聚砜阴离子交换膜的制备及结构与性能研究

以1,4-二氯甲氧基丁烷(BCMB)为氯甲基化试剂,使聚砜(PSF)发生氯甲基化反应,制得了氯甲基化聚砜(CMPSF),考察了主要因素对聚砜氯甲基化反应的影响,并使用FTIR及1H-NMR等法对CMPSF的化学结构进行了表征.采用三乙胺(TEA)、三丙胺(TPA)及三丁胺(TBA)等3种叔胺对CMPSF进行了季铵化反应,并以4,4′-联吡啶为交联剂实施了交联反应,制备了聚砜阴离子交换膜(PSFAEM).测定了交换膜PSFAEM的主要性能,包括离子交换容量(IEC)、含水量(WC)及膜电阻(Rm).实验结果表明,使用BCMB,聚砜的氯甲基化反应可顺利进行,以氯仿为溶剂,以SnCl4为Lewis酸催化剂,可制得氯甲基化程度为1.75mmol/g的CMPSF.交换膜PSFAEM的IEC、WC及Rm与季铵化反应时间及叔胺的种类密切相关.季铵化反应时间相同时,采用烷基中碳原子数少的叔胺TEA所制备的交换膜具有高的IEC与WC,低的Rm;使用同一种叔胺时,随季铵化反应时间的增长,交换膜的IEC与WC增大,Rm减小.

PREPARATION AND STRUCTURE/PROPERTY RELATIONSHIP OF POLYSULFONE ANION|EXCHANGE MEMBRANES

Polysulfone (PSF) was chloromethylated using 1,4-bis(chloromethoxy) butane (BCMB) without carcinogenitic toxicity as chloromethylation reagent,resulting in chloromethylated polysulfone ( CMPSF).The chemical structure of CMPSF was characterized by FTIR,1H-NMR and chemical analysis method.The effects of main factors on the chloromethylation reaction of PSF were examined.By using three tertiary amines,triethylamine ( TEA ),tripropylamine ( TPA ) and tri-n-butylamine ( TBA ),the quaternization reaction of CMPSF was carried out,respectively,and then the crosslinking reaction was performed with 4,4′-bipyridine as crosslinker,obtaining polysulfone anion-exchange membrane ( PSFAEM).The main properties of PSFAEM were determined including ion-exchange capacity ( IEC ),water content ( WC ) and membrane resistance (Rm).The experimental results show that the chloromethylation reaction of PSF with BCMB can be carried out favorably,and CMPSF with a chloromethylation degree of 1.75 mmol /g can be obtained as with chloroform as solvent and SnCl4 as Lewis catalyst.The properties of PSFAEM such as IEC,WC and Rm are closely related with quaternization time and the structure of the tertiary amine.In the same quaternization time,the anion-exchange membrane PSFAEM prepared with TEA,in whose molecule the number of carbon atom in alkyl group on N atom is small,has relatively high IEC,WC and lower Rm.As using the same tertiary amine,the IEC and WC of PSFAEM are increased with increasing the quaternization time,and Rm decreases.