SYNTHESIS AND CHARACTERIZATION OF

POLYACRYLONITRILE (PAN) AND CARBON FIBERS

Prof. Dr. Tahir Jamil

Chairman
Engr. Shahzad Maqsood Khan
Presenter

Department of Polymer
Engineering & Technology
University of the Punjab,
Lahore
PRESENTATION APPROACH
?
?
Carbon Fiber
? PAN

Polymer
Polymer
 POLYMER
THE SCIENCE AND ENGINEERING OF LARGE MOLECULES
• Long chain molecules
• long molecule made up by the repetition of
small unit called monomers BUILDIGNG BLOCK
POLYMER AT PLAY

Find Polymers in figure

 POLYMER CLASSES
Polymers

Inorganic Organic

Natural Natural
Organic/Inorganic
Clays, Sands, Glass, Rock- Proteins, Nucleic acids,
Siloxane, Lignins, Polysccharides,
like, Ceramics,
Polyphosphazenes, Polyisoprene, Melanin
Graphite/Diamond,
Polyphosphate esters,
Silicas
Polysilanes, Sol-gel
network
Synthetic Synthetic
Fibrous glass, Silicon PE, PS, Nylons, PET,
Carbide, Poly(boron PVC, PU, PC, PMMA,
nitrid), Poly(sulfur PVAC, PP, PTFE
nitride)
 POLYMER
-A-A-A-A-A-A-A-A- Homo Polymer

-A-B-B-A-B-A-A-B- Random Copolymer

-A-B-A-B-A-B-A-B- Alternating Copolymer

-A-A-A-A-B-B-B-B- Block Copolymer

-A-A-A-A-A-A-A-A- Graft Copolymer

B-B-B-B-B-B-
POLYMER
POLYACRYLONITRILE (PAN)
 IMPORTANCE OF PAN
Homo polymers of Polyacrylonitrile have been used as
• Fibers in hot gas filtration systems
• Outdoor awnings
• Sails for yachts
• Fiber reinforced concrete
Mostly copolymers containing Polyacrylonitrile are
used as
• Fibers to make knitted clothing, like socks and
sweaters
• Outdoor products like tents
POLYACRYLONITRILE (PAN)
• In 1893 Acrylonitrile was prepared by
reacting Propylene with Ammonia
(NH3) and oxygen in the presence of
catalysts.
• PAN is a vinyl polymer and a derivative
of the acrylate family of polymers.
• It is made from acrylonitrile monomer
through suspension methods using
free-radical initiators.
POLYACRYLONITRILE (PAN)
 PAN LAB SYNTHESIS
• Polymerization of acrylonitrile (AN) by
redox method
• Flask or lab reactor
• Nitrogen atmosphere
• Fitted with a condenser
• Reaction medium (Dimethylsulfoxide
(DMSO) solvent or water)
 PAN LAB SYNTHESIS
• Emulsifier ( e.g Sodium bisulfite (SBS) )
• Initiators ( e.g Potassium Persulfate (KPS),
Azodiisobutyronitrile (AIBN), Itaconic acid (IA) )
• Time 1–3.5 hr
• Precipitation
• Filtration
• Washing ( methanol and deionized water etc)
• Drying under vacuum till a constant weight
 PAN CHARACTERIZATION
• FTIR (Fourier Transform Infrared Spectrophotometer)
• NMR (Neutron Magnetic Resonance)
• GPC (Gel Permeation Chromatograph)
• DSC (Differential Scanning Calorimeter)
• TGA (Thermo Gravimetric Analyzer)
• TMA (Thermo Mechanical Analyzer)
 PAN CHARACTERIZATION
FTIR

R. Setnescu, S. Jipa, T. Setnescu, W. Kappel,

S. Kobayashi, Z. Osawa. IR and X-ray characterization of the ferromagnetic phase of
pyrolysed polyacrylonitrile, Carbon 37, (1999) 1–6.
 PAN CHARACTERIZATION
NMR

1H-NMR spectrum of the PAN

precursors

13C-NMR spectrum of the PAN

precursors
 PAN CHARACTERIZATION
DSC

N. Yusof and A. F. Ismail. Preparation and characterization of

polyacrylonitrile/acrylamide-based activated
carbon fibers developed using a solvent-free
coagulation process, International Journal of Chemical and Environmental Engineering. 1,
(2010) 79-84.
 PAN CHARACTERIZATION
TGA

H. B. Sadeghi, H. A. Panahi, M. Abdouss, B. Esmaiilpour,

M. N. Nezhati, E. Moniri, Z. Azizi.
Modification and Characterization of Polyacrylonitrile Fiber by Chelating Ligand for
Preconcentration and Determination of Neodymium Ion in Biological and Environmental
Samples. J. APPL. POLYM. SCI. (2013) 1125-1130.
 PAN CHARACTERIZATION
TMA

T. V. Sreekumar, T. Liu, B. G. Min, H. Guo, S. Kumar, R. H. Hauge, R. E. Smalley,

Polyacrylonitrile Single Walled Carbon Nanotube Composite Fibres. Adv. Mater. 16, (2004)
58-61.
PAN CHARACTERIZATION
DMA

Temperature v/s Storage Modulus of PAN

PAN CHARACTERIZATION
DMA

Temperature v/s Tanδ of PAN

PAN INDUSTRIAL PRODUCTION
 POLYMER SYNTHESIS PILOT PLANT
DEPARTMENT OF POLYMER ENGG. PU LHR
 POLYMER SYNTHESIS PILOT PLANT
DEPARTMENT OF POLYMER ENGG. PU LHR
 POLYMER SYNTHESIS PILOT PLANT
DEPARTMENT OF POLYMER ENGG. PU LHR
 POLYMER SYNTHESIS PILOT PLANT
DEPARTMENT OF POLYMER ENGG. PU LHR
PAN FIBER & CARBON FIBER
 IMPORTANCE OF PAN FIBER
PAN-based fibers eventually supplanted most
rayon-based fibers, and they still dominate the
world market. In addition to high modulus fibers,
researchers have also developed a low modulus
fiber from PAN that had extremely high tensile
strength. Used in
• Sporting goods such as golf clubs, tennis rackets,
fishing rods, and skis
• Military
• Commercial aircrafts
 IMPORTANCE OF CARBON FIBER
Strength: carbon fibers tensile strength is
un-matched by any metal available
(Titanium alloys, Cr Mo, steel or Aluminum
alloys)
Weight: carbon fiber/epoxy weight per
volume is less than half that of aluminum
almost 4 times lighter than titanium
Fatigue resistance of carbon fiber
surpasses that of any other structural
material
 IMPORTANCE OF CARBON FIBER
Yield strength: carbon fiber has a very high
yield strength allowing it to flex under extreme
loading and return to its original shape
Corrosion: carbon fiber/epoxy is extremely
resistant to corrosion
 IMPORTANCE OF CARBON FIBER
Carbon fiber parts will be lighter and
stronger. Because of such properties
you find this technology used in
• Aviation
• Sports
• High-end racing and
• Snowmobiles
 CARBON FIBER
Carbon fibers are derived from one of the three
precursor materials
• PAN (Polyacrylonitrile fiber)
• PITCH
• Isotropic
• Mesophase
• Rayon
 PAN FIBER INDUSTRIAL PRODUCTION
• Melt Spinning
• Dry Spinning
• Wet Spinning
• Wet/Dry Spinning
PAN FIBER FORMATION
Polyacrylonitrile fibers were produced by
wet-spinning.
The coagulation bath is normally
• DMSO/H2O system,
• Bath temperature is 60°C
• Bath concentration is 65% (namely,
DMSO/H2O=65/35(wt/wt))
• Bath minus stretch ratio is –10%
PAN FIBER INDUSTRIAL PRODUCTION
PAN FIBER INDUSTRIAL PRODUCTION
PAN FIBER INDUSTRIAL PRODUCTION
PAN FIBER INDUSTRIAL PRODUCTION
 CARBON FIBER FORMATION
Fiber changing color. The white
PAN strands at the bottom pass
through the air heated oven and
begin to darken. Quite quickly
they turn to black
CARBON FIBER INDUSTRIAL PRODUCTION
 PAN FIBER INDUSTRIAL FORMATION
• Oxidization
• Stress graphitization of
Polyacrylonitrile based carbon fiber
• Carbonization (graphitization)
 PAN FIBER INDUSTRIAL FORMATION
Oxidization
• This produces an oxidized ladder polymer
structure approximately parallel to the fiber
axis which may be regarded as the template
for the formation of the oriented carbon fiber.
• Oxidation involves heating the fibers to around
300 oC in air. This evolves hydrogen from the
fibers and adds less volatile oxygen.
• The polymer changes from a ladder to a stable
ring structure, and the fiber changes color
from white though brown to black.
 CARBON FIBER INDUSTRIAL PRODUCTION

Stress Graphitization of Polyacrylonitrile

Based Carbon Fiber
• Carbon fiber can be made by the
pyrolysis of organic polymer fiber
precursors. The strength of PAN carbon
fiber declines when heated above
1,200° C.
• Therefore increasing strength with
Young's modulus can be obtained if
stress is applied to the fiber at
graphitizing temperatures.
 CARBON FIBER INDUSTRIAL PRODUCTION
CARBONIZATION (GRAPHITIZATION)
• Involves heating the fibers up to 3000
oC in an inert atmosphere.
• Fibers are now nearly 100 % carbon
CARBON FIBER FORMATION CHEMISTRY
When we heat Polyacrylonitrile, the heat causes the cyano repeat units to form
cycles…
CARBON FIBER FORMATION CHEMISTRY
At higher temperature, carbon atoms kick off their hydrogen, and the rings become
aromatic. This polymer is a series of fused pyridine rings. This expels hydrogen gas,
and gives us a ribbon-like fused ring polymer.
CARBON FIBER FORMATION CHEMISTRY
When the temperature increases from 600 up to 1300 oC, the ribbons will
themselves join together to form even wider ribbons like this:
CARBON FIBER FORMATION CHEMISTRY
More nitrogen is
expelled and the
ribbons are really
wide, and most of
the nitrogen is
gone, leaving us
with ribbons that
are almost pure
carbon in the
graphite form.
FIBER CHARACTERIZATION
• XRD (X Ray Diffraction)
• SEM (Scanning Electron Microscopy)
• DSC (Differential Scanning Calorimeter)
• TGA (Thermo Gravimetric Analyzer)
• DMA (Dynamic Mechanical Analyzer)
• UTM (Universal Testing Machine)
PAN TO CARBON FIBER CHARACTERIZATION
XRD
PAN TO CARBON FIBER CHARACTERIZATION
XRD DATA
PAN TO CARBON FIBER CHARACTERIZATION
FTIR
 PAN CHARACTERIZATION
YOUNG’S MODULUS & TENSILE STRENGTH
GASES RELEASED DURING PYROLYSIS OF
PAN
ELEMENTAL ANALYSIS
 PAN FIBER GRADE
The Carbonization temperature will determine the grade of fiber produced:

Carbonization to 1000 1000 - 1500 1500 - 2000 2000 +

Temperature (oC) (Graphitizatio
n)

Grade of Carbon Low Standard Intermediate High

Fiber Modulus Modulus Modulus Modulus

Modulus of to 200 200 - 250 250 - 325 325 +

Elasticity (GPa)
CARBON FIBER GROUPING
FINAL HEAT TREATMENT TEMPERATURE
Type-I, high-heat-treatment carbon fibers (HTT)
Final heat treatment temperature > 2000C and can be
associated with high-modulus type fiber.
Type-II, intermediate-heat-treatment carbon fibers (IHT)
Final heat treatment temperature should be > = 1500C
and can be associated with high-strength type fiber.
Type-III, low-heat-treatment carbon fibers
Final heat treatment temperatures not greater than
1000C. These are low modulus and low strength
materials.
CARBON FIBER FORM PAN FIBER
CARBON FIBER FROM PITCH
MECHANICAL PROPERTIES OF CARBON
FIBER
 OUR RESEARCH PAPER
61 Journal of Pakistan Institute of Chemical Engineers Vol. XXXVII
Synthesis And Characterization of Polyacrylonitrile Copolymers
Waqar Ahmad, Shahzad Maqood Khan, Muhammad Arif Butt and Tahir Jamil*
Abstract
Polyacrylonitrile (PAN) and copolymers of PAN with monomers like MMA, BA, VA, AM,
AA, and S of varying compositions and molecular weights were prepared by emulsion
polymerization in a continuous aqueous phase in the presence of sodium lauryl sulfate
as emulsifier and potassium persulfate/ammonium persulfate as initiator. The
molecular weights were determined from the dilute solution viscosity using Mark-
Houwink equation. The chemical compositions of copolymers were characterized by FT-
IR spectroscopy.
Keywords: Polyacrylonitrile (PAN), Polymer, Emulsion polymerization, FT-IR
CONCLUSIONS OF OUR WORK
• The synthesis of homo and copolymers of PAN via emulsion polymerization was
successfully achieved
• Maximum yield of 94.5 % for Polyacrylonitrile (100)
• Maximum yield of 90.2 % for P(AN-co-AM-co- MAA, 96.1:3.2:0.7)
• The highest molecular weight, Mv = 144068, for copolymer P(AN-co-AM-co-
MAA, 96.1:3.2:0.7)
• followed by Mv = 75403.85 for P(AN-MMA, 96:4)
• and Mv = 75403.69 for PAN (100).
• MMA was found to be the best monomer for copolymerization of AN.
CONCLUSIONS OF OUR WORK
• As commercially available PAN precursor for carbon fiber have molecular weight
about 150000 and we have achieved 144068 MW for P(AN-co- AM-co-MAA,
96.1:3.2:0.7), this sample of PAN can be a very suitable precursor for carbon
fiber.
 ACKNOWLEGMENT
We are grateful to
• Prof. Dr. Arshad Chughtai (Chairman, Department of Textile Engineering & Technology University of
the Punjab Lahore
• Miss. Nafisa Gull (Research Officer, Department of Polymer Engineering & Technology University of
the Punjab Lahore)
• Dr. Misbah Sultan (Assistant Professor, Department of Polymer Engineering & Technology
University of the Punjab Lahore)
• Engr. Muhammad Shafiq, Engr. Aneela Sabir (Lecturer, Department of Polymer Engineering &
Technology University of the Punjab Lahore)
• Miss Saba Bahzad Khan (Lab Supervisor, Department of Polymer Engineering & Technology
University of the Punjab Lahore)
• Engr, Adnan Ahmed, Engr. Muhammad Azeem Munawar, Engr. Khurram Javed, Miss Sidra
Waheed (Research Technician, Department of Polymer Engineering & Technology University of the
Punjab Lahore)
THANKS FOR YOUR ATTENTION !

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