Thermal and structural properties of a hemp–lime biocomposite

New insulation fiberboards from sunflower cake with improved thermal and mechanical properties

“…The thermal conductivity of the bulk cake and of the twelve fiberboards was also clearly influenced by their density, and it tended to increase with increasing density (Figure 4a). Similar characteristics have been observed on several occasions, in particular for insulation boards made from durian peel and coconut coir (Khedari et al, 2003(Khedari et al, , 2004, wastes from tissue paper manufacturing and corn peel (Lertsutthiwong et al, 2008), cotton stalk fibers (Zhou et al, 2010), coconut husk and bagasse (Panyakaew & Fotios, 2011), sunflower pith (Vandenbossche et al, 2012, hemp fibers (Benfratello et al, 2013), date palm fibers (Chikhi et al, 2013), and sunflower cake from whole plant (Evon et al, 2014). At the same time, the thermal resistance logically decreased (Figure 4b), and these trends were observed at all three temperatures.…”

“…As an example, the thermal conductivity of an insulation board from sunflower pith is only 38.5 mW/m K at 25 °C with a board density of 36 kg/m 3 (Vandenbossche et al, 2012). It is comparable to that of conventional insulation of 250-350 kg/m 3 (Panyakaew & Fotios, 2011), 81.5 mW/m K for a cotton stalk fibers insulation board with a board density of 450 kg/m 3 (Zhou et al, 2010), 89.9-107.9 mW/m K for hemp fibers insulation boards with board densities of 369-475 kg/m 3 (Benfratello et al, 2013), 103.6 mW/m K for a coconut coir insulation board with a board density of 540 kg/m 3 (Khedari et al, 2003), and 150 mW/m K for a date palm fibers insulation board with a board density of 754 kg/m 3 (Chikhi et al, 2013). Nevertheless, such boards are viable options for use in building insulation (walls and ceilings).…”

“…The thermal conductivity of insulation boards is often influenced by their densities (Khedari et al, 2003(Khedari et al, , 2004Lertsutthiwong et al;Zhou et al, 2010;Panyakaew & Fotios, 2011;Vandenbossche et al, 2012;Benfratello et al, 2013;Chikhi et al, 2013), and low-density materials have the lowest thermal conductivities. As an example, the thermal conductivity of an insulation board from sunflower pith is only 38.5 mW/m K at 25 °C with a board density of 36 kg/m 3 (Vandenbossche et al, 2012).…”

“…Insulation boards can be made from maize husks and cobs (Sampathrajan et al;, 1992;Pinto et al, 2011;Paiva et al, 2012), a mixture of durian peels and coconut coir fibers (Khedari et al, 2003(Khedari et al, , 2004, cellulose (Nicolajsen, 2005), wastes from tissue paper manufacturing and corn peel (Lertsutthiwong et al;, kenaf fibers (Ardente et al, 2008), flax and hemp fibers (Kymä lä inen & Sjöberg, 2008;Korjenic et al, 2011;Benfratello et al, 2013), cotton stalk fibers (Zhou et al, 2010), jute fibers (Korjenic et al, 2011), coconut fibers (Panyakaew & Fotios, 2011;Alavez-Ramirez et al, 2012), sunflower pith (Vandenbossche et al, 2012), date palm fibers (Chikhi et al, 2013), etc.…”

Experimental measurements of the thermal conductivity of insulant elements made of natural materials: preliminary results

“…Therefore, recent studies on this topic regard raw material resources originating from agricultural sources [12] [13] or from waste or recycling [14], discussing their potential and costs [15] [16], addressing the problem of thermal property change with humidity [17], assessing their structural properties [18] or discussing their LCA [19].…”