AbstractsEngineering

Polyethylene terephthalate (PET) films can be advantageously utilised to replace both glass and metal in photovoltaic (PV) devices. However, there remain aspects of their performance in outdoor applications which may be improved upon to meet PV device requirements more efficiently. DuPont Teijin Films (DTF) employ artificial weathering techniques to investigate PET film degradation processes, such as UV degradation and hydrolysis, which occur during the outdoor application of PET films. In this Thesis, a thorough investigation into the modification of PET film properties with exposure to various artificial weathering techniques has been conducted. Techniques including infra-red spectroscopy, gel permeation chromatography, atomic force microscopy and nano-indentation have been employed to improve the understanding of the effects of artificial weathering on PET films. The effects of exposure to high intensity simulated solar radiation have also been investigated and compared with those of the combined degradation agents present during ISO standard accelerated environmental weathering. Surface modifications have been compared with those of the bulk, in particular, surface roughening and microcracking have been investigated in much greater detail than previously in the literature. Finally, the stabilizing effects of including an organic ultraviolet absorber on weathered PET film bulk and surface properties have also been assessed.