大侧基链接剂制备嵌段磺化聚芳醚砜质子交换膜及其性能研究

Preparation of Blocked Sulfonated Polyaryle Ether Sulfone and Its Proton Exchange Membrane Properties

以含苯侧基的对二(苯羰基四氟苯)为链接剂,以4,4’-二氟二苯砜分别与4,4’-二羟基二苯砜和4,4’-联苯二酚作为疏水和亲水嵌段前体,合成一系列高分子量的有序和无序的嵌段磺化聚芳醚砜(SPAES).1H-NMR显示所制备的嵌段型SPAES的磺化位点和预测的一致,且离子交换容量(IEC)的滴定值是理论值的95%以上,说明磺化位置和磺化度精确可控.SPAES质子交换膜的杨氏模量、拉伸应力和断裂伸长率高达1.92 GPa、75 MPa和58%.TGA结果表明嵌段SPAES具有两段失重,分别对应320℃左右磺化基团脱出,以及500℃以上聚合物骨架分解.相似IEC,具有苯环大侧基链接剂的SPAES的吸水率随温度变化要明显小于无链接剂SPAES,在膜面方向尺寸变化率两者相当,均为8%左右.具有相似IEC的有链接剂的有序嵌段型SPAES,如MB9(IEC=1.68 mmol·g^(-1))的质子传导率为无链接剂嵌段型SPAES B2(IEC=1.70 mmol·g^(-1))的1.2倍以上.这是由于链接剂苯环侧链结构使得膜内自由体积增加有利于质子传导.同样,有序嵌段型SPAES PEM的质子传导率高于相同IEC的无序嵌段型.

A series of high molecular weight ordered and disordered block sulfonated polyaryle ether sulfone(SPAES)were synthesized using phenyl-containing p-bis(phenylene-tetrafluorobenzene)as a linking agent,with 4,4’-difluorodiphenyl sulfone and 4,4’-dihydroxydiphenyl sulfone and 4,4’-biphenyl sulfone as hydrophobic and hydrophilic block precursors,respectively.The~1H-NMR showed that the sulfonation site of the prepared block SPAES was consistent with the prediction,and the titration value of the ion exchange capacity(IEC)was more than 95%of the theoretical value,indicating that the sulfonation position and sulfonation degree were precisely controllable.The Young’s modulus,tensile stress and elongation at break of the SPAES proton exchange membrane in this work are as high as 1.92 GPa,75 MPa and 58%.The TGA results show that the block SPAES in this work has two stages of weightlessness,namely sulfonated group detachment at about 320℃and polymer skeleton decomposition above 500℃.Similar to IEC,the water absorption rate of SPAES with benzene ring large side linker varies significantly less with temperature than that of linkless SPAES,and the rate of change in the size of the membrane surface direction is comparable,both of which are about 8%.The proton conductivity of ordered blocked SPAES with linking agents with similar IEC,such as MB9(IEC=1.68 mmol·g^(-1)),is more than 1.2 times that of linkless blocked SPAES B2(IEC=1.70 mmol·g^(-1)).This is due to the benzene ring side chain structure of the linker so that the free volume in the membrane increases favors proton conduction.Similarly,the proton conductivity of ordered blocked SPAES PEM is higher than that of the same IEC type of disordered block.