It is a composite and very useful in industrial approach

2. Melt processing and mechanical property
characterization of multi-walled carbon nano tube/high
density polyethylene (MWNT/HDPE) composite films
RESEARCH
Of:
Wenzhong Tong (2003)
Review
By:
SULEMAN HANIF (1610)
GPGCS FAISALABAD

3. General Survey
 HDPE was used as matrix material for carbon nano tube polymer
composite
 Composite were fabricated using MELT processing method
 Composite films are analysed by SEM and TEM to observe NT dispersion
 Mechanical properties are checked by PUNCH test

4. Introduction:
CNT is single sheet of Graphite,rolled into a cylinder
having several micron in length and few nm in diameter
FORMS of NT:
• Single-Walled CNT
• Multi-Walled CNT
(Single is not as specific)

6. Single-Walled CNT
1. It consists of one layer of carbon atoms through the thickness of
cylindrical wall
single-walled zigzag carbon nanotube

7. Multi-Walled CNT
1. It consists of concentric cylinders around a hollow with a constant separation
between layers
2. Each cylinder has 2 to 25 nm diameter and length may vary to several
microns
3. Graphite nature of CNT provides high stiffness, strength and conductivity
4. Elastic modulus of CNT is greater than 1.0TPa
( even steel has 0.2 ) and tensile strength ranges from 10 to 50 GPa

9. Thermal Conductivity
• Ranges from 3000 to 3200 W/mK ( too much high )
• CNT is electrically conductive or may be semi-conductive
These properties attract candidates to use it
Due to this ,the research is carried out for:
• Improving its properties
• Increasing its electrical conductivity
NOTE:
Vande Waal’s forces affects CNT due its small size,These forces make
the dispersion difficult and fabrication becomes tough.

10. Methods:
There are some methods used;
1.Direct Mixing
2.Situ Polymerization
3.Solution Method
4.Melt Process

11. 1.Direct mixing
Applied only to thermosetting polymer
CNT are dispersed by mechanical mixing
Low viscosity is obtained called epoxy resin
Resin curation in exothermic polymerization reaction
CNT polymer composite is gained

12. 2.Situ polymerization
CNT are added into unpolymerized solution
containing monomers
Nanotubes are dispersed into that solution
(sometimes chemically attachment with polymer
chain occurs )
Curing ( in exothermic non-reversible polymerization)

13. Direct VS Situ polymerization
Situ-polymerization
 Used to disperse CNT in Thermo-
plastic polymers
Direct mixing
 Used to disperse CNT in
Thermosetting polymers

14. 3.Solution Method
Solvent is used for dissolving thermoplastic polymer
CNT are added to the solution
Solvent evaporated
( large amount of solvent evaporation is not too good )
For chemical resistent HDPE, toxic solvents are used like
TOLUENE and XYLENE
Solution method is last resort because of upper 3rd point

15. 4.Melt Processing
CNT are mechanically dispersed into a melt polymer by using
a mixer
Fluid shear forces are used to break NT aggregates
This is a good process
Applied at industrial level

16. Recent Studies
1. JIN used ( PMMA ) polymethyl methacrylate and melt at 573K and then applied
pressure for getting films
2. POSTCHE mixed CNT in ( PC ) polycarbonate by using Haake co-rotating twin
screw extruder and extruded composite were compressed into bars
3. ANDREWS studied CNT/polymer composite using four different polymer system
polypropylene, ( ABS ),( PS ),(HIPS) acrylonitrile butadiene styrene,polystyrene and
High impact polystyrene respectively

17. Characterization of HDPE
Excellent chemical resistance
High impact strength
Good fatigue
Abrasive wear resistance
Low coefficient of friction
Moderate stiffness and rigidity

18. Material
Material was purchased from ILJIN NANOTECH in
South Korea

19. Fabrication
Carried out for PUNCH test
Three steps
1. Preparation of composite pellets
2. Feeding of pellets to extruder
3. Formation of thin (0.5mm) film

20. procedure
a. CNT are added to pellets
b. Heated at 573K
c. Stirration
d. Compression
e. Filming
f. Fracturing of films in composite pellets
g. Feeding into extruder
h. Compressed in between the plates of
Aluminum for getting very little
thickness to punch test

21. Characterization
NT are studied under SEM and TEM
NTs are first fractured by mechanical source
Fracture surface is scanned under SEM and TEM
( fracture is done to avoid loss of HDPE pull )

22. Punch test
1. The specimen is subjected to
a lateral indenter driven at a
constant displacement rate
through the guide hole.
2. The small punch test is
carried carefully for use in
characterizing the mechanical
properties of ultra high
molecular weight
polyethylene UHMWPE

23. Results
 The quality of polymer is
obtained by getting CNTs in
the HDPE .
 The polymer is 98% efficient
and widely used .
 No background material are
wasted out
 Is used highly in formation of
cans and bottles etc

24. Conclusion
In the present work, a melt processing method was used
to make MWNT/HDPE composite films.
The MWNTs
were dispersed into HDPE by the shearing action of a twin
screw extruder.
SEM and TEM pictures show that although
most MWNTs form small aggregates in the polymer
matrix, the aggregates are uniformly dispersed on a
size scale of 10 mm or larger.
The small punch test results
show that the stiffness, the yield strength, and the fracture
toughness of MWNT/HDPE composite films all increase
with increasing percentage of MWNTs.

26. THANK
YOU