Abstract:
A lignin based hydrogel was synthesized by physically cross-linking polyvinyl alcohol
(PVA), chitosan (Ch) and lignin (Lgn) precursors. The prepared hydrogel was subjected to
the cellulosic paper base as a biocoating. The interactions among the hydrogel precursors
and effect of hydrogel on the crystalline behavior of hydrogel was evaluated using FTIR
and XRD and the overall effect of hydrogel on the mechanical strength and barrier
properties of the newly developed materials were investigated through tear index, tensile
strength, puncture resistance, Cobb tests for water and oil and water contact angle
measurements of uncoated and biocoated paper surfaces.
The analysis of strength parameters revealed that the prepared biocoating improved the
mechanical properties of the material by 40% as compared to the uncoated paper. The water
contact angle analysis confirmed that the addition of lignin and chitosan to the PVA matrix
sufficiently improved the hydrophobicity of paper surface resulting an improved resistance
to water adsorption. The air, moisture and oil barrier properties again suggested that and
an increase in the lignin concentration improved the barrier properties of the paper. The
biodegradability of the prepared paper samples were investigated using compostability test.
A customized soil burial test was developed and the extent of biodegradability was
evaluated over a time period of 30 days. The research underscores that the prepared
PVA/chitosan/lignin based biocoating has a great potential to not only provide good
mechanical and barrier properties but also has a potential to replace synthetic packaging
materials for sustainable and eco-friendly biobased packaging material.
