Acrylic Fibre, Acrylonitrile, Acrolein & Propylene Finber Video Lecture | Chemical Technology - Chemical Engineering

Today will be discussing about the module
8 of the organic chemical technology. In the
module 8 we earlier discussed about the polymer
elastomers. And today we will be discussing
about the synthetic fiber, and already on
nylon and polyester we have covered in the
previous lecture. Today it will be on the
acrylonitrile, acrylic fiber, polyurethane
and the next lecture that will be on the viscose
rayon. So, the in case of today’s lecture
that will be acrylic fiber, modified by acrylic
fiber, acrylonitrile and acrolein, because
the acrolein that is the byproduct we are
getting during the manufacture of acryonitrite.
But some of the process are there in case
of acrynitrite will be known acrolein, propylene
fiber and the polyurethane. Because the propylene
we have already discussed so the other process
is same making, so we are not going in detail
about the propylene fiber, but polyurethane
that definitely will be discussing, because
the polyurethane that is also one of the very
important class of the plastic which we could
not discuss while discussing the polymer.
So, this will be the coverage of the lecture
introduction, historical review, characteristics
of the acrylic and modified acrylic fiber,
technological development, acrylonitrile,
acrolein manufacture, acrylic fiber and modified
acrylic fiber. And then the first we will
be discussing the polyurethane and then the
polypropylene fiber.
This you can see the by appearance and seeing
the importance’s of the acrylic fiber because
this is just like a wool like material and
what about the revolution you are seeing in
case of the acrylic fiber that is because
of the in the synthetic fiber that is because
of the coming of the acrylic fiber in the
market and now the it is capture whole wool
market and has replaced the conventional wool
material that was being used for the woolen
fabrics.
And this is the some of the product of the
acrylic fiber and even in case of the now
if you see the carpet and in case of curtain
also we are using acrylic fiber. This is a
towel; this is the sweater and other. Because
woolen a material this is the thrived of the
acrylic fiber. So, this is how the importance
of the acrylic fiber is there. And are real
revolution came in the case of the acrylic
fiber, that was the availability of the raw
material propylene from the naphtha cracker
and then the propylene to amnoxidation process
of the acryonitrite.
So, let us discuss about the first thing the
introduction of about the acrylic fiber. Acrylic
fiber is an integral part of total textile
fiber mix which consists of the cotton, wool,
silk natural and manmade fiber. Acrylic fiber
plays an important role in meeting the demand
of one of the basic needs of the clothing
and to meet the demand of the increasing population.
Driving force for growth of the acrylic fiber
is mainly due to replacement of the wool and
at the same time availability of the raw material
propylene. Because you see the here also will
be discussing what are the various routes
of the acrylonitrile which is main polymer.
Here are the sometimes it is co-polymers also
added there to when we are manufacturing the
modified acrylic fiber to enhance some of
the property which is not inherent in case
of the acrylic fiber. So, in all the whether
it is acrylic fiber modified. This is because
it has replaced the wool material even in
the blanket, in the market you are seeing
this is all made of the acrylic fiber. And
so the earlier processes which will be discussing
about the acrylonitrite. That was the acetylene
route or the ethylene route or the ethanol
route for or acetaldehyde. Because, the starting
for all these the your ethylene so that was
the route for making of the and again the
major development as I have been disusing
earlier also that is the major development
in case of the various the petrochemical products
intermediates.
And the final that was during the 1910 to
1930 that was the time of the World War 1,
World War 2 lot of the requirement of the
polymer elastomer or the synthetic fiber was
there acrylic fibers. Why the importance of
the acrylic fiber? Because it is having the
specific property appearances like wool which
I have shown in the picture that the how it
looks like this is just like a woolen material.
Acrylic fiber are characterized by softness
that is the basic requirement in case of the
wool like feel superior thermal insulation,
very good shape, resistance, fastness to light,
moth, mildew and the insects resistance. Because
these are the some of the property which is
the requirement for the carpet which was earlier
we normally it was the woolen material that
was being used. And another property with
the light weight resilience property resistances
to all biological and most chemical agent
little affected by weak acids, weak alkali
and organic solvent. Low water absorption,
quick water transport means the drying so
that is much faster in case of the acrylic
fiber. And this is the reason why the material
made from the acrylic fiber the washing is
also easier. And the because the water drainage
is.
Another important characteristic of the acrylic
and modified acrylic fiber is their flammability
and the ignition behavior. Because these are
the two another important in case of the modified
acrylic fiber that is, the flammability and
the ignition behavior. And because the vinyl
chloride that has been incorporated as monomer
while making the modified acrylic fiber acrylic.
Fiber is available as stable and tow filament
products high bulk bi-component fibers and
modified acrylic and the fire resistances
fiber. In the world polyester and its blend
with the cotton is the most popular fiber
in the India. It has been blended as I told
you now whatever the synthetic fiber various
blend of the cotton or the viscose or it may
be the acrylic are there just to improve some
of the property or some of the deficiency
of the polyester which is improved with the
help of the when you are having the acrylic
fiber or the viscose.
Acrylic fiber used as a substitute for wool.
As I told you other fibers like cotton, nylon
and polyester due to its characteristics such
as the durability, bulking and superior dry
ability. The water density property is good
easy wash and wears properties easy wash and
because that is also one of the basic requirement
in case of the textile, or the when you are
using the various. Even in case of the hosiery
material in case of the carpet you are able
to wash it in case of the acrylic fiber. Use
of acrylic fiber new application has been
increasing and these are the some of the driving
force for the more and more consumption of
the acrylic fiber.
In acrylic fiber monomer is the acryolnitrite.
While in case of the modified acrylic fiber,
acrylonitrite is co polymerized with vinylidiene
chloride or vinyl chloride. These are the
two material coordinate compound which are
being co polymerized along with the acryl
nitrite the halogenated monomers impart flame
resistance and are suitable for home furnishing
protective coating, sleepwear and hospital
blankets so these are the some of the advantage
why we are going for the modified acrylic
fiber.
Usage of the acrylic fiber in new application
has been increasing higher demand potential
of the application such as blanket stuffed
toys. We are using lot of the acrylic fiber
although the amount that is less if you compare
to other user but, the in this stuffed toys
we are using lot of the acrylic fiber material
furnishing and woven garments will lead to
higher demand of the acrylic fiber.
Acrylic fiber plant in India includes consolidated
fibers and chemicals, Indian acrylic, IPCL.
IPCL in India petro petrochemical complex
that is now reliance industry at Vadodara
that was the one of the unit large integrated
unit that was started during the 70’s which
we discussed while discussing the petrochemicals.
And so that is also having the acrylonitrite
plant. Pasupati acrylon that is one of the
major producers of the acrylic fiber, where
they are making the acrylic fiber and modified
acrylic fiber. Another important Vardhaman
acrylics because vardhaman wool and another
thing they are very important. They have also
grown in the case of the making of the acrylic
because you see the now the cost of the wool
material the natural wool that is very high
in compression to the acrylic fiber. And that
is the reason why it has been almost completely
replaced the conventional wool material which
in the hosiery and other application so IPCL
and Pasupati acrylon both are expanding their
respective capacities.
According to SRI consulting report two 2010
the consumption of acrylic fiber were both
around production consumption both were around
1 point 9 million tones with the global capacity
utilization of 62 point 5 percent.
So, the acrylic fiber used as I told you the
substitute for cotton, nylon, polyester due
to its characteristics, durability, bulking,
superior dry ability. easy wash and wear property
acrylic fiber already here actually the how
the we differentiate between the acrylic fiber
and the modified acrylic fiber.
Two major types of acrylic fiber are acrylic
fiber containing at least 85 percent by mass
acrylonitrile units Orlon. Orlon was the trade
name that was given to the acrylic fiber like
tyrene or the decron in case of the polyester.
So, orlon that was the name given due point
because deposit that has been the pioneer
in case of the synthetic fiber, whether it
was the nylon or it was the acrylic fiber
so modified acrylic fiber should have between
35 to 85 percent of the acrylonitrile. And
in case of the acrylic fiber it is the 85
percent the acryonitrile unit here.
It is around the 35 to 85 percent rest is
the other co monomer. So, this is the basic
difference and normally as I told you we are
using the vinyl chloride and so these are
the two actually the chlorinated compound
which imparting the water fire resistant property
to the acrylic fiber.
These are the major technology supplier licenses
the DuPont, Ashai Japan, Exlan Anta Vicosa,
Monte fiber, American cyanide and American
cyanide and Countauids. Development in the
acrylic fiber: specialty the fibers like gel,
these are another special quality of the acrylic
fiber. So, the specialty fiber like gel dyed
acrylic fiber, porous acrylic fiber, optically
bright acrylic fiber, super bright acrylic
fiber and flame retardant acrylic fiber are
the some of the catalyst. For that we will
be discussing separately the retardant acrylic
fiber.
The global acrylic fiber consumption expected
to the average growth of 4 point 6 percent
per year from 2009 to 2014 and around 1 point
1 percent from 214 to 19. Apparel uses accounted
for over half of the total global acrylic
fiber consumption in 2009. Other applications
include industrial uses and the home furnishing.
This is already discussed this part of the
work non woven manmade fibers. Here you can
see the acrylic fiber around 2 to 3 percent
that we are using in case of the non woven
manmade fibers.
This is the status of the acrylic fiber production
capacity and the production in India that
is the acrylonitrile and acrylic fiber this
is forty 41,000 and that is the and 39,000.
Here acrylic fiber 143 and 91,000 and this
is the about the capacity and production of
the acrylic fiber.
These are some of the characteristics which
I discus about the acrylic fiber. That is
the acrylic fiber here the monomer and basic
chemicals acrylonitritile propylene and ammonia
and ammonia oxidation of the propylene that
we are using here. The technology, the characteristic
is density 1 point 17, moisture again 1 point
52 to 2 point 5, melting point around two
235 degree centigrade, silk like luster, good
resistances to weathering alkalis and acids
high bulking high bulking and that is the
property in case of the woolen material.
Also the tensile strength 2 to 3 gram per
denier elongations at breaks 16 to 21 percent.
And at the same time its wool like appearance
that is what it is giving its use in the woolen
industry where we are making a lot of the
woolen material. It may be the hosiery or
it may be blanket, or even in case of the
carpet other areas where we are using.
Modified acrylic fibers that is the acrylonitrite,
vinyl chloride and vinylidene chloride, here
propylene and ammonia and ethylene that may
be depending up on the route but, the propylene
ammonia that is the now the most of the process
they are using the propylene and the ammonia.
So, moisture regain, melting point 235, good
resistances to weathering, alkalis and acids
high bulking good resistances to combustion.
Now discuss the, let us discuss the raw material
for the acrylic and modified acrylic fiber,
acrylonitrile, acetylene because that was
the earlier route acetylene, acetaldehyde,
ethylene oxide then the propylene and ammonia.
This is the now the route which we are using
the raw material ammonia and propylene for
ammon oxidation of the propylene and for making
acrylonitrile vinyl chloride and vinylidene
chloride that is needed in case of the modified
acrylic fiber and the demethyl formamide.
That is the solvent which we are using because
earlier in case of the acrylic fiber wet spinning
was there and now we are using the dry spinning
in case of the acrylic fiber.
This was only possible with the availability
of the demethyl fromamide and that is the
product from the synthesis gas. And some of
the fertilizer company integrated fertilizer
complexes they are making dimethyl fromamide.
Although the dimethyl fromamide it has been
used as the solvent that has been reported
for other purposes also but, the change over
from the wet spinning to the dry spinning
in case of the acrylic fiber that was only
possible because of the dimethyl formamide
solvent.
So, this is the one of the important solvent
because you see I have already discuss about
the spinning. We are having the 3 type of
the spinning1 is the melt spinning where the
polymer is melted and then it is passed to
the spinneret or in case of the dyes that
is solution from then it is pass to the spinneret.
Then the dying is taking place and removal
stripping of the solvent. And then we are
having the oronal steples from that and but,
in case of the wet spinning which was earlier
done by for acrylic fiber, that was wet spinning
process means the wet bath spinning bath was
there through which the your material that
is the polymers that was passed and there
is the fiber that we are getting from that.
Acrylonitrile: now, let us discuss about the
acrylonitrile which is the raw material for
the acrylic fiber and the importance of acrylonitrile
that is not only because of the acrylic fiber
but, there are very various combination of
acrylonitrile butadiene an styrene, for making
of the synthetic rubber also which are having
the better silent properties towards oiling.
So, acrylonitrite was first synthesized by
Moureu in 1893. Acrylonitrile is a versatile
and the reactive chemical orolon was developed
in 1950 which as the driving force for the
development of new technology for acrylonitrile.
Because as I told there has been continuous
development in the process technology from
the manufacture of the acrylonitrile and the
starting that was the acetylene. As in case
of the other petro chemicals, we are making
through the petroleum route. Shio process
using ammonooxidation that came in to 1950
and after that number of the process licenses
of the technology based on the ammono oxide
oxidation that has been used even in case
of the technological development. In the reactor
fixed bed to the fluidized bed reactor. We
are using in case of the now the mostly it
is fluidized bed reactor in case of the acrylonitrile
manufacture.
So, over the past decades as I told the rapidly
expanding market for acrylonitrile and the
modified shifted towards the acrylic. And
the modified acrylic fiber and resins acrylonitrile,
butadiene, styrene and styrene acrylonitrile.
So, these are the various combination of the
rubber also which has lead to the development
of acrylonitrile in industry.
Acrylonitrile is one of the important monomer
for the acrylic fiber. Earlier, routes of
the acrylic, acrylonitrile manufacture were
the acetylene route, ethylene oxide route
or the acetaldehyde. Because from ethylene
you can get the ethylene oxide, ethylene oxide
to acetyldehyde for the ethylene more specific
routes was there earlier and still we are
manufacturing lot of the ethylene through
the molasses route. So, this is the conventional
methyl earlier before coming of the propylene
route where we are doing the ammoniation of
the ammono oxidation of the propylene. So,
this is the process and the process became
cheaper because of the availability of the
propylene from the steam cracker plant.
If you can see the how we are getting from
the acetylene route hydro cyanide reacting
with acetylene that we are getting the acrylonitrile.
Earlier, this was the ethylene oxide route.
And ethylene oxide has cyanohydrins. Cyanohydrins
to acrylonitrile so by dehydration these were
the other technology that was earlier used
before coming of the pure propylene the ammono
oxidation of the propylene.
Another process that is the acetaldehyde,
again the acetaldehyde as you know that we
are making to the ethylene route so that is
also available and then we can make the acetylene.
But, if you see the propylene route now it
is more common and most of the even due point
in the earlier stages they used. Some other
technology not the ammonia but, that was the
oxides of the nitrogen for the propylene route
but, here again direct that is also we are
getting from the process during the process
of NH3 and the oxygen is there and.
So, this is the process ammono oxidation of
your acrylonitrile this propylene to acrylonitrile.
That is the process we are using another two
step process that we are having because you
see the propylene how to get the propylene,
because the it is not only the cracker but,
also we can get the propylene from the dehydrogenation
of the propane. That is one purpose of propylene.
And so the propylene to propane to propylene
and followed by ammono oxidation of the propylene.
So, this is the how the various technological
developments that is that has taken place
regarding the raw material. But, you see the
one of the method which i told you because
the most of the development in the earlier
stages of the organic chemical industry that
was the acetylene route. And for that as u
know the calcium carbide to acetylene and
that is we need the lime stone and the coal.
So, that was process earlier that was used
for the making of it. And then it was of course,
the ethylene oxide to and the ethylene oxide
again you can get the ethylene form the alcohol.
Now, let us discuss about the acrylonitrile
from the propylene route. Acrylonitrile is
one of the important monomer for manufacture
of acrylic fiber. However, earlier routes
of the acrylonitrile manufacture of acetylene
by acetylene, ethylene oxide or acetaldehyde
route has been replaced by propylene route
due to the availability of the cheaper propylene
from steam cracker.
The process involves ammono-oxidation of propylene.
Other uses of acrylonitrile are in the manufacture
of nitrile rubber. ABS acrylonitrile butadiene
styrene or the styrene acrylonitrile plastic,
adiponitrile and acryl amide these are the
other uses of the acrylonitrile. And this
is the one of the major that is the ABS acrylonitrile
butadiene or the styrene acrylonitrile plastic.
The elastomers also this is one of the important
outlet for the acrylonitrile. In addition
it is also used in the manufacture of acrylates,
intermediates, of flocculants pharmaceuticals,
antioxidants dyes and surface active agent.
The catalyst: the various stages involves
first is the catalyst preparation bismuth
and molybdenum mixing of the propylene, ammonia
and oxygen in this ratio along with the catalyst.
Then the reaction where your acetonitrile,
hydrogen cyanide unreacted mixture of the
propylene, ammonia and oxygen are fed to the
fluidized bed reactor. Various production
reaction product from the reactor or the acrylonitrile,
acetonitril the hydro cyanide these are the
some of the raw byproduct also we are getting
along with the reaction is highly this reaction
of the because of the as we know we are doing
the oxidation this reaction is highly exothermic.
Absorption: the next step the absorption of
the component from the ammonia free gas in
water to separate the non-condensable unconverted
propylene, Propane, nitrogen, c o and co2.
Removal of ammonia, stripping of the organic
component and separation of the hydrogen cyanide.
Separation of the acrylonitrle and acetonitrile
which are because the here also because the
acrylonitrile and the acetonitrile they are
having the close boiling point so that is
separated by extracted distillation column
using water as a solvent. Because the otherwise
it may not be possible, it will not possible
for separation of the acrylonitrile and the
acetonitrile.
Then the dilute solution of the acrylonitrile
is separated, which is recovered and concentrated,
Purification of the acetonitrile final purification
of the acrylonitrile.
This is the process which we are using in
case of the acrylonitrile manufacture I told
you that normally now the most of the technology,
they are based on the fluidized bed reactor.
But, in the earlier stages it was the fixed
bed reactor that was being used for the manufacture
of the acrylonitrile. So, the propylene and
ammonia in the air that is going to fluidized
bed reactor cyclones are there for separation
of the catalyst. And then it is going to the
absorber separator then the azeotropic distillation
for the separation of the acrylonitrile. And
here actually the acetonitrile that is going
to the again separator and then the finally,
acrylonitrile that we are getting as a byproduct.
So, this is the process that we are using
in manufacturing of the acrylonitrile. So,
this was the major because in the process
acetonitrile that will be also form. So, that
will be important by product of the acrylonitrile
or now the technology are also there that
may be acetonitrile that may be optional as
in case of the dew point process.
In this process, the dew point process acrylonitrile
is made by oxidation of propylene and ammonia
in a fluidized bed reactor using propriety
catalyst. The process produces high purity
acrylonitrile, hydrogen cyanide and acetonitrile.
So, here as I told you, the acetonitrile that
may be optional. The other process that has
been that is the Montedison UOP process here
also we are using the same fluidized bed reactor.
In this process ammono oxidation of the propylene
is done in fluidized bed reactor which give
better temperature control and remove the
limitation of propylene ammonia concentration.
Because here the explosive mixture that is
there in case of the propylene and ammonia
so this process remove the limitation of propylene
ammonia concentration. Due to explicability
of the feed mixture the process is capitalized
by high conversion rate and which is the basic
requirement in case of the any process.
This is the reaction in case of the acrylonitrile
manufacture. We are in the process we are
also getting the acetonitrile. This is the
oxygen propylene oxide from the propylene
oxide and the ammonia that you are using for
the acrylonitrile this is the overall reaction
that is taking place.
These are the side reaction that is taking
place in case of the acrylonitrile where the
HCN or the CH3 cyclone nitrile is there. So,
that is the how the separation that can be
there for the separation of HCN and the acetonitrile.
Now, let us come to the fiber part. From the
acrylonitrile to acrylic fiber the process
technology the two major steps are there.
In the polymerization and spinning and after
spinning definitely the fiber which is coming
will be of going for the dying and the cutting
bailing. That is the different that will be
always there in all the process that is there.
So, polymerization includes the co-polymer
composition, catalyst system polymerization,
reaction and monomer recovery. So, co-polymer
means the when you are going to the modified
acrylic fiber spinning process. This includes
solution or the dope preparation or it may
be the dye spinning techniques and finishing
operation including after treatment cutting
and bailing.
Then the major polymerization processes are
bulk permission, suspension polymerization,
emulsion polymerization and the solution polymerization.
All the four process that can be but, common
process which we are using for the acrylic
fiber manufacture specially for the fiber
grade that is, the suspension polymerization
which gives the high percentage of conversion,
better product, whiteness, shorter residences
time and easy control of the polymerization.
Redox initiation is normally used in production
of the acrylic fiber. The most common redox
system consists of the ammonium or the potassium
persulphate,, sodium bisulphate and the ferric
or the ferrous ion. Now, as I told you the
after the polymer is made the next step in
any synthetic fiber is the spinning process.
Depending up on the type of the material which
you are having type of polymer which we are
having the different type of the spinning
process that is available. As I told you that
dry spinning wet spinning or it may be melt
spinning.
So, spinning include the solution or dope
preparation spinning techniques and finishing
operation including after treatment, cutting
and baling. Dry spinning: in dry spinning
of the acrylic fiber dimethyl form amide is
used. As I told you earlier also the DMF spin
dope contains the polymer in the DMF thermal
stabilizer, delustrant the DMF evaporated
by circulating the inert gas through the tower
at about 30 to 35 degree centigrade.
And in the wet spinning sodium thiocyanate
are commonly used as the solvent. Wet spinning
fiber is spun into a liquid bath containing
a solvent non-solvent mixture called the coagulant.
Non solvent is usually water. The fiber emerging
from the spin bath are washed and dried fallowed
by cutting and bailing.
This is the process which we are having in
case of the preparation of the acrylonitrile
tow or the cutting to staple fiber is there
for the acrylonitrile. So, mixing time where
you are using the where adding the acrylonitrile
catalyst or if you are using the co-monomer
then, the co-monomer will be also there. Jacketed
polymerization, the monomer stripping which
is recycled back and then the slurry handling,
centrifuging, polymer storage then dissolver.
Here we are having the dissolver but, here
you see what is happening, here it is being
passed through the spinning bath and after
whatever are there that is going for the drying,
crimping annealing tow cutting. If you are
having in the staple fiber then it is cut
and so the same case. If you are interested
in the fiber staple yarns then it will go
through the spinneret. Here actually if you
see in case of the wet spinning with the spinning
bath it is going from a large number of the
spray continuous moving and then rotating.
And so whatever the fibers that is drawn that
is going to the crimper then the annealing
and finally, we are getting the acrylic fiber
as staples.
Now, let us discuss about the polyurethane
that is also one of the important polymer.
The polyurethanes are versatile class of the
thermoset polymers and are offer the elasticity
of the rubber combined with the toughness
and durability of metal. So, basic polyurethane
chemistry was developed in 1937 by Dr Otto
Bayer. In 1940 rigid foam was first introduced
for aircraft.
Use of polyurethane in adhesive between rubber,
metal and the glass introduces in 1941. First
insulation application in 1942-48. Introduction
of the spandex fiber was in 1958. As the synthetic
fiber industry for the textile started some
of the polyurethane are also there that is
being used especially the spandex fiber.
The rigid polyurethane foams are most widely
preferred to insulate and find application
in refrigerator manufacture of thermo ware,
cold sore panel, refrigerated trucks and wagons.
Polyurethanes find application in the form
of film sheet, foam fiber, coatings, adhesives,
and sealants. Some of the resins they are
also going to the coating and adhesives purposes
for insulation of variety of tanks where it
has broad application for insulation purpose.
Which we use to have the glass whole, vessels
pipes, domestic application such as refrigerators,
freezers, furniture, cushion backs and arm
rests. Then the bedding full foam, mattresses
topper pads for inner spring mattresses. So,
these are the some of the broad application
of the polyurethane.
Worldwide demand for polyurethane expected
to grow at CAGR of 5 point 8 percent from
12 point 0 million tons in 2010 to 116 point
8 million tons in 2016 with Asia pacific region
accounting for over 60 percent.
Polyurethane is polymer formed by combining
2 or more isocyanade functional group and
2 or more hydroxyl group. Commonly used isocyanades
are toluene diisocyanade this is the one of
the major consumer of the toluene. As I told
you earlier while discussing the aromatic
diphenyl methane, diisocyanade, hexamethylene
diisocynanade HDI. Polyols may be either polyether
polyols or polyester polyols. The catalysts
used in the polyurethane manufacture are aliphatic
and cyclo-aliphatic tertiary amines and the
organic tin compound organic tin compounds.
This is the reaction typical reaction that
is taking place in case of the isocynates
and the poly hydroxyl compounds which is we
are using for the making of the polyurethane.
Another type that is now it has become important
in uses at the polyurethane foam.
So, polyurethane rigid foam is characterized
by good structure strength, excellent adhesion
to most substance, processing flexibility
and longer life. So, these are the some of
the advantages of the in case of the polyurethane
foam. So, this was about the acrylic fiber,
modified acrylic fiber and then the about
the importance of the acrylonitrile and the
polyurethane fiber. Acrylic fiber as I told
you that has replaced because of its low cost.
The conventional wool martial which is now
just like in the cotton that is that has been
replaced by the blend of the polyester and
the your viscose rayon. So, the in case of
the synthetic fiber industry the cellulosic
raw material base fibers are also playing
very important role and they are also very
important sector.
Although it is not considered a part of the
chemical organic chemical industry or the
petrochemical that is more concerned connected
with the pulp manufacturing or the pulp and
paper industry. Because some of the paper
industry they are making the your rayon grade
pulp and that is one of the century rayon
which is having one unit and harrier ploy
the Birla’s they are the pioneer in case
of the making of the rayon in the it may be
viscose rayon by the harrier poly fiber by
Grasim industry that is the they are having
a at Nagaba.
So these this is the importance in case of
the viscose rayon and then we are having the
acetate rayon which is having the silk like
appearances so that will be discuses in the
next lecture in the lecture number 8 of the
this module .