Silvia Bordoni

BUILDING INNOVATION AT EXPO SHANHAI2010

<p><strong>New Composite Insulating panel from renewable material</strong></p> <p><em>Larco-Icos of Ricos Research Consortium </em></p> <p><em>Physical and Inorganic Chemistry Dept of the University of Bologna </em></p> <p>&nbsp;</p> <p>Silvia Bordoni, professor of Inorganic Chemistry at the Physical and Inorganic Chemistry Department (Faculty of Industrial Chemistry of the University of Bologna) in cooperation with the Larco Icos laboratory are developing a research on the feasibility of a composite insulating panel made by eco-friendly renewable material, for building applications.</p> <p>As member of the Ri.Cos Consortium (Research and technology transfer in construction including Fondazione Cassa di Risparmio in Bologna and ICIE-Cooperative Institute for Innovation) Larco Icos laboratory is one of High Technology Centers for research and technology transfer, owing to the Emilia Romagna Network, involved in industrial research on the sustainable and efficient strategies for construction.</p> <p>The more common insulating panels, currently used in construction sector, are made by synthetic foam material, as expanded polyurethane or polystyrene. The expected goal of this research is to develop an insulation material based on lignin-sulfonate, coming from waste of ligno-cellulosic production. This material must guarantee expansibility, homogeneity, high thermal and mechanical resistance, as well as a dramatically reduced environmental impact.</p> <p>Lignin is a natural polymer, which constitutes the inner structural core of the wood. The huge potential of lignin as an underutilized (or wasted) raw material has been pointed out repeatedly (<a href="#_edn1">[1]</a>). Commercial lignosulfonates are complex anionic polymers obtained as co-products of wood pulping. They are obtained from spent sulfite pulping liquors (Figure 1)</p> <p>&nbsp;</p> <p><em>&nbsp;&nbsp;&nbsp;&nbsp; Figure 1: One probable structure of the lignin sulfonate polymer</em></p> <p><strong><em>&nbsp;</em></strong></p> <p>For this reason, its structure is undetermined, but basically composed by different combination of three main alcohol (coniferilic, sinapilic, cumarilic), largely depending on the wood species (soft or hard).</p> <p>The lignin insulation material could be used to make simple or composite panels, for application on wall and roof. Composites are sandwiches, in which wood or metal external skins are stuffed by an insulating lignin core.</p> <p>In both the cases, the lignin vitreous-based layer is able to combine thermal properties with mechanical resistance, further improved by the rigid skins to meet the more severe requirements for specific applications.</p> <p>Preliminary prototypes were made by using lignin sulfonate as starting material, having different grades of alkaline metals added to a silica sol-gel solutions obtained from TEOS (tetrahydroxysilicate) from areogels to xerogels. Pre-treated maize starch has been added as glue and thickener keeping homogeneous phase as much as possible an together with addition of kenaf fibers as mechanical binders to microcells. The introduction of controlled amounts of partially hydrolized vegetable oil may increase the hydrophobic sites, acting as plasticizers. Furter, solid CO2 or ammonium carbonate is added to the viscous material, as promoter for a proper expansion grade, strictly related to the drying procedures adopted.</p> <p>Structure and physico-chemical characterizations of the meso or microporous material are still investigated to elucidate features and behaviour in evaluating its attitude as eco-friendly component for building insulation.</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p><a href="#_ednref1">[1]</a> Glasser, W. G, <em>Classification of Lignin According to Chemical and Molecular Structure</em>; in: Glasser, W., el al; <em>Lignin: Historical, Biological, and Materials Perspectives;</em> American Chemical Society: Washington, DC, 1999, Ch.9, (ACS Symposium Series, Volume 742)</p>