Sustainable insulation for sustainable DHC

The piping network is the essence of DHC. Its insulation is fundamental for its correct and efficient functioning. State of the art DHC networks are insulated with polyurethane (PU) foam, which presents outstanding mechanical and insulating properties. However, the high toxicity of the diisocyanates (European Chemical Agency, 2008) required for its production and the recently approved European Restriction on their Use (European Commission, 2020) highlight the need for sustainable alternatives.Polyethylene terephthalate (PET) foam has been previously identified as a promising candidate for DHC given its mechanical properties (Ramnäs, 2008) and high insulation capacity retention, due to slow gas diffusion (Mangs, 2005) . However, its behavior upon ageing remains unexplored. Without this knowledge, the material cannot be reliably introduced in the market. The objective of this work is to experimentally investigate PET foam’s ageing behavior, with a focus on the effects of thermal cycling, thermally induced crystallinity and hygrothermal degradation on its mechanical properties.Different ageing trials were conducted in an environmental chamber. The effects on the mechanical properties and crystalline structure were evaluated. No degradation was found in the scenarios covered by this study. Service temperature over 100 °C is found possible thanks to thermally induced crystallization