Al Lafi Abdul G, Rihawy Mohammed S, Allaf Abdul W, Alzier Ali, Hasan Reem
Division of Polymer Chemistry, Department of Chemistry, Atomic Energy Commission, P.O. Box: 6091, Damascus, Syrian Arab Republic.
IBA Laboratory, Department of Physics, Atomic Energy Commission, P.O. Box: 6091, Damascus, Syrian Arab Republic.
Heliyon. 2025 Jan 7;11(2):e41708. doi: 10.1016/j.heliyon.2025.e41708. eCollection 2025 Jan 30.
The degree of sulfonation (DS) is a key property of sulfonated polymers, as it significantly influences their swelling behaviour, conductivity and mechanical properties. Accurately determining the DS is essential for optimizing these materials for various applications. In this work, the DS of sulfonated poly (ether ether ketone) (SPEEK) was evaluated using a combination of analytical techniques, including titration, back titration, Fourier Transform Infrared (FTIR), Ultra-Violet (UV) and proton nuclear magnetic resonance (H NMR) spectroscopies, Thermogravimetric analysis (TGA), Rutherford backscattering (RBS) and particle induced X-ray emission (PIXE) analysis. Both non-cross-linked and cross-linked SPEEK were examined to assess the advantages and limitations of these methods. Classical approaches, such as titration and back titration are suitable for all sulfonated samples; however, they are limited by challenges like the extended time required for neutralization reaction due to hydrogen bonding between sulfonic acid groups. In contrast, molecular spectroscopic methods particularly UV and H NMR spectroscopy, are more efficient for soluble samples. H NMR spectroscopy is especially accurate, though it necessities additional steps, such as determining T relaxation times to ensure complete magnetization recovery. FTIR spectroscopy emerges as a versatile and effective method for DS determination across all samples types, particularly when enhanced with ATR accessories and calibrated with H NMR data. Combining with two-dimensional correlation spectroscopic analysis further improves its reliability.
磺化度（DS）是磺化聚合物的一个关键特性，因为它会显著影响其溶胀行为、导电性和机械性能。准确测定磺化度对于优化这些材料在各种应用中的性能至关重要。在这项工作中，使用了多种分析技术相结合的方法来评估磺化聚醚醚酮（SPEEK）的磺化度，这些技术包括滴定法、反滴定法、傅里叶变换红外光谱（FTIR）、紫外光谱（UV）、质子核磁共振（H NMR）光谱、热重分析（TGA）、卢瑟福背散射（RBS）和粒子诱导X射线发射（PIXE）分析。对未交联和交联的SPEEK都进行了研究，以评估这些方法的优缺点。经典方法，如滴定法和反滴定法适用于所有磺化样品；然而，它们受到一些挑战的限制，比如由于磺酸基团之间的氢键作用，中和反应所需时间较长。相比之下，分子光谱方法，特别是紫外光谱和H NMR光谱，对于可溶样品更为有效。H NMR光谱尤其准确，不过它需要额外的步骤，比如确定T弛豫时间以确保完全的磁化恢复。FTIR光谱是一种适用于所有样品类型的测定磺化度的通用且有效的方法，特别是当使用衰减全反射（ATR）附件增强并结合H NMR数据进行校准时。结合二维相关光谱分析可进一步提高其可靠性。
