1. Nanocomposites of Cellulose For Medical Application
Asif Rasheed
Lecturer, Department of Chemistry
University of Wisconsin, Whitewater
800 West Main Street, Whitewater, WI 53190

2. Cellulose: The most abundant, biodegradable and biocompatible polymer
Applications include fiber, paper, membrane, polymer and paint industries
Tissue engineering
Nanocomposites
Strong intra and intermolecular hydrogen bonding hence difficult for processing
H - bonding is reduced by partial replacement of hydroxyl groups, this process involves complex multiple steps and uses toxic chemicals => Conern to Environment
Effect on Nano-filler

3. Cellulose Dissolution
Ionic Liquid: Able to break down H-bonding in biopolymers, hence can dissolve biopolymers e.g. cellulose and silk
1-ethyl-3-methylimidazolium acetate (EMI acetate)
Cellulose pulp paper (Grade V-60) from Buckeye Technologies Inc.
Degree of Polymerization ~ 820
Control cellulose film regenerated from ionic liquid

4. Composites of cellulose and vapor grown carbon nanofiber (VGCNF) and carbon nanotubes
Composites of cellulose and hydroxyapatite (HAP)

5. 1) Cellulose-CNT Nanocomposite
SWNT
MWNT
VGCNF
Young’s Modulus ~ 1 TPa
Electrical Conductivity
~ 100 times Stronger than Steel at 1/6th of weight
Thermal Conductivity

6. Previous Experience with Polyacrylonitrile (PAN)/VGCNF Nanocomposites
Mechanical Properties
Electrical Conductivity
Thermal Stability
Experimental and theoretical specific modulus of various PAN/VGCNF composite films assuming the modulus of VGCNF to be 50 GPa. (a) Experimental modulus, (b) theoretical modulus assuming VGCNF length to be 0.2 m, (c) 1 m, (d) 10 m and (e) 100 m.
Electrical conductivity of PAN/VGCNF composite films.
Tan δ (below) as a function of temperature for (a) Control PAN, (b) PAN/5%VGCNF, (c) PAN/10%VGNCF, (d) PAN/20%VGCNF, (e) PAN/40%VGCNF and (f) PAN/90%VGCNF composite films.
Guo, H.; Rasheed, A.; Kumar, Satish J Mater Sci (2008) 43:

7. Enhance tensile strength and tensile modulus Impart thermal stability
Incorporation of a nano-filler (SWNT, MWNT, VGCNF) into cellulose matrix is expected to
Enhance tensile strength and tensile modulus
Impart thermal stability
Reduce shrinkage (dimensional stability)
Result in electrical conductivity in the nanocomposite
Electroactive paper
Actuators/sensors
Medical Devices
Cellulose+5%VGCNF

8. 2) Cellulose/Hydroxyapatite Nanocomposites
Hydroxyapatite (HAP) Ca10(PO4)6(OH)2 finds many applications as bio-material
Filler to replace amputated bone
Coated to promote bone in-growth into prosthetic implants
Cellulose Hydroxyapatite composites have great potential to be used in bone tissue engineering

9. Previous Reports: Cellulose/HAP Composites
Precipitated on cellulose in-situ from aqueous solution*
Deposition of HAP limited to surface
The process is extensively long (up to ~14 days) to prepare the composite
Current Approach
Homogenous dispersion of HAP in cellulose matrix
Fast processing
Composition of composite can be easily varied
Cellulose+10% HAP
Cellulose+60% HAP
*Materials Letters 60 (2006)
Hong, L.; Wang Y. L.; Jia, S. R.; Huang, C. G.; Wan, Y. Z Hydroxyapatite/bacterial Cellulose Composites Synthesized via Biomimetic Route. Materials Letter. 60:

10. Acknowledgments
Students (Peter Zastraw, Matthew Magruder, Travis Martin)
Prof. Peter Jacobs (Geology Department, UW-Whitewater) for XRD
UW-Whitewater for funding
Department of Chemistry, UW-Whitewater

12. Cellulose/HAP Composites: XRD
Testing for biocompatibility