Synthesis, performance and mechanism of a hyperbranched polymer with diethyl diphenyl-p-phenylenediamine as centronucleus

A hyperbranched polymer (PDPD) was synthesized using diethyl diphenyl-p-phenylenediamine as centronucleus. Its chemical structure was characterized by 1H NMR and FT-IR, and thermal stability was evaluated by thermogravimetric analysis. The effect of concentration, temperature, settling time and salinity on the demulsification performance was systematically studied in oily wastewater. The transmittance of separated water (TSW) and oil removal ratio (ORR) could reach 85.7% and 99.6%, respectively, after demulsifying with 80 mg/L of PDPD for 4 h at 25 °C. Moreover, PDPD also had high salt tolerance. In addition, the dynamic interfacial tension (IFT), zeta potential and microscopic observation were utilized to explore a possible demulsification mechanism. This work not only provides a new hyperbranched demulsifier for the demulsification of oily wastewater, but also brings some references for the study of demulsification mechanism.