具有稳定刚性/超润湿界面的芳杂环聚芳醚类膜材料构建及油水分离构效关系研究

Polymer microporous membrane with super-wetting property is one of the most effective methods to realize the oil/water emulsion separation. However, the practical application of it in oil/water separation is restricted by two disadvantages. On the one hand, the operating temperature of membrane separation should be kept below 50 oC, which indicates the low heat resistance of polymer membrane. On the other hand, the micro-/nano- structure on the membrane surface tends to creep under strong physical and chemical damage (such as high temperature, chemical corrosion, water pressure and fluid shear), leading to the disappearance of super-wettability. Therefore, the key to solve these problems is to construct a thermostable polymer membrane material with robust/super-wetting interface. In this project, based on the poly (arylene ether) special engineering polymer, novel hydrophilic and thermally stable poly (arylene ether nitrile) copolymers (PEN) are synthesized by introducing the special functional group (such as aromatic side group and non-coplanar twisted chain structure) into the polymer chains. Then, PEN microporous membrane with hierarchical surface is prepared by phase separation and template peeling. Based on this, novel thermostable poly (aryl ether nitrile) separation membrane with robust/super-wetting interface is constructed by the combination of one-step mussel-inspired immobilization and model of plant root holding the soil. Therefore, this project realizes efficient and stable separation of oily wastewater in complex environment, and provides theoretical basis for exploring high performance oil-water separation membrane materials.

基于聚合物微孔膜构建具有超润湿界面的复合材料是目前油水（乳液）分离最有效的手段之一。但在实际应用过程中受两大问题制约：一是，大多数聚合物膜材料耐热性不高，其长期操作温度需控制在50oC以下；二是，膜表面的微/纳结构易在强物理和化学损伤下（高温、化学腐蚀、水体压力和流体剪切等）蠕变导致超润湿特性消失。因此，构建具有稳定刚性/超润湿界面的耐温聚合物膜材料是解决上述问题的关键。本项目基于聚芳醚类特种工程高分子，首先通过分子设计将芳侧基、非共平面扭曲链结构如双酚芴、酚酞等引入分子链中合成新型亲水耐温芳杂环聚芳醚腈共聚物，并通过相转化及模板法结合制备具有根状微/纳结构表面的聚芳醚腈微孔膜。其次，在上述基础上采用新颖的仿生一步浸泡法与仿生植物根系固定土壤模型协同构建具有稳定刚性/超润湿界面的耐温聚芳醚腈分离膜，进而实现对复杂环境下含油废水的高效、稳定分离应用，并为探索高性能油水分离膜材料提供理论基础。

油田开发、石油储运、化工机械等行业以及频发的海上漏油事件产生了大量的复杂含油废水，对膜分离技术提出了更大的挑战。因此，开发新型稳固超润湿/多功能膜材料是实现对复杂环境下含油废水高效处理的一个重要研究课题。本项目首先通过亲核取代反应引入酚酞啉单体合成了羧基聚芳醚腈聚合物，由于羧基聚芳醚腈含有独特的氰基、苯环等刚性结构，在热稳定性方面表现出优异的性能，其玻璃转换温度达195℃，并且在热失重5%时分解温度达405℃。在此基础上采用非溶剂相转换技术制备了亲水耐温型羧基聚芳醚腈分离膜，系统研究了液膜厚度、致孔剂含量、聚合物浓度等对分离膜形貌及亲水性能的影响，并确定了最佳分离膜制备工艺。研究结果表明，分离膜的亲水性有显著提高，膜的接触角由86°降低至28°；羧基聚芳醚腈分离膜对各种水包油乳液均具有440 L/m2·h的渗透通量和高达99.21%的分离效率；进一步采用模板剥离技术与仿生一步共沉积技术结合将纳米功能材料稳定负载于膜表面，成功制备了一种新型超亲水/水下超疏油羧基聚芳醚腈复合膜。该复合膜对无表面活性剂水包油乳液具有609±31.4L/m2·h的渗透通量和99.56%的分离效率；复合膜对表面活性剂稳定的油包水乳液具有439±17.9L/m2·h的渗透通量和99.36%的分离效率。此外，复合膜在80℃/4M HCl和80℃/1M NaOH条件下具有优异的耐腐蚀和耐高温性能，使其在严苛环境下具有稳定的超润湿特性和分离效率。项目建立了膜表面的化学组成、物理性质与润湿性能的相互关系，阐明了聚芳醚腈膜材料对油水乳液的分离和抗油污性的内在机制。本项目提出通过简单、高效仿生法构建具有稳定刚性/超润湿界面的耐温聚合物膜分离材料，对于当前复杂环境下含油废水处理和科学研究都有重要的意义。