Preparation and benchmarking of novel cellulose nanopaper

Abstract

Synthetic polymers and plastics which are currently used as barrier materials in packaging applications are neither renewable nor biodegradable. Nanopaper, which is obtained by breaking down cellulose fibers into nanoscale particles, have unique properties with the potential to replace synthetic packaging materials, but requires very high energy to mechanically process the fibers into nanopaper. This research investigates whether refining alone can be used to produce nanopaper with sufficient quality for packaging applications. Nanopaper was produced from Bleached Eucalyptus Kraft (BEK) refined with a PFI mill and from Northern Bleached Softwood Kraft (NBSK) refined in a pilot disc refiner. Both trials found a plateau for oxygen permeability and water vapour permeability that was reached after 1800 kWh/t and 12,000 kWh/t for refining in the pilot disc refiner and PFI mill, respectively. Refining beyond these optima produced either little or no reduction in permeability, while increasing the drainage time to form a sheet. However, elastic modulus, strain at break and sheet light transmittance did continue to increase. The plateau oxygen permeability of ~ 1.24 (cc µm)/(m2 day kPa) is 1–3 orders of magnitude lower than the oxygen permeability for PET and LDPE, respectively, while the plateau water vapour permeability ~ 3 × 10–11 g/m.s. Pa was 1–2 orders of magnitude higher than for PET and LDPE. The improved strength and barrier properties of nanopaper achieved at lab and pilot scale mechanical refining process promises a sustainable alternative to conventional packaging. Graphical abstract

Efficient Preparation of Cellulose Nanofibers in High Yield Using Low Concentration of Organic Acid

“…Nanocellulose is mainly categorized into cellulose nanofibers (CNF) and cellulose nanocrystals (CNC) [3] . CNF consists of the amorphous and crystalline regions of cellulose with 5–30 nm in diameter and 300–5000 nm in length [4] . While CNC shows the high crystallinity from the selective removal of amorphous region, which is 4–25 nm in diameter and length ranging from 10 to 500 nm [5] .…”

Multi-layer barrier coating technology using nano-fibrillated cellulose and a hydrophobic coating agent

“…It has a low density, high aspect ratio, high biodegradability, high tensile strength, and stiffness (Julkapli et al 2017;Wang et al 2020). Additionally, NFC is an effective barrier coating agent because of excellent film formation, transparency, and gas barrier properties, and it can replace synthetic polymers that cause environmental pollution (Afra et al 2016;Fotie et al 2020;Kargupta et al 2022). However, the NFC made from woody cellulose fibers has a negative charge and hydrophilic property because of the presence of carboxylic acid and hydroxyl groups on the cellulose molecule (Sjöström 1989;Nishiyama 2009).…”

Advanced Green Thermoset Resin Tailored for Nanocellulose‐Based Filament‐Reinforced Polymer Composite and Sustainable Development

“…Furthermore, high‐throughput filament fabrication is more cumbersome and unlikely with the pilot system used for filament fabrication. Furthermore, transferring the excellent strength of nanocellulose fibers to the macroscale has encountered deterrents entrenched in high production costs, time‐consuming pilot systems and processes, [ 19 ] and unsatisfactory resin performance. For nanocellulose‐based all‐green composites to compete effectively with synthetic plastics, the processing time, yield, and economies of scale must be considered.…”

“…[ 26 ] While starch is an abundant, low‐cost material, its poor performance has impeded its use in advanced high‐strength and green applications. [ 19,20 ] In addition, the mechanical properties of starch‐based resins used in fiber‐reinforced polymer composites have not exceeded 6 MPa. [ 26,27 ] Natural resources such as lignin have often been used to enhance the performance of green composites, although the rigid aromatic structure and heterogeneity of lignin limit its functionality.…”