| Alkaline anion exchange membrane fuel cell?AAEMFC?has become one of the current research hotspots due to its high energy conversion rate,low pollution and low cost.Anion exchange membrane?AEM?is one of the core components,and still has shortcomings such as low ionic conductivity and poor alkali resistance,which limits the development of AAEMFC.In this thesis,an amine-substituted poly?aryl ether ketone?was synthesized by polycondensation reaction,and a side-chain structure was introduced by using an amine group as a reaction site,synthesizing and preparing a series of side-chain-type poly?aryl ether ketone?anion exchange membranes.The side-chain structure promotes the formation of a microphase separation structure favorable for efficient ion transport in the membrane,and can effectively improve the ion conductivity and alkali stability of the anion exchange membrane.In this thesis,a series of side-chain-type poly?aryl ether ketone?anion exchange membranes were first prepared by ionic liquid method.The preparation method adopts the amino group on the poly?aryl ether ketone?as a branching site and directly introduces the ionic liquid containing the terminal bromine,which is a simple and controllable method for preparing the side-chain-type anion exchange membrane.The prepared membrane has excellent performance,and the ionic conductivity can reach 74.4 mS cm-1.In addition,after the membrane is immersed in 1 M KOH solution at 60°C for 768 h,its chemical structure has not changed significantly,indicating that it has good alkali stability.In order to weaken the destruction of the polymer main chain and the ionic group caused by the high temperature and strong alkaline reaction environment in the ionic liquid method,the introduction of the side-chain structure and the functional group are seperated into two steps.The introduction of the side-chain structure starts to use reaction environment with low basicity and room temperature,and the introduction of the functional group can be completed only by heating condition.A series of side-chain-type poly?aryl ether ketone?anion exchange membranes were prepared using this stepwise method.The test results show that this method can control the ion exchange capacity?IEC?of the membrane more precisely.Compared with the membrane prepared by the ionic liquid method,the elongation at break of the membrane is improved,and the highest conductivity is increased to 100.5 mS cm-1.The immersion time in 1 M KOH solution at 60°C of the membrane can be extended to 1008 h,but the IEC,ionic conductivity and chemical structure have no significant changes during the process,showing better performance of the membrane.In order to further improve the ionic conductivity of the membrane,a crosslinked structure is introduced using N,N,N,N-tetramethyl-1,6-hexanediamine as crosslinking reagent on the basis of the side-chain structure,which allows the membrane to increase IEC without sacrificing mechanical properties and dimensional stability.A series of side-chain-type poly?aryl ether ketone?anion exchange membranes were prepared by this way.The IEC of the structured membrane can reach 1.63 mmol g-1,and the highest conductivity increases to 109.8mS cm-11 with the increase of IEC.The swelling ratio of the membrane hardly changes with the increase of temperature,with the highest value of only 21.2%at 80°C. |
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