM)对血小板的综合影响最小[血小板浓度(637.00±2.65)×10^(9)/L,血小板最大聚集率(62.45±0.61)%,CD62p阳性表达率(37.39±0.42)%,血小板HSR(53.51±0.58)%]。结论表面接枝AA+AM的PBT对血小板的黏附及功能损伤的综合影响明显小于接枝其他单体的PBT,有望进一步开发用于血小板制剂中去除白细胞的过滤材料。