关键词: 自由基聚合, 聚丙烯酸, 绿色化学, 实验时长, 智能手机识别-比色分析法

Abstract: The experimental preparation of polyacrylic acid by free radical polymerization is an important and classic teaching content in the course of Polymer Chemistry Experiments. The monomer is easy to obtain and the reaction conditions are mild. As a representative experiment to master the free radical polymerization reaction and the preparation of porous adsorption materials, it is offered in many colleges and universities. However, in the preparation experiments of polyacrylic acid in existing textbooks, the reaction system is easy to gelate and produces more waste liquid. The process took 30.5 to 33 hours and could not be completed within one teaching session. The characterization process is complicated. Therefore, natural and cheap sodium alginate was used as thickener in this improved experiment to stabilize the viscosity of the reaction system and prevent the gelation of the reaction system caused by the sharp increase of local viscosity. Using the same natural and cheap porous diatomite as filler, the porous resin was prepared by co-precipitation with the polyacrylic acid solution prepared by free radical polymerization reaction, which greatly reduced the use and consumption of organic solvents. In addition, this improved experiment follows the academic frontier, and introduces the smartphone identification-colorimetric analysis to characterize the adsorption performance of the product, which is fast and convenient. The new method of hole formation and representation reduced the duration of the experiment to 5 hours, ensuring the continuity of teaching, while retaining the characteristics of the original experiment, making the experiment more meaningful and conducive to stimulate students’ interest in learning this experimental course.

Key words: Free radical polymerization, Polyacrylic acid, Green chemistry, Duration of experiment, martphone identification-colorimetric analysis