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981.
Weixin Guan Xiaochen Yang Chenyuan Dong Xiaoming Yan Wenji Zheng Yuan Xi Xuehua Ruan Yan Dai Gaohong He 《应用聚合物科学杂志》2021,138(8):49895
The packing pattern of two-dimensional (2D) sheet-like fillers in membranes is relatively random, leading to the unfavorable permeability from tortuous diffusion pathway. A new strategy that using prestructured materials with uniform channels as fillers was proposed. In this work, Ti3AlC2 is etched to prepare multilayered MXene (m-MXene), the channels aggregate as a whole unit, ensure the impossibility of ineffective packing compared with traditional individual sheets, largely facilitating the selective permeation. Then, the m-MXene/Poly (amide-6-b-ethylene oxide) (Pebax) MMMs are synthesized. SEM images demonstrate the accordion shaped structure of filler, which is the multi-channels laminates. Furthermore, the results of gas permeation test exhibit enhanced performance of m-MXene/Pebax MMMs. MMM with 0.5 wt.% m-MXene behaved best, CO2 permeability of 86.22 Barrer as well as CO2/N2 selectivity of 104.85, transcending the Robeson upper bound (2008). Having distinct enhancement for CO2 separation, the m-MXene/Pebax MMMs in this work offer prospective practical applications. 相似文献
982.
In this work, low density hollow glass beads (HGB)/silicon rubber (SR) composites were prepared by solution method and flocculation process. The prepared samples were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, tensile test, and friction test. The results show that the densities of SR composites decrease from 1.140 to 0.792 g/cm3 with the addition of HGB. By comparing theoretical density with true density, it can be estimated that the ratio of shattered HGB increase from 8.79% to 24.76%. Especially, the mechanical properties of SR composites were improved by surface modification of HGB. By adding surface-modified HGB at 5 and 10 wt%, the tensile strengths of SR composites were enhanced by 17.8% and 28.2%, respectively. In addition, tear strength, shore A hardness, compression set, and friction property were significantly ameliorated. Furthermore, the mechanism of surface-modified HGB in mechanical properties was analyzed. 相似文献
983.
The flame retardant polypropylene containing the micro-envelope core-shell structure flame retardant, which encapsulated ammonium polyphosphate into melamine-formaldehyde resin and sodium silicate through in situ polymerization was prepared with polyamide 6, added as a carbon-forming agent. The composition of ammonium polyphosphate, encapsulated ammonium polyphosphate with melamine-formaldehyde resin and the micro-envelope core-shell structure flame retardant were characterized. The fire safety and thermal stability were investigated and showed an improvement including limiting oxygen index, thermogravimetric analysis, vertical burning tests, and microscale combustion calorimeter. The burned compounds were also studied to confirm the burning mechanism. The results showed the flame retardant performance had been greatly improved, while polyamide 6 had better char-forming effect. Besides, the water solubility of flame retardants and their influence on the mechanical properties of polypropylene were also investigated. The results on the effects of additives demonstrated a high efficiency flame retardant to polypropylene. A core-shell flame retardant that sodium silicate and melamine-formaldehyde resin-coated ammonium polyphosphate had been constructed. The effect of the built flame retardant system on the combustion performance of polypropylene was studied from the mechanism and performance. The LOI of the most flame retardant polypropylene reached 28.6%, and UL-94 reached the V-0 level. 相似文献
984.
Junfeng Yue Xuejiao Fu Jun Lu Shuidong Zhang Dong Li Yi He Quan Wei Changhua Liu Lin Gan Ishak Ahmad Jin Huang 《应用聚合物科学杂志》2021,138(45):51330
Sustainable development strategy has aroused a great interest in biomass resources as alternative raw materials. A kind of biomass-derived poly(butylene succinate) (PBS), has been developed as porous foams to reduce resource exhaustion and meet lightweight demands. For fire-safety in-service, graphene oxide (GO) was functionalized by 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) to combine flame-retardant elements and heat-barrier function. Hence, a very low loading level of P-containing GO as only 5 wt% could reduce peak heat release rate (pHRR) and total heat release (THR) of PBS-based foams by 58.5% and 22.3%, respectively. Meanwhile, N-/P-doped mesoporous char with a specific surface area of 136 m2/g, which derived from combustion of flame-retardant foaming PBS, contributes to a potential of energy storage applications in the capacitor or the anode of Li-ion battery with long-term stability. Overall, the sustainability of bio-based polyester could integrate lightweight of foaming, and be extended to utilization after use via facile combustion inspired by flame-retardancy design. 相似文献
985.
Cleide Borsoi Betina Hansen Ruan Ezequiel Gemmer Marcos Aurélio Dahlem Júnior Edson Luiz Francisquetti Ademir José Zattera Ruth Marlene Campomanes Santana André Luis Catto 《应用聚合物科学杂志》2021,138(45):51350
This study presents the preparation of post-consumer polypropylene (r-PP) composites filled with 30 wt% yerba mate (YM) stick particles. To improve the fiber–matrix adhesion, three surface treatments were performed: alkaline treatment with sodium hydroxide (NaOH) and use of 3-aminopropyltriethoxysilane (APTS) and maleic anhydride graft polypropylene copolymer (PP-g-MA) as coupling agents. Mechanical properties including tensile, flexural, and impact resistance were determined, and chemical (Fourier transform infrared spectroscopy [FTIR]), physical (water absorption), and morphological analyses were performed. The main findings show that the treatments were efficient in improving the mechanical properties of the composites, with emphasis on the r-PP/YM30/APTS and r-PP/YM30/PP-g-MA composites, which proved to be superior in tensile, flexion and impact strength and absorption of water compared to the untreated composite. The morphological analysis showed a better interaction between the fiber and the polymeric matrix for the composites with YM/APTS and YM/PP-g-MA, which corroborates the results of tensile and flexural strength, as well as with the spectra of FTIR in which the chemical modification of the fibers is observed. However, the results show that these treatments are promising in obtaining composites with recycled matrix with better properties. 相似文献
986.
A simple and feasible method to enhance the wear resistance of ultra-high molecular weight polyethylene (UHMWPE) fibers was reported. The graphite oxide (GO) prepared using improved Hummer's method was surface modified with hexadecylamine to improve its compatibility with UHMWPE. Combined with well-dispersion of modified-GO (m-GO) in dichloromethane and the fact that the viscosity of UHMWPE suspension can be decreased by dichloromethane, the well dispersed m-GO/dichloromethane was added into UHMWPE suspension to improve m-GO dispersion in UHMWPE fibers. Finally, UHMWPE fibers with different m-GO concentration were prepared using gel spinning technology. The effect of m-GO concentration on the structure and properties of modified UHMWPE fibers were investigated. The results indicated that the melting temperature and crystallinity of m-GO modified UHMWPE fibers increased with increasing of m-GO concentration, while the fiber's crystal sizes and orientation increased, thus the tensile strength of m-GO modified UHMWPE fibers remained almost undamaged. The introduction of m-GO is beneficial to the formation of smooth transfer film on fiber's surface, which enhanced the self-lubrication of UHMWPE fibers. Compared with pure UHMWPE fiber, the UHMWPE fiber containing 1.5 wt% m-GO had enhanced wear resistance by 55.4% and still maintained high tensile strength of 29.98 cN dtex−1. 相似文献
987.
永磁直线同步电机(permanent magnet linear synchronous motor,PMLSM)存在齿槽力,影响电机的控制性能。 本文提出一
种基于软磁、硬磁材料混搭的新型复合磁性槽楔结构(composite magnetic slot wedge,CMSW),能有效抑制 PMLSM 推力波动。 首
先,分析了单一磁性槽楔的材料、尺寸和空间位置分布对 PMLSM 输出推力和推力波动的变化规律。 然后,研究新型复合磁性
槽楔的软磁、硬磁材料配比和位置分布,对电机输出推力、推力波动和齿槽力等电磁性能的影响。 以最大推力和推力波动最小
为优化目标,利用正交优化法对复合磁性槽楔的尺寸进行优化。 研究表明,采用新型复合磁性槽楔可有效降低推力波动和损
耗,推力波动降低 79. 4%,而平均推力基本不变,为 PMLSM 推力波动抑制提供新的技术途径。 相似文献
988.
考虑供水系统深度响应的微网经济调度策略 总被引:1,自引:0,他引:1
高风电渗透率微网(microgrid,MG)存在实时功率平衡和经济运行难的问题。为此,该文提出一种考虑供水系统(water supply system,WSS)深度响应的MG经济调度策略。首先,将WSS主动解列成多个独立运行的子系统,降低系统关联约束,提高调节灵活性。进而,建立水压的波动性约束,提出WSS需求侧响应模型。在此基础上,充分考虑外电网调峰、调频等需求,提出一种新型的MG经济调度策略。最后,引入近似线性化的方法,将非线性模型转化为经典的混合整数线性规划(mixed-integerlinearprogramming,MILP)问题,提高求解速度。基于15节点的WSS和典型MG的仿真结果表明,WSS深度响应能够显著改善MG运行经济性。该文研究成果为MG可再生能源消纳问题的解决提供了一个崭新的视角。 相似文献
989.
990.