PVP/HEC分子间缔合作用机理探讨

通过粘度、紫外光谱、红外光谱和DSC谱的测定 ,探讨了PVP/HEC分子间的缔合机理 .结果表明 ,PVP/HEC复合体系相对于单一体系产生了粘度的负协同效应 ,NaCl的加入使单一体系和复合体系的粘度均下降 ;在紫外可见吸收光谱中 ,PVP/HEC复合体系的最大吸收波长λmax相对于PVP、HEC各自的λmax都发生红移 ;PVP/HEC复合物的红外光谱在 2 370cm-1出现新的吸收峰 ;DSC谱中复合物的峰温高于简单混合物 ,而其焓变低于简单混合物 ,这一切均证明HEC与PVP之间未发生疏水缔合 ,而是HEC的羟基与PVP的羰基之间通过氢键缔合成复合物 ,复合物的分子链排列较为紧密 .

Study on Mechanism of Association between Hydroxy Ethyl Cellulose and Polyvinylpyrrolidone

The mechanism of association between hydroxy ethyl cellulose (HEC) and polyvinylpyrrolidone (PVP) has been studied by viscosity, UV, FTIR and DSC methods. The results indicated that the viscosity of PVP/HEC mixed systems displayed negative synergic effect, but the viscosity of HEC resistant to NaCl was enhanced in the presence of PVP. The reduced viscosity of the HEC solution was decreased when NaCl was being added and it became smaller with the concentration of NaCl increasing. The maximum absorb spectrum of the PVP/HEC mixed system had a red shift compared with their single systems. There appeared a new peak at 2370 cm -1 in the FTIR spectrum for the complex system. Both UV and FTIR spectra showed that PVP/HEC complex was formed through the hydrogen bond. The investigation of DSC showed that the macromolecule chains were tightened due to the formation of the complexes.