Lignin is one of the most abundant by-products of pulp and paper manufacturing and second-generation
biorefineries. Presently it is mainly used for energy production, but it is evident that higher added-value
utilization options would be beneficial. One possible process is to use lignin as building block for chemical
synthesis. In this work, lignin was used as a raw material for the production of aerogels as special
class of porous materials. Lignin obtained from Liquid Hot Water (LHW) pretreatment of wheat straw
has been cross-linked with oligo(ethylene glycol)- and oligo(propylene glycol)-a,x-diglycidyl ethers of
varying length, aiming at the preparation of lignin-based hydrogels and their conversion to aerogels.
The effect of cross-linking conditions, such as lignin concentration, cross-linker-to-lignin ratio, gelation
temperature and solvent exchange conditions, on the textural properties of the resulting aerogels were
studied. The obtained aerogels had a surface area of up to 120 m2 g1
, bulk density as low as 0.15 g cm3
and a thermal conductivity of about 50 mW m1 K1
.