Hydrocarbon-based electrode ionomer for proton exchange membrane fuel cells

The electrode ionomer is a key factor that significantly affects the catalyst layer morphology and fuel cell performance. Herein, sulfonated poly(arylene ether sulfone)-based electrode ionomers with polymers of various molecular weights and alcohol/water mixtures were prepared, and those comprising the alcohol/water mixture showed a higher performance than the ones prepared using higher boiling solvents, such as dimethylacetamide; this is owing to the formation of the uniformly dispersed ionomer catalyst layer. The relation between ionomer molecular weight for the same polymer structure and the sulfonation degree was investigated. Because the chain length of polymer varies with molecular weight and chain entanglement degree, its molecular weight affects the electrode morphology. As the ionomer covered the catalyst, the agglomerates formed were of different morphologies according to their molecular weight, which could be deduced indirectly through dynamic light scattering and scanning electron microscopy. Additionally, the fuel cell performance was confirmed in the current-voltage curve.     

Investigation on sulphonated zinc oxide nanorod incorporated sulphonated poly (1,4-phenylene ether ether sulfone) nanocomposite membranes for improved performance of microbial fuel cell

Hydrothermally prepared zinc oxide nanorods are sulphonated (S–ZnO NR) and incorporated into 15% Sulphonated Poly (1,4-Phenylene Ether Ether Sulfone) (SPEES) to improve the hydrophilicity, water uptake and ion transfer capacity. Water uptake and ion transfer capacity increased to 34.6 ± 0.6% and 2.0 ± 0.05 meq g^?1 from 29.8 ± 0.3% and 1.4 ± 0.04 meq g^?1 by adding 7.5 wt% S–ZnO NR to SPEES. Morphological studies show the prepared S–ZnO NR is well dispersed in the polymer matrix. SPEES +7.5 wt% S–ZnO NR membrane exhibits optimum performance after three-weeks of continual operation in a fabricated microbial fuel cell (MFC) to produce a maximum power density of 142 ± 1.2 mW m^?2 with a reduced biofilm compared to plain SPEES (59 ± 0.8 mW m^?2), unsulphonated filler incorporated SPEES (SPEES + 7.5 wt% ZnO, 68 ± 1.1 mW m^?2) and Nafion (130 ± 1.5 mW m^?2) thereby suggesting its suitability as a sustainable and improved cation exchange membrane (CEM) for MFCs.     

聚醚砜中空纤维的成形条件对其宏观结构的影响

主要讨论了纺速、填充液压力、凝固浴浓度和拉伸率成形条件的设置对中空纤维的宏观结构的影响 ,为设计具有合理的宏观结构的中空纤维膜提供参考     

Photodegradation mechanism and stabilization of polyphenylene oxide and rigid‐rod polymers

Poly(2,4‐dimethyl‐1,4‐phenylene oxide) (PPO), poly(benzo[1,2‐d:5,4‐d′]bisoxazole‐2,6‐diyl‐1,4‐phenylene) (PBO) and poly(benzo[1,2‐d:4,5‐d′]bisthiazole‐2,6‐diyl‐1,4‐phenylene) (PBZT), which are polymers with extended conjugated structures, undergo a self‐sensitized photo‐induced electron‐transfer reaction. A second component is not required. This article presents many similar observations on these polymers when they are exposed to light and evidence to support the proposed photo‐induced electron‐transfer mechanism. Methods to stabilize these polymers against photo‐oxidation are also described. Workers investigating other conjugated polymeric systems may find the experimental methods, observations and polymer stabilization approaches discussed in this review useful. Copyright © 2005 Society of Chemical Industry     

三氧化硫磺化甲苯反应的工艺条件研究

采用稀释SO3磺化甲苯工艺，研究了磺化温度．SO3配气比，原料中水含量和二甲苯砜抑制剂等工艺因素对反应转化率，产物中甲苯磺酸异构体含量及副产物二甲苯砜含量的影响。在10℃．SO3浓度为6％（volume）的操作条件下，二甲苯砜为抑制剂，甲苯转化率达到35％（mass）．反应产物中没有新增二甲苯砜，对甲苯磺酸含量达到88．24％．间甲苯磺酸含量降低到0．97％。     

甲苯三氧化硫磺化反应抑制副产物二甲苯砜的研究

对SO3磺化甲苯反应的副产物二甲苯砜成因及反应历程进行了分析,通过实验比较了醋酸与二甲苯砜的抑制效果,提出用磺化副产物二甲苯砜自身抑制的新方法.考察了二甲苯砜力入量和甲苯转化率对抑制副反应的影响.反应温度:10℃,三氧化硫:6%,甲苯转化率为35%时,外加甲苯质量3.3%的二甲苯砜就能控制二甲苯砜含量不增加,且甲苯磺酸异构体的对位含量由84%上升到89%,间位含量由2.5%下降到1%.     

PPESK／PS共混物流变性能的研究

以溶液共沉淀的方法制备了含二氮杂萘联本结构的聚芳醚砜酮（PPESK）。聚苯乙烯（PS）共混物，用毛细管流变仪测定了共混物的流为性能。结果表明，在本实验条件下，PPESK／PS共混物熔体属假塑性非牛顿汉体，其熔体粘度随PS含量的增加、温度的升高、剪切速率的增大而下降。PS的加入有利于改善PPESK的熔融加工流动性。     

Graft polymerization of acrylic acid onto polyphenylene sulfide nonwoven initiated by low temperature plasma

Graft copolymerization of acrylic acid (AA) onto polyphenylene sulfide (PPS) nonwoven initiated by low temperature plasma was studied. The effects of various conditions on graft reaction and the grafting rate were investigated. SEM images showed that PPS nonwoven was grafted, and the graft copolymerization only occurred on the surface of PPS. It may be due to the chain transference going with the graft copolymerization. It was found that with the increasing of plasma power, treatment time, space between electrodes, monomer concentration, and temperature of graft polymerization, the grafting rate increased at first, went to the top, and then decreased. The PPS nonwoven surface graft reaction could be optimized by the following processing conditions: 120 s of plasma treatment time, 50 W of plasma power, 1.5 cm of space between electrodes, 30% (w/w) of monomer concentration, and 50°C of temperature of graft polymerization. Measurement of XPS showed that the peak of C1s of graft polyacrylic acid was existed, and the peak area increased with the increase of the grafting rate. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5884–5889, 2006     

2,2￠,6,6￠-四甲基-4,4￠-二苯氧基二苯砜、二苯醚和对苯二甲酰氯三元无规共聚物的合成与表征

以2,2￠,6,6￠-四甲基-4,4￠-二苯氧基二苯砜(o-M2DPODPS)、二苯醚(DPE)和对苯二甲酰氯(TPC)为单体，在无水AlCl3和N,N-二甲基甲酰胺(DMF)存在的条件下，于1,2-二氯乙烷(DCE)中进行低温溶液无规共缩聚，合成了一系列新型线型高分子量含双邻甲基取代结构的聚醚砜醚酮酮(DM-PESEKK)/聚醚酮酮(PEKK)无规共聚物，并用IR, DSC, XRD, TGA和1H-NMR等方法对共聚物进行了表征分析，考察了共聚物的溶解性能. 结果表明，随着DM-PESEKK含量的增加，玻璃化转变温度(Tg)逐渐升高，熔融温度(Tm)逐渐降低，结晶度下降，溶解性得到明显改善.     

The tribological behavior of micrometer and nanometer TiO2 particle‐filled poly(phthalazine ether sulfone ketone) composites

Micrometer and nanometer TiO₂ particle‐filled poly(phthalazine ether sulfone ketone) (PPESK) composites with various filler volume fractions from 0.5 to 7.5 vol % were prepared by heating compression molding. The friction and wear behaviors of the PPESK composites were evaluated using the block‐on‐ring test rig by sliding PPESK‐based composite blocks against a mild carbon steel ring under dry friction conditions. The wear debris and the worn surfaces of the PPESK composites filled with micrometer and nanometer TiO₂ particles were investigated by using a scanning electron microscope (SEM), while the structures of PPESK composites and wear debris were analyzed with IR spectra. Experimental results show that antiwear properties of the PPESK composites can be improved greatly by filling nanometer TiO₂ particles, and the friction coefficient decreases when the filler volume fraction is below 2.5%, but when the filler volume fraction is above 2.5% the friction coefficient increases gradually with increasing filler volume fraction. In the case of micrometer TiO₂ filler, wear rates increase with increasing filler volume fractions under identical test conditions, and the friction coefficients are less sensitive to the filler volume fraction. It was also found that the wear mechanism of micrometer TiO₂ particle‐filled PPESK is mainly severe adhesion and abrasive wear, while that of nanometer TiO₂ particle‐filled PPESK is mainly slight abrasive wear. In the former case, there are no transfer film formed on the surface of the counterpart steel, and wear debris are in the form of long and large ribbon. While in the latter case, the wear debris was granule and their size was about 10 μm. In case of 1 vol % nanometer TiO₂ particle‐filled PPESK composites, the transfer film was fairly thinner and smoother, and the transfer film provided better coverage on the surface of steel ring, while that of 7.5 vol % was thicker and discrete. These account for the different friction and wear behavior of micrometer and nanometer TiO₂ particle‐filled PPESK composite. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 906–914, 2004