Structural Analysis and Design of Foundations: A Comprehensive Handbook for S...
Nanocomposites via spray coating
1. Developing Nano clay Nanocellulose
Composites for Barrier Applications
Via Spray Coating
S.Kirubanandan
Ph.D. Student
8th June 2018, BAMI Industrial Chapter, Bioprocessing Resource Institute of Australia,
Department of Chemical Engineering, Monash University
Maisha Maliha
Ph.D. Student
7. Nanocellulose – Potential Barrier
• Bio degradable
• Non toxic
• Extreme High Surface Area
• Crystallinity
• Tuneable surface for
functionalization
Martin Hubbe et al, Nano cellulose in Packaging: A Review, Bio Resources 12(1), 2143-2233.
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8. Overview of Barrier Materials
Aulin and Lindström, Biopolymer Coatings for Paper and Paperboard, John Wiley & Sons, Ltd, 2011, pp. 255-276
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9. Effect of Inorganics Addition
Müller, Kerstin (2017). Nanomaterials. 7. 47. 10.3390/nano7040074.U.M. Garusinghe et al, Colloids and Surfaces A,540, 2018,233-241.
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10. Nanocomposite films preparation techniques
1. Casting and Solvent evaporation
2. Vacuum filtration
Filtration Separation Drying
Processing time – 3 - 72 hrs
Drying time -10 mins
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Processing and Drying time – 72 hrs
Laboratory scale
25. Works to be performed
• XRD Analysis of Nanocomposites
• Cross-section analysis of Nanocomposites
• Optical Profilometry
• Mechanical Strength
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26. Conclusion
• An optimized and rapid technique to prepare
nanocellulose/montmorillonite (MMT) was
developed.
• Low permeance of air and water vapour
• Platform for sustainability to replace synthetic
packaging
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27. Acknowledgement
• Assoc Prof. Warren Batchelor and Prof. Gil Garnier
• Dr. Swambabu Varanasi
• Student friends and Staff members at BioPRIA
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Good Morning everyone,
Thanks for attending my presentation on nanocellulose as barrier materials ,
Thanks Prof Warren for introducing me to Audience ,
I am working on the research topic on nanocellulose sheet and its composites as high performance barrier materials and developing these materials using spray coating, an alternative for vacuum filtration.
In technical seminor, I would like to talk about Introduction and Background of the research, Research aims , Preliminary research and Proposed research
Conclusion of this research work
I have previously presented the development of nanocellulose film via spray coating and its barrier performance and compared with the sheet prepared from vaccum filtration. I need to high light the performance of spray coating
The spraying of nanocellulose on the polished metal surface to create a unique surface such as rough surface on the atmosphere side and smooth surface on the metal side
The operation time for sheet formation is less than 1 min and comparable uniformity and thickness of the sheet with vaccum filtration
The properties of the sheet can be tailored by simple adjusting the suspensison concentration and other process parameters in experimental configuration such as velocity and nozzle type
When I see the barrier properties of nanocellusose filme is quite good compared with sheet from vaccum filtration.
In this presentation, I had like to talk about the development of nanocellulose based composites via spraying and evaluate its barrier performance and compared with the nanocomposties prepared via vaccum filtration that previously reported.
Cellulose is the most abundant biopolymer on the earth. Wood fibers are composed of 40–45% cellulose, which is produced in
nature via photosynthesis and ubiquitously used in the everyday
life.56 The cell wall of natural wood bers has a 3 dimensional
(3D) hierarchical structure designed for the metabolic ion
transportation and to possess mechanical stability,
The microbril bundles are composed of microbril cellulose
(MFC) and nanobril cellulose (NFC). MFC is delaminated from
wood pulp through mechanical treatments before and/or aer
enzymatic or chemical pretreatment, which has a diameter of 5–
60 nm with a length of several micrometers.
It has specific characteristics to make many functional sustainable materials
Due to its biodegradability, it has good alternative for synthetic polymers
It has potential of recyclable
It is non –toxic material
Due to its biocompatibility, it can be used as base substrate for development of tissue engineering scaffolds
It is eco –friendly material
Nowdays Nanocellulos is a potential biomaterials and applying in many fields
Our research group focus on nanocellulose based packaging
Cellulose based products such as paper and boards are good packaging materials however it is poor barrier properties due to its wide pores
Its barrier performance enhanced by coating with wax or laminated with aluminium or plastics , however these coating and extrusion is not recyclable and not biodegradable
The challenge is to develop recyclable and sustainable packaging materials
Nanocellulose is potential barrier material and its minute pores in the web like structure delays and decrease the transfer of water vapour and air
The reduction of fibres leaded to reduction of pore size and resulting better barrier properties.
This graph concludes nanocellulose has good oxygen barrier and poor water vapour due to its hydrophilicity
Due to high polarity of nanocellulose, water vapour affects the fibre –fibre bonds.
Also this material characteristic weakens the original strong bonds holding the dry 2D structure, decreasing water permeability and deterioarating material stability
The water vapour permeability of nanocellulose should be improved and to bring to synthetic polymer range.
Effect of Inorganics Addition in the nanocellulose:
In the design of sustainable packaging material , controlling water vapour transmission rate is more critical to extend the shelf life of moisture sentitive foods.
To enhance the barrier properties of nanocellulose sheets, inorganic nanomaterials are introducted to the fibre matrix result the formation of nanocomposites .
Recently, Uthpala developed nanocomposite with montmorillonite (MMT) and nanocellulose via vaccum filtration and confirmed low water vapour permeabilyt and oxygen transfer rate.
The mechnisism of low permeance of water vapour and air is creatiin of tortuous path when MMT arranged orthogonally in fibre matrix and results low op and wvp.
There are few methods available for nanocellulose films for various functionality.
Casting of the nanocellulose suspension is the most common technique at laboratory scale and it requires longest drying time for evaporation of solvent in the suspension.
Vacuum filtration is the most method for making the films. It requires processing time from 10 mins to 4 hours in the nanocellulose film and in the case of nanocomposite, it requires 24 hrs s for dewatering in the filateration process
3. Spray coating is recently reported to replace the filtration process , however after coating , the same filteration is used to removed the excess water formed sheet and it required time which is not reported in the literatue.
Therefore, these methods have problem in the scale up , it requires alternative process for fabrication nanocellulose film
Spray coating is a contactless coating and provides contour coating and possible to coat tear sensitive material and easy to control the coating material.
In this coating method, the topography of the substrate has no influence on the coating weight. For example, on uneven surfaces a contour coat can be applied.
This could result in a reduction of cost and an improvement of quality.
Atomization is the integral part of spray coating , this process is highly governed by the physical property of coating fluid such as density , surface tension and viscosity.
Contactless
Contour coating
Coating of tear sensitive material
Controlling the coating material
I have attempted to prepared the nanocellulose composite via spray coating.
Nanoclay is added with respect to fibre content in suspension and disintegrated at 15000 revoultions and sprayed on the stainless steel at a specified conditions.
I have performed experiments with two catagories
With homoginization of fibres
Without homoginization of Diacel MFC
I have prepared the nanocomposite with three typers of nanoclay Closite Na Closite Ca Closite 116
I have focused only Closite Na and prepared the nanocomposite with homoginzed nanocellulose witj claosie Na++
The nanocellulose –montmorillonite (MMT) compsites were preared via spraying and engineered its barrier performace by varying the MMT loading ( from 5 to 75% of nanoclay into the nanocellulose suspension)
All composites are flexible and foldable.
For example The composites prepared from clostie Na yellowshed as the MMT conten increased
Similarly The composites preared from clostie Ca reddished as the MMT content increased
From the plot of Density vs Nanoclay content, The appratent detnsity of nanocomposite from homoginized via spray coating are similar the sheets from vaccum filtration.
Concluding that its higly compact structure than that of the nanocomposite prepared from unhomogenized cellulose via spraying
SEM investigation of surface of nanocomposite confirms the distribution of nanoclay in the fibrious matrix based content of MMT in suspension
When comparing the plain nanocellulose film with nanocomposite, the nanoclay distributed widely on the surface confirming the spray coating is a good method to prepare nanocompostie
EDX spectr of the nanocomposite along surface of the nanocomposite confirms the distribution of nanoclay on the composite and Carbon and Oxygen from chemical structure of nanocellulose and other elecments are present in the strure of MMT.
The air permeability of the nanocomposite was less than 0.003 μm/Pa.S, which is the detection
limit of the instrument, confirming the film is highly impermeable for packaging application.
WVP of nanocomposite increased with MMT content increased due to agglomeration of nanoclay in composite at high loading of MMT and not created a tortuous path for permeating water molecules. I need to investigate the structure of nanocomposite via XRD studies
Generally, The water vapour permeability of the nanocomposites is affected by many parameters such as type and structure of MMT, its dispersion and content in the nanocellulose matrix.
After Homoginization of Nanocellulose with nanoclay, WVP decreased for nanocomposite via spraying upto 20% loading and increased due to small aggregation after 30% and values bit higher than that of nanocomposite via vaccum filtration
This might be the arrangement of MMT Platelet’s largest dimension perpendicular to the diffusion pathway producing a tortuous path reducting WVP.
When nanocomposite compare with synthetic polymers, its has significant WVP to be sustainable packaging materials
A rapid and commercially scalable, economically feasible method for preparing nanocellulose sheet is developed to produce high basis weight and quality nanofiber sheet and to replace the standard method of vacuum filtration. The basis weight is controlled by the spraying time and nanocellulose concentration in the suspension. The processing time for producing the sheet is less than 1 min and the quality of the spray coated sheet is confirmed by the uniformity in thickness of the sheet.
I would like to thank my supervisor for guiding this work successfully.