Assessment of photooxidation in multi-layer coating systems by time-of-flight secondary ion mass spectrometry

• Published in: Polymer degradation and stability Vol. 47; no. 3; pp. 405 - 411
• Main Authors: Gerlock, J.L., Prater, T.J., Kaberline, S.L., deVries, J.E.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 1995; Elsevier Science
• Subjects: Applied sciences; Exact sciences and technology; Forms of application and semi-finished materials; Polymer industry, paints, wood; Sheets and films; Technology of polymers; Acrylic acid copolymer; Coating material; Multilayer coating; Epoxy resin; Experimental study; Urethane copolymer; Analysis method; Time of flight method; Oxidative degradation; Weathering; Melamine resin; Model test; Mass spectrometry; Photochemical degradation
• ISSN: 0141-3910; 1873-2321
• DOI: 10.1016/0141-3910(95)00007-0

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) has been used to assess the formation of 18O-labeled photooxidation products in two multi-layer coating systems held in 20% 18O 2/80% nitrogen atmosphere during brief Xenon arc weatherometer exposure. A four-layer model coating system without hindered amine light stabilizer or ultraviolet light absorber additives was examined first. The model was exposed for 8 days in the weatherometer, and then its TOF-SIMS- 18O − response was recorded. This response tracks the known photooxidation resistance of the coating layers used to prepare the model system. Next, the technique was extended to a fully formulated six-layer ‘repair’ paint panel that had been weathered for 4 years in Florida prior to 10 additional days of weatherometer exposure in 20% 18O 2/80% nitrogen atmosphere. The TOF-SIMS- 18O − response observed clearly suggests that the TOF-SIMS- 18O − technique can be used to assess the relative photooxidation rates of individual coating layers in fully formulated, multi-layer coating systems.