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Nanocomposites of Cellulose For Medical Application

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Presentation on theme: "Nanocomposites of Cellulose For Medical Application"— Presentation transcript:

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

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