Valorization of lignin into nanoparticles and nanogel: Characterization and application

A simple, time efficient process for valorization of lignin into lignin nanoparticles (LNPs) and further into nanogels was developed. LNPs were morphologically spherical with average size of ~136 nm as observed through SEM and particle size analysis. LNPs were applied for nanogel synthesis through UV-curing process in indigenously designed and developed curing cabinet by incorporating them into acrylamide, bis-acrylamide and 1-hydroxycyclohexyl phenyl ketone acting as monomer, cross-linker and photoinitiator, respectively. Nanogels were characterized through SEM, FTIR and compared with hydrogel (gel without LNPs). Mechanical properties of nanogel were analyzed through compression test. Nanogel was found to have better load bearing capacity and Young's modulus (0.8 kPa), which was 4× higher than hydrogel (0.2 kPa). Further, nanogel was used for water retention application and showed 1.6 times higher water retention capacity as compared to hydrogel. Developed nanogel has suitable application in drought prone areas due to its water retention capacity.