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1Department of Engineering Design and Materials

Biopolymer based nanocomposites; Characterization

Ingvild Kvien

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Outline

• Project description• Determination of structure• Where are we today?• Problems to solve• Progress plan/publications

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MatrixPLA (Polylactic acid)

(Cargill Dow)CAB (Cellulose ester)

ReinforcementCellulose crystals(MCC, Borregaard)

Biopolymerbased

Nanocomposite

Material propertiesStructure

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Nanocomposite propertiesdetermined by:

• Size and size-distribution of cellulose whiskers

• Spatial distribution and orientation of the whiskers in the matrix

• Physical and chemical bonding between the reinforcement and matrix

Microscopy

TEM (Transmission Electron Microscope)SEM (Scanning Electron Microscope)AFM (Atomic Force Microscopy)

X-ray techniqueWAXD (Wide angle X-ray diffraction)

Common structure techniques for nanocomposites: TEM and X-ray

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5Department of Engineering Design and Materials

Cellulose whiskers

AFM, TEM, SEM

Nanocomposite

TEM

SEM, AFM

X-ray

Combination of different X-raytechniques to determine:

- Size and size-distribution of whiskers?

- Orientation in the matrix?

But: cutting the whiskers

?

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Challenges:- apply instruments

developed for metals on polymers

- in nanoscale

- both phases are organic

Goal:to combine microscopy and X-ray techniques to have an overall picture of thenanocomposite

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Examples

• Preparation• Contrast• Agglomeration• Electrons are ”burning” the sample• Dimensions (orientation) 500 nm

2 µm

CAB + cellulose crystals (AFM, NTNU)

Cellulose crystals (TEM, NTNU)

Cellulose crystals (AFM, NTNU)

8Department of Engineering Design and Materials

TEM-picture of PLA +graft + PEG + cellulose crystals (IPM, NTNU)

So far:

Nanocomposite

But micro…..

PLA+graft+PEG+cellulose crystals (TEM, NTNU)

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Problems to solve

1. Separation of micro crystallinecellulose

chemical: mechanical: - sulphuric acid - ultrasound- DMAc/LiCl - stirring

(- homogenization)

Investments: - centrifuge- freeze dryer- homogeniziser(future studies)

2. Compatibility between reinforcement/matrix

- chemically modify the polymer - surface modification of MCC - surfactants

3. Processing

- parameters- feeding (how and where)

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(AFM, NTNU)

1 Separation of MCC (success)

500 nm

2.5 µm

MCC

(AFM, NTNU)

(SEM, NTNU)

Organic solvent (DMAc/LiCl)

Sulphuric acid

Moving on to stage 2 and 3….

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It is possible

Solution casted nanocomposite (AFM, NTNU)

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Progress plan

500 nmPublications

1. Dispersion of microcrystalline cellulose in DMAc/LiCl

2. Investigation of structure and distribution of cellulose nano whiskers in polylactic acid (PLA) by TEM, SEM, AFM and X-ray diffraction

Conference in Madison, May 2005

Tasks 2003 2004 2005 2006

1. Litterature studyxx

xxxx

2. Nanofiber treatments and separation process xxxxxx

3. Characterization of nanofibers (TEM,AFM,X-Ray)xxxxxxx

xxxxx

4. Characterization of nanocomposites properties and structure (DMTA, TEM, AFM, XRD, DSC) xxxx

xxxxxxxxxxxx xxxx

5. Preparation of PhD-thesis and defence of the work xxxxx