树脂填充EVAL纤维吸附剂的制备及其吸附性能表征

采用具有亲水性的乙烯-乙烯醇共聚物(EVAL)作为纤维吸附剂基质材料,粉末型Lewatit阳离子交换树脂CNP80ws为功能材料,采用可控相分离方法,制备了不同表面形态结构的树脂填充EVAL吸附剂.当使用外部液体调控相分离过程时,在纤维的表面形成了粗糙的开孔结构,并且随树脂的填充量提高纤维表面的粗糙度与开孔度有所提高.研究结果表明:树脂填充EVAL纤维吸附剂具有较大的吸附容量与较高的脱附率,其吸附容量不低于53.9mg BSA/g吸附剂(树脂填充量50%).     

Latest advances in zwitterionic structures modified dialysis membranes

End-stage renal diseases are affecting many patients and as a result, demand to receive dialysis service is growing annually. Morbidity and mortality rates are reported to be higher in comparison with healthy humans. The reason is reported to be the hemoincompatiblity of blood purification membranes, which hinders patients’ lives. Activation of different immune systems in the body, in case of blood-membrane interaction, results in several side effects, of which cardiovascular shocks have been mentioned to be a major one. Efforts to solve this issue have resulted in different generations of dialysis membranes. Zwitterionic immobilized membranes are the latest (third) generation, which owns a higher degree of hemocompatiblity with more stability of immobilized structures. This critical review intends to cover recent efforts conducted over the zwitterionization of polymeric membrane surfaces with the goal of improving hemocompatibility. Different aspects of third-generation membranes are discussed for a better understanding of the current gap and gathering the knowledge to further develop the field. Accordingly, this critical survey provides an in-depth understanding of blood purification membranes zwitterionization for paving the way for the optimum enhancement of hemodialysis membrane hemocompatibility.     

热致相分离法制备微孔EVAL中空纤维膜的探索

比较了羟基含量不同的两种乙烯－醋酸乙烯酯共聚物（EVA）的醇解产物和聚乙二醇组成的两元体系的相图的差异，在此基础上，以聚乙二醇为稀释剂，采用了热致相分离方法制备了微孔EVA的醇解产物中空纤维膜。结果表明纺丝时的冷却水溶温度、稀释剂的抽提温度以及EVA的醇解产物与聚乙二醇的比例对微孔中空纤维的透气性有明显的影响。     

A modification of the surface of the thin membranes of EVAL (ethylene vinylalcohol copolymer) by Langmuir-Blodgett films

The surface modification of the membrane as an artificial kidney made of two kinds of ethylene-vinylalcohol copolymers with 32 and 44 mol % contents of ethylene group (EVAL) have been studied by depositing the polymer monolayer on the membrane surface using the Langmuir-Blodgett technique.The permeability to PSS (physiological salt solution) and albumin rejection of the membranes were measured against the number of multilayers. The UFR (ultrafiltration rate) of PSS containing albumin decreased with the increase of the built up layers up to 2 layers and showed constant values from 3 to 10 layers of LB films.On the other hand, albumin rejection increased with the increase of built up layers. Albumin rejection for these deposited membranes of multilayer of EVAL-32 showed 21 times effectiveness more than that of ordinary membrane and 16 times for EVAL-44.Modification of the membrane has been performed by such a network structure formed by the built-up films.     

Study on the relationship between the ternary interaction parameter and the structure of water by the effect of aliphatic alcohols and phenol on the swelling behavior of poly(ethylene-co-vinyl alcohol) membrane in aqueous solution

The effect of very low concentrations of ethanol, 2-propanol and phenol on the swelling degree of poly(ethylene-co-vinyl alcohol) (EVAL) in water was investigated. The effect of phenol on the swelling degree of EVAL was remarkably large compared to that of ethanol and that of 2-propanol. Theoretical analysis on the basis of Flory-Huggins theory using three binary interaction parameters could appropriately predict the EVAL swelling degree in ethanol/water and 2-propanol/water mixtures. However, the theoretical swelling degree of EVAL in phenol/water mixtures needed a ternary interaction parameter (χ_T) to match with experimental data points. An optimum value of χ_T for the water-phenol-EVAL system was found to be −3.3. The relationship between the ternary interaction parameter and the structure of water from observations of the effect of phenol on the EVAL swelling was discussed. Based on the analysis of low-frequency Raman spectroscopy reported by Suzuki et al. [J. Chem. Phys. 107 (1997) 5890], the contribution of χ_T to the EVAL swelling was attributed to the increase of the entropy in bulk water due to the effect of phenol on the disruption of the tetrahedral hydrogen-bonded networks of water molecules. This, in turn, induced an increase of water absorption in EVAL.