Synthetic packaging materials are neither reprocessable, renewable nor biodegradable barrier and also difficult to recycle into useful products. While cellulose-based packaging is widely known as a renewable, reprocessable, recyclable and biodegradable material it has limited air and water vapour barrier properties. Nanocellulose (NC) has the potential to become a renewable alternative to plastic packaging barrier layers but its recyclability has not been reported. This investigation is focused on the production of spray-coated nanocellulose (NC) films and its recyclability via dispersion in water and vacuum filtration to form sheets again. Physical properties such as barrier performance and strength of NC films have been evaluated pre- and post- recycling. The recycled films retained 80% of tensile strength and significant barrier performance although the H2O vapour permeability (WVP) approximately doubled, increasing to 9.83 x 10-11 g.m-1.s-1 Pa-1, providing comparable values with for most synthetic packaging. SEM micrographs reveal no fibre agglomeration at the micro level and no damage to the fibres during recycling. The retained strength and barrier properties and facile reprocessability of the spray coated NC film promises a sustainable and recyclable alternative to conventional packaging, providing a sustainable platform for packaging industries.

1. PRESENTED BY:
Warren Batchelor
Associate Professor
BioPRIA, Monash University
Kirubanandan Shanmugam, Hamid Doosthosseini,
Swambabu Varanasi, Gil Garnier, Warren Batchelor
Recyclability of Nanocellulose
films

2. Applications of Nanocellulose
Packaging1 Oil and water separation2 Photo catalyst3
Gels for Biomedical
Applications5
Nanocellulose
based composites6
Nanocomposites as High
Performance Barrier7
Membrane4
1. K.Shanmugam et al, Cellulose, 2017,24, 7, 2669–2676.
2. Z. he et al, RSC Adv., 2016, 6, 21435-21438
5. Mendoza et al, J Colloid Interface Sci. 2018 1;509:39-46.
7. U.M. Garusinghe et al, Colloids and Surfaces A,540, 2018,233-241.
3. U.M. Garusinghe et al, Scientific Reports, 8, 2306 (2018)
4. V. Swambabu et al , Chemical Engineering Journal 265(1) 2015.
2

3. Barrier materials
Wax
Aluminium
Plastics
Limitation:
Poor barrier
properties
3

4. Overview of Barrier Materials
Aulin and Lindström, Biopolymer Coatings for Paper and Paperboard, John Wiley & Sons, Ltd, 2011, pp. 255-276
4

5. Nanocellulose – Potential Barrier
• Bio degradable
• Non toxic
• Extreme High Surface Area
• Crystallinity
• Tuneable surface for
functionalization
Martin Hubbe el al, Nano cellulose in Packaging: A Review, Bio Resources 12(1), 2143-2233.
5

6. Nanocellulose film preparation techniques
1. Casting and Solvent evaporation 2. Vacuum filtration
Filtration Separation Drying
3. Spray coating followed by Vacuum filtration
Processing time – 10 min – 24 hrs
Drying time -10 mins
Processing Time –10-27 mins
Beneventi, D., Zeno, E., & Chaussy, D. (2015)
Processing and Drying time – 72 hrs
Laboratory scale
6

7. Rapid Preparation of NC films
7

8. Objective
To recycle and reprocess the spray
coated NC film
– Evaluate barrier properties of Virgin and
recycled NC
– Investigate effect of recycling on strength
of NC
Vacuum Filtration
8

9. Sheet Preparation Process
(British hand
sheet maker)
Recycled NC
Film
Virgin NC
Film
• 600 g of 0.2 wt.% suspension  60 gsm sheet
• No retention aid/on filter paper
Comparison
Properties
9

10. Recycling of Nanocellulose
Before Recycling
69.8± 11.3 nm
After Recycling
69.6± 12.6 nm
0 50 100 150 200 250 300 350
0
5
10
15
20
25
30
35
Bin
Fibre diameter in nm
Virgin NC Fibres
0 50 100 150 200 250
0
5
10
15
20
25
30
Fibre Diameter in nm
Bins
Recycled NC Fibre
10

11. Apparent Density
650
670
690
710
730
750
770
790
810
830
850
80 90 100 110 120 130 140
ApparentDensityinKg/m3
Basis weight in g/m2
Virgin NC film
Recycled NC film
11

12. Barrier Properties of Virgin and Recycled NC
0
2E-11
4E-11
6E-11
8E-11
1E-10
1.2E-10
1.4E-10
1.6E-10
90 100 110 120 130 140
Watervapourpermeability
g.m-1.s-1Pa-1
Basis weight in g/m2
Virgin NC Film
Recycled NC Film
Air Permanence
Virgin NC Film < 0.003 µm/Pa.S
Recycled sheet - 0.0045 µm/Pa.S
12

13. Effect of Recycling on strength of NC
20
30
40
50
60
70
80
90
100
110
80 85 90 95 100 105 110 115 120 125
TensileIndexinNm/g
Basis Weight in g/m2
Virgin NC Film-Instron Method
Recycled NC film -Instron Method
Virgin NC film -Zero span
Recycled NC film - Zero Span
13

14. Effect of Recycling on Uniformity
0.1
0.3
0.5
0.7
0.9
1.1
1.3
1.5
0 5 10 15 20 25 30 35 40
RelativeIndex
Components in mm
117.6 g/m2 Recycled NC Film
128.7 g/m2 Recycled NC Film
110.7 g/m2 Recycled NC Film
102.7 g/m2 Recycled NC Film
100.5 g/m2 Virgin NC Film
14

15. Surface Topography- SEM Micrographs at 2µm
15
Virgin Film-Filter side Recycled Film-Filter side
Virgin Film-Free side Recycled Film-Free side
1

16. SEM Micrographs at 10 µm
16
Virgin NC Film Recycled NC Film

17. Optical Profilometry
17
1
Virgin Film Recycled Film
Optical Profilometry of Free side of NC Film and Recycled NC Film (50 X Magnification)

18. 18
Measurement Technique Area examined Effect of Recycling compared to virgin fibres
SEM Measurement of Fibre
diameter
1 micron scale bar None
SEM Measurement of Film
Surface
2 micron scale bar Nothing conclusive
SEM Measurement of Film
Surface
10 micron scale bar None
Optical Profilometry roughness 100 x 90 microns None
SEM Measurement of Film
Surface
100 micron scale bar None
Film thickness 159 mm Diameter of film Higher thickness at the same basis weight (g/m2)
Zero-span strength Estimated 300 micron span length 30 % Less
PPF tester of optical uniformity 1-15 mm inspection areas
16-39 mm inspection areas
Decrease in uniformity at lower areas of Inspection
Increase in uniformity at higher areas of Inspection
Water Vapour Permeability 63.5 mm diameter circle of film Higher permeability
˜ Doubled WVP
Air permeability 50 cm2 sample Higher permeability: permeability increased above the
detection limit of the instrument.
Tensile strength via Instron
Method
100 mm test span 30 % less strength

19. Comparison with WVP of Synthetic Polymers
Barrier Polymers Water
Transmission Rate
(g/m2 day)
Average
Thickness of the
film (µm)
Water Vapour Permeability
(g/m.s.Pa) x 10-11
The NC Film Vacuum
Filtration (100 g/m2)
52.9 119.4 4.97
Recycled Cellulose film
from Spray coated NC
89.5 133 9.83
Polyethylene (PE) 16.8 18.3 0.1
Plasticized (PVC) 118.6 12.7 0.49
Aluminium Foil
2.4 18.3
0.014
LDPE
18 25
0.088
HDPE
9 25
0.044
PS 109 to 155 25 0.53 - 0.75
PP 6 25 0.029
19

20. Conclusions
 Low permeance of air and water vapour even after recycling
 Retained 70% of the tensile strength
 Agglomeration of fibres affects initial film formation, concluding that the fibres are
not completely broke down.
 Recycled sheet shows limited reductions in barrier performance
 Platform for sustainability to replace synthetic packaging
20

21. Acknowledgment
• Monash Centre for Electron Microscopy
• Melbourne centre for Nanofabrication for Optical Profilometry Investigation
• Australian Research Council – BAMI Hub Grant

22. PRESENTED BY:
Warren Batchelor
Associate Professor
BioPRIA, Monash University
Thank you