Synthesis of cyclic polystyrene in supercritical carbon dioxide green solvent

Abstract

This study presents the synthesis of cyclic polystyrene (cPS) in the supercritical carbon dioxide (SC-CO2) media for the first time. For this purpose, first of all α-ω difunctionalized polystyrene was prepared in the SC-CO2 solvent within the pressure range from 100 to 230 bar and at a temperature below the conventional methods 80℃. The end-to-end reaction method was then used to make cPS in SC-CO2 solvent with CH2Cl2 as a co-solvent. The effects of several factors such as pressure, time, and initiator concentration on polymer yield, morphology, and molecular weight were studied. FTIR, 1H NMR, GPC, HPLC, DSC, TGA and SEM analyses were used to characterize the product and evaluate the effect of mentioned factors. The results indicated a prominent influence of SC-CO2 pressure on the product. Applying a green solvent, such as SC-CO2 allows us to produce a clean polymer with lower molecular weight and higher environmental compatibility.