Ionic liquids (ILs) have attracted widespread interest in recent years because of their favorable characteristics. A highly crosslinked poly(1-vinyl-3-allylimidazolium) (C-PVAm) was synthesized by free radical polymerization and quaternization followed by radiation processing. An allyl group was covalently incorporated into the polymer matrix to enhance the properties of the PVAm. The chemical structures of the synthesized pristine and crosslinked PVAm containing a C=C bond were confirmed by 1H NMR and FTIR spectra. The thermal properties of the C-PVAm analyzed by differential scanning calorimetry (DSC) were significantly improved because of the thermal stability of the crosslinked networks.

최근에 이온성 액체의 뛰어난 특성으로 인해 관심이 증가하고 있다. 자유 라디칼 중합공정과 친핵성 치환 반응을 이용하여 poly(1-vinyl-3-allylimidazolium)(PVAm)을 제조하였으며, 이를 전자빔을 이용하여 가교하였다(CPVAm). 고분자의 물성을 향상시키기 위해 가교 가능한 알릴 그룹을 공유 결합으로 도입하였다. 전자빔 조사에 의해 가교된 PVAm의 화학적 구조를 적외선 분광분석과 핵자기 공명 분석을 통하여 확인하였으며, 시차 주사 열량 분석(DSC)을 통하여 가교된 PVAm의 열적 안정성이 향상됨을 확인하였다.

Keywords: ionic liquid, crosslinking, thermal property, electron beam, energy device

Electrochemical energy storage and conversion devices, such as batteries, fuel cells, supercapacitors, dye-sensitized solar cells, etc., have been the focus of recent studies due to their important role in the utilization of renewable energy.¹ Expansion of energy storage systems for next generation devices, such as electric transportation and large scale energy storage systems, however, relies on further developments towards a superior energy density, and a longer durability.² To date, most studies have focused on the design of new electrode materials and stable electrolytes in the hard environments of energy storage systems, and only few groups have reported on the polymeric binder so far.³
Besides other key components in energy storage systems, such as electrodes and the electrolyte, an efficient binder is important to sustain both the electronic and mechanical properties of the electrodes. The effect of polymeric binders on the overall behavior of the whole electrode system is highly relevant for the cycling stability of energy storage systems.
Ionic liquids (ILs) have attracted widespread interest in recent years because of their favorable characteristics, such as being chemically inert and having electrochemical stability, non-volatility, and high ionic conductivity, for use as electrolytes. ^4-9 In the last few years, polymers prepared with ionic liquid moieties (PILs) have also been studied as solid polymer electrolytes for various applications.^10-12
To improve the properties of polymers, many innovative techniques have been developed such as crosslinking,^13-15 fabricating composite with inorganic materials, and blending with other polymers.^16-18 Among these techniques, crosslinking has been preferred because it is a simple and efficient method, which can improve the thermal and mechanical stability.
A polymer can be crosslinked either by conventional thermal treatment or by exposure to radiation from either radioactive sources or highly accelerated electrons. Radiationinduced crosslinking is a well-known and established technique that does not need any additives. The advantages of radiation induced crosslinking are (1) homogenous and temperature-independent; (2) the gel contents can be easily modified by controlling the irradiation conditions; (3) more polymers can be crosslinked by radiation than by any chemical method; and (4) the chemistry of the reaction system is free from contamination.¹⁹
In this paper, we describe a direct route to fabricate a highly C-PVAm. For this, PVAm was crosslinked by electron beam irradiation to obtain a high thermal stability under various conditions.