3. Carbon Fiber
• Also called graphite fiber.
• It is in the form of several
long strands of a material
mainly composed by
carbon atoms.
• Each strand is 0.005 –
0.010 mm thick in
diameter.
• First made by Dr.
Roger Bacon.
Carbon Fiber.flv
5. Advantages
• It has the greatest compressive strength of all
reinforcing materials.
• High strength to weight ratio.
• Low coefficient of thermal
expansion.
• Its density is much lower
than the density of steel.
6. Applications
• Used to reinforce composite materials
• Used structurally in high-temperature
applications.
• As an electrode with
• high surface area and
• impeccable corrosion
• resistance.
• Anti-static component.
7. Creation
• Spinning: A polyacrylonitrile plastic is spun into
fibers which are then washed and stretched to
the desired diameter.
• Stabilizing: fibers are heated with O2 to make
their bonding more thermally stable.
• Carbonizing: fibers then are heated without
oxygen, they lose non carbon atoms and bonded
carbon crystals are made.
• Treating surface: the surface is slightly oxidized.
• Sizing: fibers are coated and wounded into
bobbins.
8. Carbon Fiber’s Future
• Alternate Energy: wind turbines, compressed
natural gas storage and transportation fuel cells.
• Fuel Efficient Automobiles: moving towards large
production series cars.
• Construction Infrastructure: light weight pre-cast
concrete, earthquake protection.
• Oil Exploration: Deep sea drilling platforms,
buoyancy, umbilical, choke, kill lines and drill
pipes.
9.
10. Summary
• Carbon fiber composite manufacturing and
application is fairly mature, however lifetime
of composite structures is strictly defined to
~ 15 dpa, or a year in a fusion reactor.
Tritium retention in CFC’s can be reduced,
but never eliminated.
12. Introduction
• The applications of textile materials in
extracorporeal devices are receiving constant
attention for more innovative developments to
provide better care and cure, state S N Chaudhary
and S P Borkar, who discuss both traditional and
new developments in extracorporeal devices, such
as artificial kidney, liver and lung. The textile
scenario is rapidly changing from conventional
textiles to apparel and household industry to hi-tech
areas of industrial and medical applications. This
change is due to constant research going on in
different countries in the field of medical textiles. It
is one of the most dynamically expanding sectors in
the technical textile market. Hence with the advent
of nonwoven micro-fiber meshes, nano-fibers spun
by Electro spinning technique and hi-tech fibers,
the applications of medical textiles is becoming an
indispensable part in medicine and surgery.
Medical textiles are broadly classified as non-
implantable, implantable, extracorporeal devices,
and healthcare and hygiene products.
13. What is Extra Corporeal Devices?
• Extracorporeal devices are mechanical organs that are used for
blood purification
• include the artificial kidney (dialyser), the artificial liver, and the
mechanical lung (blood oxygenator).
• These devices must possess certain requirements, including:
» anti-allergic
» anti-carcinogenic properties
» good resistance to micro organisms
» antibacterial
» air permeability
» non-toxic and ability to be sterilized.
• The function and performance of these devices depend on the fibers
used.
14. What is Extra Corporeal Devices?
• These devices lie outside (extra) the body (corporeal) andare usually connected to
the patient by an arteriovenous shunt.In some respects they may be thought of as
artificial organs.(A shunt is a means of diverting flow, in this case blood, from an
arterythrough a device and then back into the body via a vein)
• Their function is based on the use of physical and chemicalprocesses to replace the
function of a failed organ or to removean unwanted constituent from the blood. The
patient’s bloodbefore entering these devices is infused with heparin to preventclotting.
• A variety of ancillary equipment may also be present tocomplete the system. This
may include items such as pumps,flow monitors, bubble and blood detectors, as well
as controlsystems for pressure, temperature, and concentration.
• It is important to note that these devices do not generallycontain any living cells.
Devices containing living cells arecalled bioartificial organs.
• A variety of extracorporeal devices have been developed.Perhaps the best known are
blood oxygenators that are used insuch procedures as open heart surgery and
hemodialysis to replace the function of failed kidneys.
15. Principles of blood purification
1. Principles of blood purification therapies are dialysis,
filtration and adsorption.
2. Separation membranes and adsorbents are used in blood
purification devices.
3. The membrane separation depends on membrane pore
size.
4. Purification methods are hemodialysis (dialysis,
membrane pore size 1 - 8 nm), hemofiltration (filtration,
membrane pore size 3 - 60 nm), plasma exchange
(filtration, porous membrane pore size 0.2 - 0.6
micrometer) and hemoadsorption.
5. Hemodialysis accounts for more than 90% of the blood
purification treatment in the world which corresponds to
30 million treatments per year keeping 3,00,000 patients
alive.
6. Hemodialysis includes removal of metabolic substances,
adjustment of electrolytes and pH, removal of excess
water by ultrafiltration and, dialysis which is usually a
membrane separation process.
7. During the process, blood contacts with dialysate through
a membrane (Figure 1).
8. Ultrafine membrane with blood on one side and dialysis
fluid on the other, the urea molecules which are much
more smaller than blood plasma get separated from blood
by using ultrafiltration.
16. Textile materials for
Extracorporeal devices
• Extracorporeal fibers are those used in mechanical organs such as hemodialyser (artificial kidney), artificial liver
and mechanical lung. Textile materials used in extracorporeal devices for blood purification and the function of
each device is shown in Table 1.
• Table 1. Materials used in Extracorporeal Devices
Product
application
Function System Fiber Type Key Points for
medical use
Artificial Kidney To remove waste
products from
patient's blood
Hemodialysis (HD)
Hemofiltration (HF)
Hemodifiltration
(HDF)
Hollow
viscose,hollow
polyster,fibre,
cuprophan,
Cuprammonium
hollow fiber
Moderate
mechanical
strength and
permeability,
blood
compatibility,
suppression of
complementary
activation
Artificial Liver To separate and
dispose of patient's
plasma and supply
fresh plasma
Plasmapheresis
(PP)
Hemoperfusion
(HP)
Hollow Viscose Blood
Compatibility,
adsorptive activity
Mechanical Lung To remove carbon
dioxide from
patient's blood and
supply fresh
oxygen
Hemoperfusion
(HP)
Hollow
polypropylene
fiber, hollow
silicone, hollow
silicone membrane
Gas exchange
effect blood
compatibility,
suppression of
blood plasma leak
17. Textile materials for
Extracorporeal devices
• Fiber material design by copying fibers within the living body is very important in order to protect human health in
an ever ageing society.
• The human body is a larger user of fiber material such as artificial kidney and artificial blood vessels.
• Of course, the human body is itself a fiber manufacturer and produces various kinds
• Of course, the human body is itself a fiber manufacturer and produces various kinds of fiber to protect our health.
• The communication between nanofibers in a cell (DNA) and nanofibers in clothes will be possible by the middle of
the century.
• A good example is the artificial kidney used for hemodialysis.
• Historically regenerated cellulose fibers in the form of cellophane have been utilized to retain waste products from
blood.
• Japan is the world leader in fiber technology to make 'Hollow fiber' for the artificial kidney.
• Over the past 20 years, cellulosic membranes have improved considerably due to the ability form: (i) Thinner
membranes. (ii) Controlled pore size (iii) Improvement of surface properties. These are now the basis of the
production of a range of artificial kidneys for treatment of chronic renal failure, and for this purpose the
membranes are made from cuprammonium solution and saponified cellulose triacetate.
18. Now-a-days most cellulose membranes are of the hollow-
fibre type, which fall into two categories:
• Conventional hollow fibres (AM-SD
Series)
• In this latter series, the biocompatibility of
the cellulose membrane is improved by
polyethylene glycol grafting technology.
• Specification for AK are as follows: Surface
membrane, 0.8 - 2.0 m2; Inner diameter,
180 µm; Membrane thickness membrane,
15 µm. Ordinary hemodialysis membranes
are believed to have a mean pore diameter
of 2 - 3 nm. Biocompatible membranes have
a larger pore size (4-10 nm).
• The sieving coefficient Sc, is defined as the
ratio of substrate in the filtrate to that in
supplying solution of ß2 microglobulin
(molecular weight 11800, molecular size c
4.5 x 2.5 x 2.0 nm3) = 0.6 and Sc of albumin
= 0.02.
• Biocompatible artificial kidney (AK) with
standard and middle flux range (AD-Bio
Series).
• The biomaterials Cuprophan (CU) and
acrylonitrile AN 69 membranes are both
currently used in bioreactors and
hemodialysers.
• appears to be very hydrophilic (due to OH
groups in the cellobiose units of the
cellulose molecule) as attested by a 22?0
water contact angle.
• Cuprophan, a cellulose membrane, has
been the material of choice due to the
selective removal of urea and creatinine
while retaining nutritive molecules such as
vitamin B12 in the bloodstream.
• Other medical applications of modified
cellulose include hemodialysis membranes
(vitamin E modified cellulose) and cellulose
diacetate membranes.
19. Artificial kidney
• The kidneys serve as filtering devices of the blood.
• The nephrons, the working units of the kidney, filter waste materials out of the blood and produce
urine to secrete toxins from body.
• The kidneys also maintain normal concentrations of body fluids, which play a key role in
homeostasis.
• . In the natural kidney, ultrafiltration of the blood occurs through the glomerular capillaries leading
to the removal of waste products and the purification of blood.
• In an artificial unit a membrane-dependent-ultrafiltration achieves essentially the same result.
• hemodialysis is indispensable for people suffering from kidney disease.
20. Functions of an Artificial Kidney
• The function of the artificial kidney is achieved by circulating the blood through a membrane, which may be either a flat sheet or a bundle
of hollow regenerated cellulose fibres in the form of cellophane that retain the unwanted waste materials.
• Multilayer fibres composed of numerous layers of needle-punched fabrics with varying densities may also be used and are designed to
remove the waste materials rapidly and efficiently.
• The synthetic polymer substitute being experimented with is a polyethylene glycol-polyethylene terephthalate block copolymer membrane
which can selectively filter.
• The synthetic polymer substitute being experimented with is a polyethylene glycol-polyethylene terephthalate block copolymer membrane
which can selectively filter. The material used in dialysis membranes are regenerated cellulose, cellulose triacetate, acrylonitrile
copolymer, poly (methyl methacrylate), ethylene-vinyl alcohol copolymer, polusulfone and polyamide which can be grouped as cellulose
and synthetic polymer systems.
• The development of artificial kidneys depends on the development of hollow fibre membrane.
• The purpose of the development of artificial kidney dialysis membrane is to mimic the ability of kidney to completely remove wastes like
urea and albumin.
21. Mechanical lung
• Mechanical lungs use microporous
membranes that provide high permeability
for gases (both O2 and CO2) but low
permeability for liquid flow and functions in
the same manner as the natural lung
allowing oxygen to come into contact with
the patient's blood.
• The mechanical lung was first developed as
a device to replace lung function during
heart surgery, and is now extensively used
for this purpose in the USA (about 250,000
per year) and Japan (20,000 per year).
• A newer form of artificial lung can also be
used as a supplementary respiratory device
over a longer term to assist the breathing of
patients suffering from acute lung or heart
failure, or older people with weak lung
function.
22. Functions of a Mechanical lung
• During the flow, oxygen, which is maintained at a high partial pressure, displaces carbon dioxide,
thus effecting purification.
• In this devices, oxygen flows around hollow fibres at extremely low pressure.
• . Blood flow inside of the fibre.
• The oxygen permeats the micropores of the fibre and comes in contact with the blood.
• The pressure gradient between the blood and oxygen is kept near zero to prevent mixing of
oxygen and blood.
• Red blood cells capture oxygen by diffusion process.
23. Artificial liver
• The liver is a remarkable organ; Like the skin, it can regenerate after severe trauma. In fact, a
patient can recover with only 20% of his or her liver still functional, as the liver grows back.
• However, there is a point of 'No return' after which the liver cannot regenerate, and there are
underlying disease conditions that, in some cases, make a transplant the only alternative.
• Unlike the heart, lung or kidneys, which have one primary function, the liver has multiple functions
essential to maintain life including carbohydrate metabolism, synthesis of proteins, amino acid
metabolism, urea synthesis, lipid metabolism, drug biotransformation and waste removal.
• Therefore the preferred artificial liver support system would perform these various liver functions.
• The artificial liver utilises the functions of separating, disposing & supply of fresh plasma in hollow
viscose fibres or membranes similar to those used for artificial kidney to perform their function.
• In the case of extracorporeal devices, cells are grown to confluence in devices resembling
dialysis cartridges, and then inserted into a 'Circuit' outside the patient's body, where blood from
the patient flows through the cartridge, contacting the cells, and then back into the patient.
• Extracorporeal liver assist device (ELAD) or bioartificial liver (BAL). The principal goal of the
ELAD is to circulate a patient's plasma extracorporeally through a bioreactor that contains
metabolically active hepatocytes.
24. Functions of an Artificial liver
• The artificial liver utilizes hollow fibers
or membranes similar to those used
for the artificial kidney to perform their
function.
• Organ cells are placed around the
fibers and blood flows inside the fiber.
• Blood nutrients pass through the fiber
wall to the oxygen cells and enzymes
pass from the cells to the blood.
• The metabolism of the liver is very
complicated which poses problems for
the artificial liver.
• This can be solved by using a double
lumen structure with a hollow fiber
within a hollow fiber.
• Blood runs outside and in contact with
liver cells and blood, and after
purification it runs inside the fiber.
25. Hemodialysis
• The basic functional unit of the kidney is the
nephron. Eachkidney contains about 1
million nephrons. Only about one-thirdof
these nephrons are needed to maintain
normal levels of wasteproducts in the blood.
• An external artificial kidney, a
haemodialyser, is used which can perform
many of the functions of a kidney.
• It is made up from a bundle of hollow fibres
through which the blood circulates.
• The objective is to improve the surface of
hollow fibres so that the leucocyte decrease
does not occur.
• Hemodialysis includes removal of metabolic
substances, adjustment of electrolytes and
pH and removal of excess water by
ultrafiltration and dialysis, which is usually a
membrane separation process. Ultrafine
membrane with blood on one side and
dialysis fluid on the other, the urea
molecules which are much more smaller
than blood plasma get separated from blood
by using ultrafiltration.
26. Basic operation of Hemodialysis
• Heparinized blood flowsthrough a
device containing a membrane.
The dialysate or exchange fluid
flows on the membrane side
opposite the blood.Solutes are
exchanged by diffusion between
the blood and thedialysate fluid.
• The membranes are usually made
from such materials ascellulose,
cellulose acetate, polyacrylonitrile
and polycarbonate.The membrane
surface area is on the order of 1
m2. Blood flowrates are in the
range of several hundred ml/min
and thedialysate flow rate is about
twice that of the blood.
28. Summary
• Advances in textile technology and advanced
composite materials containing combinations of
fibres and fabrics have been developed for
application where biocompatibility and strength
are required and will clearly bring a new and
improved group of biomedical devices.
• As it is an interdisciplinary field, collaboration
between medical and textile technocrats is the
need of hour. Possible developments include
pancreas, myocardium, bone and other
replacements.
29. CONCLUSION
• Thus the application of textile in high performance and specialized
fields are increasing day by day.
• There will be an increasing role for medical textile in future. Thus
the textile will be used in all extra corporal devices, external or
implanted materials, healthcare and hygienic products.
• Textile materials continue to serve an important function in the
development of a range of medical and surgical products.
• The introduction of new materials, the improvement in production
techniques and fiber properties, and the use of more accurate and
comprehensive testing have all had significant influence on
advancing fibers and fabrics for medical applications.
• As more is understood about medical textiles, there is every
reason to believe that a host of valuable and innovative products will
emerge.
30. References
• Edwards Vincent J, Buschle-Diller G & Goheen S C: Modified Fibres
with Medical and Speciality Applications, Springer, Netherlands,
2006, pp 6, 35-45.
• Hongu T, Phillips G O & Machiko Takigami: New Millenium Fibres,
The Textile Institute, Woodhead Publishing Ltd, Cambridge,
England, 2005, pp 52-54,175,179-180, 254.
• Tarafdar N & Bose P: A Review of Application of Hollow Fibres in
Extracorporeal Devices in Medical Textiles, Man-made Textiles in
India, April 2005, pp 141-144.
• Rajendran S & Anand S C: Developments in Medical Textiles,
Textile Progress, 32 (4) (2002), pp 12.
• Wooding C: Regenerated Cellulose Fibres, The Textile Institute,
Woodhead Publishing Ltd, Cambridge, England, 2001, pp 147-148.
