Three-Stage Polymerization Model For Free Radical Polymerization And Experimental Studies On The Polymerization Of Potassium Acrylate

Free radical polymerization plays a key role in modern polymerization reaction engineering. In free radical polymerization, gel effect and glass effect are two common phenomena , which are especially pronounced in bulk systems. Classical free radical polymerization theory, however, can not account for such complex phenomena, and the kinetic models thus far proposed have suffered from some adjustable parameters and/or parameters that can not be evaluated experimentally, and the predictions of these models against experimental results are not satisfying. In this dissertation, a simple and useful model, Three-Stage Polymerization Model(TSPM), proposed on the basis of recent experimental evidences and our elemental data processing of literature kinetic experiment results, is presented to account for the polymerization kinetics of such phenomena and the model covers the entire conversion range. In TSPM, the calculation of conversion and number-average polymerization degree can be simply achieved. In order to investigate its applicability, TSPM is applied to several polymerization systems and model predictions are compared with numerous literature kinetic experiment data. Finally, polypotassium acrylates, a very important kind of super absorbent polymer, are synthesized and the effects of different reaction conditions, such as initiator amount, reaction temperature, cross linking agent amount and types, on the absorbency capacity of the polymers are investigated. The reactivity ratio of acrylic acid with potassium acrylate is obtained by analysis of copolymer composition with the use of FT-IR technique. Also, the polymerization behavior of this system is investigated by DSC technique and the applicability of TSPM is tested against the experiment results. Seven chapters are consisted in this dissertation.Chapter 1 is the preface, which briefly describes the application and development of polymer industry and the characteristics of four most important polymerization methods.Chapter 2, which consists five parts, regards to the reference review in related areas of this dissertation and the proposition of TSPM. First, the kinetic models for free radical polymerization are reviewed. Then, the new advances and discoveries of modern experimental technique are summarized, on the basis of which TSPM is proposed. The key points of TSPM is...