Aspects of the thermal, photodegradation and photostabilisation of water-borne fluorinated-acrylic coating systems

• Published in: Polymer degradation and stability Vol. 58; no. 1; pp. 149 - 157
• Main Authors: Allen, N.S., Regan, C.J., Dunk, W.A.E., McIntyre, R., Johnson, B.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 1997; Elsevier Science
• Subjects: Applied sciences; Exact sciences and technology; Physical properties; Polymer industry, paints, wood; Properties and testing; Radiation influence; Technology of polymers; Differential scanning calorimetry; Scanning electron microscopy; Fluorine containing copolymer; Coating material; Methyl methacrylate copolymer; Butyl acrylate copolymer; Thermal stability; Infrared spectrometry; Near ultraviolet radiation; Oxidative degradation; Photochemical stability; Photochemical degradation; Thermal degradation
• ISSN: 0141-3910; 1873-2321
• DOI: 10.1016/S0141-3910(97)00039-6

Emulsions based on a polymerised 50:50 formulation of methyl methacrylate (MMA) and butyl acrylate/fluorinated acrylates have been prepared with and without reactive acrylated hindered piperidine and benzotriazole stabilisers. The rates of oxidation during irradiation are monitored by both hydroperoxide formation and functional group changes by using reflectance Fourier transform infra-red spectroscopy. De-esterification and hydroperoxide formation are found to be important processes during latex photooxidation and highly dependent upon the comonomer ratio, while the addition of low levels of comonomer, methacrylic acid, to the emulsion gives latices with improved photostability. The effects of co-reactive acrylated hindered piperidine and benzotriazole stabilisers were found to be concentration-dependent, with the latter exhibiting the greater effect. Scanning electron microscopy of unstabilised films showed rough and crazed surfaces before and after irradiation, respectively, while the co-reacted stabilised films retained a smooth surface before and after extensive periods of light exposure. Differential scanning calorimetry showed that the fluorinated copolymers were much less stable, exhibiting two main endotherms due to the destabilising effect of the fluorine component. Addition of the co-stabilisers, however, increased the thermal stability of the MMA latex.