Preparation And Properties Of SPEEK/BT Composite Proton Exchange Membranes

SPEEK is widely concerned because of its good heat resistance,excellent resistance to alcohol,good proton conductivity and relatively simple preparation technology.However,the pure SPEEK proton exchange membrane has some disadvantages such as poor stability,high sulfonation degree with uncoordinated methanol permeability.This paper uses doping modification method,which uses the inorganic particles with “proton conductor”-barium titanate(BT)as the main body in doping to prepare a series of SPEEK/BT composite proton exchange membrane s.Then this paper characterizes the performance of the composite proton exchange membranes from the following aspects such as dimensional stability,water absorption,proton conductivity,methanol permeability and so on various aspects.First,the SPEEK/BT composite proton exchange membrane was prepared with BT as a dopant.The experimental results show that the doping of BT can obviously improve the proton conductivity of the membrane.The proton conductivity of the SPEEK/BT-0.5 membrane was the best of SPEEK/BT membranes when the BT doping was 0.5 wt%.Then,the conductivity of the composite membrane decreases with the agglomeration of BT when the amount of BT doping increases.Secondly,in order to improve the compatibility between BT and the SPEEK matrix,this paper modified the surface of BT respectively by KH550,PDA,KH570 surfactants.These BT products(KH550-BT,PDA-BT,KH570-BT)respectively has three kinds of organic groups in the surface of the BT material.The three particles were doped into the SPEEK matrix,which were respectively obtained by SPEEK/KH550-BT,SPEEK/PDA-BT,SPEEK/KH570-BT composite proton exchange membranes.Respectively from SEM,electric conductivity,water absorption and dimensional stability to characterize these proton exchange membranes,the conductivity of SPEEK/KH570-BT membranes are best which can also improve the dispersion of the BT in the membrane.And the best performance of composite membrane was from SPEEK/BT-0.5 to SPEEK/KH570-BT-1.0,which BT particle doping amount increased from 0.5 wt% to 1.0 wt%.So,KH570-BT only with silicon surface oxygen groups in composite membrane can effectively improved the dispersibility of BT particles.Due to the hydrophilicity of inorganic particles and surfactants,the swelling rate and water absorption rate of the composite membranes increased slightly.Finally,the best spinning condition of barium titanate hollow fiber(HFBT)was prepared by using electrostatic spinning method,and then the SPEEK/HFBT composite proton exchange membrane was prepared.HFBT is composed of a large number of BT particles.Therefore,the performance of the SPEEK/HFBT membranes are not good.In order to improve the performance of the composite membranes,this paper takes HFBT as the carrier and loads the "effective proton conductor" phosphotungstic acid(HPW)onto its surface to obtain HPW-HFBT fiber composite material.As a dopant,SPEEK/HPW-HFBT composite membrane was prepared with better performance.