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

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Presentation on theme: "Nanocomposites of Cellulose For Medical Application Asif Rasheed Lecturer, Department of Chemistry University of Wisconsin, Whitewater 800 West Main Street,"— 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

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 Cellulose pulp paper (Grade V-60) from Buckeye Technologies Inc. Degree of Polymerization ~ 820 Control cellulose film regenerated from ionic liquid 1-ethyl-3-methylimidazolium acetate (EMI acetate)

4 1)Composites of cellulose and vapor grown carbon nanofiber (VGCNF) and carbon nanotubes 2)Composites of cellulose and hydroxyapatite (HAP)

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

6 Previous Experience with Polyacrylonitrile (PAN)/VGCNF Nanocomposites 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: Mechanical PropertiesElectrical ConductivityThermal Stability

7 Electroactive paper Actuators/sensors Medical Devices Cellulose+5%VGCNF 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

8 2) Cellulose/Hydroxyapatite Nanocomposites Hydroxyapatite (HAP) Ca 10 (PO 4 ) 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 *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: Current Approach Homogenous dispersion of HAP in cellulose matrix Fast processing Composition of composite can be easily varied Cellulose+10% HAPCellulose+60% HAP

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

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12 Cellulose/HAP Composites: XRD Testing for biocompatibility


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