Vinyl polymers containing amido and carboxyl groups as side substituents, 2. Thermodynamic and fourier‐transform infrared spectroscopic studies for the protonation of poly(N‐acryloylglycine) and poly(N‐acryloyl‐6‐aminocaproic acid)
Vinyl polymers containing amido and carboxyl groups as side substituents, 2. Thermodynamic and fourier‐transform infrared spectroscopic studies for the protonation of poly(N‐acryloylglycine) and poly(N‐acryloyl‐6‐aminocaproic acid)
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含有酰胺基和羧基作为侧取代基的乙烯基聚合物，2.聚（N-丙烯酰甘氨酸）和聚（N-丙烯酰-6-氨基己酸）质子化的热力学和傅里叶变换红外光谱研究
DOI：
10.1002/macp.1989.021901027
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发表时间：
1989
影响因子：
2.5
通讯作者：
A. Magnani
中科院分区：
文献类型：
--
作者：
R. Barbucci;M. Casolaro;A. Magnani
用热力学（电位法、量热法）和傅里叶变换红外（FT-IR）光谱法在水溶液中研究了合成的聚（n -丙烯酰甘氨酸）（聚[1-（羧甲基氨基甲酰基）乙烯]，1a）和聚（n -丙烯酰-6-氨基己酸）（聚{1-[5-（羧戊基）氨基甲酰基）乙烯}，1b)。根据Henderson-Hasselbalch方程计算，相对于羧酸基的质子化，碱度常数（log K）的值随着质子化程度(a)的增加而降低，而两种聚合物的焓变都是“真实的”。侧脂肪链长度的增加导致多电解质效应减弱，水分子释放导致质子化的熵变增大ΔS°。在低pH下，聚合物1b的FT-IR光谱在1 628 cm−1处有一个强波段，而聚合物1a的光谱中没有。在这个pH值下，1b更紧凑的大分子结构可能有利于几个单体单元的酰胺基之间的相互作用。
Synthetic poly(N-acryloylglycine) (poly[1-(carboxymethylcarbamoyl)ethylene], 1a) and poly-(N-acryloyl-6-aminocaproic acid) (poly{1-[5-(carboxypentyl)carbamoyl]ethylene}, 1b) were studied in aqueous solution by thermodynamic (potentiometry, calorimetry) and Fouriertransform infrared (FT-IR) spectroscopic methods. The values of the basicity constant (log K), calculated with the Henderson-Hasselbalch equation, relative to the protonation of the carboxylate group, decreases with increasing degree of protonation (a), while the enthalpy changes are “real” for both polymers. The increased length of the lateral aliphatic chain causes a decrease in the polyelectrolyte effect and a greater entropy change ΔS° of protonation due to liberation of water molecules. At low pH the FT-IR spectra reveal a strong band at 1 628 cm−1 for polymer 1b which does not occur in the spectra of polymer 1a. At this pH the more compact macromolecular structure of 1b may favour interactions among the amido groups of several monomeric units.