Low density NANOnanocellular POLymers for thermal insulation in buildings: basic heat transfer mechanisms and life cycle assessment

• Grant number: 19/13441-1
• Support Opportunities: Regular Research Grants
• Start date: October 01, 2020
• End date: January 31, 2023
• Field of knowledge: Applied Social Sciences - Architecture and Town Planning - Architecture and Urbanism Technology
• Agreement: M-ERA.NET
• Principal Investigator: Vanessa Gomes da Silva
• Grantee: Vanessa Gomes da Silva
• Principal researcher abroad: Miguel Angel Rodríguez Pérez
• Institution abroad: Universidad de Valladolid (UVa), Spain
• Principal researcher abroad: Shu-Kai Yeh
• Institution abroad: National Taiwan University (NTU), Taiwan
• Host Institution: Faculdade de Engenharia Civil, Arquitetura e Urbanismo (FEC). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

The building sector is increasingly demanding more advanced thermal insulating materials with higher performances, but at an affordable cost, to be able to fulfil the stringent requirements of the EU and worldwide regarding energy efficiency and GHG emissions. CellMat Technologies is intensively working to develop at a lab scale a new advanced thermal insulating material based on a nanocellular polymer foam (NANOPOL) which will be able to reach ultra-low thermal conductivity (») values but at a very competitive cost. Three times reduction in » with respect to conventional polymer foams for thermal insulation (XPS, EPS and PUR) are expected if the targets of the project are achieved. The key concept underlying such low » values in NANOPOL lies in an enormous reduction of the cell size from the microscale to the nanoscale (d300 nm) which supress the main heat transfer mechanism in a low density polymer foam: the gas phase conduction (70% of the total ») because gas molecules are confined within the cells. NANOPOL will bring about enormous benefits for the building sector because the wall thickness may be reduced up to 3 times. In addition, lower GHG emissions from heating/cooling are expected. Finally, the foam will be fully recyclable (non-cross-linked polymer matrix), which will make the wastes generated during manufacturing reusable ("towards a circular economy in Europe"). However, there are still some important drawbacks that need to be scientifically addressed before considering NANOPOL as a real advance thermal insulating material, being the most relevant one that the lowest density achieved so far is still very high (H200 kg/m3), hence, » is higher than expected for a thermal insulating material with nanocells (current values H 40 mW/mK). Therefore, the main objectives of NANOPOL project are: 1-Researching novel strategies in the field of synthetic polymer foams to reduce NANOPOL´s density down to 100 kg/m3 which is the threshold to have ultra-low thermal conductivities (» d 13 mW/Mk) in a nanocellular foam. The approach will be to disperse nanoparticles randomly and/or hierarchically (top/bottom layers) throughout the polymer matrix to promote a "hard-shell" effect and to prevent blowing agent from being lost before expansion. Several types of nanoparticles with platelet-shape and/or combinations or them will be selected for this purpose which will additionally play a multifunctional role to improve its fire behaviour (European class C is targeted), its mechanical properties and to reduce further the » values because their acting as IR blockers. 2-To analyse accurately the heat transfer mechanisms throughout this novel polymer foam with a nanocellular structure, which are unknow so far. Current models used for micrometric polymer foams will be specifically adapted to the peculiarities of NANOPOL´s structure (presence of nanocells). 3-To perform a life cycle assessment (LCA) with the aim of revealing the enormous environmental benefits that this new polymer foams will have in the building sector in many different climate scenarios across the world (from South America to northern Europe). A transnational consortium with 3 partners with the required level of scientific expertise has been formed to carry out NANOPOL research over this two-year project: CellMat Technologies-CELLMAT (Spain) is the owner of the know-how to develop NANOPOL and has the required level of expertise to study their physical properties and the heat transfer mechanisms, National Taiwan University of Science and Technology-NTUST (TAIWAN) has a wide experience in the development of nanocellular polymers reinforced with nanoparticles, and the University of Campinas-UNICAMP (Brazil) has lead numerous research projects, inventory data collection and published several articles in the field of life cycle assessment (LCA) of innovative materials, components and whole-buildings, which will be key to develop NANOPOL's environmental assessment. (AU)