Study On The Preparation And Performace Of Polyphenylene Ether Based Organic-inorganic Hybrid Anion Exchange Membrane

Alkaline anion-exchange membrane fuel cell?AEMFC?is a highly efficient and environmental-friendly energy conversion device,which have been extensively studied because of their advantages such as rapid oxidation rate and the use of inexpensive metallic materials as catalysts.Among them,anion exchange membrane?AEM?as a core component of AEMFC,its performance has a direct impact on the performance and lifetime of AEMFC.At present,most anion-exchange membranes have two major defects in lower ionic conductivity and poor alkaline resistance,which cannot meet the requirements of fuel cell under high temperature and high alkaline conditions.Therefore,this paper's main research content is to prepare an anion exchange membrane with higher ionic conductivity and better alkaline resistance.In this paper,two different anion-exchange membranes based on imidazole polyphenylene ether were prepared with 1,2-dimethylimidazole?DIM?as the ion conducting unit,then their properties were tested and characterized.The details are as follows:?1?Imidazole polyphenylene ether organic/inorganic anion exchange membrane.In this experiment,we choose polyphenylene ether?PPO?as raw material,after bromination,partial hydroxylation and imidazoleization react,and open-loop grafting of GPTMS epoxy onto the molecular backbone and preparation of anion exchange membranes with different inorganic fractions by sol-gel process.¹H NMR and FTIR tests demonstrate the success of the chemical reaction,the successful hydrolysis and cross-linking of the siloxane.XRD analysis show that the prepared anion exchange membranes are all amorphous.SEM results show that the microstructure of the membranes are very dense and uniform,and there is no phase separation or voids.TG analysis showed that the prepared anion exchange membrane have excellent thermal stability under 190?.Besides,the membranes have excellent mechanical properties and dimensional stability.The IEC and ionic conductivity of the membrane both increase first and then decrease with increasing inorganic content.The IEC can reach up to 2.63 mmol·g^-1,and the ionic conductivity can reach up to 0.036 S·cm^-1 at 80?.After immersed in sodium hydroxide solution of 2 mol·L^-1 at 60? for 10 days,the ionic conductivity of the membrane can still be maintained at 0.0218 S·cm^-1,which show good alkaline resistance.?2?Polyvinyl alcohol modified imidazole polyphenylene ether anion-exchange membrane.Different proportions of polyvinyl alcohol?PVA?are chemically bonded to the?1?system by chemical reaction,and the corresponding anion exchange membrane is prepared by a solution casting method.FTIR and XRD measurements show that the PVA successfully cross-linked in the molecular chain in the form of chemical bonds,and the addition of PVA had no effect on the formation of Si-O-Si.SEM analysis shows that the modified membrane has a uniform microstructure.The TG-DSC curve display that the thermal stability of the membrane is significantly improved.The ionic conductivity test show that the ionic conductivity of the membrane decrease with the increasing of PVA content and increased with the increasing of temperature.In the same environment,the reduction rate of the ionic conductivity of the anion exchange membrane after PVA modification can be reduced by 6%,which indicate that the alkaline resistance performance is improved,and it can meet the operating requirements of alkaline fuel cells under high temperature and high alkaline conditions.