Silk Fibre Composites

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Silk Fibre Composites
SAMPE Europe 27th International Conference Aart
W. van Vuure, Karen Wolnik, Sofie Dupont, Jan
Vanderbeke, Nedda El-Asmar Ignaas
Verpoest Katholieke Universiteit Leuven,
Belgium 27th March 2006
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Silk Fibre Composites Introduction

• Why natural fibre composites?
• Environmental reasons
• Renewable resources
• Thermally recyclable, biodegradable, CO2 neutral
• Low energy consumption

2) Cost often (potentially) low cost (not
silk!)
3) Health safety less abrasive, more pleasant
to handle
4) Good specific mechanical properties
5) Natural image
Potential drawbacks variability
hydrophilicity (moisture) weak interface
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Silk Fibre Composites Introduction
What makes Silk fibres special?
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Silk Fibre Composites Test results
Impact Performance
Excellent falling weight impact performance!

• Plate thickness 0.75 mm
• No effect of thickness measured

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Silk Fibre Composites Test results
Tensile properties
High composite (tensile) strain to failure for
thermoplastic matrices high toughness
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Silk Fibre Composites Test results
Tensile properties

• Tensile modulus in 0º and 45º directions as
  expected
• Tensile strength in 0 direction matches with
  strength of silk fibres
• Tensile strength in 45 direction (for PBS) much
  higher than expected
• Strength isotropy?

Modulus
Strain to failure
Strength
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Silk Fibre Composites Interface
First characterisation of interface
properties Transverse 3 Point Bending on UD
composites
Low strength values suggest weak interface
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Silk Fibre Composites Processing

• So far limited effects seen from dye treatments
  and teflon treatment
• on mechanical performance
• 2)

Hypothesis Dryness imperfect wetting but no
effect seen on mechanical performance
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Silk fabric composites Mechanical performance

• Overall hypothesis Mechanical performance is
  controlled
• by properties of tough silk fabric? (embedded in
  tough matrix)
• Weak interface would not be so bad? (already
  known for impact)
• Verify by tests on fabrics
• Still need to see if interface properties can be
  optimised

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Silk Fibre Composites Thermoforming

• Twill weave silk/PP and silk/PBS
• Can be formed rather well
• Friction/polymer starvation at high deformation
• Improve by
• More deformable weaves (satin) or knits

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Silk Fibre Composites Conclusions

• Light and very tough and impact resistant
  material
• Can be shaped into complex shapes
• Natural material biodegradable composite
  demonstrated
• Improvement of interface needs attention, but
  current mechanical performance already ready for
  applications

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Silk Fibre Composites Applications?

• Impact prone consumer and industrial products
• Design fabrics (waste) can be used
• Bio-recyclable products