Effect of polymer molecular weight on the long-term process stability of crosslinked polybenzimidazole organic solvent nanofiltration (OSN) membranes
Effect of polymer molecular weight on the long-term process stability of crosslinked polybenzimidazole organic solvent nanofiltration (OSN) membranes
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DOI：
10.1016/j.memsci.2023.122149
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发表时间：
2023-10
影响因子：
9.5
通讯作者：
Adam Oxley;Andrew Guy Livingston
中科院分区：
文献类型：
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作者：
Adam Oxley;Andrew Guy Livingston
研究了聚合物分子量对有机溶剂中聚苯并咪唑（PBI）膜长期性能的重要性。PBI膜由两种不同的聚合物分子量制成：PBI聚合物的标准分子量，几乎普遍用于有机溶剂稳定膜的文献（1027，000 g mol-1），以及未经测试的两倍高分子量（1060，000 g mol-1）。交联后，所有PBI膜都是化学和机械稳定的。然而，在DMF中连续长期加压过滤期间，标准分子量PBI膜的渗透率随着时间的推移缓慢下降。这归因于交联聚合物链的重排。增加交联程度降低了膜渗透率下降的速率，但没有提供完全工艺稳定的膜。使用更高分子量的PBI和类似程度的交联，得到具有恒定渗透性和优异工艺稳定性的膜，即使在120 °C下连续DMF过滤期间也是如此。这是由于高分子量聚合物中链间相互作用和缠结增加，从而降低了链重排和压缩的速率。这项工作证明了聚合物分子量对于降低膜压实和提供有机溶剂中的工艺稳定性的重要性。
The importance of polymer molecular weight on the long-term performance of polybenzimidazole (PBI) membranes in organic solvents was investigated. PBI membranes were manufactured from two different polymer molecular weights: the standard molecular weight of PBI polymer, used almost universally across literature for organic solvent stable membranes (∼27,000 g mol-1), and an untested ∼ two-fold higher molecular weight (∼60,000 g mol-1). After crosslinking, all PBI membranes were chemically and mechanically stable. However, during continuous long-term pressurised filtration in DMF, the standard molecular weight PBI membranes suffered slow permeance decline over time. This was attributed to rearrangement of the crosslinked polymer chains. Increasing the extent of crosslinking reduced the rate of membrane permeance decline but did not provide a fully process stable membrane. Using a higher molecular weight PBI, and a similar extent of crosslinking, resulted in a membrane with constant permeance and excellent process stability, even during continuous DMF filtration at 120 °C. This was attributed to the increased interchain interactions and entanglement in the high molecular weight polymer, which reduced the rate of chain rearrangement and compaction. This work demonstrates the importance of polymer molecular weight for reducing membrane compaction and providing process stability in organic solvents.