Carboxymethyl cellulose-based supramolecular hydrogel with thermo-responsive gel-sol transition for temporary plugging of oil pipeline in hot work

Temporary plugging of the pipeline is necessary for safety in the hot work process of a flame-cutting pipeline. Chemical hydrogel plugging materials may block valves or sensors in the pipeline due to incomplete breakage. Herein, we prepared a carboxymethyl cellulose-based supramolecular hydrogel with thermo-responsive gel-sol transition, crosslinked by hydrogen bonding and π-π stacking between melamine (MEL) and 6-aminouracil modified carboxymethyl cellulose (AUCMC). The supramolecular hydrogel exhibits tunable mechanical properties and good self-recovery. Furthermore, the result of rheo-kinetics suggests a rapid gel-sol transition of the hydrogel with thermal stimulus due to the hydrogen bonding. The pressure resistance test indicates that the hydrogel has a good plugging effect in the simulated pipeline, and the great flame retardancy of the hydrogel can ensure the safety of operation. The residual hydrogel was completely broken and the simulated pipeline with the plugging length of 10 cm was dredged within 21 min by flushing hot water above 70 °C. The supramolecular hydrogel, as the plugging materials for hot work of oil pipeline, exhibits obvious advantages such as ensuring the safety of hot work, simplifying the operation process, and avoiding secondary damage to the pipeline, which further widens the application field of CMC.