Why Does The Strength Of Epoxy Resin Sleeve Decrease After Long-term Contact With The Pipeline Medium?

Chemical swelling disrupts the molecular cross-linking network. Small molecules in oils, solvents, or chemical reagents transported through pipelines can penetrate into epoxy bushing manufacturer and insert between polymer chain segments. This penetration causes the material to expand in volume, breaking down the original three-dimensional cross-linked structure and weakening intermolecular forces, macroscopically manifesting as a decrease in tensile and flexural strength.

Hydrolysis degrades the ester bond structure. Epoxy resin cured products contain hydrophilic groups such as ester and hydroxyl groups, which undergo hydrolysis and chain breakage in aqueous media. Increased temperature accelerates this process; the broken molecular chains can no longer bear loads, and the material gradually transforms from a dense state to a loose, porous structure.

Stress corrosion exacerbates microcrack propagation. epoxy bushing for transformer is subjected to a certain mechanical stress in the installed state, and corrosive ions in the medium preferentially corrode in the stress concentration area. The high stress field at the microcrack tip promotes chemical reactions, leading to stress corrosion cracking. Cracks propagate along grain boundaries or phase interfaces, ultimately resulting in brittle fracture.

Plasticizer precipitation alters material properties. Toughening agents, diluents, and other additives in epoxy resin formulations can be extracted and dissolved by the medium during long-term immersion. The loss of these components significantly reduces the material's toughness, drastically shortens its impact strength and fatigue life, and fails to meet the long-term service requirements of piping systems.