Sulfonation of blocky brominated PEEK to prepare hydrophilic-hydrophobic blocky copolymers for efficient proton conduction
Sulfonation of blocky brominated PEEK to prepare hydrophilic-hydrophobic blocky copolymers for efficient proton conduction
复制标题
DOI：
10.1016/j.ssi.2019.03.006
复制
发表时间：
2019-08-01
影响因子：
3.2
通讯作者：
Moore, Robert B.
中科院分区：
文献类型：
--
作者：
Anderson, Lindsey J.;Moore, Robert B.
采用两步后聚合法制备了聚醚醚酮（PEEK）亲水-疏水嵌段共聚物。首先，PEEK在半结晶凝胶状态下溴化以产生块状BrPEEK模板，其随后通过磺化未官能化的PEEK单元的剩余运行而官能化。所得到的块状溴化，磺化PEEK（BrSPEEK）共聚物的磺化度与溴化度呈负相关，并得到26至71摩尔%的磺化度范围内的溴化度在27和144摩尔%之间。使用DSC和DMA的热分析揭示了不同的多相行为的块状BrSPEEK共聚物的磺化度高达40摩尔%，表明相分离之间的密集溴化嵌段和磺化嵌段成疏水和亲水域，分别。与随机SPEEK膜相比，这种相分离有助于改善块状BrSPEEK膜在溶胀时的尺寸稳定性和在较低水含量下增强的质子传输。最后，使用SAXS的形态分析表明，离子聚集体的大小保持相对不变的块状BrSPEEK在所有程度的磺化，和离子聚集体变得更加紧密的间隔与磺化度的增加。总体而言，这项工作证明了一种简便的后聚合技术，以制备亲水性，疏水性嵌段共聚物，具有优异的尺寸溶胀和传输性能，可与直接聚合的嵌段共聚物相媲美。
Hydrophilic-hydrophobic blocky copolymers of poly(ether ether ketone) (PEEK) were prepared using a two-step post-polymerization technique. First, PEEK was brominated in the semicrystalline gel state to create a blocky BrPEEK template, which was subsequently functionalized by sulfonating the remaining runs of unfunctionalized PEEK units. The resultant degree of sulfonation of the blocky brominated, sulfonated PEEK (BrSPEEK) copolymers was inversely related to the degree of bromination, and degrees of sulfonation ranging from 26 to 71 mol% were obtained for degrees of bromination between 27 and 144 mol%. Thermal analysis using DSC and DMA revealed distinct multi-phase behavior for blocky BrSPEEK copolymers at degrees of sulfonation up to 40 mol%, suggesting phase separation between the densely brominated blocks and the sulfonated blocks into hydrophobic and hydrophilic domains, respectively. This phase separation contributed to improved dimensional stability upon swelling and enhanced proton transport at lower water content for blocky BrSPEEK membranes compared to random SPEEK membranes. Finally, morphological analysis using SAXS demonstrated that ionic aggregate size remained relatively unchanged for blocky BrSPEEK at all degrees of sulfonation, and the ionic aggregates became more closely spaced with increasing degree of sulfonation. Overall, this work demonstrates a facile, post polymerization technique to prepare hydrophilic, hydrophobic blocky copolymers with excellent dimensional swelling and transport properties that rival those of directly polymerized block copolymers.