磺化条件对SPEEK膜性能的影响

Effect of sulfonation conditions on the performance of SPEEK membrane

本文采用浓硫酸作为磺化剂,以聚醚醚酮(PEEK)为原料研究了在25℃、35℃、40℃、45℃、50℃和55℃以及2至24h磺化时间下所获得的SPEEK膜的物理化学性质,探讨了磺化温度、磺化时间对SPEEK膜的各项性能的影响。SPEEK膜的磺化度、离子交换容、含水率、导电率和钒离子渗透率等均随磺化温度和磺化时间的增加而呈现相同的增加趋势,而温度对膜性能的影响尤为明显。磺化温度在40℃~45℃,磺化时间在4h^6h所获得的膜综合性能最好:质子导电率达0.11S/cm,钒离子渗透率为3.2×10-7cm2/min,仅为Nafion膜(2.9×10-6cm2/min)的十分之一,选择性为2.13,是Nafion膜(0.35)的6倍。此外,膜的含水率和机械性能也适中。与常温相比,升高磺化温度,缩短了磺化反应时间,降低生产成本,提高生产效率,且所获得膜的综合性也能满足钒液流电池的应用。

SPEEK membranes were prepared by using sulfonation of poly（ether ether ketone）（PEEK）in the concentrated H2SO4 under different sulfonation time and various temperatures from 25℃ to 55℃.The influence of sulfonation sulfonation time and temperature was carefully studied.The ion exchange capacity（IEC）,degree of solfonation（DS）,proton conductivity,and vanadium（Ⅳ）ion permeability of SPEEK membranes were increased as the sulfonation time and sulfonation temperature were increased.The latter is found to be more remarkable on the properties of SPEEK.The experimental results showed that the best synthesis conditions for SPEEK were the sulfonation temperature bewteen 40℃ and 45℃ with the sulfonation time in a range of 4 to 6 hours.Upon above condition the synthesized SPPEK membranes had the proton conductivity of 0.11S/cm,Vanadium（Ⅳ）ion permeability of 3.2×10-7cm2/min,only 1/10 of Nafion（2.9×10-6cm2/min）.and the selectivity of 2.13,which is 6 times higher than Nafion（0.35）.In addition,the water uptake and mechanical properties of the membranes are remained moderate.Raising the sulfonation temperature and shortening the sulfonation reaction time are good for commerialization,the membranes are met requirement for vanadium redox battery application.