论文部分内容阅读
以对苯二酚为原料经过三步反应,合成了含叔胺取代基的二胺单体2,5-二((二甲氨基)亚甲基)-1,4-二(对氨基苯氧基)苯(DMAPB),并与1,4,5,8-四酸萘二酐(NTDA)、磺化二胺4,4’-二氨基二苯醚-2,2’-二磺酸(ODADS)高温聚合,通过改变磺化二胺单体(ODADS)的含量,制备了一系列具有不同磺化度的侧链含氮原子磺化聚酰亚胺.采用间甲酚为溶剂,通过溶液浇铸法制备成膜.由于将N-原子引入到聚酰亚胺的侧链,使得其与磺酸基更易形成较强的离子交联,从而有效地控制膜溶胀,提高了膜稳定性.新的磺化聚酰亚胺的热稳定性高达330℃并显示了良好的氧稳定性,其阻醇性能也得到了提高,在20℃下,膜的甲醇渗透系数为2.05×10-7至5.11×10-7cm2/s,远低于Nafion 117(2×10-6cm2/s)一个数量级.磺化度40%的磺化聚酰亚胺膜在100℃去离子水中测试1000 h以上仍能保持较好的机械性能.膜在高湿条件下也显示了良好的机械性能.然而,膜的质子传输率有所下降,这应该是较强的离子交联导致膜产生较致密的结构,减少了含水量并阻碍了水和H+的移动.同时,磺酸基与氮原子发生离子交联,减少了参与质子传输的磺酸基数量,降低了聚合物膜的酸性.
Using hydroquinone as raw material, the diamine monomer 2,5-bis ((dimethylamino) methylene) -1,4-bis (p-aminophenoxy (DMAPB) and reacted with 1,4,5,8-tetracarboxylic dianhydride (NTDA), sulfonated diamine 4,4’-diaminodiphenyl ether-2,2’-disulfonic acid ODADS), a series of side chain nitrogen-containing sulfonated polyimides with different degree of sulfonation were prepared by changing the content of sulfonated diamine monomer (ODADS) Casting method to prepare the film.Because the N atom is introduced into the side chain of the polyimide to make it easier to form strong ionic crosslinking with the sulfonic acid group so as to effectively control the film swelling and improve the film stability. Sulfonated polyimide has a thermal stability of up to 330 ° C and shows good oxygen stability, and its alcohol resistance is also improved. The methanol permeability coefficient of the film at 20 ° C is 2.05 × 10 -7 to 5.11 × 10-7cm2 / s which is an order of magnitude lower than that of Nafion 117 (2 × 10-6cm2 / s) .Sulfonated polyimide membranes with 40% degree of sulfonation can still be maintained at 1000 ℃ in deionized water for more than 1000 h Better mechanical properties. The film also shows good machine under high humidity conditions However, the proton transport rate of the membrane decreases, which is due to the stronger ionic cross-linking that results in a denser structure of the membrane, reducing the water content and impeding the movement of water and H +. In the meantime, Atomic ion crosslinking, reducing the number of sulfonic acid groups involved in proton transport, reducing the acidity of the polymer membrane.