Solvent-resistant porous membranes using poly(ether−ether ketone): preparation and application

Poly(ether−ether ketone) (PEEK) is a linear aromatic macromolecule, which can form semi-crystalline aggregative status, allowing PEEK materials to have strong environment tolerance and excellent physicochemical properties. PEEK materials have become a promising alternative to fabricate particular membranes used in extreme conditions. In the past few decades, many researches and evolutions have emerged in membrane fabrication with PEEK materials and its applications for treating organic solvents and their mixtures; however, there are little systematic and comprehensive literature to summarize fabrication approaches, compile applications, and elaborate PEEK property-structure relationship. In this review, the main approaches to fabricate PEEK-based membranes are illustrated concretely, including conventional thermal-induced and non-solvent-induced phase separation, and novel chemical-induced crystallization; the representative applications in ultrafiltration, nanofiltration and membrane contactor containing organic solvents are demonstrated systematically. Meanwhile, the mechanism to tune PEEK solubility in solvents, which can be achieved by altering monomers in synthesis processes or changing membrane preparation routes, is deeply analyzed. Moreover, the existing problems and the future prospects are also discussed. This review provides positive guidance for designing and fabricating membranes using PEEK and its derivative materials for task-specific applications in harsh conditions.     

Chemically triggered life control of “smart” hydrogels through click and declick reactions

The degradation of polymeric materials is recognized as one of the goals to be fulfilled for the sustainable economy. In this study, a novel methodology was presented to synthesize multiple highly cross-linked polymers (i.e., hydrogels) through amine–thiol scrambling under mild conditions. Amine-terminated poly(ethylene glycol) (PEG-NH₂) was reacted with the representative conjugate acceptors to synthesize hydrogels in organic and aqueous solutions, respectively. The materials above exhibited high water-swelling properties, distributed porous structures, as well as prominent mechanical strengths. It is noteworthy that the mentioned hydrogels could be degraded efficiently in hours to release the original coupling partner, which were induced by ethylene diamine at ambient temperature through amine-amine metathesis. The recovered PEG-NH₂ reagent could be employed again to regenerate hydrogels. Due to the multiple architectures and functions in polymeric synthesis, degradation and regeneration, a new generation of “smart” materials is revealed.     

Biobased Green Lubricants: Physicochemical,Tribological and Toxicological Properties of Fatty Acid Ionic Liquids

Fatty acid ionic liquids (FAILs) were designed and synthesized by combining quaternary ammonium cations with a range of biobased fatty acid anions. They were found to be good and universal lubricants for steel–steel, steel–copper, and steel–aluminum friction pairs, which possess low corrosivities, moderate viscosity indexes, and thermal stabilities compared to commercially available synthetic oil polyalphaolefin (PAO) 10 and traditional ionic liquid (IL) L-F104. Among them, N₁₄₄₄Oct and N₄₄₄₄Oct were found to have far lower toxicity than L-F104. Investigation of the lubricating mechanism revealed that firm and effective physical adsorption and tribochemical reaction films can be easily formed on the sliding surface due to the polarity of the fatty acid anions and the aliphatic tails, which prevent metal–metal contact and further antiwear and reduce friction.     

基于虚拟环境下的电液伺服性能测试系统设计

为了满足军事武器系统对液压测试技术的需要,研究了基于LabVIEW虚拟仪器开发平台的液压测试系统的软硬件结构,阐述了软件开发的模块化设计思想理念,介绍了虚拟环境下测试系统的软件实现方法,提出了现代液压测试系统的技术方案。     

青海元石山镍铁矿综合利用项目设计与生产实践-设计篇

青海元石山镍铁矿综合利用项目根据当地条件采用烟煤作还原剂、两段回转窑焙烧、萃取分离、磁选等技术。并根据工艺流程特点,因地制宜合理布置车间设备,降低物料运输距离和系统能耗,达到物料输送顺畅。生产实践证明,元石山镍铁矿采用还原焙烧-氨浸-萃取-磁选工艺是可行的,生产出了精制硫酸镍国家标准一级S产品,年处理镍铁矿石30万吨,Ni、Fe总回收率分别为70.70%、58.85%。主产品为精制硫酸镍和铁精矿,副产品为磁选尾矿(销售给水泥厂)和硫化钴精矿。整个工艺流程,实现无渣冶炼,没有固废排放,废水在系统内循环利用,废气经过净化回收后排空,基本实现污染物“零排放”,既减轻了环境污染的压力,又降低了生产成本。该项目的设计与生产实践为将来类似红土镍矿综合利用项目提供示范和技术支撑。     

Design and Analysis of a Multi-Legged Robot with Pitch Adjustive Units

The paper proposes a novel multi-legged robot with pitch adjustive units aiming at obstacle surmounting.With only 6 degrees of freedom,the robot with 16 mechanical legs walks steadily and surmounts the obstacles on the complex terrain.The leg unit with adjustive pitch provides a large workspace and empowers the legs to climb up obstacles in large sizes,which enhances the obstacle surmounting capability.The pitch adjustment in leg unit requires as few independent adjusting actuators as possible.Based on the kinematic analysis of the mechanical leg,the biped and quadruped leg units with adjustive pitch are analyzed and compared.The configuration of the robot is designed to obtain a compact structure and pragmatic performance.The uncertainty of the obstacle size and position in the surmounting process is taken into consideration and the parameters of the adjustments and the feasible strategies for obstacle surmounting are presented.Then the 3D virtual model and the robot prototype are built and the multi-body dynamic simulations and prototype experiments are carried out.The results from the simulations and the experi-ments show that the robot possesses good obstacle surmounting capabilities.     

Investigation on the Electric‐Induced Light Scattering of PLZT Transparent Ceramics

Transparent ceramics of Pb_1?xLa_x(Zr_1?yTi_y)_1?x/4O₃ (PLZT) were fabricated by the two‐stage sintering method. The electric‐induced light scattering phenomenon for two compositions of PLZT ceramics was investigated. It was found that the composition with relatively bigger ferroelectric domains exhibits a relatively smaller light scattering driving field, but simultaneously a lower transparency in the original state. The dielectric properties, ferroelectric hysteresis loops, and ferroelectric domain structures of the two compositions were studied which are consistent with the electric‐induced light scattering results.     

Flame‐retardant materials based on phosphorus‐containing polyhedral oligomeric silsesquioxane and bismaleimide/diallylbisphenol a with improved thermal resistance and dielectric properties

Polyhedral oligomeric silsesquioxane containing 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DP) was used to flame‐retard 4,4′‐bismaleimidophenyl methane (BDM)/2,2′‐dially bisphenol A (DBA) resins, and the integrated properties of the resins were investigated. The fire resistance of BDM/DBA resins containing DP was analyzed by limiting oxygen index (LOI) and vertical burning (UL94) tests. The results show that DP increased the LOI of the resins from 25.3 to 38.5%. The BDM/DBA resins were evaluated to have a UL‐94 V‐1 rating, which did not satisfy the high standards of industry. On the other hand, BDM/DBA containing DP achieved a UL‐94 V‐0 rating. The thermal stability and char formation were studied by thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy. TGA and scanning electron microscopy–energy‐dispersive X‐ray spectrometry measurements demonstrated that the DP resulted in an increase in the char yield and the formation of the thermally stable carbonaceous char. The results of Raman spectroscopy showed that the DP enhanced the graphitization degree of the resin during combustion. Moreover, the modified BDM/DBA resins exhibited improved dielectric properties. Specifically, the dielectric constant and loss at 1 MHz of the BDM/DBA/15% DP resin were 3.11 and 0.008, respectively, only about 93 and 73% of those of the BDM/DBA resin. All of the investigations showed that DP was an effective additive for developing high‐performance resins with attractive flame‐retardant and dielectric properties. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41545.     

缺氧/好氧接触氧化工艺处理高含盐废水

贵州某煤化工企业生产废水含有大量硝酸盐和亚硝酸盐,硝态氮含量高,处理难度大。采用自主研发的缺氧+好氧接触氧化反应器对该厂的模拟废水进行生物脱氮除碳处理。通过污泥的驯化培养,在温度25℃以上,进水COD为3500 mg/L,硝态氮为14000 mg/L,电导为25 ms/cm条件下,系统出水能够处理到COD 200 mg/L以下,并且运行稳定。     

IC—N/D—A~3/O~3工艺在垃圾渗滤液处理中的应用

采用IC厌氧反应器—亚硝化反硝化—A3/O3工艺处理天津大港第二垃圾焚烧厂的垃圾渗滤液,介绍了该工艺的重要构筑物及其设计参数。实际运行结果表明,工艺运行稳定,出水水质可达到《污水综合排放标准》(GB8978—1997)的三级标准要求,对COD、氨氮的去除率分别可达99.2%、99.6%,并对工艺运行的经济性进行了分析。