Nanomodified Polymer Composite Bandage Systems for Repair of Oil and Gas Pipeline Systems

The reliability of pipelines in the gas and oil transportation complex is largely determined by corrosion damage and mechanical defects on the external and internal surfaces. The purpose of this study is to develop nanomodified epoxy composite bandage systems with improved thermophysical characteristics for pipeline repair. The studies show that controlled introduction of micro- and nanodispersed fillers into the polymer matrix significantly increases the thermal stability of epoxy composites. In particular, the temperature of the onset of mass loss increases by 47-55 K compared to the unmodified epoxy matrix. It was established that the rational ratio of components (10 wt. % of trimethoprim and 0.050 wt. % of fullerene-carbon black mixture) in the epoxy matrix ensures the formation of a polymer with the maximum value of the activation energy of thermal destruction (Eₐ = 175 kJ/mol). The improvement of the thermophysical characteristics of the polymer is due to the formation of a hybrid structure, which is realized through the combined action of three mechanisms: the barrier effect of nanofillers, which form a compacted structure and limit the diffusion of oxygen; chemical crosslinking due to the interaction of trimethoprim amino groups with epoxy functional groups; physical interfacial interaction, in particular –-interaction with the graphite-like surface of nanoparticles, which leads to a decrease in the segmental mobility of macromolecules and an increase in the energy barriers of the course of thermal destruction processes. The scientific novelty of the work lies in establishing a combined chemical-physical mechanism for stabilizing epoxy composites modified with a bidisperse system of functional fillers, which provides coordinated control over diffusion processes, the polymer network's crosslinking density, and the kinetics of thermal degradation at elevated temperatures. The developed materials exhibit reduced mass loss and increased resistance to thermal-oxidative degradation, confirming their feasibility as highly effective matrices for polymer bandage systems used to repair oil and gas pipelines operating under elevated temperature loads.