Elimination and Substitution Compete During Amination of Poly(vinyl chloride) with Ehtylenediamine: XPS Analysis and Approach of Active Site Index

Various chemical modification methods have been tried on PVC polymer materials for recycling and functionalization purpose. These methods employ substitution, elimination (dehydrochlorination) and grafting polymerization processes. PVC is treated with ethylenediamine (EDA) for amine grafting since it is a reactive amine for substitution and efficient removal of chlorides. Nevertheless, optimum conditions for substitution (amination) and significance of its competition with elimination have not been reported in detail so far. In this study, PVC resin has been treated with 99% EDA and 80% EDA (aqueous), and also 9.1% THF solution of PVC has been treated with 99% EDA at varying temperatures (RT to 85 °C or RT to 65 °C). Additionally, PVC membranes have been treated with 99% EDA and 80% EDA (aqueous) at three different temperatures (RT, 50 °C, 75 °C). Effects of temperature and solvent on the degrees of amination and dehydrochlorination have been elaborated. Up to 99% dechlorination and 34% amination is possible with the use of EDA. Direct amination of membranes facilitates production of ready-cast aminated PVC membranes. FTIR Spectroscopy was used to study chemical structures. Morphology was observed via scanning electron microscopy (SEM) and atomic contents were analyzed via X-ray photoelectron spectroscopy (XPS) in order to survey the degree of amination etc. UV-Visible Spectroscopy was used to characterize the length of conjugation.