Preparation and characterization of conductive poly(vinyl alcohol)/polyaniline doped by dodecyl benzene sulfonic acid (PVA/PANDB) blend films

In this study a solution‐blend method is adopted to prepare conductive poly(vinyl alcohol)/polyaniline doped by dodecyl benzene sulfonic acid (PVA/PANDB) blend films. Emeraldine base (EB)‐type polyaniline (PANI) is dissolved in N‐methyl‐2‐pyrrolidinone (NMP) and then blended with PVA/dodecyl benzene sulfonic acid (DBSA) solution by various amounts. It is found that the electrical conductivity and the thermal degradation onset temperature of the PVA/PANDB blend film are increased as the amount of EB‐type PANI solution is increased. Fourier transform infrared (FTIR) spectra show that the intensity of the characteristic peak of the functional groups in the blend film is significantly changed as the amount of EB‐type PANI is changed. From optical microscopy examination, it indicates that the amount and size of green particles are increased with increasing the amount of EB‐type PANI solution. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3415–3422, 2007     

An interpolymer anionic composite reverse osmosis membrane derived from poly(vinyl alcohol) and poly(styrene sulfonic acid)

An interpolymer anionic composite membrane for reverse osmosis was prepared from poly(vinyl alcohol) and poly(styrene sulfonic acid). The effects of composition of a casting solution, heat-curing periods, and casting thickness on the reverse osmosis performance of resulted membranes have been examined. A mixture of water and ethyl alcohol (12/7, wt %) was found to be a proper solvent for casting an interpolymer membrane on the supporter. The composite membrane was formed by casting the polymer solution in ultrathin film on a microporous polypropylene supporter, evaporating the solvent, and heat-curing at 120°C for a proper period. the optimum composition of a casting solution was as follows: wt % of poly(vinyl alcohol)/poly(styrene sulfonic acid)/solvent was 3/2/95. The membrane heat-cured at 120°C for 2 h has a good performance for reverse osmosis, viz., water flux of 9.1–28.4 L/m².h at salt rejection level of 88.1–93.4% under applied pressure of 80 kg/cm² with 0.5% NaCl aqueous solution. The formation mechanism of a water-insoluble membrane was discussed.     

Thermally crosslinkable poly(phenylene sulfide)/poly(ether sulfone)/polymerization of monomer reactant–polyimide blends

The effects of thermally crosslinkable polymerization of monomer reactant–polyimide (POI) on the miscibility, morphology, and crystallization of partially miscible poly(ether sulfone) (PES)/poly(phenylene sulfide) (PPS) blends were investigated with differential scanning calorimetry and scanning electron microscopy. The addition of POI led to a significant reduction in the size of PPS particles, and the interfacial tension between PPS and crosslinked POI was smaller than that between PES and crosslinked POI. During melt blending, crosslinking and grafting reactions of POI with PES and PPS homopolymers were detected; however, the reaction activity of POI with PPS was much higher than that with PES. The crosslinking and grafting reactions were developed further when blends were annealed at higher temperatures. Moreover, POI was an effective nucleation agent of the crystallization of PPS, but crosslinking and grafting hindered the crystallization of PPS. The final effect of POI on the crystallinity of the PPS phase was determined by competition between the two contradictory factors. The crosslinking and grafting reactions between the two components was controlled by the dosage of POI in the blends, the premixing sequence of POI with the two components, the annealing time, and the temperature. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2906–2914, 2002; DOI 10.1002/app.10287     

Synthesis and proton conductivity of poly(styrene sulfonic acid)/heterocycle‐based membranes

BACKGROUND: High proton conduction through anhydrous polymer electrolyte membranes is crucial for the application to chemical energy conversion devices such as fuel cells. In this context, novel proton conductors were produced by doping poly(styrene sulfonic acid) (PSSA) with 1H‐1,2,4‐triazole (Tri) and 1.12‐diimidazol‐2‐yl‐2,5,8,11‐tetraoxadodecane (imi3), and their physicochemical properties were investigated. RESULTS: Different polymer electrolyte membranes were produced by doping of PSSA with Tri and imi3. PSSATri_x and PSSAimi3_x electrolytes were obtained where x is the doping ratio describing moles of Tri or imi3 per mole of ? SO₃H unit. The membranes demonstrated adequate thermal stability at least up to 200 °C and the dopants acted as plasticizers shifting the T_g values to lower temperatures. PSSATri₁ has a maximum proton conductivity of 0.016 S cm^?1 at 150 °C and the proton conductivity of PSSAimi3_0.5 is approximately 10^?4 S cm^?1 at room temperature. CONCLUSIONS: Transparent, homogeneous and freestanding films of PSSATri_x and PSSAimi3_x were produced. It was demonstrated that both Tri and imi3 are efficient proton solvents in PSSA host matrix, and they yielded promising defect‐type conductivities compared to benzimidazole. Tri‐doped membranes clearly showed better conductivity performance at higher temperatures (T > 100 °C). Both PSSATri_x and PSSAimi3_x polymer electrolytes can be suggested for fuel cell applications. Copyright © 2007 Society of Chemical Industry     

可溶于水的导电性聚苯乙烯磺酸掺杂聚苯胺的合成

以苯胺（An)为单体,过硫酸铵（APS）为氧化剂,在聚苯乙烯磺酸（PSSA）的水溶液中合成了可完全溶于水的导电性聚苯乙烯磺酸掺杂聚苯胺。结果表明,当APS与An的摩尔比为1：2,PSSA的浓度为0．19mol/L,APS溶液的滴加时间为3h,反应温度为14℃,产物电导率的最高值为0．13S/cm,而且可完全溶于水,形成稳定的墨绿色溶液。     

Alkaline blend polymer electrolytes based on polyvinyl alcohol (PVA)/tetraethyl ammonium chloride (TEAC)

Alkaline blend polymer electrolytes based on PVA/TEAC were obtained by a solution casting technique. Tetraethyl ammonium chloride (TEAC) was added to PVA polymer matrix to form an alkaline blend polymer electrolyte exhibiting excellent ionic transport and mechanical properties. The ionic conductivity of the alkaline PVA/TEAC blend polymer electrolyte was found to be of the order of 10⁻² S cm⁻¹ at ambient temperature when the blend ratio of PVA:TEAC varied from 1:0.2 to 1:2. The characteristic properties of alkaline PVA/TEAC blend polymer electrolytes were examined using DSC, TGA, XRD, SEM, EA, stress–strain tests and AC impedance spectroscopy. The ionic transport properties for the blend polymer electrolytes were measured using Hittorf’s method. It was found that the anionic transport numbers (t ⁻) were between 0.82 and 0.99; the membranes are highly dependent on the types of alkali metal salts and the chemical composition of the polymer blend. The ionic transport and mechanical properties were greatly improved at the expense of the ionic conductivity. In this work we demonstrate that alkaline blend polymer electrolyte can be tailored with a blend technique to achieve specific characteristic properties for battery applications.     

Water in different poly(styrene sulfonic acid)‐grafted fluoropolymers

We investigated the water present in a series of radiation‐grafted fluoropolymers with similar poly(styrene sulfonic acid) (PSSA) contents with the aim of determining the influence of the initial fluoropolymer. Radiation‐grafted membranes were compared with Nafion 117 and 105. Sorption curves and differential scanning calorimetry thermograms showed that all the membranes contained the same number of water molecules tightly bound to the sulfonic acid groups; this water did not freeze. In radiation‐grafted membranes, the content of freezing water absorbed from the liquid‐phase water varied according to the swelling abilities of the membrane, which were dependent on the initial fluoropolymer. Larger pores accompanied high water uptakes and high conductivity. The amount of water absorbed from the vapor phase was similar for all radiation‐grafted membranes with similar PSSA contents, irrespective of matrix material. Nafion membranes had higher conductivities at intermediate hydration levels, and the relaxation times measured by NMR were longer than for the radiation‐grafted materials. This suggests that the channels for water and proton conduction are different in the two types of materials. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 33–42, 2002     

聚乙烯醇/二氧化硅杂化膜的制备及渗透蒸发分离环己醇（酮）/环己烷

以聚乙烯醇（PVA）和正硅酸乙酯（TEOS）为原料,经溶胶-凝胶（sol-gel）法制备了不同二氧化硅（SiO2）含量的 PVA/SiO2杂化膜。傅里叶变换红外光谱（FT-IR）表明,随着SiO2含量增大,1060cm?1和970cm?1处Si—O—Si特征吸收峰的相对强度逐渐加强,说明TEOS与PVA发生了交联反应;同时膜的分解温度从248℃升高到342℃。杂化膜的SiO2含量从10 %增大到40 %,其玻璃态温度从115℃升高到124℃。以水为溶剂,测定了杂化膜的耐溶剂性能,与PVA膜相比,杂化膜的耐溶剂性能显著提高。以质量比为0.950/0.025/0.025的环己烷/环己醇/环己酮为原料,测定杂化膜的分离性能,结果表明SiO2含量从10 %增大到40 %,通量从15.94 g/(m2?h)升高到75.69 g/(m2?h),环己醇的分离因子从1.8升高到2.65。     

Synthesis and characterization of poly(ether sulfone) grafted poly(styrene sulfonic acid) for proton conducting membranes

Two-step synthesis of proton-conducting poly(ether sulfone) (PES) graft copolymer electrolyte membrane is proposed. Fridel Craft alkylation reaction was used to introduce chloromethyl pendant group onto the PES polymer backbone. Later on, atom transfer radical polymerization (ATRP) was applied to synthesize a series of poly(ether sulfone) grafted poly(styrene sulfonic acid) (PES-g-PSSA). Successful chloromethyl substitution and grafting of the pendant group was characterized by the ¹H-NMR and elemental analysis. Electrochemical properties such as ion exchange capacity (IEC), water uptake and proton conductivity increased with increasing PSSA contents. Thermal gravimetric analysis (TGA) showed the thermal stability of membranes up to 270 °C. Proton conductivity for maximum amount of grafting was 0.00297 S/cm.     

Rheological properties of high molecular weight (HMW) syndiotactic poly(vinyl alcohol) (PVA)/HMW atactic PVA blend solutions

To identify the effect of blend ratios of syndiotacticity‐rich poly(vinyl alcohol) (s‐PVA)/atactic PVA (a‐PVA) having similar number‐average degrees of polymerization (P_n)s of 4000 and degrees of saponification (DS)s of 99.9% on the rheological properties of s‐PVA/a‐PVA/water solutions, water‐soluble s‐PVA and a‐PVA with different syndiotactic diad contents of 58.5 and 54.0%, respectively, were prepared by bulk copolymerization of vinyl pivalate and vinyl acetate (VAc) and solution polymerization of VAc, followed by saponifying the corresponding copoly(vinyl pivalate/vinyl acetate) and poly(vinyl acetate). The blend ratios played a significant role in rheological behavior. Over the frequency range of 10^?1–10² rad/s, s‐PVA/a‐PVA blend solutions with larger s‐PVA content show more shear thinning at similar (P_n)s and (DS)s of polymer, suggesting that PVA molecules are more readily oriented as s‐PVA content increases. Yield stress is higher for s‐PVA/a‐PVA blend solutions with larger s‐PVA content at similar (P_n)s and (DS)s of polymer. This indicates that more domains with internal order are produced at larger s‐PVA content in s‐PVA/a‐PVA blend solutions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3934–3939, 2006     

聚乳酸/聚乙烯醇纳米纤维的制备及结构

以二甲基亚砜为溶剂,制备不同配比的聚乳酸(PLLA)和聚乙烯醇(PVA)的混合溶液,静电纺丝制得PLLA/PVA纳米纤维。采用红外光谱仪、原子力显微镜等对PLLA/PVA纳米纤维结构与性能进行了表征。结果表明:PLLA/PVA纳米纤维中PVA上的羟基与PLLA上的羰基形成了氢键,PLLA与PVA之间存在一定的相互作用,但PLLA/PVA纳米纤维存在相分离现象;混合溶液的PLLA质量分数为11%,PVA质量分数为8%时可以得到较好的PLLA/PVA纳米纤维,但PVA质量分数为6%时出现液滴及珠丝,PVA质量分数为4%时,不能制得纳米纤维。     

Measurement of the electrochemical response time and electron paramagnetic resonance behavior of poly(o‐phenetidine)–poly(styrene sulfonic acid) and poly(2‐ethylaniline)–poly(styrene sulfonic acid) complexes

Two studies were mainly focused on the measurement of electrochemical response time and the electron paramagnetic resonance (EPR) of the substituted polyaniline (PANI) complexes poly(o‐phenetidine) (POP)–poly(styrene sulfonic acid) (PSSA) and poly(2‐ethylaniline) (P2E)–PSSA, which were prepared by the electrochemical polymerization of the monomer (o‐phenetidine or 2‐ethylaniline) with PSSA, with indium tin oxide (ITO) as a working electrode in a 1M HCl solution. Ultraviolet–visible spectra measurements showed evidence for the doped substituted PANI system to have a highly electrochemical response time recorded at a temperature of 298 K, and the results were further analyzed on the basis of the color–discolor model, which is typical of protonation systems. At the reaction time (3 s) and monomer concentration (0.6M) with PSSA (0.15 μ), the best electrochemical color/discolor time of the POP–PSSA complexes was 125/125 ms (thickness = 3.00 μm), which was faster than that of the P2E–PSSA complexes. At the same thickness (10 μm), the best electrochemical color/discolor time of the POP–PSSA complexes was 500/250 ms, which was faster than the P2E–PSSA complexes (750/500 ms). With regard to film growth rate, the POP–PSSA complexes (1.0 μm/s) were faster than the P2E–PSSA complexes (0.79 μm/s); this was attributed to the substituted PANI having a steric effect and to good reactivity by the ethoxy group (? OC₂H₅) in the molecules. The EPR spectra of the two samples were recorded both at 298 and 77 K and were further analyzed on the basis of the polaron–bipolaron model. The narrower line width of the substituted PANI complexes arose due to polarons; that is, we propose that charge transport took place through both polarons and bipolarons. Compared to their salts, this could be attributed to the lower degree of structural disorder, the oxygen absorption on the molecules, and the steric effect by the side chain group. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1211–1221, 2005     

丝素-聚乙烯醇共混溶液静电纺丝及其含银纳米纤维形态研究

研究了不同丝素-聚乙烯醇（SF-PVA）配比的共混溶液和加入硝酸银的丝素-聚乙烯醇（SF-PVA）共混溶液的静电纺丝,利用扫描电镜观察纤维的形态变化。结果表明：在丝素（SF）或聚乙烯醇（PVA）占绝大部分时,整个体系溶解性保持相对稳定,容易形成比较均一的溶液,且纺丝后纤维形态比较均匀、规则;而在两组分含量接近时整个体系的溶解性能较差,不易形成比较均一的溶液,表现为溶液粘度的显著增大,纺丝后纤维不均匀、不规则。笔者选用SF/PVA=1：9（质量比）的共混纺丝液加入硝酸银,随着硝酸银在溶液中含量的增加,溶液电导率会明显增加,纤维的直径明显下降;但随着电导率的增大,纤维中珠状物会增多,纤维均一性也变差。     

Sustained release behavior of pH‐responsive poly(vinyl alcohol)/poly(acrylic acid) hydrogels containing activated carbon fibers

The composites of pH‐responsive poly(vinyl alcohol)/poly(acrylic acid) hydrogel and activated carbon fibers (ACFs) were prepared as sustained drug release system with excellent mechanical properties. The mechanical properties of hydrogels were improved greatly by addition of ACFs. The thinner ACFs were more effective in increasing the mechanical properties of composite hydrogels. The cumulative amount of release and the release period were dependent on the surface area and the pore volume of ACFs. The drug release was maximized at basic condition due to the pH‐sensitive hydrogel matrices and the initial bust phenomenon was alleviated by incorporating ACFs in the hydrogels. The drug release was sustained about four times longer and the mechanical property was increased about 2.6 times higher because ACFs worked as drug reservoir and reinforcement. Cytotoxicity evaluation confirmed the biocompatible characteristics of the ACFs‐containing hydrogels. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

生物基聚3-羟基丁酸-戊酸酯/聚乳酸共混纤维的鉴别方法研究

根据FZ/T 01057.2—2007,FZ/T 01057.3—2007,FZ/T 01057.4—2007,FZ/T 01057.8—2012标准,采用燃烧法、显微镜法、溶解法和红外光谱法对聚3-羟基丁酸-戊酸酯/聚乳酸(PHBV/PLA)共混纤维进行了鉴别。结果表明:PHBV/PLA共混纤维的燃烧特征及显微镜下观察的表观和截面形态与常见的合成纤维的特征相似,燃烧特征的具体表现为靠近火焰时熔缩,接触火焰时有熔滴现象且冒白烟,离开火焰时继续燃烧,燃烧时具有特异气味,残留物呈黑色硬块状; PHBV/PLA共混纤维的横截面形态为近似圆形或略呈多边形,纵面形态为表面光滑或略有不平整,未见较深沟槽;使用燃烧法和显微镜法,能够较易将PHBV/PLA共混纤维和棉、毛等天然纤维、粘胶纤维等再生纤维素纤维相区别;PHBV/PLA共混纤维在常温下溶于98%硫酸、二氯甲烷,70℃下溶于甲酸/氯化锌溶液,通过溶解法,可将PHBV/PLA共混纤维和涤纶、锦纶、腈纶、丙纶等常见合成纤维相区别;PHBV/PLA共混纤维在1 722 cm^-1和1 748 cm^-1处出现...     

Preparation and characterization of proton conducting polysulfone grafted poly(styrene sulfonic acid) polyelectrolyte membranes

The syntheses of series of proton conducting comb copolymer membrane involving polysulfone back bone as main chain and poly(styrene sulfonic acid) (PSSA) being side chain, i.e. polysulfone grafted poly(styrene sulfonic acid) (PSU-g-PSSA) are presented. Chloromethylation of the polysulfone backbone was done by Fridel Craft alkylation reaction. Atom transfer radical polymerization was used for control grafting from the chloromethylated positions. The successful substitution of the chloromethyl group and its grafting with PSSA was characterized by elemental analysis and proton nuclear magnetic resonance. Water uptake, electrochemical properties like ion exchange capacity (IEC) and proton conductivities increase with increase in PSSA contents. Thermal gravimetric analysis (TGA) showed the thermal stability of membranes up to 250 °C. Proton conductivity for maximum amount of grafting is 0.02 S/cm.     

Fouling behavior of poly(vinylidene fluoride) (PVDF) ultrafiltration membrane by polyvinyl alcohol (PVA) and chemical cleaning method

Severe fouling to poly(vinylidene fluoride) (PVDF) membrane is usually caused as filtrating the papermaking wastewater in the ultrafiltration (UF) process. In the paper, fouling behavior and mechanism were investigated, and the low-concentration polyvinyl alcohol (PVA) contained in the sedimentation tank wastewater was found as the main foulant. Consequently, the corresponding cleaning approach was proposed. The experiment and modeling results elaborated that the fouling mode developed from pore blockage to cake layer along with filtration time. Chemical cleaning conditions including the composition and concentration of reagents, cleaning duration and trans-membrane pressure were investigated for their effect on cleaning efficiency. Pure water flux was recovered by over 95% after cleaning the PVDF membrane using the optimal conditions 0.5 wt% NaClO (as oxidant) and 0.1 wt% sodium dodecyl benzene sulfonate (SDBS, as surfactant) at 0.04 MPa for 100 min. In the chemical cleaning method, hypochlorite (ClO^-) could first chain-scissor PVA macromolecules to small molecules and SDBS could wrap the fragments in micelles, so that the foulants were removed from the pores and surface of membrane. After eight cycling tests, pure water flux recovery maintained above 95% and the reused membrane was found intact without defects.     

Fouling behavior of poly(vinylidene fluoride) (PVDF) ultrafiltration membrane by polyvinyl alcohol (PVA) and chemical cleaning method

Severe fouling to poly(vinylidene fluoride) (PVDF) membrane is usually caused as filtrating the papermaking wastewater in the ultrafiltration (UF) process. In the paper, fouling behavior and mechanism were investigated, and the low-concentration polyvinyl alcohol (PVA) contained in the sedimentation tank wastewater was found as the main foulant. Consequently, the corresponding cleaning approach was proposed. The experiment and modeling results elaborated that the fouling mode developed from pore blockage to cake layer along with filtration time. Chemical cleaning conditions including the composition and concentration of reagents, cleaning duration and trans-membrane pressure were investigated for their effect on cleaning efficiency. Pure water flux was recovered by over 95% after cleaning the PVDF membrane using the optimal conditions 0.5 wt% NaClO (as oxidant) and 0.1 wt% sodium dodecyl benzene sulfonate (SDBS, as surfactant) at 0.04 MPa for 100 min. In the chemical cleaning method, hypochlorite (ClO⁻) could first chain-scissor PVA macromolecules to small molecules and SDBS could wrap the fragments in micelles, so that the foulants were removed from the pores and surface of membrane. After eight cycling tests, pure water flux recovery maintained above 95% and the reused membrane was found intact without defects.     

Preparation and characterization of polyvinyl borate/polyvinyl alcohol (PVB/PVA) blend nanofibers

In this study, it was aimed to prepare polyvinyl borate/polyvinyl alcohol blend nanofibers by electrospinning process. Polyvinyl borate was synthesized by the condensation reaction of polyvinyl alcohol and boric acid. Polyvinyl borate itself was not suitable for electrospinning process. To improve fiber formation capability, polyvinyl borate was blended with polyvinyl alcohol before electrospinning process. A series of nanofibers with various polyvinyl borate concentrations in polyvinyl alcohol were prepared. Homogeneous and highly porous mat containing 100–250 nm diameter nanofibers were obtained by electrospinning process. According to the FTIR results, boron atoms were found to be integrated into the polymer network. There is not any significant effect of polyvinyl borate content on fiber morphologies according to SEM images. The blend composition with the highest polyvinyl borate content was found to be suitable for thermally stable nanofiber formation according to the TGA results. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Highly dispersed hydrous ruthenium oxide in poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) for supercapacitor electrode

Hydrous RuO₂ particles were electrochemically loaded into poly(3,4-ethylenedioxythiophene) doped poly(styrene sulfonic acid), PEDOT-PSS, matrix by employing various potential cycles in cyclic voltammetry and to fabricate the PEDOT-PSS-RuO₂·xH₂O electrode. The amount of hydrous RuO₂ particles loaded into the PEDOT-PSS matrix was easily controlled by varying the number of potential cycles. Scanning electron microscopy photographs reveal a uniform dispersion of hydrous RuO₂ particles in the porous structure of PEDOT-PSS matrix. Raman spectrum confirms the incorporation of hydrous RuO₂ into PEDOT-PSS matrix. Chronopotentiometry and cyclic voltammetry were employed in 0.5 M H₂SO₄ to evaluate the capacitor properties. Specific capacitance values were determined by chronoamperometry. An increasing trend in specific capacitance with loaded amount of hydrous RuO₂ particles in PEDOT-PSS was noticed. A maximum specific capacitance of 653 F/g was achieved.