ABSTRACT
The University of Leipzig research programme on the long-term durability of elastomeric building sealants comprises the following tests which are being carried out on a total of fourteen commercially available, room temperature curing sealants (based on polysulfide, polyurethane and silicone polymers) as well as on two heat vulcanised EPDM and polychloroprene rubber samples:
accelerated ageing with ultraviolet light (fluorescent lamps) and water condensation (irradiation carried out at 60°C, 70°C, 80°C and 90°C);
accelerated ageing with ultraviolet light (xenon arc lamp), heat at 80°C and water immersion;
dry thermal ageing at 60°C, 70°C, 80°C and 90°C with shortened exposure periods up to 140°C;
combination of artificial weathering with acid rain;
combination of artificial weathering with enforced cyclic movement (in extension and compression);
outdoor exposure (at Leipzig);
room storage (as reference).
Changes in material properties are characterised by mechanical test methods (tensile strength and elongation at break), thermoanalysis (DSC) and chemical spectroscopy (FT-IR, PAS).