Effects of artificial and natural ageing on impact-modified poly(vinyl chloride) (PVC)

In order to establish a correlation between results of natural and artifici al tests, a weathering programme for periods up to 12 years of natural agei ng in Boras, Sweden was carried out using several impact-modified commercia l poly(vinyl chloride) (PVC) materials. The artificial tests were performed in a Weather-O-Meter(R) instrument equipped with a xenon are as the light source, Some tests were performed ill accordance with ISO 4892 Part 2 and s ome tests using specially designed weathering cycles. The effects of ageing were monitored using measurements of impact strength and colour change. No significant correlation was found between results of the artificial and na tural ageing. The effect of temperature on the rate of degradation was eval uated in weathering cycles at different temperatures. The results were used to calculate activation energy, and gave a value of 11.2 kJ/mol for a Ca/Z n-stabilised material and 29.1 kJ/mol for other materials containing a mixt ure of Ba/Cd and Pb stabilisers or purl Pb stabiliser. (C) 2001 Elsevier Sc ience Ltd. All rights reserved.