Enhancement of insulating paper performances by DBD plasma modification with 3-aminopropyltriethoxysilane addition

In this paper, an atmospheric-pressure dielectric barrier discharge plasma is employed to modify the cellulose paper for simultaneous enhancement of electrical and mechanical performances. A cross-linked Si–O–Si network with –NH2 groups at the side branch is established with the addition of the precursor aminopropyltriethoxysilane (APTES). The influence of the precursor flow rate and treatment duration on the modification effect is systematically investigated, obtaining the optimal condition sand performances. It is indicated by the results that the tensile strength, flashover voltage, and breakdown strength of the paper are enhanced by 29.5%, 9.2%, and 6.0%, respectively, at a flow rate of 450 ml/min and treatment time of 6 min. Notably, for oil-impregnated paper, the surface and bulk insulation strength are improved by 10.8% and 25.3%, respectively. By characterization with scanning electron microscopy, an energy-dispersive spectrometer, and Fourier-transform infrared spectroscopy, it is demonstrated that low-polarity species (e.g., Si–O–Si and Si-CHx) produced by APTES fragmentation are deposited on the paper surface and further transported into internal pores, which not only suppress charge accumulation and partial discharge with introduction of deep traps but also reinforce structural rigidity with Si–O backbone crosslinking and hydrogen bonds.