不同体系下氢键对聚丙烯酰胺光谱的影响

The Effect of Hydrogen Bonding on the Spectrum of HPAM in Various Systems

采用红外,紫外光谱分析不同体系下氢键对部分水解高分子聚丙烯酰胺光谱的影响。研究表明,高分子聚丙烯酰胺中的酰胺基与部分水解的羧酸基能形成分子内氢键导致酰胺基中游离-NH2特征吸收峰向低频方向移动;聚丙烯酰胺在水溶液中随浓度的增大主要形成分子内氢键使最大吸收波长发生红移;在含中等浓度钠离子和钙离子的水溶液体系下,分子内氢键和分子间氢键同时存在,在含高浓度钠离子和钙离子体系下,则主要形成分子间氢键。不同体系下,氢键对聚丙烯酰胺光谱的影响不同:在水溶液体系下,其最大吸收波长红移8nm,在钠离子单独存在的体系下,最大吸收波长红移4nm,在钙离子和钠离子同时存在的体系下,最大吸收波长红移2nm。

IR and UV-Vis was employed to analyzed the spectrum effect of hydrogen bonding on the partially hydrolyzed polyacrylamide polymer（HPAM）.The study reveals that,the characteristic absorption peak of free amino group moves to the low frequency due to the formation of intramolecular hydrogen bonding between amide group and carboxyl group.In the water solution,intramolecular hydrogen bonding is the main factor that shifted maximal absorption towards long wavelength.Intramolecular hydrogen bonding and intermolecular hydrogen bonds exist at the same time in the water solution contains intermediate sodium and calcium ions.While in the high concentration solution,the main form between amide group and carboxyl group is intermolecular hydrogen bonding.The effect of hydrogen bonding on the spectrum of HPAM demonstrates different extent in various systems.In the water solution,the maximum absorption wavelength red shifts 8nm.In the system contains sodium ions,this shift is 4nm.And this shift is only 2nm in the solution contains both sodium ions and calcium ions.