UV resistance is the ability of a coating or of a polymer to keep its appearance and its mechanical properties under prolonged ultraviolet exposure. The damage begins with the absorption of a photon by a chromophore, and the resulting radical initiates chain scission or crosslinking [1]. Accelerated weathering reproduces the trend but not the absolute rate, because the spectral power distribution of the lamp differs from that of sunlight [2]. Inorganic absorbers scatter or absorb the ultraviolet before it reaches the bulk, and a clear coating needs particles well below the wavelength of light [3]. Test standards differ in cycle length and in the inclusion of a condensation step, so results from different laboratories are not directly comparable [4]. Water taken up during a humidity cycle accelerates the loss more than the ultraviolet dose alone [5].
- photodegradation
- accelerated weathering
- ultraviolet absorber
- chain scission
- coating durability
- colour retention
- condensation cycle
References
- Decker, C.; Masson, F.; Schwalm, R.; Weathering resistance of waterbased UV-cured polyurethane-acrylate coatings. Polymer Degradation and Stability 2004, 83, 309-320, 10.1016/s0141-3910(03)00276-3.
- Awad, S.A.; Mahini, S.S.; Fellows, C.M.; Modification of the resistance of two epoxy resins to accelerated weathering using calcium sulfate as a photostabilizer. Journal of Macromolecular Science, Part A 2019, 56, 316-326, 10.1080/10601325.2019.1578179.
- Majidi, R.; Keramatinia, M.; Ramezanzadeh, B.; Ramezanzadeh, M.; Weathering resistance (UV-shielding) improvement of a polyurethane automotive clear-coating applying metal-organic framework (MOF) modified GO nano-flakes (GO-ZIF-7). Polymer Degradation and Stability 2023, 207, 110211, 10.1016/j.polymdegradstab.2022.110211.
- Sudoł, E.; Kozikowska, E.; Szewczak, E.; Artificial Weathering Resistance Test Methods for Building Performance Assessment of Profiles Made of Natural Fibre-Reinforced Polymer Composites. Materials 2021, 15, 296, 10.3390/ma15010296.
- Patti, A.; Acierno, D.; The Puncture and Water Resistance of Polyurethane- Impregnated Fabrics after UV Weathering. Polymers 2019, 12, 15, 10.3390/polym12010015.