Livinalli Nathália Ferronato, Duarte Jocelei, Silvestre Wendel Paulo, Baldasso Camila
Postgraduate Program in Process Engineering and Technologies (PGEPROTEC), University of Caxias do Sul, Street Francisco Getúlio Vargas. 1130, Petrópolis, Caxias do Sul, RS 95070-560, Brazil.
ACS Omega. 2025 May 28;10(22):22909-22918. doi: 10.1021/acsomega.5c00467. eCollection 2025 Jun 10.
This study investigated the impact of time on the structure and performance of hybrid polysulfone (PSU) membranes containing graphene nanoplatelets (GNP), synthesized in 2022. FTIR, SEM, TGA, and BET were used to analyze structural and functional changes after two years of storage. The membranes exhibited distinct behaviors depending on GNP concentration and usage conditions. Pristine membranes showed larger average pore size (16-17 nm) and lower surface area (4.7-16.9 m·g), whereas compacted membranes exhibited smaller pores (3.6-5.4 nm) and higher surface area (up to 322.7 m·g). Compaction and storage drastically reduced hydraulic permeability, attributed to fouling, nanoparticle agglomeration, and oxidative degradation of the polymeric matrix. Furthermore, pristine membranes were tested after two years and ruptured during compaction and permeability tests, revealing mechanical fragility caused by aging. FTIR results suggested chemical degradation, with changes in absorption band intensities. SEM micrographs displayed stress marks, cracks, and biological contamination on used membranes, while pristine membranes showed less resilient morphology. TGA analyses revealed a reduction in maximum degradation temperature, indicating thermal stability loss. BET results highlighted the impact of usage and time on pore redistribution and surface area. This research emphasizes the need to optimize storage conditions and explore strategies to improve membranes' thermal and mechanical stability. Future studies should investigate chemical modifications to the polymeric matrix and evaluate new additives to mitigate degradation during long-term storage.
本研究调查了时间对2022年合成的含石墨烯纳米片（GNP）的混合聚砜（PSU）膜的结构和性能的影响。使用傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）、热重分析（TGA）和比表面积分析（BET）来分析储存两年后的结构和功能变化。这些膜根据GNP浓度和使用条件表现出不同的行为。原始膜显示出较大的平均孔径（16 - 17纳米）和较低的表面积（4.7 - 16.9平方米/克），而压实后的膜具有较小的孔径（3.6 - 5.4纳米）和较高的表面积（高达322.7平方米/克）。压实和储存极大地降低了水渗透性，这归因于污染、纳米颗粒团聚以及聚合物基体的氧化降解。此外，原始膜在两年后进行测试时，在压实和渗透性测试过程中破裂，揭示了老化导致的机械脆性。FTIR结果表明存在化学降解，吸收带强度发生了变化。SEM显微照片显示使用过的膜上有应力痕迹、裂缝和生物污染，而原始膜的形态弹性较小。TGA分析显示最大降解温度降低，表明热稳定性丧失。BET结果突出了使用和时间对孔重新分布和表面积的影响。本研究强调需要优化储存条件，并探索提高膜的热稳定性和机械稳定性的策略。未来的研究应调查对聚合物基体的化学改性，并评估新的添加剂以减轻长期储存期间的降解。
