Freibewitterung von Lichtplatten aus Kunststoffen. Eine Langzeitstudie während elf Jahren

Natural Weathered Transparent Double-Skin Sheets Made of Polymers

Abstract

Due to their numerous advantages such as low weight, high transparency and impact resistance, transparent multible-skin plastic sheets (e.g., PVC, PMMA, PC, GF-UP) are widely used in applications such as greenhouses, windows, roofs etc. Since degradation due to sunlight and humidity is a critical behaviour inherent to most polymeric materials, it is necessary to determine the influence of prolonged weathering. With this aim, nineteen different sheets were exposed over a period of eleven years at Dübendorf. Test methods as visual inspection, average light transmittance and resistance to hail impact turned out to characterise the influence of weathering on the sheets very well. On the base of the mentioned test methods, the four different materials could be classified in the following range. Because of moderate changing of mechanical behaviour and appearance, the GF-UP materials were most suitable for the application followed by PC sheets. PMMA materials do have an advantage because of their excellent optical properties, but the mechanical behaviour is unsuitable from the beginning. Sheets from PVC showed strong changes of their optical and mechanical behaviours after short-time period and aren't well applicable for long-term exposure.