同质增强型高性能中空纤维膜结构设计与成形机理研究

Based on the principles and novel methods of polymer processing, according to thermal dynamic theory and shear-core spinning principle of chemical fibers, using self-reinforced method, the composition of spinning dope (surface separation layer) and two kinds of reinforced matrix structure including PVDF hollow fiber membrane and PAN three-dimensional hollow braided tube would be designed. The evolution mechanism of structure and the physical-chemical reaction between the surface separation layer and the reinforced matrix during the continuous spinning dope and reinforced matrix co-extrusion-interaction-coagulation and post-treatment processes would be clarified . The effective methods to control the bonding state of surface separation layer and the reinforced matrix and to adjust the porous structure of the surface separation layer would be explored. By functional modification, the durable hydrophilic property or pH responsibility would be realized on the surface separation layer. The relationship between the surface/interface structure and hollow fiber membrane properties (separation properties, mechanical properties, backwash resistance as well as service life) would be clarified. Thus the key problem of heterogeneous reinforced hollow fiber membrane whose interfacial bonding between surface separation layer and the reinforced matrix is relatively poor would be solved. Meanwhile, the theory of hollow fiber membrane formation would be enriched, which would provide theoretical basis for development of new generation self-reinforced PVDF and PAN hollow fiber membranes having not only excellent mechanical properties but also high precision of separation for water treatment.

从高分子加工原理和新方法角度出发，根据热力学相容性理论和化学纤维皮/芯复合纺丝原理，采用同质增强方式，设计铸膜液（表面分离层）组成和两类增强体（熔融纺丝法聚偏氟乙烯中空纤维多孔基膜和聚丙烯腈纤维立体中空编织物）结构，阐明连续铸膜液/增强体共挤出-复合-固化成形及后处理过程中表面分离层与增强体之间物理、化学作用和结构演变机制，建立调控表面分离层与增强体之间界面结合状态、表面分离层多孔结构及聚集态结构的有效方法，通过功能化修饰赋予表面分离层耐久性亲水化或pH值响应功能，建立表面/界面结构与中空纤维膜分离性能、力学性能、耐反洗性能及使用寿命的模型关系，解决异质增强型中空纤维膜表面分离层与增强体之间界面结合状态不良等关键基础性问题，丰富中空纤维膜成形理论，为规模开发面向水处理应用、集增强体力学性能优异和溶液纺丝法膜分离精度高特点于一体的新一代同质增强型高性能中空纤维膜提供科学依据。

根据热力学相容性理论和化学纤维皮/芯复合纺丝原理，以熔融纺丝-拉伸法聚偏氟乙烯(PVDF)中空纤维多孔膜和聚丙烯腈(PAN)编织管为增强体，分别调置PVDF及PAN铸膜液，采用溶液相转化法在线于多孔基膜及编织管表面复合表面分离层制备了同质增强型PVDF及同质编织管增强型PAN中空纤维膜，研究了铸膜液中聚合物浓度和纺丝工艺对同质增强型PVDF及同质编织管增强型PAN中空纤维膜结构与性能的影响，并研究了同质增强型PVDF及同质编织管增强型PAN中空纤维膜界面结合性能；选用碳素墨水、牛血清蛋白、活性污泥为过滤介质，对同质增强型PVDF中空纤维膜过滤性能及抗污染性能进行研究，分析了同质增强型PVDF中空纤维膜的污染机理；利用表面偏析，以聚乙烯醇（PVA）为共混聚合物对同质增强型PVDF中空纤维膜的表面分离层亲水化改性；将制备的同质增强型PVDF中空纤维膜应用于膜生物反应器(MBR)系统，研究其抗污染情况以及膜污染物的组成等。同时在项目执行过程中，还成功制备了同质增强聚氯乙烯(PVC)中空纤维膜及同质编织管增强型醋酸纤维素(CA)中空纤维膜。成功解决异质增强型中空纤维膜表面分离层与增强体之间界面结合状态不良等关键基础性问题。 .研究成果获得产业化实施，与企业合作建成国内外首条同质增强型中空纤维膜生产线，获2014年度中华全国工商业联合会科技进步奖一等奖，开发1项国家重点新产品“同质增强型PVDF中空纤维膜及膜组件”，获1项天津市专利金奖，发表期刊论文19篇(其中SCI收录14篇，Ei 收录2篇)，申请发明专利 15项（含美国专利3项，日本专利1项），获授权发明专利8项（含美国专利 1项，日本专利1项）。