Abstract

The structure and properties of ultrafiltration membranes synthesized from bicomponent solutions in N,N-dimethylformamide using five commercial acrylonitrile copolymers of various compositions and molecular masses have been studied. The molecular mass characteristics of the copolymers (M_w, M_w/M_n) have been determined; the viscosity properties of dilute and concentrated solutions have been studied. It has been shown that depending on the chemical composition and molecular mass of the copolymer, the concentration dependence of the water flux is different: for copolymers with a molecular mass of M_w of 76 000–81 000 g/mol, with an increase in the copolymer concentration in solution from 12 to 16%, the water flux of the membranes decreases from 300–500 to 40–150 L/(m² h) depending on the copolymer composition. For samples with a higher molecular mass (M_w = 99 000 and 107 000 g/mol), the water flux of the membranes hardly depends on the copolymer concentration in the casting solution; it is 150 and 75 L/(m² h), respectively. The rejection factor of the membranes with a molecular mass of 40 000 g/mol for polyvinylpyrrolidone increases with increasing copolymer concentration in the casting solution regardless of the chemical composition and molecular mass of the copolymer. Scanning electron microscopy studies of the membrane structure have shown that membranes synthesized from copolymers with a higher molecular mass have a denser structure and a thicker selective layer than the respective parameters of membranes synthesized from acrylonitrile copolymers with a lower molecular mass, which are characterized by the presence of large macrovoids in the membrane matrix. These differences in the membrane structure are attributed to different viscosities of the casting solutions at identical copolymer concentrations.

中文翻译：

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基于各种丙烯腈共聚物的超滤膜

摘要

研究了由五种不同组成和分子质量的商业丙烯腈共聚物在N，N-二甲基甲酰胺中的双组分溶液合成的超滤膜的结构和性能。确定了共聚物的分子量特征（M _w，M _w / M _n）；已经研究了稀溶液和浓溶液的粘度特性。已经表明，取决于共聚物的化学组成和分子量，水通量的浓度依赖性是不同的：对于分子量为M _w的共聚物膜的水通量从76 000–81 000 g / mol增加到12％至16％时，膜的水通量从300–500降低至40–150 L /（m ² h），具体取决于共聚物组成。对于分子量较高的样品（M _w = 99000和107 000 g / mol），膜的水通量几乎不取决于流延溶液中共聚物的浓度。它是150和75 L /（m ²h）。分子量为40 000 g / mol的聚乙烯吡咯烷酮膜的截留系数随流延溶液中共聚物浓度的增加而增加，而与共聚物的化学组成和分子量无关。膜结构的扫描电子显微镜研究表明，与由较低分子量的丙烯腈共聚物合成的膜的各个参数相比，由具有较高分子量的共聚物合成的膜具有更致密的结构和较厚的选择性层。膜基质中存在大孔洞。膜结构的这些差异归因于在相同共聚物浓度下流延溶液的粘度不同。