Isolation of Nanocrystalline Cellulose: A Technological Route for Valorizing Recycled Tetra Pak Aseptic Multilayered Food Packaging Wastes

Cellulose fibres were extracted from recycled Tetra Pak food packaging which can be a source of low cost biomass using a simple process. According to the FT-IR and XRD results, alkaline purification and bleaching have removed 99 % of the lignin that remained in the recycled cellulose fibres (up to 10 %). TEM analysis showed that depending on cellulose purity and reaction time, the average particle lengths of nanocrystalline cellulose (NCC) successfully isolated from the recycled material using acid hydrolysis ranged from 127 +/- 42 to 258 +/- 54 nm with average widths varying between 11.4 +/- 2.8 and 14 +/- 4.1 nm. Extending the reaction time to 180 min led to short rod-like particles displaying crystallinity comparable to those of the reference NCC isolated from commercial microcrystalline cellulose. A decline in the NCC thermal stability was noticed following the extraction process, NCA isolated from unpurified starting fibres showed a slightly higher stability with Tmax = 204 A degrees C. Overall, a length to diameter aspect ratio > 10 was obtained for all NCC particles, indifferently of the purity of the starting materials.