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首页> 外文学位 >Fabricating robust nanoporous materials and polymer electrolyte membranes from reactive block copolymers by metathesis reactions.
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Fabricating robust nanoporous materials and polymer electrolyte membranes from reactive block copolymers by metathesis reactions.

机译：通过复分解反应从反应性嵌段共聚物制备坚固的纳米多孔材料和聚合物电解质膜。

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摘要

Polymer membranes have been studied for several decades, and conventional utility of these membranes has been realized over a wide range of applications such as water purification, gas separation, and fuel cells. Separation performance of polymer membranes for these applications can be evaluated from different aspects including selectivity, material cost, and thermal and mechanical stabilities.;This research focused on the design of crosslinked polymer membranes from reactive block copolymers, which could possess some attractive features such as controlled functionality and morphology. Novel block copolymers containing a chemically crosslinkable block and a chemically modifiable block were of particular interest. Metathesis reactions were employed to crosslink these copolymers with additional tough polymers such as polycyclooctene (PCOE) and polydicyclopentadiene (polyDCPD), to realize enhanced toughness in the resulting materials.;First, a norbornene-functionalized polystyrene-polylactide (PNS-PLA) block copolymer was synthesized. A self-assembled blend containing this copolymer and DCPD was cured by metathesis reactions, and nanoporous monoliths with a cylindrical morphology were successfully produced after removing the PLA component. These monoliths exhibited pronounced mechanical and thermal stabilities superior to nanoporous polystyrene (PS).;Second, polymerization induced phase separation (PIPS) during the ring-opening metathesis polymerization (ROMP) of DCPD in the presence of the PNS-PLA copolymer rendered continuous PLA nanodomains in a crosslinked PNS/polyDCPD matrix. Upon etching the PLA component, the resultant nanoporous membranes exhibited well-defined percolated nanopores and good thermal and mechanical stabilities. Preliminary diffusion measurements demonstrated potential utility of such membranes in ultrafiltration.;Third, crosslinked polymer electrolyte membranes (PEMs) were fabricated from a PNS-poly(n-propyl-p-styrenesulfonate) (PSSP) block polymer and COE/DCPD via the PIPS scheme followed by deprotection of the PSSP block. These PEMs possessed a bicontinuous morphology and mechanical and thermal robustness. Select PEMs exhibited high proton conductivity similar to Nafion at high humidity and reduced methanol crossover. Tunable domain size and mechanical strength of the resulting PEMs are advantageous attributes of this preparation protocol. Additionally, the use of such PEMs for NH 3 separation from gas mixtures was demonstrated.;The appendix chapter represented our efforts to produce amine-functionalized polymer membranes from PNS-poly(dimethylaminoethylmethacrylate) (PNS-PDMAEMA) and COE by metathesis reactions, potentially useful for CO2 separation from gas mixtures.
机译：聚合物膜已经研究了几十年，并且已经在诸如水净化，气体分离和燃料电池的广泛应用中实现了这些膜的常规用途。可以从不同方面评估聚合物膜在这些应用中的分离性能，包括选择性，材料成本以及热和机械稳定性。该研究的重点是从反应性嵌段共聚物设计交联的聚合物膜，该膜可能具有一些吸引人的特性，例如受控的功能和形态。包含化学可交联的嵌段和化学可改性的嵌段的新型嵌段共聚物特别令人关注。使用复分解反应将这些共聚物与其他强韧的聚合物（例如聚环辛烯（PCOE）和聚二环戊二烯（polyDCPD））交联，以提高所得材料的韧性。首先，降冰片烯官能化的聚苯乙烯-聚丙交酯（PNS-PLA）嵌段共聚物是合成的。通过复分解反应使包含该共聚物和DCPD的自组装共混物固化，并在除去PLA组分后成功制备出具有圆柱形形态的纳米多孔整料。这些整体材料表现出明显优于纳米多孔聚苯乙烯（PS）的明显的机械和热稳定性。第二，在PNS-PLA共聚物存在下DCPD的开环易位聚合（ROMP）过程中，聚合诱导相分离（PIPS）交联的PNS / polyDCPD基质中的纳米域。在蚀刻PLA组分时，所得的纳米多孔膜表现出明确的渗透纳米孔以及良好的热稳定性和机械稳定性。初步扩散测量证明了此类膜在超滤中的潜在用途。；第三种交联的聚合物电解质膜（PEM）由PNS-聚（n-丙基-对苯乙烯磺酸酯）（PSSP）嵌段聚合物和COE / DCPD通过PIPS制成方案，然后取消对PSSP块的保护。这些PEM具有双连续形态，机械和热稳定性。精选的PEM在高湿度下表现出与Nafion相似的高质子传导性，并减少了甲醇穿透。所得PEM的可调域大小和机械强度是该制备方案的有利属性。此外，还证明了将此类PEM用于从气体混合物中分离NH 3的情况。附录一章表示我们通过易位反应从PNS-聚（甲基丙烯酸二甲基氨基乙酯）（PNS-PDMAEMA）和COE制备胺官能化聚合物膜的努力可用于从混合气体中分离出二氧化碳。

著录项

  • 作者

    Chen, Liang.;

  • 作者单位

    University of Minnesota.;

  • 授予单位 University of Minnesota.;
  • 学科 Chemistry Polymer.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 274 p.
  • 总页数 274
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 高分子化学（高聚物）;
  • 关键词

  • 入库时间 2022-08-17 11:38:24

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