In the last years, a particular attention has been paid to “green” materials. Among these there are geopolymers, inorganic polymeric materials obtained by mixing a solid aluminosilicate precursor with an alkaline solution (Davidovits, 1991). They represent innovative products in terms of recycling and sustainability since their synthesis is carried at low temperature and involves the re-use of waste materials from human activity (Mina, 2014). Moreover, they produce low emissions of CO2 and energy consumption compared to Portland cements (McLellan et al., 2011). Recent innovations in geopolymer technology have led to the development of various types of geopolymeric products, including highly porous geopolymer-based foams, which are formed by the addition of foaming agents to a geopolymer matrix (Zhang et al., 2014). The hardened structure which results in the formation of a low-density material can be used for applications in acoustic panels or for thermal insulation purposes. This study was carried out within the project “Advanced Green Materials for Cultural Heritage” (AGM for CuHe), carried by the University of Catania, which aims to use and valorize local raw materials as precursors to produce geopolymers. This study focused on analysing the mechanisms of formation and the structure of geopolymer foams by using different local volcanic materials that are available and suitable in terms of chemical, mineralogical, mechanical and aesthetic compatibility, as required by good conservation practices (Barone et al., 2020; Occhipinti et al., 2020). The samples obtained were analysed under X-Ray powder diffraction (XRD) and scanning electron microscope (SEM), in order to evaluate their chemical, textural and structural features. Preliminary results have shown that the porosity of geopolymers – whose pore volume and shape is varied, according to the kind and percentage of the foaming agent used – can be artificially tailored for the final application without losing the structure of the polymeric matrices. This allows to obtain binders with low dry unit weight and controlled porosity that may have good adaptability to the substrate and good breathability. This may open the way to the synthesis of alternative light materials, highlighting their potential role in Cultural Heritage preservation where homogeneous, compact amorphous matrix and a colour - which has to simulate the original stone - is required.
Geopolymer foams obtained starting from Sicilian volcanic precursors
Zafarana S. E.
;Barone G.;Lanzafame G.;Mazzoleni P.;Occhipinti R.
2021-01-01
Abstract
In the last years, a particular attention has been paid to “green” materials. Among these there are geopolymers, inorganic polymeric materials obtained by mixing a solid aluminosilicate precursor with an alkaline solution (Davidovits, 1991). They represent innovative products in terms of recycling and sustainability since their synthesis is carried at low temperature and involves the re-use of waste materials from human activity (Mina, 2014). Moreover, they produce low emissions of CO2 and energy consumption compared to Portland cements (McLellan et al., 2011). Recent innovations in geopolymer technology have led to the development of various types of geopolymeric products, including highly porous geopolymer-based foams, which are formed by the addition of foaming agents to a geopolymer matrix (Zhang et al., 2014). The hardened structure which results in the formation of a low-density material can be used for applications in acoustic panels or for thermal insulation purposes. This study was carried out within the project “Advanced Green Materials for Cultural Heritage” (AGM for CuHe), carried by the University of Catania, which aims to use and valorize local raw materials as precursors to produce geopolymers. This study focused on analysing the mechanisms of formation and the structure of geopolymer foams by using different local volcanic materials that are available and suitable in terms of chemical, mineralogical, mechanical and aesthetic compatibility, as required by good conservation practices (Barone et al., 2020; Occhipinti et al., 2020). The samples obtained were analysed under X-Ray powder diffraction (XRD) and scanning electron microscope (SEM), in order to evaluate their chemical, textural and structural features. Preliminary results have shown that the porosity of geopolymers – whose pore volume and shape is varied, according to the kind and percentage of the foaming agent used – can be artificially tailored for the final application without losing the structure of the polymeric matrices. This allows to obtain binders with low dry unit weight and controlled porosity that may have good adaptability to the substrate and good breathability. This may open the way to the synthesis of alternative light materials, highlighting their potential role in Cultural Heritage preservation where homogeneous, compact amorphous matrix and a colour - which has to simulate the original stone - is required.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
