XPS study of the changes during the service life of polyester powder coatings

Abstract

Polyester powder coatings have been used for many years on architectural products, such as aluminium window trim. This study investigates the degradation mechanism of naturally weathered coatings that have been exposed to aggressive climatic conditions, including high ultraviolet radiation and coastal atmospheres containing salt. These conditions provide a harsh test regime over a period of 10 years. X-ray photoelectron spectroscopy (XPS) was useful for detecting the initial stages of coating degradation. The technique allows for the testing of new polymer coating materials under real conditions in much shorter time spans. The XPS study is supported by photoacoustic Fourier transform infrared spectroscopy and electrochemical impedance spectroscopy.

X‐Ray photoelectron spectroscopic investigations of powder coated steel

“…This means that the amount of contamination is reduced applying the alkaline cleaner and plasma treatment. The reduction of the sp 3 component after plasma-treatment is in accordance with findings of Haverkamp et al [3] for samples after weathering. The silicoater process preserves the composition from the alkaline cleaning underneath a SiO x layer.…”

“…2), the C 1s signal, therefore, consists of three components (sp 3 carbon plus contamination (285.0 eV), from C-O-(286.1 eV), and C --O groups (288.6 eV), respectively). The O 1s peak can be fitted by two components (from C --O and OH À groups (532.0 eV) and also C-O-C units (533.8 eV), respectively), as also found by Haverkamp et al [3] on a similar system (polyester powder coating on aluminum). Especially from the relative intensities of the oxygen components follow statements whether the sample surfaces are hydrophilic (the low-energy component prevails; besides C --O groups, mainly OH À groups contribute to the signal) or hydrophobic (about equal intensities of the contributions from both C --O and C-O-C groups, respectively).…”

“…Only in this case a N 1s peak appears, which can be fitted by two components at 400.3 and 401.9 eV. The low-energy peak may appear due to an imide type of structure [3] which is now within the photoelectron sampling depth, and the high-energy one due to the plasma treatment.…”

An investigation of the effect of pigment on the degradation of a naturally weathered polyester coating

“…Color and gloss measurements have long been used as industrial quality control methods. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) are widely used to analyze surface morphologies, 10,11 while X-ray photo-electron spectroscopy (XPS) 12,13 and time-of-flight secondary iron mass spectrometry (ToF-SIMS) 14 have been used to investigate the surface chemistry of coatings, before and after exposure to the environment. Photo-acoustic (PA) Fourier transform infrared spectroscopy (FTIR) with step-scan capacity, 15,16 on the other hand, provides excellent bulk chemistry analysis with a sampling depth ranging from 6 to 20 lm.…”

Intercoat adhesion failure in a multilayer organic coating system: An X-ray photoelectron spectroscopy study

“…The use of polymer based coatings on substrates as diverse as wood [1], concrete [2,3], glass [4], oxides [5] and metals [6] has been the centre of much research interest. In particular, polymeric coatings on metal substrates have wide ranging applications including architectural (coil coating) [7], aerospace [8], automotive [9], marine [10,11], medical implant [12] and microelectronics [13] industries.…”