Sulfonated Aromatic Polypentenamers: Scope of the Acetyl Sulfate Reaction,Macromolecules

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Sulfonated Aromatic Polypentenamers: Scope of the Acetyl Sulfate Reaction
Macromolecules ( IF 5.1 ) Pub Date : 2024-08-24 , DOI: 10.1021/acs.macromol.4c01145
Courtney M. Leo ₁ , Skylar N. Alonzo ₁ , Emily Grumbles ₁ , Justin G. Kennemur ₁

Affiliation

A precision polymer featuring one phenyl pendant at every fifth carbon on a polyethylene backbone was modified to varying degrees of sulfonation (DS = 33–98%) using acetyl sulfate with standard conditions by varying reaction times (up to 48 h). This soft, homogeneous method allows for evenly distributed phenylsulfonic acid groups with minimal side reactions and results in light brown, transparent materials with glass transition temperatures of 33–78 °C that increase with DS and parent polymer molar mass. The DS was accurately determined through well-resolved ¹H NMR (DS_HNMR) signals of the regularly spaced phenyl groups and corroborated by inverse-gated decoupling ¹³C NMR analysis. These analyses were compared to a series of other commonly accepted methods for DS determination including titration and elemental analysis (EA). The DS by titration (DS_titr) also increased with reaction time but was consistently lower than those determined by NMR. Significant discrepancies between theoretical and measured sulfur mass were observed for several samples through EA. Qualitative methods, such as infrared spectroscopy and thermal analyses, were also performed and correlated well with the DS determined by NMR. This study presents a promising method to achieve a complete scope of homogeneous sulfonation from mild reaction conditions and presents a case to determine DS through multiple methods, with spectroscopic analyses, such as NMR, being potentially the most valuable.

中文翻译：

磺化芳香族聚戊烯体：乙酰硫酸酯反应的范围

在标准条件下，通过不同的反应时间（最多 48 小时），使用乙酰硫酸盐将聚乙烯主链上每五个碳原子上有一个苯基侧基的精密聚合物改性为不同程度的磺化（DS = 33–98%）。这种柔软、均质的方法可以使苯磺酸基团均匀分布，副反应最少，并产生玻璃化转变温度为 33-78 °C 的浅棕色透明材料，玻璃化转变温度随着 DS 和母体聚合物摩尔质量的增加而增加。通过规则间隔的苯基的良好分辨的¹ H NMR (DS _HNMR ) 信号准确测定 DS，并通过反向门控去偶¹³ C NMR 分析得到证实。这些分析与一系列其他普遍接受的 DS 测定方法（包括滴定和元素分析 (EA)）进行了比较。滴定的 DS (DS _titr ) 也随着反应时间而增加，但始终低于 NMR 测定的值。通过 EA 观察到多个样品的理论硫质量与实测硫质量之间存在显着差异。还进行了红外光谱和热分析等定性方法，并与 NMR 测定的 DS 很好地相关。这项研究提出了一种有前景的方法，可以在温和的反应条件下实现全面的均相磺化，并提供了通过多种方法确定 DS 的案例，其中光谱分析（例如 NMR）可能是最有价值的。

更新日期：2024-08-24

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