A facile fabrication of functionalized rGO crosslinked chemically stable polysulfone-based anion exchange membranes with enhanced performance

Introducing more ionic conductive groups in polymer-based anion exchange membranes (AEMs) can improve the ion exchange capacity and further overcome the disadvantage of low ion conductivity for AEMs. However, the excessive swelling of AEMs caused by exorbitant IEC value may reduce the dimensional stability of membranes. So it is extremely important to modify the structures of AEMs. Herein, we proposed a facile strategy to construct reduced graphene oxide (rGO) stable crosslinked polysulfone-based AEMs with improved properties. rGO was non-covalently modified with pyrene-containing tertiary amine small molecule and polymer via π-π interactions. The as-prepared functionalized rGO (TrGO and PrGO) as both cross-linkers and fillers to fabricate quaternized polysulfone (QPSU)-based AEMs (CQPSU-X-TrGO and CQPSU-X-PrGO) for the first time. The cross-linked membranes can tighten the internal packing structure, and enhance the alkaline resistance, ion conductivity and oxidative stability of AEMs. Furthermore, the hydrophilicity and flexibility of the CQPSU-X-PrGO membranes were significantly improved as compared with that of CQPSU-X-TrGO membranes. PrGO-crosslinked membranes (CQPSU-2%-PrGO, σ_OH⁻ = 117.7 mS/cm) displayed higher ionic conductivities at 80 °C than TrGO-crosslinked membranes (CQPSU-1%-TrGO, σ_OH⁻ = 87.2 mS/cm). The remarkable nanophase separation can be observed in the CQPSU-X-PrGO membranes by TEM. This feasible strategy can be efficiently used to prepare new type of crosslinked organic-inorganic nanohybrid AEMs with excellent chemical stability and high ionic conductivity.     

自润滑微胶囊的制备及LLDPE基复合材料的摩擦性能

以聚砜为壁材,润滑油为芯材,采用溶剂挥发法制备了自润滑微胶囊,考察了芯壁比对微胶囊芯材含量和壁厚的影响。所制备的微胶囊具有高的热稳定性,初始降解温度为240℃,平均粒径为130 μm,壁厚约5 μm, 芯材含量占微胶囊质量分数的53.25%。将制得的微胶囊添加到线性低密度聚乙烯（LLDPE）基体中,制得LLDPE基自润滑复合材料,对其摩擦磨损性能进行了测定,揭示了自润滑机理。结果表明,当润滑油微胶囊添加量为LLDPE质量分数的20%时,LLDPE基功能化自润滑复合材料的摩擦系数最低,磨损率最小,相较于纯LLDPE分别降低了24.8%和65.3%。     

Sulfonated polysulfone as promising membranes for polymer electrolyte fuel cells

A new, milder sulfonation process was used to produce ion‐exchange polymers from a commercial polysulfone (PSU). Membranes obtained from the sulfonated polysulfone are potential substitutes for perfluorosulfonic acid membranes used now in polymer electrolyte fuel cells. Sulfonation levels from 20 to 50% were easily achieved by varying the content of the sulfonating agent and the reaction time. Ion‐exchange capacities from 0.5 to 1.2 mmol SO₃H/g polymer were found via elemental analysis and titration. Proton conductivities between 10⁻⁶ and 10⁻² S cm⁻¹ were measured at room temperature. An increase in intrinsic viscosity with increasing sulfonation degree confirms that the sulfonation process helps to preserve the polymer chain from degradation. Thermal analysis of the sulfonated polysulfone (SPSU) samples reveals higher glass transition temperatures and lower decomposition temperatures with respect to the unsulfonated sample (PSU). Amorphous structures for both PSU and SPSU membranes were detected by X‐ray diffraction analysis and differential scanning calorimetry. Preliminary tests in fuel cells have shown encouraging results in terms of cell performance. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1250–1257, 2000     

Effects of molecular weight of polysulfone on phase separation behavior for cyanate ester/polysulfone blends

The effects of molecular weight of polysulfone (PSF) on the morphology of bisphenol‐A dicyanate (BADCy)/PSF blends were studied. Because the viscosity of the blend increased and the miscibility between BADCy and PSF decreased with the increase of PSF molecular weight, these two competing effects on the phase‐separation were investigated. It was observed that the effect of viscosity was predominant: the viscosity of the blends at the onset point of phase separation increased with the increase of PSF molecular weight. The phase separation mechanism depends on the viscosity of the blends at the onset point of phase separation and determines the morphology of the blends. Because the increasing viscosity with increasing the molecular weight of PSF suppressed the nucleation and growth even with 10 phr of PSF content, phase separation occurred through spinodal decomposition to form the combined morphology having both PSF particle structure and BADCy particle structure. The combined morphology and the BADCy particle structure were obtained with a smaller amount of high molecular weight PSF content. This indicates that the viscosity of the blends at the onset point of phase separation is the critical parameter that determines the morphology of the blends. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 921–927, 2000     

Amine-terminated polysulfone as modifier for epoxy resin

The synthesis of carboxyl-terminated poly(ethylene glycol adipate) (CTPA) and amine-terminated poly(amide sulfone) (ATPS) based on the CTPA and 4,4′-diaminodiphenyl sulfone (DDS) is described. The products were characterized by IR and ¹³C-NMR spectroscopic analysis, nonaqueous titration, viscosity measurement, and solubility characteristics. The developed ATPS was incorporated as a modifier into the epoxy matrix and its effect was studied by DSC and DMTA. It was found that ATPS forms a compatible blend with epoxy and imparts flexibility to the epoxy matrix. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:901–907, 1997     

稀溶液粘度法测定TPU/PSF和TPU/PMMA相容性

以N,N-二甲基甲酰胺(DMF)为溶剂,采用DSV研究了聚氨酯/聚砜(TPU/PSF)和聚氨酯/聚甲基丙烯酸甲酯(TPU/PMMA)两种共混体系的相容性。运用μ和α判据分别对TPU/PSF和TPU/PMMA两共混体系的相容性进行了判断,结论完全一致,TPU/PSF体系相容,而TPU/PMMA体系不相容。     

具有耐污染性的SiO2/聚砜共混膜的研究

我国的水资源日益短缺.为缓解供水不足的紧张局面,可进行污水的深度处理回用.膜分离是一种有效的回用方法,但膜易受污染,导致通量下降.作者采用溶胶-凝胶法制备了耐污染性强的SiO2/聚砜复合膜,并对其进行了性能表征.SEM图像显示该膜具有双皮层不对称结构,膜内均匀分散有SiO2粒子,该粒子既能增强膜的强度,又能提高膜的耐污染能力.以自来水对该膜进行了水通量测试,测试表明所制膜水通量较高,在0.10 MPa下可达250～300L/(m2·h).     

原位缩聚合成含聚芳酰胺/酯的微相复合物 V.共聚酰胺与聚砜的微相复合物制备

用原位缩聚法合成了芳香-脂肪共聚酰胺与聚砜的微相复合物(PAA/PSF).初步结果表明:PAA/PSF微相复合物具有热致液晶性能;PAA的加入大大提高了微相复合物的力学性能.以PA30(PAA=29.5ω)为例,拉伸强度和模量分别提高到原来的2.5倍和3.5倍.     

荷负电手性壳聚糖纳复合滤膜的制备与性能研究

以聚砜超滤膜作为基膜,以壳聚糖和壳聚糖衍生物的混合物为功能层制备纳滤膜。P2-5复合纳滤（NF）膜对Na2SO4的截留率为93%,相应的通量501.3 L/（m2·h）。电荷效应对NaCl几乎没有影响,而对Na2SO4影响显著。该膜为典型的荷负电膜,适合分离高价阴离子。     

抗污染超滤膜的研制

本文研制了氯甲基化／季铵化聚砜与聚偏氟乙烯共混超滤膜用于阴极电泳漆超滤系统。首先优化了氯甲基化／季铵化聚砜超滤膜的制备工艺，在此基础上，用聚偏氟乙烯部分代替氯甲基化聚砜制备共混超滤膜。结果表明：氯甲基化／季铵化聚砜与聚偏氟乙烯共混超滤膜不仅具有优良的分离性能，而且改善了膜的抗污染性。