Gelatin-reinforced hydrogel crosslinked by hydrogen bonds as a thermo-reversible temporary plugging material for hot work of oil pipelines

Abstract

Hot work can make oil pipeline maintenance more efficient but is dangerous. Traditional chemical hydrogels can plug oil pipelines to ensure the safety of hot work, but they cannot be completely removed afterward. Herein, we prepared a gelatin-reinforced hydrogel with thermal reversibility, which can be easily removed by injecting hot water. The hydrogel was prepared by the hydrogen bonds of the copolymer of N-acryloyl glycinamide (NAGA) and acrylamide (AM) as well as the interaction of the gelatin interpenetrating network. It was found that the hydrogen bonding interaction between the NAGA motif is the main driving force for the formation of hydrogels. The strength of the hydrogel is increased by 10 times after adding gelatin equivalent to the polymer. The thixotropic recovery properties test indicated that the hydrogel posed tunable mechanical and self-recovery properties, which contributed to the excellent plugging ability and injectability of hydrogels. Besides, the hydrogels exhibit favorable thermo-reversible gel-sol transition behavior, driven by the reversible disruption of hydrogen bonding interactions in response to temperature changes. Hydrogel showed good flame retardancy with values of heat release rate (HRR) below 5 kW/m² during the test time of 200 s, which is beneficial to the safety in the construction of hot work. Our findings confirmed that the hydrogel demonstrated an effective plugging effect in the simulated pipeline, and the residual hydrogel could be easily removed by injecting hot water. Hydrogels with thermo-reversibility can meet the plugging requirements for oil pipelines during hot work, simplifying the operation process and enhancing work efficiency.

Graphical abstract