Structure characterization and properties of polyamine chelating fiber

Polyamine chelating fiber was synthesized by chemical modification, with the raw material of polyacrylonitrile fiber. The chemical structure and active function groups were characterized by IR. From IR spectrogram, it was found that the nitrile group was almost completely disappeared and the new -N-C=N characteristic absorption band was appeared at 1644 cm^-1. These results proved that polyamine chelating fiber was successfully synthesized, and the fiber has structural characteristics of N, N coordinative functional group-amidino and polyamine group, it can also be confirmed by the changes of bending vibration bands of -NH₂ group and -NH group respectively near 1600 cm^-1 and 1580 cm^-1. Thermal stability was characterized by differential scanning calorimetry (DSC) and the change of thermal stability was analyzed. After amination reaction, the structure of the fiber was changed and heat stability of the fiber was relatively decreased. The micro configuration of fibers was characterized by SEM, the relationship between the micro configuration and adsorbability was explained. Mechanical capability of fibers was studied by mechanical strength and diameter measurements, and the influencing factors for preparing high intensity fiber was analyzed. Based on titration curve and exchange content, the chemical stability and quality of self-made chelating fiber were analyzed. The results indicate that the self-made polyamine chelating fiber exhibits finer mechanical capability and chemical stability, having furrow and cellular structure in its surface and cross section. The average exchange capacity is 10 mmol·g^-1 and the fiber can be well used in the pH range of 2. 0 -8.0.