Experimental Characterization of Polymer Surfaces Subject to Corona Discharges in Controlled Atmospheres

Abstract

Polymeric dielectrics are employed extensively in the power transmission industry, thanks to their excellent properties; however, under normal operating conditions these materials tend to degrade and fail. In this study, samples of low-density polyethylene, polypropylene, polymethyl methacrylate, and polytetrafluorethylene were subjected to corona discharges under nitrogen and air atmospheres. The discharges introduced structural modifications over the polymer surface. From a chemical perspective, the alterations are analogous among the non-fluorinated polymers (i.e., polyethylene (PE), polypropylene (PP), and polymethyl methacrylate (PMMA)). A simulation of the corona discharge allowed the identification of highly reactive species in the proximity of the surface. The results are consistent with the degradation of insulating polymers in high-voltage applications due to internal partial discharges that ultimately lead to the breakdown of the material.

Damage Mechanisms in Medium-Voltage Insulating Polymers under Hemispherical-Plane Electrodes

“…The increase is larger for the films submitted to electrical stress. Similar results have been reported in PE and XLPE submitted to corona discharges in air [8][9][10] and artificial weathering [17]. This result is thus the signature of discharged-induced ageing at the polymer surface.…”

“…Gamez-Garcia et al have studied chemical reactions at XLPE surfaces subjected to discharges in controlled atmospheres [8] and also studied the impact of temperature up to 160°C [9]. More recently, Leon-Garzon et al have studied the effects of corona discharges over polymeric slabs and characterized the modifications of the surfaces [10]. These studies show that chemical reactions occurring in solid dielectrics submitted to PDs produce gaseous, liquid and solid by-products, which concentration and nature depend on the ageing conditions.…”

Electronic structure of defected polyethylene for Schottky emission

“…2. Now we pass to consider several types of oxidized systems shown in Tables 3 and 4 The hypothesis on the existence of surface oxidized centres has been suggested by previous experimental measurements, which indicated a noticeable degree of oxidation in untreated industrial PE samples [62][63][64]. The presence of the carbonyl group, like in system nr.…”

“…The chemical defects in system nr. 10 are designed to reproduce the oxidation degree observed in XPS data [64], which denoted a surface elemental composition ratio O/C = 0.08. Therefore, 3 oxygen atoms (in the form of three detached oxidative groups, see Table 3) have been added to the unit cell containing 40 carbon atoms (41 considering the C in the aldehyde group).…”

Functionalization of Polymers and Nanomaterials for Biomedical Applications: Antimicrobial Platforms and Drug Carriers

“…Another major site of modification is the surfaces of the polymers. Dry surface treatment techniques e.g., corona discharges [3], oxygen plasma [4], ultraviolet light-ozone [5], and cold atmospheric jet [6] have been applied for improving polymer/polymer or polymer/ceramic adhesions. To make corrections in the polymer surfaces, wettability properties of polymers can be altered to govern the adhesion of various coatings.…”