1. 1
Structure - Processing Linkages
in
Polyethylene
David Brough
Abhiram Kannan
Final Presentation
ME 8883
2. Outline
‣ Motivation & Objective
‣ X Ray Scattering Datasets of Polyethylene
‣ Workflow
‣ Results and Discussions
‣ Future Work
‣ Summary
‣ Acknowledgements
3. Motivation
Jancar, J. et al. Current issues in research on structure - property relationships in polymer
nanocomposites.
Polymer 51, 3321–3343 (2010)
Hierarchical structural assembly of a material influences the
properties on the macroscopic scale
4. Motivation & Objective
Processing
Condition a
Processing
Condition b
Microstructure
Set a
Microstructure
Set b
Properties
Set a
Properties
Set b
PE
Temperature
Pressure
Isotropic vs Anisotropic
Homogeneous vs Heterogeneous
Yield
Strength
Polyethylene (PE)
5. X Ray Scattering Data of
PE
Small Angle X Ray Scattering (SAXS) data is related to spatial
statistics
200 µm x 200 µm
Lamella
Inter
Crystalline
Amorphous
6. Play
Film sample is strained continuously while being probed by X
rays
X Ray Scattering Data of
PE
7. Bulk
Density
Processing Condition Film Thickness (µm)
0.912
gms/cc
1 20 30 75
2 20 30 75
0.923
gms/cc
1 20 30 75
2 20 30 75
Workflow
spatial
statistics
dimensionality
reduction
processing
linkage
SAXS
Data
Principal
Components
Analysis (PCA)
Transfer
Function
Model (TFM)
8. Principal Components
Analysis
• 3200 .tif images across 12 samples (~250 per sample)
• Log intensity scaled by mean to account for thickness
effects
• Scaled images fed to PCA Algorithm
• Outputs of PCA Algorithm visualized in D3
Compare :-
1. Effects of Processing Conditions
2. Effects of Density
3. Effects of Thickness
9. Transfer Function Model
Linkage
• For sample 6,10 each Principal Component is fit to a
Transfer Function model of order (2,1,5)
• Using obtained coefficients, predictions for the remaining
samples are made
• Comparison of Predicted and True Low Dimensional
Trajectories.
Model Equation:-
10. Summary
• Dimensionality Reduction of time resolved data by PCA
• Objective comparison between strain derived
microstructures of PE
• Minimization of User Bias incurred from traditional analysis
protocols
• Applied method for deriving processing linkages via
Transfer Function Model might hold potential
11. Future Work
• Extraction of spatial statistics by via transformation of
SAXS data
• Reconstruction of 2 Phase Crystalline - Amorphous
Microstructures
• Extend Transfer Function Model to incorporate Stress
Values
• Property Linkage with Crystallinity, Orientation etc.
• Additional Length Scales (~0.1 nm) from Wide Angle
Scattering Data (WAXS)
12. Acknowledgement
s
• Dr. Surya Kalidindi (GT)
• Dr. Hamid Garmestani (GT)
• Dr. Tony Fast (GT)
• Dr. David Bucknall (GT)
• Dr. David Fiscus (ExxonMobil)
Editor's Notes
Microstructure defined as everything under the micron scale.
Structural arrangement at different length scales results in different macroscopic properties.
The structural arrangement and therefore final properties depend on the processing conditions under which the microstructures are fabricated.
For example, under certain conditions of temperature and pressure, PE can form microstructures that result in material properties useful for making toothbrushes.
Under different conditions of of temperature and pressure, PE can form microstructures that result in material properties useful for making bullet proof fabrics.
Our objective in this project is to link different PE microstructures with their processing conditions and ultimately to their properties.
What is discretization?
What are spatial statistics?
What are the methods of dimension reduction?
What is the linkage and how do we come up with it?
This slide needs work.
Our data is in fourier space. But it is directly related to the spatial stats in fourier space.
We use SAXS data from 12 films as input data to dimensionality reduction because of the similarity between SAXS data and 2 pt stats in PE..