Using glycerol esters to prevent microbial growth on sunflower-based insulation panels

In the indoor environment, the growth of microorganisms on building materials leads to the deterioration of both the materials and indoor air quality. As bio-based building materials usually contain cellulose or derivatives, they are likely to be much more sensitive to such degradation. Using glycerol esters could be a way to protect bio-based materials from microorganisms. Indeed, previous studies have highlighted the significant antimicrobial effect of glycerol esters and they are commonly used in the food industry as antimicrobial agents. In addition, as glycerol is a valuable by-product of the agroindustry, it would be an eco-friendly alternative, consistent with human health, to the classic ways of protecting bio-based materials against microorganisms. This study is part of a project that aims to (a) assess the hygrothermal performances and reaction to fire of sunflower panels and (b) study the antimicrobial efficiency of glycerol esters for the protection of such bio-based materials from microbial proliferation. The materials presented physical, thermal and hygroscopic properties similar to those of bio-based materials such as wood or hemp, encouraging their use as insulation materials. In addition, the glycerol esters showed significant antimicrobial effects but also a susceptibility to flammability. One unanticipated finding was that the untreated insulation material made of sunflower pith was classified as non-flammable