Synthesis and Properties of Nonfluoro Aminated Poly(vinylbenzyl chloride-co-ethyl methacrylate-co-styrene) Anion Exchange Membranes for MCDI Process
Koo JS, Kwak NS, Hwang TS
막 축전식 탈염용 비불소계 아민화 Poly(vinylbenzyl chloride-co-ethyl methacrylate-co-styrene) 음이온교환막의 합성 및 특성
구진선, 곽노석, 황택성
Abstract
A terpolymer of vinylbenzyl chloride-co-ethyl methacrylate-co-styrene (VBC-EMA-St) was prepared for membrane capacitive deionization (MCDI) by radical polymerization and amination reaction of various amination times. Nonfluoro aminated VBC-EMA-St anion-exchange membranes were characterized by Fourier transform infrared (FTIR) spectrometry. Molecular weight, polydispersity and thermal stability were obtained by gel permeation chromatography
(GPC) and thermogravimetric analysis (TGA). The basic properties such as water uptake, ion exchange capacity, electrical resistance and CDI charge-discharge current were measured. The optimal values of ion exchange capacity, water uptake, electrical resistance and molecular weight of synthesized anion-exchange membrane were 1.69 meq/g, 23.7%, 1.61 Ω·cm and 3.4×104 g/mol, respectively. As compared with conventional membrane, the pattern of cyclic charge-discharge current of synthesized anion-exchange membrane indicated efficient electrosorption and desorption.
본 연구에서는 막축전식 탈염(membrane capacitive deionization, MCDI) 공정용 음이온교환막의 제조를 위하여 vinylbenzyl chloride-co-ethyl methacrylate-co-styrene(VBC-EMA-St) 공중합체를 합성하였으며, 아민화 반응과 열처리를 통하여 음이온교환막을 제조하였다. 구조확인을 위하여 FTIR 분석을 하였고, GPC와 TGA를 통하여 합성한 고분자의 분자량과 분자분포, 열안정성을 분석하였으며, 함수율 및 이온교환용량을 측정하였다. 또한 LCR meter로 전기저항을 측정하고, MCDI 공정에 적용하기 위하여 제조한 음이온교환막을 충방전 시험 측정하였다. 이온교환용량, 함수율, 전기저항, 분자량은 각각 1.69 meq/g, 23.7%, 1.61 Ω·cm, 3.4×104 g/mol이었으며, CDI 충방전 시험 결과 상용화막인 AMX보다 우수한 성능을 나타내었다.
Keywords: VBC-EMA-St; anion exchange membrane; water uptake; MCDI; electrical resistance.