Strong, UV-blocking, and hydrophobic PVA composite films containing tunable lignin nanoparticles

In the present work, hollow and solid lignin nanoparticles (LNPs) were synthesized through a self-assembling process using the organosolv pretreatment of lignin from the eucalyptus and willow byproducts. The SEM , TEM, and zeta potential establish the LNPs of a uniform spherical morphology, and the hollow lignin nanoparticles (HLNPs) display the inner cavity and shell. The polyvinyl alcohol (PVA) nanocomposite films containing the LNPs suggest that the presence of HLNPs results in a “room” like network structure in the films and differs from the solid lignin nanoparticles (SLNPs) induced structural changes. The LNPs inclusion increases the mechanical properties. The films with solid eucalyptus lignin nanoparticles showed excellent tensile strength (132 MPa), while those with hollow eucalyptus lignin nanoparticles resulted in exceptional elongation at break (324%). Hydrophobicity tests revealed that both LNPs incorporation in the PVA film results in a water contact angle of more than 90°. The outcome promises novel opportunities for LNPs in the designing and development of plastic replacement packaging films.