Aerogels are very low density, porous materials, which offer high potential for innovative applications in packaging and insulation applications. First generation aerogels based on mineral matrices are brittle, with poor mechanical performance. This is improved by integrating organic polymers. This study assessed the use of biosourced porcine gelatin (a by-product of slaughter houses) as a PIN flame retardant in a 50%/50% PVA/clay aerogel: poly(vinyl alcohol) and montmorillonite. At c. 20% gelatin incorporation, mechanical performance was improved (compressive modulus multiplied by three) as was fire performance (LOI – limiting oxygen index – increased from 24 to 28, vertical burn test extinguishing time approximately halved and peak heat release rate reduced by around 15%. The authors conclude that the porcine gelatin is a potentially effective green PIN flame retardant for these mineral-organic aerogels, improving both fire resistance and mechanical performance.
“Green Approach to Improving the Strength and Flame Retardancy of Poly(vinyl alcohol)/Clay Aerogels: Incorporating Biobased Gelatin”, Y-T. Wang et al., ACS Appl. Mater. Interfaces 2017, 9 (48), pp 42258–42265 http://dx.doi.org/10.1021/acsami.7b14958