Michael Grosshauser, Fraunhofer LBF
Michael Grosshauser, Fraunhofer LBF, summarised tests of ageing of cable compounds (polyethylene, EVA) with nano-clays. Nano-clays cause premature degradation of these polymers with weathering, because of carbonyl formation, accentuated when used with ATH (aluminium tri hydroxide), which neutralises the antioxidant by adsorption. Degradation is particularly marked with organo-clays, because these absorb ultraviolet light energy, leading to destabilisation. Clays with lower surface area show lower degradation effect for similar fire performance. These problems can be addressed by adding HALS stabiliser to the compounds.