Variations in some of the properties of PVC sheets during natural and artificial ageing

Abstract

We have investigated variations in mechanical properties such as tensile strength and specific elongation as well as the variations in electrical properties such as the dielectric loss angle, permitivity and surface resistivity of PVC sheets of various thicknesses exposed during 2 4 months in weathering and up to 400 h in a Xenotest-1200. Using the test data, an evaluation of the influence of the scale coefficfent durtnq ageing was achieved. The test data showed that lower variations in the investigated properties were seen in the case of the thicker sheets. After various ageing periods a correlation between the surface roughness, mechanical and electrical properties could be seen. More important variations could be seen during the ageing period ranging from 50 h to 6 months. Speculations were made about the reasons causing the variations observed in the properties of PVC sheets during ageing.

Testing Methods of Weathered Specimen

“…Elongation changes 40,86,128,129,136,423,425,[428][429][430]436,441,[453][454][455][456][457][458] (Table 13.4) are much less precise than tensile strength measurements (see Table 13.3). Elongation changes 40,86,128,129,136,423,425,[428][429][430]436,441,[453][454][455][456][457][458] (Table 13.4) are much less precise than tensile strength measurements (see Table 13.3).…”

“…Flexural strength retention 400,424,425,429,[459][460][461][462][463] is important for many products, especially structural composites used in demanding applications. Flexural strength retention follows the pattern of tensile strength retention (Figure 13.54).…”