Hydrophobically modified hyperbranched polymer and its demulsification performance in W/O emulsion

The separation of water-in-oil (W/O) emulsion causes a major problem in the process of crude oil extraction. To address this challenge, amphipathic hyperbranched polymer demulsifiers were developed, incorporating dendritic polyamide-amine as the hydrophilic core and alkyl glycidyl ether as hydrophobic branch. This structure allows for switching the amphiphilicity of demulsifiers by regulating the length of hydrophobic branch, thereby achieving the demulsification of W/O emulsion. Specifically, the demulsification experiments showed that at a concentration of 500 mg/L, TEM 8 demulsifier achieved a demulsification efficiency (DE) of 100 % within 150 min at 45 ℃. Moreover, it also had superior DE across a wide pH value from 4 to 12. Interfacial characteristic experiments −including three-phase contact angle (TCA), surface tension (SFT), dynamic interfacial tension (IFT) and viscoelasticity modulus (VM)- were performed to elucidate the demulsification mechanism. In summary, TEM 8 effectively reduces interfacial tension and substitutes the natural surfactants at oil–water interface. This causes the rupture of interfacial film and coalescence of droplets, which facilitates demulsification. These findings highlight the potential of the hyperbranched polymer demulsifier for the effective separation of W/O emulsions at low temperature, suggesting its promising applications in advanced water–oil separation.