A new material with low density and low thermal conductivity using post-consumer Tetra Pak packages

Abstract

This paper shows the process for making a solid foam from post-consumer Tetra Pak packages at the laboratory level. We have found that it is relatively simple to include the gas phase using an endothermic foaming agent consisting of a mixture of sodium bicarbonate and sodium citrate. We performed the manufacturing by removing the entire paperboard from the container and using a 5% foaming agent through compression molding with hot plates. We achieved an expansion of twice the initial volume and a thermal conductivity of 0.2572 W/mK, which is lower than that of polyethylene 0.33 W/mK, a constituent of lower conductivity within the composite. Thus, we can use the resulting material in the construction industry and the automotive industry that requires low density and low thermal conductivity materials. The developed material is low cost and generates new applications for Tetra Pak waste, which could become an essential point in the packaging recycling chain, thus minimizing its environmental impact.