大幅度剪切变稀型胶束对飞机防冰液流变特性影响机理研究

Using polymer as thickener in anti-icing fluid leads to potential risks to flight safety, because polymer-based thickener tends to form hydration gel during flight. In order to explore new thickener, we introduced wormlike micelles to the anti-icing fluid field in last NSFC project (U1233122), which resolved the hydration gel problem. However, the rheological properties of wormlike micelles needs further investigation in order to meet the requirement of anti-icing fluid. Therefore we attempt to employ a physical crosslinking agent to connect the wormlike micelles which are dispersed in the solution without entanglement, into a tri-dimensional network. The tri-dimensional network is built by the crosslinked wormlike micelles instead of entangled ones. The target thickener can be finally formed when acquiring aim rheological properties after further investigation on the interaction between the crosslinking agent and wormlike micelles and the disintegration course of the network under low-temperature environment. The interrelation among the structure of crosslinking agent, tri-dimensional network and rheological properties is investigated in detail in order to fine tune the rheological properties of the solution. The research has an innovative significance to the wormlike micelles in theory. It also contributes to develop new anti-icing fluid to enhance the flight safety in winter.

目前防冰液采用聚合物型增稠剂，在使用过程中易生成水合凝胶，影响飞行安全。在上一个自然基金（U1233122）中我们引入了另一类增稠剂—蠕虫状胶束，虽然解决了水合凝胶问题，但其剪切变稀流变特性需要进一步完善。基于此，本项目拟通过引入物理“交联剂”，将尚未形成缠绕结构的蠕虫状胶束通过疏水缔合作用“交联”成三维网络状结构，旨在克服由蠕虫状胶束互相缠绕形成的三维网络状结构所面临的剪切变稀程度不足的问题，实现溶液具有大幅度剪切变稀流变特性的目的。进一步研究醇水体系以及低温环境下“交联剂”与蠕虫状胶束的疏水缔合作用，以及在特征剪切程序下三维网络状结构的破坏历程，获得在醇水和低温环境下满足大幅度剪切变稀流变性要求的新型增稠剂体系。该研究不仅具有一定的理论意义，还将为研发新型防冰液提供理论基础，将有助于提高我国冬季航空运营安全的保障水平。

增稠型飞机防冰液是由增稠剂、润湿剂和缓蚀剂等组成的醇水混合溶液，在冬季雨雪天气保障飞机安全飞行中起着重要作用。增稠剂提供的粘度和流变特性是影响飞机防冰液防冰和低温空气动力学性能的关键因素。研发基于表面活性剂小分子自组装的胶束体系的增稠剂是目前大分子增稠剂的一个重要替代方向。本项目采用流变技术、SANS、冷冻透射电镜、荧光探针等技术，考察低温高水溶性的超长链表面活性剂（C22）EDAB在醇水溶剂中的溶解行为、自组装行为、胶束形态和溶液的流变特性等，首次制备出在低温领域（-20℃）具有符合飞机防冰特性要求的流变性的粘弹性流体。同时考察了该蠕虫状胶束体系与增稠剂的协同作用，引入极少量大分子增稠剂便能大幅度提升胶束体系的粘度和流变特性，能同时降低表面活性剂和聚合物大分子的使用量，提升增稠效率，又能避免目前大分子增稠面临的易形成水合凝胶的安全隐患。通过本项目研究制备出在低温醇水领域的符合防冰液流变特性的增稠剂体系，不仅解决了目前防冰液增稠剂面临的技术弊端，也为防冰液增稠剂的筛选提供了一个全新的思路和研究方向，也是表面活性剂在醇水和低温领域聚集行为的有益探索，具有重要的理论意义和应用价值。