An excerpt of master thesis in Design & Engineering, academic year 2010/2011 by Marta Musitelli
School of Design, Politecnico di Milano
Speaker: Barbara Prof.ssa Del Curto
Co-rapporteur: Prof.ssa MariaPia Pedeferri
Sustainable Smart Insulation is the thesis of the research conducted by Marta Musitelli at Politecnico di Milano. The project aims at the development of sustainable and innovative insulating panels, achievable through the use of two components: the cellulose, obtained from recycling waste paper, and Phase Change Materials (or PCMs), substances capable of accumulating and releasing heat on a scheduled basis.
Through the mixing of two substances during processing of recovered paper, it was possible to obtain a composite material with an entirely new set of features, which combine the thermal properties of the two components. In the construction field, the PCM is used and studied for several years to improve the capabilities of heat insulation of the walls. Cellulose fibers are used as ecological insulating material. The aim of the research is to get an array of cellulose insulation enriched by thermal properties of PCM and carry out studies and tests to verify its suitability in the context of use. Several ideas for optimizing material properties, such as lightness, mechanical resistance, fire resistance, resistance to water absorption and environmental sustainability, were proposed and tested .
The presence of air zones within the structure of a material reduces the density and at the same time improve the insulating properties. In order to achieve a more efficient and lightweight Panel several techniques of inclusion of air inside the new material in waste paper and PCM have been tested, such as:
- Lyophilization process
- Proving process
- Distribution of flakes
- Shape modeling
An effective method to get air pockets within a structure is lyophilization.
A second method is to use leavening agents such as baking soda, able to decompose at high temperatures and to create carbon dioxide particles inside the wet pulp, which during drying in stove increase in volume due to the boiling water. The addition of sodium bicarbonate in various quantities gives different results: the Panel made with 30% of baking shows a significant increase compared to the panel thickness without additives; the Panel with 50% of baking shows a thickness increase further compared with the previous coming to be about double the Panel without additives.
A third method is to get a get a lightweight structure through the layering of cellulose flakes obtained by grinding. This method allows you to obtain lightness thanks to the air that is trapped between disordered fibers, but it is not suitable for use in the construction field because it is not workable and mechanically resistant.