Modification of Bitumen Properties Using Polyethylene Glycol: Towards Improved Outer Wrap Tapes for Gas Pipeline Coating in Cold Regions

Coating gas pipelines is a crucial practice in the gas industry to enhance pipeline integrity, longevity, and safety. Recently, the outer wrap tape of bitumen impregnated glass fiber have been developed as the part of protective layers for the underground pipelines. Outer tapes prepared of pre-modified 10/20-grade bitumen by styrene–ethylene/butylene–styrene (SEBS), styrene–butadiene–styrene (SBS), and talk powder suffer from some problems such as brittleness at low temperatures, inadequate adhesion between the two glass fiber layers, and high weight. Therefore, the aim of this study was to survey the physical, rheological, and adhesion characteristics of pre-modified bitumen after addition of polyethylene glycol (PEG) 2000 and then to investigate the quality of the tape produced with this bitumen. Improvement of flexibility and decrease of susceptibility to deformation at low temperatures of PEG-modified samples were confirmed by penetration, softening point, and penetration index (PI) tests. The storage stability investigation showed that at higher PEG concentrations phase separation may happen. Dynamic shear rheological (DSR) test indicated that PEG-modified samples have lower complex modulus and complex viscosity. Tapes produced with PEG-modified bitumen displayed less brittleness and enhanced adhesion than those produced with unmodified bitumen. Generally, this study highlights the potential of PEG as a promising additive to prepare bitumen with desired properties. These findings contribute to the development of gas pipe coating technology in cold regions, specifically the production of outer wrap tapes.

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