Transcript Document
West Coast – East Coast: Research in Cellulose Nanotechnology
Bioinspired Sustainable Nanotechnology at Georgia Tech People
Art Ragauskas (Chemistry & Biochemistry, Institute of Paper Science & Technology): biorefinery chemistry, cellulose nanostructures Bob Snyder (Materials Science & Engineering): engineering cellulose nanocrystal polymer composites Rina Tannenbaum (Materials Science & Engineering): in-situ polymerization with cellulosic nanowhiskers Carson Meredith (Chemical & Biomolecular Engineering): assembly of nanostructured renewable advanced optical materials
“Combining renewable bioresources with natural hierarchical nanoassembly to create novel advanced materials“
m mm 100 m m 1 m m 10 nm 10 m m O HO O HO OH OH O OH O OH O HO O HO OH OH O OH O OH O O 1 nm OH O HO OH OH O HO OH O HO HO O OH OH O OH O OH O-Cellulose O-Cellulose
Extraction and application of cellulose nanowhiskers (CNWs) and nanoballs (CNBs)
A. Ragauskas
1000
Goal:
Develop methods to extract cellulose nanocrystals from bioresources.
Approach:
modified hydrolysis of bleached softwood kraft pulp 800 600 NaOH/DMSO Acid, Sonication cellulose nanoballs Acid cellulose nanowhiskers
Application 1.
CNWs and CNBs form super absorbent hydrogels with hydrophilic polymers 400 200 0 0 PMA-PEG/CNW25 PMA-PEG/CNW50 PMA-PEG/CNW75 2000
Time(min)
4000 6000 whisker Acacia fiber
200 nm
Application 2.
CNWs increase acrylic strength by > 110% 16 12 8 4 0 0 Acknowledgement: NSF EEC-0332554 5 10 15 Content, wt % 20 25
Chemistry and Processing of Bio-based Multi-Component Nanocomposites
R. Tannenbaum & B. Snyder
AFM image of CNWs
Goal 1:
explore novel chemical routes to
Goal 2:
novel processing of CNW/nano CNW-polymer matrix nanocomposites clay/polymer composites
Approach:
in-situ polymerization in presence of polymerizable solvent furfuryl alcohol (FA)
4.8 um Approach: layer-by-layer deposition
coupled with
in-situ polymerization
In-situ polymerization ensures a uniform distribution and orientation of the CNW phase.
CNW O SO 3 >60 o C OH + H 2 SO 4 Desulfonation at CNW surface FA O-SO 3 Initial Mixing
Result: 80 ° C increase in degradation onset in polyfurfuryl-CNW nanocomposite
PFA H 2 SO 4 -catalyzed Polymerization of FA
L. A. Pranger and R. Tannenbaum, Macromolecules 2008 ,
41(22)
, 8682-8687.
Step 1. coat alternating monolayers of CNW and nano-kaolin particles in FA.
Step 2. polymerize FA at high T (100 °) Result: transparent composites with strength approaching that of steel.
Self-Assembly of cellulose- and chitin-based bio-inspired optical materials
C. Meredith
Inspiration: Cyphochilus , “White beetle”: Brilliant white due to efficient light scattering 1 1 m m
Nanofibrillar chitin: A cellulose analog
Approach :
(1)Mimic natural assembly of fibrous nanostructures
Applications
for high brightness & whiteness 1. paper – use chitin or cellulose nanofibrils as green replacements of energy-intensive, nonrenewable whitening and sizing agents
A Exploratory Paths for Assembling Fibrous Nanostructures
(a) Phase Separation (b) Fibril Self-Assembly (c) Particle-Templates (2)Scale-up processes for advanced materials and paper
B
2. renewable OLEDs, sensors