Aging performance investigation and improvement of modified polyurethane composites for composite overhead transmission line towers

Colorless, Transparent, and High-Performance Polyurethane with Intrinsic Ultraviolet Resistance and Its Anti-UV Mechanism

“…There are three commonly used methods to improve the UV resistance of PU, including the addition of nonreactive anti-UV additives, − or anti-UV nanofillers, − and using bio-based antioxidant molecules as reaction raw materials. − According to the mechanism of action, nonreactive anti-UV additives can be divided into free radical scavengers that can capture active radicals generated during the UV aging of polymers, and UV absorbers that can absorb UV rays. , It has been reported that adding one type of anti-UV additive alone or combining two additives can improve the anti-UV properties of PU. − However, the nonreactive anti-UV additives in the PU composites are present in free form, which may migrate during long-term use, significantly affecting the stability and mechanical properties of the composites. Anti-UV nanofillers such as TiO 2 , ZnO, etc., can absorb UV energy by internal electron leap from the valence band to conduction band and convert it to other energy releases with less energy, thus playing the role of UV absorption and shielding. , However, the addition of functional fillers may damage the mechanical properties of the composites and strongly reduce the light transmittance in the visible range, resulting in opaque composites and thus limiting the application scope.…”