Facile Synthesis of Cyclic Polyamidine with High Cationic Degree Using Environmentally Benign Approach

An environmentally benign approach was developed to fabricate cyclic polyamidine via polymerization in supercritical carbon dioxide (SCCO(2)) and subsequently amidinization in water. Synthetic parameters were evaluated using response surface methodology. In comparison with aqueous solution polymerization for the fabrication of PNVF-co-PAN, polymerization using SCCO(2) is favorable to promote the yield and viscosity of PNVF-co-PAN and diminished reaction time on account of excellent solvation capacity and transport property of SCCO(2). Replacing the traditional water solution with SCCO(2) as a green solvent could heighten the purity of PNVF-co-PAN by virtue of the excellent extraction of SCCO(2). The cationic degree (5.66 mmol/g) of polyamidine fabricated by environmentally benign approach was significantly higher than that in previous reported studies.