Shape-memory polymers are smart materials that have the ability to return from a deformed state to their original shape induced by an external stimulus, such as temperature change.

1. SHAPE MEMORY POLYMERS
By
NITHEESH D NAYAK

2. AGENDA
 INTRODUCTION
 LITERATURE REVIEW
 STRUCTURE OF SMP
 COMPARISON OF SHAPE MEMORY POLYMERS WITH SHAPE MEMORY ALLOYS
 SHAPE MEMORY POLYURETHANE (SMPU’s)
 APPLICATIONS
 CONCLUSION
 REFERENCES

3. INTRODUCTION
 SHAPE MEMORY MATERIALS
• A material that remember its permanent shape.
• Shape change is triggered by an external stimulus.
 SHAPE MEMORY EFFECT
The property of a material to gain back its original shape when activated with suitable condition
s
 Shape memory alloys (SMA)
 Shape memory Ceramics
 Shape memory polymers
 Shape memory gels

4.  SHAPE MEMORY POLYMERS
• It is a polymeric smart material
• SMP’s can retain two or sometimes three shapes
 WAYS TO ACTIVATE SHAPE MEMORY EFFECT
• Thermo responsive shape memory effect
• Electrical heating induced shape memory effect
• Light induced shape memory effect
• Magnetically induced shape memory effect
• Water activated shape memory effect
INTRODUCTION Cont…

5. LITERATURE REVIEW
 M.John and G.Li
• They investigated the possibilities of creating a self-healing shape memory polymer based on
a foam structure
• Reverse transforming the polymer by heating, brings the crack faces back into contact
 Q.Meng, J. Hu
• They looked into blends to create an improved shape memory polymer
• The time to recover is improved by increasing thermal conductivity
• Filling conductive powder help in fabricating SMP sensitive to electricity, light and moisture
 B.Yang, W.M.Huang
• They investigated the effect of moisture on the glass transition temperature of a
polyurethane shape memory polymers
 J.Diani, C.Fredy, P.Gilormini
• A new torsion device was designed and built for testing the shape fixity and shape recovery
of shape memory polymers at large deformations

6. STRUCTURE OF SMP
 SMP are compound plastics polymers that have
a special chemical structure
 Glass transition temperature (Tg) plays
important role in SMP
 SMP become rubbery elastic and flexible above
Tg
 Deformed shape become fixed and shape will
remain stable
Shape Memory Effect in SMP relay on
• Crystallization and cross-linking
• Entanglement of polymer chain
• Microstructure of polymer
Position 1 - The polymer will be in active stage
Position 2 - Inelastic or frozen
Position 3 – Polymer will be hard and rigid
Position 4 - Elastic and flexible state

7. PARAMETERS FOR CHARACTERIZATION OF SMP’s
STRUCTURE OF SMP Cont..
• Shape or strain fixity
• Recovery stress
• Strain or shape recovery
• Recovery time
LO is the original length
LS is maximum value of deformation
LD is final temporary shape
LF is the final length after shape recovery cycle.

8. COMPARISON OF SHAPE MEMORY POLYMERS
WITH SHAPE MEMORY ALLOYS
PROPERTY SMP SMA
Density (g/m3) 0.9-1.25 6-8
Phase Transformation Glass Transition Martensitic Transformation
Strain (%) Up to 400% Up to 8%
Recovery Speed (s) 1s to several min <1s
Bio compatibility and
degradability
High Not all
Condition at high temp Soft Hard
Condition at low temp Hard Soft
Cost Cheap More expensive
Shape training Easy and fast Difficult
Fabrication/ processing
Condition
< 200⁰C, low pressure > 1000⁰C, high pressure

9. SHAPE MEMORY POLYURETHANE (SMPU’s)
 These types of polyurethane are characterized by a segmented structure and the
morphology depends on chemical composition and the length of the segment
 PROPERTIES OF SMPU
o Shape Memory Effect
o Permeability
o Young’s modulus
 Shape memory PU is composed of three basic materials,
• Long chain polyether or polyester polyol,
• Diisocyanate
• Glycol (chain extender).
Hard Segment
Soft Segment

10. APPLICATIONS
 BIOMEDICAL APPLICATIONS
• CATHETERS
• ORTHOPEDIC BRACES AND SPLINTS
• LASER-ACTIVATED SMP MICROACTUATOR
• FIBER SUTURE
 TEXTILE
 DAMPING ELEMENTS
 STRUCTURAL MATERIALS

11.  The future of advanced materials is unpredictable
 These materials may have possibility in solving engineering problems with unachievable
effectiveness
 The materials scientists are now attempting to develop shape memory polymers which
can memorize more than one position in future
 Develop smart textiles with shape memory functions using SMPU
CONCLUSION

12. [1] Parliamentary Office of Science and Technology. 2008. “Smart Materials and Systems”.
Available from: http://researchbriefings.parliament.uk/ResearchBriefing/Summary/POST-PN-
299
[2] Brent, V. 2006. “Characterization of Shape Memory Polymers”. Research and Technology
directorate Mechanics of Structures and Materials Branch. 11, pp. 877-886.
[3] Wolfgang Wagermaier, Karl Kratz, Mallias Heuehel, and Andreas Lendlein, 2009,
“Characterization Method of Shape Memory Polymer”, Springer Verlag Berlin Heidalburg, pp
97-114.
[4] Gil, E. S. and Hudson, S. M. 2004. “Stimuli-responsive polymers and their bioconjugates”.
Progress in Polymer Science. 29, pp. 1173-1222.
[5] Julie Diani, Carole Fredy, Pierre Gilormini, Yannick Merckel, Gilles Regnier, et al. A torsion test
for the study of the large deformation recovery of shape memory polymers. Polymer Testing,
Elsevier, 2011, 30 (3), pp.335-341.
[6] Manu John and Guoqiang Li1 (2010) “Self-healing of sandwich structures with a grid
stiffened shape memory polymer syntactic foam core”, Department of Mechanical Engineering,
Louisiana State University
[7] Bin Yang, Wei Min Huang *, Chuan Li, Jun Hoe Chor (November 2004)“ Effects of moisture
on the glass transition temperature of polyurethane shape memory polymer filled with nano-
carbon powder” School of MPE, Nanyang Technological University.
[8] Siskind, R. D. 2008. “Model Development for Shape Memory Polymers”. North Carolina State
University. Pp. 1-10
REFERENCES

13. QUESTIONS ?

14. THANK YOU