1. IN-PLANT TRAINING REPORT
At
(17th July to 14th August 2014)
Product Application and Research Centre, Chembur,
Mumbai
Degree of Bachelor of Technology in petroleum
Engineering
Submitted by:
Amit nitharwal
B.Tech 2nd year in petroleum Engineering
College roll no. -12/385
University college of engineering,
Rajasthan Technical University,kota
2. Acknowledgements
A summer training is a golden opportunity for learning and self development.I consider
myself very lucky and honored to have so many wonderful people lead me through in
completion of this training.
I wish to express my indebeted gratitude and special thanks to Mr. S.V.Raju, Head of the
Department - Product Application and Research Center (PARC), Reliance Industries Ltd
(RIL) who in spite of being extraordinarily busy with her duties,took time out to hear for
extending its training facilities and giving me an opportunity to gain an insight into the
working of an industry.
I express my deepest thanks to Dr. Nitin Joshi, my guide for his vital encouragement and
keep me on the correct path and allowing me to carry out my industrial training work at
their estmeed organization and extending during the training.I do not know where I would
been without him. I choose this moment to acknowledge their contribution gratefully.
I am highly indebted to the executive & technical officers of PARC for their everyday
guidance and help. I pay special thanks to Mr. Anant Pawar , Mr. Lalit Pathaskar,Mr. Ajit
Gate for their help in the processing centre.
I would specially like to thank Mr. Tushar Dongre, Mr. Kunjan Mhatre and Mr. Kulkarni
for their support and co-operation throughout the training period in spite of their busy
schedules.
It is my glowing feeling to place on record my best ,deepest sense of gratitude to Mr.
Anshul Rajgarhia, Mr. Ashish Sharma, Mr. Jigar Palecha, Mr. Ravi Kute, Ms. Parul
Sachdeva and Ms. Smita Kumbhare, Mr. Rupesh Rhane for their continuous help during
the training.
Finally I would like to thank all the office and support staff for extending their cooperation
throughout the course of this training.
Amit nitharwal
13th august 2014
4. 1. company profile
Reliance Group, founded by Shri Dhirubhai H. Ambani (1932-2002), is India's largest
private sector enterprise, with businesses in the energy and materials value chain.
Reliance Industries Limited (RIL) is an Indian conglomerate holding company
headquartered in Mumbai, Maharashtra, India. The company currently operates in five
major segments: exploration and production, refining and marketing, petrochemicals,
retail and telecommunications. The company is ranked 99th
on Fortune Global 500 list
of the world's biggest corporations for the year 2012. RIL is one of the largest publicly
traded companies in India by market capitalization. It is the second largest company in
India by revenue after Indian Oil Corporation. RIL’s revenue is US$ 68.4 billion as of FY
2012-2013. Reliance enjoys global leadership in its businesses, being the largest polyester
yarn and fiber producer in the world and among the top five to ten producers in the world
in major petrochemical products.
RIL manufactures Polypropylene (PP), Polyethylene (PE) and Polyvinyl Chloride
(PVC) sold under the brand names Repol, Relene & Reon respectively.
Diverse applications across packaging, agriculture, automotive, housing,
healthcare, water and gas transportation and consumer durables.
Repol PP can turn any of your 'plastic' ideas into a reality.
Relene PE has completely transformed the concept of packaging.
Reon PVC is a versatile polymer with applications ranging from soft to rigid.
RIL has manufacturing sites at Hazira, Nagothane, Jamnagar, Baroda, and
Gandhar.
RIL is the largest producer of PE & PP in India.
RIL manufactures LDPE which no other Indian manufacturer produces.
Reliance's polymer business is integrated with its cracker facility at Hazira, as well as its
refinery at Jamnagar, ensuring feedstock availability at all times. The company operates
world-scale plants for Polyolefins and PVC with state-of-art technologies from global
licensors like Novacor, Geon and Union Carbide. Along with IPCL, Reliance is among the
world's top 10 plastic producers.
5. Reliance Industries Limited is Asia's largest manufacturer of Polypropylene (PP).
Reliance figures the Fifth largest Polypropylene producers in the world. Reliance holds a
67% share of the Indian Market and caters to 3% of the world’s consumption of PP. The
four production sites offer a wide range of Homopolymer, Random and Impact copolymer
grades. These can cater to the entire spectrum of Extrusion, Injection & Blow molding
processes.
“Relene” HDPE is available in densities ranging from 0.941g/cc to 0.965g/cc & melt flow
index from as low as fractional to 20. Relene HDPE is widely used for numerous extrusion
& molding applications. Specially formulated HDPE Raffia grade has placed "Relene"
way above the competing materials for this application. The grade has excellent
processability on high output raffia lines & exhibits superior balance of tenacity /
elongation.
Reliance LLDPE grades are marketed under trade name "Reclair" & is available in
density range of 0.916 to 0.935 g/cc & MFI range from fractional to as high as 50g /10min.
8. 3. INTRODUCTION TO PRODUCT
APPLICATION & RESEARCH CENTRE
The product application & research centre (PARC), Reliance Industries Limited
petrochemical division was established in 1990 at Chembur, Mumbai as a technical wing
of the polymer marketing division. It is deeply involved in the development of new grades
& the optimization of the existing grades in terms of cost & properties. It also carries out
continuous valuation of various lots produced at Jamnagar & Hazira plants. PARC is
committed to deliver value addition to polymer business of Reliance Industries Limited by
providing technical service, constant product up gradation and initiating market
development with the sole objective of total customer satisfaction. It also carries out
testing and trials of various modified and developmental grades.
PARC is a conduit between business enterprises and their vendors, converting basic needs
into commercially viable technology and helping to produce useful products. To fulfill
these objectives, sophisticated analytical & processing facilities have been established at
PARC.
PARC is recognized by the department of science and industrial research as an in-house
research & development wing of reliance-plastic & petrochemical division.
Functions of PARC:
Product development
Process development
Customer Support / Technical service
Co-ordination with plant & marketing department for benchmarking exercises
Training & manpower development
The Activities of PARC can be divided into:
Testing
Processing
9. 4. Testing Division
Testing of raw material is absolutely necessary for quality control &
characterization. The analytical laboratory is involved in the analysis & testing of resin and
product samples received from the customers as well as from the PARC division.
Testing for resin:
Melt Flow Index
Ash Content
Bulk Density
Funnel Flow Time(FFT)
FTIR Spectroscopy
Measurement of Colour
Density
Testing for plastic films:
Shrinkage Test for films
Tear Strength
Coefficient of Friction (COF)
Haze
Dart Impact Strength
Tensile Properties
Testing for Moulded samples:
Tensile properties
Scanning Electron Microscope(SEM)
Izod-Impact strength
Shrinkage Test
10. TESTING FOR RESIN
Melt Flow Index Determination
Reference: ASTM D1238
Machine Make:Davenport Flow Indexer.
Summary: For this, molten polymer is extruded through a die and flow of polymer is
measured under a specified load and at particular temperature per 10 min
Scope: This procedure is used to determine melt flow properties of resins with the help of
Davenport Flow Indexer. Melt Index is an inverse measure of molecular weight. Since
11. flow characteristics are inversely proportional to the molecular weight, a low molecular
polymer weight polymer will have a high melt index value and vice versa.
Apparatus: (I) Melt Flow Indexer (Davenport make) with accessories:
Temperature: PE: 1900C
PP: 2300C
Prheating time :
PP: 6 min
PE:5 min
Barrel diameter= 9.5504 0.0016 mm
Die diameter= 2.0955 0.0016 mm
Die Length= 8 0.025 mm
Weight= 2.16 kg, 6.48 kg ( 0.5% of the total weight)
Procedure:
1. Manual
A small amount of the polymer sample (around 4 to 5 grams) is taken as per the
expected MFI of material in the specially designed MFI apparatus. The apparatus
consists of a small die inserted into the apparatus, with the diameter of the die
being around 2 mm.
The material is packed properly with the help of suitable piston inside the barrel to
avoid formation of air pockets.
A piston is introduced which acts as the medium that causes extrusion of the
molten polymer.
The sample is preheated for a specified amount of time: 5 min at 190°C for
polyethylene and 6 min at 230°C for polypropylene.
Push the piston a little above the mark to ensure good packing (known as purging).
12.
After the preheating a specified weight is introduced onto the piston. Examples of
standard weights are 2.16 kg, 5 kg, etc.
The weight exerts a force on the molten polymer and it immediately starts flowing
through the die.
A sample of the melt is cut in regular intervals of time and is weighed accurately.
MFI is expressed as grams of polymer/10 minutes of flow time.
2. Automatic
Weigh the specimen and put it in the apparatus as per the expected MFI.
Select remote control on apparatus and start the computer.
In the computer start console software.
Feed polymer type, melt density, cut-off length and file name.
Start the test.
Purge after 3 minutes just before the mark on piston.
Put the arrester of 71mm or 81mm height depending on whether the material is Hi-Flow or
Low-Flow.
Put the weight on plate above the apparatus.
Record the output.
13. ASH CONTENT
Reference: ASTM D2584, D5630
Machine Make:Mettler Balance, Bunsen burner
Scope: This test is used to measure the ash content and filler content of plastic samples
Sample specification: 3-5 g of sample
Procedure
1. The sample weight and the weight of the empty crucible are note.
2. In case of PVC sample (self-extinguishing in nature) the sample is now wetted completely
with 98% sulphuric acid and it is again heated to give out CaSO4. After
heating, the PVC sample is now put in the oven for 1 hour at 850C.
3. For other samples, after burning is completed they are put in an oven maintained at
550C
4. Now the sample is kept in a desiccant (containing silica gel) for ½ hour to absorb all the
moisture.
5. It is then weighed and the ash content is found.
6. Calculation : % Ash Content = Wt. of Ash x 100
Wt. Of Sample
14. Fourier Transform Infrared Spectroscopy(FTIR)
Reference: ASTM E1252
Machine make- Perkin Elmer, spectrum 100 series
Principle:
FTIR utilize an ingenious device called Michelson interferometer, which was developed many
years ago by A. A. Michelson for making precise measurement of the wavelengths of
electromagnetic radiations.
FTIR instruments contain no dispersing elements and all wavelengths are detected and
measured simultaneously. Instead of a monochromator an interferometer is used to produce
interference patterns that contain the infrared spectral information.
In FTIR when an infrared spectrum is introduced to a sample stretching and bending of
various bonds takes place and due to different bond energies, each molecule absorbs energy
at a different frequency.
One of the components of an electromagnetic wave is a rapidly reversing electric field
(E). This field alternately stretches and compresses a polar bond. When the electric field is in the
same direction as the dipole moment, the bond is compressed and its dipole moment decreases.
15. When the field is opposite the dipole moment, the bond stretches and its dipole moment
increases. If this alternate stretching and compressing of the bond occurs at the frequency of the
molecule's natural rate of vibration, energy may be absorbed. The energy is absorbed by a
molecule only when there is a change in dipole moment.
1. The Source: Infrared energy is emitted from a glowing black-body source. This beam passes
through an aperture which controls the amount of energy presented to the sample (and,
ultimately, to the detector).
2. The Interferometer: The beam enters the interferometer where the “spectral encoding”
takes place. The resulting interferogram signal then exits the interferometer.
3. The Sample: The beam enters the sample compartment where it is transmitted through or
reflected off of the surface of the sample, depending on the type of analysis being accomplished.
This is where specific frequencies of energy, which are uniquely characteristic of the sample, are
absorbed.
4. The Detector: The beam finally passes to the detector for final measurement. The detectors
used are specially designed to measure the special interferogram signal.
The Computer: The measured signal is digitized and sent to the computer where the Fourier
transformation takes place. The final infrared spectrum is then presented to the user for
interpretation and any further manipulation
16. Procedure:
1. Take small amount of material on a glass slide and place it on a hot plate. Ensure the
material melts and press it into a uniform film by applying steady pressure by means of
another glass plate. If material is already in film form it can be used directly.
2. Once the background scan has been completed the spectroscopy of the material is carried
out.
3. Place the film sample on the Universal Attenuated Total Reflectance Cell and scan it for
background radiation.
4. The interference pattern of the material is obtained which is converted by the Fourier
analyser into a spectrum
5. . The graph obtained is of % transmittance v/s wave number.
A typical FTIR spectrum
17. Determination of Density
Reference: ASTM D792
Apparatus:
Weighing Balance (METTLER )
Density meter assembly: Beaker stand, Beaker (500mL), a frame attached to the weighing
pan and a sample holder which facilitates weight in air and in liquid.
Sample Specification:
1 cm x 1 cm smoothly cut sample is used for density determination. The sample should
not have any sharp edges.
18. Procedure:
The weight of the sample was measured in air and then in a liquid (n-butyl acetate) of known
density. The density of the liquid used was less than the expected density of the sample. The
ratio of weight in air to loss of weight in liquid was used to calculate the density of the sample.
Calculation:
Density of sample at Tm =
Wa
s
Wa Ws
Where:
Tm = Temperature of measurement Wa
= Weight in air
Ws = Weight in the liquid
s = Density of the liquid at Tm
19. TESTING FOR PLASTIC FILMS
Shrinkage Testfor films
Reference: ASTM D2732
Scope: This test method covers determination of the degree of unrestrained linear thermal
shrinkage at given specimen temperatures of plastic film and sheeting of 0.76 mm [0.030 in.]
thickness or less.
Sample specification: 150mm x 10mm
Requirements: Constant temperature bath, Silicone oil, Free Shrink Holder, Stop-watch
Procedure:
1. Cut the specimen as per required dimensions in both machine direction (MD) &
transverse direction (TD).
2. Start heating the silicone oil and set its temperature to 130 degrees Celsius.
3. Now hold the sample with free shrink holder in the upper 50 mm length.
4. Place the specimen in the bath for 20 seconds.
5. Now observe the change in length.
6. Repeat the same procedure for other direction.
7. Calculate the % change in length.
(Application of shrink wrap films)
20. Determination of TearStrength of films
Reference: ASTM D1938
Machine Make: CEAST Italy
Scope: Used to measure the tear strength of plastic films.
Principle:
The force to propagate a tear across a film or sheeting specimen is measured. The force
necessary to propagate the tear is measured.
Apparatus: CEAST ED 30 machine, Digital micrometer
Sample Specification:
The specimens shall be of the single tear type and shall consist of strips 76 mm long by 64 mm
wide. The thickness of the specimen is noted along the path where tear will occur. The samples
are cut in the machine direction (MD) and the transverse direction (TD).
Procedure: Different weights available are 4000mN, 8000mN, 16000mN, 32000mN, 64000mN,
50N, 100N. The weight is selected such that the film reading lies between 20-90% of the weight.
The blank reading is taken and the machine is calibrated. The sample is inserted in the pneumatic
sample holder. The cover is shut and the film tears. The reading is noted from the display.
Calculation: Tear Strength (in g/m) = Force in cN / thickness (m)
21. Determination of Coefficientof friction of Plastic Films
Reference: ASTM D1894
Machine Make: Davenport
Scope: Used to find coefficient of friction between a plastic film with respect to other films
and metal surfaces.
Principle:
Frictional force f is related to the normal force acting on a body at rest as follows: f = N
Where is the coefficient of friction. The COF associated with the force required to start a body
from rest is known as coefficient of static friction and that associated with a moving body is
known as the coefficient of kinetic friction.
Apparatus: Davenport friction measuring apparatus, template, vacuum pump
Sample Specification: 675 mm x 255 mm should be attached to the testing plane and 6.5 mm x
6.5 mm minimum for sliding.
Analytical Procedure:
The vacuum is switched on and the film is placed on the plane, without wrinkles. The film is
attached to the 200g sled with cellophane tape taking care to avoid wrinkles. The cord is attached
to the sled and placed gently on the plane at two fixed points parallel to the machine direction.
The speed is selected to be 15 cm/min.
Calculation:
COSF = Static force/ weight of the sled
COKF = Kinetic force/ weight of the sled
22. Determination of Dart Impact Strength for Plastic Films
Reference: ASTM D1709
Apparatus: Dart Impact Testing apparatus (International Engineering Industries), Weights
Sample Specification: Greater than the diameter of the specimen holder
Scope: Used to measure the dart impact strength of plastic films
Principle:
Dart Impact strength values are very important for plastics packaging. They theoretically give the
impact strength of the plastic film. In the test, falling weights from a specified height are made to
fall on the film until fracture occurs. The weight at which 50% of the samples fail is the dart
impact weight value. This value divided by thickness in microns gives dart impact strength.
23. Analytical Procedure:
The two different types of dart used are:
A: 38.1 0.13 mm of 55g weight
B: 50.8 0.13 mm of 283g weight
Vacuum applied is 700 mm of Hg
A: Dropped from 66 cm and is used for films requiring masses of about 50g to 2 kg to
fracture
B: Dropped from 152 cm and used for films requiring masses of 0.3 to 2 kg to fracture
10 samples are tested on each weight level and the weight at which 50% failure occurs is
reported.
Calculation:
Dart Impact Strength (g/m) = Weight to cause 50% fracture (g)/ thickness (m)
24. Determination of Tensile Properties of Plastic Films
Reference: ASTM D882
Machine make: Lloyd, LRX plus
Sample specifications: The width of the sample should be 15 mm - 25 mm and the gauge
length should be 5 cm.
Principle:
Plastic products when subjected to tensile force initially resist deformation, get elongated and
finally break. Tensile elongation and tensile modulus measurements are amongst the most
important indications of strength in a material and are the most widely specified properties of the
plastic materials. Tensile test, in a broad sense, is a measurement of the ability of the material to
withstand forces that tend to pull it apart and to determine to what extent the material stretches .
Procedure:
The film is cut in exact dimensions making sure that the sides are uniform. The sample is
clamped carefully and the thickness of the film is measured using a digital micrometer. The
dimensions and batch references are entered in the software. The initial load is tare and the speed
of testing is set to 500 mm/min and the machine is started. The stress vs. extension curve of the
specimen is recorded and the required values are taken.
25. TESTING FOR MOLDED SAMPLES
Determination of Tensile Properties of Moulded Plastics
Reference: ASTM D638
Scope: This test is used to determine the tensile properties of moulded polymer samples.
Principle:
Plastic products when subjected to tensile force initially resist deformation, get elongated and
then finally break. Tensile elongation and tensile modulus measurements are among the most
important indications of strength in a material and are most widely specified properties of plastic
materials. Tensile test in a broad sense is a measurement of the ability of a material to withstand
forces that tend to pull it apart and to determine to what extent the material stretches before
breaking. Tensile modulus, an indication of the relative stiffness of a material can be determined
from a stress-strain diagram.
26. Apparatus:
(i) Universal Testing Machine
(ii) Grips for mounting the specimen
(iii) Vernier Callipers
Sample Specification: Five specimens are tested as per the following specifications:
Sample PE PP
Sample Type ASTM D638 Type IV Type I
Grip separation rate 50mm/min 50 mm/min
Distance between the grips 64 5 mm 114 1 mm
Procedure:
The testing machine is switched on and the program for determining the tensile properties is
selected. Test samples, previously conditioned are used for testing. Two marks, 1.0 0.1 inches
apart are on all the test samples at the center of the narrow portion of the sample. The width and
thickness of the sample is measured to the nearest 0.001 mm and entered as data. The specimen
is placed in the grips of the testing machine and the grips are tightened. The extensometer is then
attached on the marks made on the sample. The initial load is tare. The speed of the testing
machine is set and the machine is started. The load vs. extension curve of the specimen is
recorded and the load and extension at the yield point and the point of rupture are noted. Tensile
strength at yield (TYS), UTS, % elongation at break and % elongation at yield were directly
displayed on the screen.
27. Calculations:
Tensile modulus was calculated from the points on the stress-strain curve
Tensile Modulus = Difference in stress/difference in corresponding strain
Tensile strength= force/ area
28. Scanning ElectronMicroscope (SEM)
Scope: This test is used to see the finer details of the surface of polymeric sample. It finds
application when the dispersion and size of rubber droplets in Impact co-polymer
polypropylene (ICP) is to be found or surface defects are to be evaluated.
Principle:
A scanning electron microscope (SEM) is a type of electron microscope that produces images
of a sample by scanning it with a focused beam of electrons. The electrons interact with
electrons in the sample, producing various signals that can be detected and that contain
information about the sample's surface topography and composition. The electron beam is
generally scanned in a raster scan pattern, and the beam's position is combined with the detected
signal to produce an image. SEM can achieve resolution better than 1 nanometer. Specimens can
be observed in high vacuum, low vacuum and in eenvironmental SEM specimens can be
observed in wet conditions.
In a typical SEM, an electron beam is thermionically emitted from an electron gun fitted with a
tungsten filament cathode. Tungsten is normally used in thermionic electron guns because it has
the highest melting point and lowest vapor pressure of all metals, thereby allowing it to be heated
for electron emission, and because of its low cost. Other types of electron emitters include
lanthanum hexaboride (LaB6) cathodes, which can be used in a standard tungsten filament SEM
29. if the vacuum system is upgraded and FEG, which may be of the cold-cathode type using
tungsten single crystal emitters or the thermally assisted Schottky type, using emitters of
zirconium oxide.
The electron beam, which typically has an energy ranging from 0.2 keV to 40 keV, is focused by
one or two condenser lenses to a spot about 0.4 nm to 5 nm in diameter. The beam passes
through pairs of scanning coils or pairs of deflector plates in the electron column, typically in the
final lens, which deflect the beam in the x and y axes so that it scans in a raster fashion over a
rectangular area of the sample surface. When the primary electron beam interacts with the
sample, the electrons lose energy by repeated random scattering and absorption within a
teardrop-shaped volume of the specimen known as the interaction volume, which extends from
less than 100 nm to around 5 μm into the surface.
The size of the interaction volume depends on the electron's landing energy, the atomic number
of the specimen and the specimen's density. The energy exchange between the electron beam and
the sample results in the reflection of high-energy electrons by elastic scattering, emission of
secondary electrons by inelastic scattering and the emission of electromagnetic radiation, each of
which can be detected by specialized detectors. The beam current absorbed by the specimen can
also be detected and used to create images of the distribution of specimen current. Electronic
amplifiers of various types are used to amplify the signals, which are displayed as variations in
brightness on a computer monitor (or, for vintage models, on a cathode ray tube). Each pixel of
computer video memory is synchronized with the position of the beam on the specimen in the
microscope, and the resulting image is therefore a distribution map of the intensity of the signal
being emitted from the scanned area of the specimen. In older microscopes image may be
captured by photography from a high-resolution cathode ray tube, but in modern machines image
is saved to computer data storage.
30. Procedure:
1. Cut the sample by microtoming if Tg of polymer is below room temperature it is cut by
cryogenic microtomy (i.e. in an atmosphere of Nitrogen because of its low boiling point) else
its microtomed at ambient conditions.
2. Put the double stick carbon tape on sample stub.
3. Place the sample on the stub.
4. Now take out the rod and watch the indicator where green signifies vacuum and red
indicates air, as air enters the current increases.
5. Now control and regulate the voltage and filters to observe the specimen.
(An image formed SEM)
31. Determination of Izod-Impact Strength of Plastics
Reference: ASTM D256
Machine Make: Resil Impactor
Scope: This procedure is used to determine the impact strength of molded polymer
samples.
Summary: Notched specimens were subjected to impact with the help of a striking
pendulum hammer. Energy required for the sample to break was noted.
Principle:
Impact test indicates the energy required to break standard test specimens of a specified size.
Energy lost by the pendulum during the breaking of the specimen was noted.
The objective of the Izod Impact test is to measure the relative susceptibility of a standard test
specimen to the pendulum-type impact load. The results are expressed in terms of energy
consumed by the pendulum in order to break the specimen. The energy required to break a
standard specimen is actually the sum of the energies needed to deform it, to initiate its fracture
32. and to propagate the fracture across it, and the energy needed to throw the broken ends of the
specimen.
Apparatus:
Izod Impact Tester- CEAST (Resil-25)
Notch cutter with micrometer-screw gauge
Vernier Calipers- Accuracy 0.01 mm
Notchcutter
Sample specification: Molded specimens have width between 3.17 and 12.7 mm. The depth of
the plastic material remaining in the bar under the notch was 10.16 0.05 mm and the distance
of the notch from the end was between 31.5 to 32 mm.
Analytical Procedure:
1. Hammer was selected along with the relevant range and installed by means of the
33. range selector and the range switch.
2. The hammer was manually checked so as to ensure that it could be swung freely
between the anvils.
3. The hammer was initially released without the specimen and the value displayed
indicated the amount of energy lost due to friction, wind age, and other factors.
4. This value was subtracted from each of the final sample readings.
5. The hammer was positioned on the anvil and the test samples (conditioned for 40 hours at
232 C) were positioned and tightened with the torque wrench.
6. The hammer was then released and the breaking energy value on the digital display
was noted down.
7. If the display exceeded 70% of the 2.75 J, then the hammer was replaced by a higher
energy hammer and the above steps were repeated again.
Calculation:
Izod Impact Energy required to break the specimen – Air resistance
Energy = Thickness
34. Determination of Flexural Properties of Plastics
Reference: ASTM D790
Scope: This procedure is used to determine the flexural properties of plastic materials
Principle: Plastic Products when subjected to flexural strain resist deformation. Flexural strength
is the ability of the material to withstand bending forces applied perpendicular to its longitudinal
axis. The stresses induced due to the flexural load are a combination of compressive and tensile
stresses. Flexural properties are reported and calculated in terms of the maximum stress and
strain that occur at the outside surface of the test bar. Many polymers do not break under flexure
even after a large deflection that makes determination of the ultimate flexural strength
impractical for many polymers.
Apparatus:
(i) Universal Testing Machine (Lloyd)
(ii) Loading noses and supports
(iii) Vernier Callipers (Mitotoyo make)
Sample specification:
35. Five samples of the following dimensions are tested:
Length = 127 5mm
Width = 12.7 1mm
Thickness = 3.2 0.4 m
Support span length is 16 times the specimen thickness (Tolerance +4 or –2 mm)
Analytical Procedure:
An appropriate load cell (depending upon the type of material) is mounted on the machine. The
loading nose is attached to the load cell and the supports to the stationary crosshead. The parallel
alignment of the loading nose and supports is critical here. The machine is switched on and the
following instrumental parameters are set:
Speed of testing for the PP samples = 1.3 mm/min
The appropriate program for flexural properties is selected. Previously conditioned (Maintained
at 23 2C for 40 hours) test specimens are used. The width and thickness of the samples being
tested are entered as data and the support span is set at 50 2mm for PP. The specimen is
entered on the supports. The experiment was performed and the load deflection curve was
displayed and the program gave the flexural yield strength, modulus of elasticity, and 1% secant
modulus directly.
Calculation:
Eb=L3F/ (4bh3Y)
σf =3FL/ (2bh2)
F: Force @ midpoint
L: Span
b: Width
h: Thickness
36. Measurementof Colour of Plastics
Reference: ASTM E313
Machine make: Color quest II, Hunterlab
Scope: This test is used to measure the L*, a*, b* values of the given sample and also the
Yellowness Index, Whiteness Index, and colour differences between the standard and sample.
Sample specifications: Typically a 50 mm (2") or 100 mm (4") disk, although any flat sample
that the specimen holder will grasp can be tested.
Procedure:
The instrument is first standardized for color measurements and the instructions in the
computer are followed to get the required values.
L* indicates brightness,
a* indicated greenness or redness,
b* indicates blueness or yellowness.
ΔE= ((L* )2 (b* )2 (a* )2 )
Standardization includes selection of specular reflectance mode with large area of view and
UV filter out.
The standard light trap is then inserted followed by the standard white and the standard gray
tiles.
37.
The test sample is inserted into the specimen holder, and the spectrophotometer takes the
reading
The result obtained is in the form of L, a, b values, whiteness index (WI) and yellowness
index (YI).
Color analysis can be used to match adjacent parts molded from different materials, or to
evaluate color change due to outdoor exposure. Visual color and Spectrophotometer readings can
also be affected by surface texture, molding parameters, processing method, and viewing light
sources.
39. Principle:
In the process the material is plasticized and melted by the heat added through barrel heaters
and friction due to shearing.
Then the material is injected through nozzle into a relatively cold mold to get the desired
shape.
After the shape is formed, the ejector pins push the specimen out of the mould.
The process is used to make solid articles like caps, plugs, bobbins, furniture & house ware
products, industrial & automobile parts etc.
Mould:
Machines available:
Klockner Windsor FR 110
Klockner Windsor SP 180 (Family mould machine)
40. Arburg 320C All-rounder (ASTM standards)
Parts of a moulded specimen:
Injection moulding machine detail specification
Specifications Units DGP Klockner Arburg
Windsor Windsor All rounder
SP180 FR110 320 C 500-100
Screw diameter Mm 50 45 30
Injection pressure Bar 1800 1900 1550
L/D - 18:1 19:1 20:1
Clamping force KN 1800 1100 500
Min mould height Mm 350 250 200
Max mould height Mm 900 700 200
The theory of injection moulding can be reduced to four simple individual steps:
Plasticizing, Injection, Cooling, and Ejection. Each of those steps is distinct from the others
41. and correct control of each is essential to success of the total process.
The steps are as follows:
Plasticizing - describes the conversion of the polymer material from its normal hard
granular form at room temperatures, to the melt necessary for injection at its
correct melt temperature.
Injection - is the stage during which this melt is introduced into a mould to completely
fill a cavity or cavities.
Cooling - is the action of removing heat from the melt to convert it from melt back to its
original rigid state. As the material cools, it also shrinks.
Ejection - is the removal of the cooled, moulded part from the mould cavity and from
any cores or inserts.
Limitations of Injection Moulding
High initial equipment investment
High start-up and running costs possible
Part must be designed for effective moulding
Accurate cost prediction for moulding job is difficult
Application: PARC uses injection moulding machine for manufacturing of spiral flow test
sample, tensile testing sample, flexural testing sample, Izod testing sample, disc shape sample
and colour testing sample.
42.
43.
Blown Film Plant
PE Monolayer Blown Film Plant:
Blown film extrusion process andsalient features:
Blown film extrusion is the process by which most commodity and specialized plastic films are
made for the packaging industry. In this process extruded material flows through the tubular die,
which is like a combination of an offset die and a pipe die in that the material turns as it flows
into the die. The upward motion is preferred as it makes gravity uniform over the entire part. The
melt exits the die in the form of a tube. A cooling ring is placed at the exit of the die to give the
tube some dimensional stability since the material is air cooled. Air is then introduced through
the back of the die and flows upward inside the middle of the tube. This air pushes the tube
outward creating a bubble. The bubble thus formed continues to expand, cool and crystallize.
44. The bubble is then forced into a flat sheet by collapsing guides and moved into the nip rolls.
The nip rolls are present at the apex of the flattening planes. One of them is made of rubber and
other is made of steel, which draw the film through the take-off. They are about 15 to 30 cm in
diameter, with even larger diameters needed for widest films .The rpm of the nip rolls is
modified as per the thickness of the film is required.
Generally single layered films of 7-200 microns can be made on a monolayer blown film plant.
The line on the bubble that marks the onset of close-packed molecular arrangement can be
identified by loss of clarity and is known as the frost line.
The tube size is specified as the lay-flat size which is the width of the finished roll i.e. half the
circumference of the expanded tube.
Tubular films show excellent toughness as they are a mild form of biaxial orientation. Tubular
lines produce products which can be easily made in to bags, edge-trimming can be frequently
avoided and a film width is easily changed simply by blowing a bigger tube.
Machine Specifications:
LDPE/LLDPE plant HM/HDPE plant
Make Rajoo Engineers Limited Rajoo Engineers Limited
Model No RELL-4040 LAB REHD-4040 LAB
Screw diameter 40mm 40mm
Screw length 1200mm 1200mm
L/D ratio 30:1 30:1
Screw speed range 10-100rpm 10-100rpm
Die diameter 110mm spiral type 75mm spiral type
Die gap 1.2, 1.5,1.8mm 0.8,1.2mm
45.
46. Parts of a tubular blown film plant:
Extruder
Extruders comprise of hopper, barrel/screw and dies. Fig shows the component of a
modern extruder.
Hopper:
All the extruder has an opening in the barrel at the driven end, through which the plastic graduals
enter the extruder. The hopper, a simple sheet –metal enclosure, is mounted above the opening
and holds about a hopper’s capacity material. Hopper is provided with heating system, if the
material has to be preheated before entering the extruder.
Screw:
This is the heart of the extruder. Screw conveys the molten polymer to the opening of the die
after properly homogenizing the molten polymer.
47. There is considerable variation in the design of the screw for various materials, the most
important variable being the depth of the channels. Despite much desire for universal screw, it is
advisable to use a different design for each material to achieve the best results. PE screw is
designed to have shallow channels, sudden compression and long metering join.
Screw dia : 20-250mm,CR: 2.5-3: 1,L/D: 24-33: 1
Mixing Heads
The metering section of a standard is not a good mixer. Smooth laminar flow patterns are
established in the channel, which do not mix dissimilar elements in the melt. Mixing devices are
frequently installed in screw to disrupt these flow patterns and improve melt homogenization.
Breaker plate/screen pack:
Breaker plate with screen packs inserted is kept in the adapter, which connect the dies and
extruder barrel. This assembly has several functions.
1. Arrest the rotational flow of the melt and convert into axial flow.
2. Improves melt homogeneity by splitting and recombining the flow.
3. Improves mixing by increasing backpressure.
4. Remove any contamination and unmelt.
Screen packs are made up of series of screen of differing mesh. With the coarse screen placed
against the breaker plate to support the finer screens.
48. Die
The dies used for tubular extrusion are centre-fed or side-fed. Centre fed dies are better as all the
points on the lip are equidistant from the feed-entry point. This gives uniform flow and uniform
thickness. The spider arms of the centre-fed die always divide the flow into separate paths which
must come together and weld completely before leaving the die or else weld lines are formed,
which are lines of weakness.
Die gap is also a very important parameter as too small die gap may cause increase in die
resistance and cause overheating in extruder and reduce output rate. And if the gap is too large
resistance becomes so less that weld lines may appear.
For the processing of PE, a die with spiral is used as shown in the figure. As the plastic flows
from the entry point it spirals around the mandrel section of the die. The land depth between the
spiral section and wall increases as the wall increases as the material progress through the die, .as
a result, the distribution around the die periphery made uniform in order to control the gauge of
extruded tube.
Corona Treatment
Many plastics, such as polyethylene and polypropylene, have chemically inert and nonporous
surfaces with low surface tensions causing them to be non-receptive to bonding with printing
inks, coatings, and adhesives. Although results are invisible to the naked eye, surface treating
modifies surfaces to improve adhesion.
Corona treatment (sometimes referred to as air plasma) is a surface modification technique that
uses a low temperature corona discharge plasma to impart changes in the properties of a surface.
The corona plasma is generated by the application of high voltage to sharp electrode tips which
forms plasma at the ends of the sharp tips. A linear array of electrodes is often used to create a
curtain of corona plasma.
49. Parameterof blown film extrusion:
Temperature:
A lower temperature is needed for tubular film (e.g., 170oC for PE of 2.0 MFI) since the cooling
capacity often limits the output as a higher temperature may mean lower output. The other
possible disadvantages of higher temperature are:
Increased blocking
Reduced bubble stability
Promotion of decomposition in the die with resultant impaired appearance
Possible bubble breaks.
Blow up Ratio:
The blow-up ratio is defined as the ratio of the bubble diameter to the die diameter and is one of
the important factors to determine the final film size and properties. A high blow ratio means that
a smaller and less expensive die is needed for any given film size, but a high blow-up ratio yields
the strongest film as the increased stretching has an orientation effect. However, high blow-up
ratio also encourages bubble instability, requires more drawdown and magnifies all the
imperfections in the die, thus a compromise blow-up ratio is needed. Bubble instability is a
major problem in tubular film extrusion as it produces wrinkles, thickness variation, and
“walking” of the film along the windup roll.
The blow-up ratio is determined in advance, when a die is selected to do a given job. Die gap
also has significant effect on the film properties. Increasing die gap will increase machine
50. direction orientation which then results in lower machine direction tear strength, lower machine
elongation, improved transverse direction tear strength, & improved machine direction tensile
strength.
Frost-Line Height:
The area of change, where the viscous fluid is changed to solid film, is called the "frost-line"
because here the hardening film first appears "frosty" in some films. An irregularity here
indicates that something is wrong with the filmmaking process, and this may result in poor film.
Increasing FLH will decrease machine direction orientation with slower quenching rates
resulting in higher film crystallanity. Optical properties will reach an optimum & then start to
decrease.
The frost line can be raised or lowered by means of extruder output, take-off speed, and the
volume of cooling air blown against the bubble. When the screw speed goes up the distance
between the die and the frost line is increased; when more cooling air is blown against the
bubble, the frost line drops. The frost line can be change by adjusting the cooling-air volume.
The frost line in the bubble can effectively be raised by means of a so-called annealing chamber
(or "chimney") placed between the die and the air ring.
Start-up & shutdown of the process:
The first minutes of the production always yield scrap material as the system much yield
equilibrium. The die bolts may have to adjust to get the uniform thickness, and the extrusion
speed and the winder speeds must be balanced to get the desired overall thickness. The process is
started quite cool in order to minimize formation of decomposed material in the system, which
could subsequently contaminate the film and cause streaks. Once the screw is turning and plastic
is running through the die, the temperatures are raise to normal values. As the tube is being
formed, air is introduced through the die in small amounts to keep the tube slightly blown. After
the threading is complete, more air is blown in to bring the bubble to the desired size. Care must
be taken to keep the die faces clear of the molten resin as this may later be decomposed and
cause die lines.
Shut down is one of the most vital steps in blown film extrusion in order to avoid damage to
51. the head and the die. Such decomposition can be caused by the degradation, oxidation of hot
plastic in contact with air, or by both. For all materials degradation and decomposition may
produce hardened bits of material which can break off and lodge in the die lips. Such bits
form weld lines which are not only unsightly but are also lines of weakness.
When the film line is shut down, material is kept moving as the zones cool to about 130oC
(LDPE) then the extruder is stopped and the die and head are cooled with air as fast as possible
to inhibit decomposition. Polyethylene is often left in the extruder barrel as well as inside the die
to prevent air from entering the system and oxidizing any bits of plastic left. Likewise, before
start-up the die is not left hot any longer than absolutely necessary.
Winding:
Winding is the final operation in the film manufacturing process. In blown film, because there
are two sides of the tube, two winders are requires. Film is wound on a spiral wound paper core
which is supported by the winding shaft. This shaft is attached to the winder at the ends. The
core is secured to the shaft using either a cable lock mechanisms or lugs which are pneumatically
protruded from the shaft surface.
Two basics techniques used for winding films are: driving the winding roll from the centre
using a driven wind up shaft, or applying a driven roll directly to the surface of the
winding roll of the film
Centre winders : Centre winders have the advantage in that the tension in the film can be
controlled as the diameter of the film increases. This is done by sensing the diameter of the film
& decreasing the tension of the film as the diameter of the film increases. Tension is controlled
by controlling the differences in speed between the nip rolls & the winding rolls Tension can also
be controlled by a pneumatically activated idler roll that applies pressure on the film web. This
roll is called the dancer since it pivots up& down as it maintains the constant pressure in the web.
With the higher force required to move the dancer roll, more tension will be applied to the film.
Decreasing the tension as the roll diameter grows up, helps to keep the film roll form winding
too tight. Tight winding will cause the film to block & make it sensitive to shrink as it cools on
the toll. If winding is too tight, the shrinking film will become distorted & difficult to print or
laminate.
Surface winders : Surface winders are easy to operate since they don’t have the
52. complex methods of tension control. In case of surface winders, tension is applied to the
film by winding the film faster than the nip rolls. However, this does not allow for the
finer adjustments in tension as in a dancer-bar arrangement. Surface winders rely on the
pressure of the drive roll to control the roll hardness. Therefore, because some pressure is
required to drive the roll, they tend to wind harder rolls than centre winders. However,
because there is not the variation in tension & because there is no dancer rolls, some
processors believe that surface winders can wind flatter rolls than centre winders. It is
difficult, however, to change the direction of the wind on a surface winder compared to
the centre winder.
53.
CompressionMoulding Machine
Machine Specifications: Compression cylinder: 6 inch diameter
Make: Carver Inc. LMV 50H-15-C (50T)
Process: The process of compression molding may be simply described by reference to Fig.
Two-piece mold provides a cavity in the shape of the desired molded article. The mold is heated,
and an appropriate amount of molding material is loaded into the lower half of the mold. The two
parts of the mold are brought together under pressure. The compound, softened by heat, is
thereby molded into a continuous mass having the shape of the cavity. The mass then must be
hardened, so that it can be removed without distortion when the mold is opened.
Advantages
Compression Moulding
Mould costs tend to be lower because the moulds are simpler.
Low volume jobs are better suited to compression moulding because start up is usually
quicker, easier and generates less scrap.
Cycle times for compression moulded is more than injection moulding
Disadvantages of Compression Moulding
Compression molded parts usually are more labour intensive. Preforms must be made,
heated and loaded into the mold by an operator or a robot.
Across parting line dimensions can be more difficult to control.
Application: PARC uses compression moulding for manufacturing of thermoplastic
sheet (testing sample are punch from sheet)
54. COMPOUNDING
A) Single screw compounding extruder:
Make: Thermo Electron Corporation
Machine Specifications:
Screw diameter: 19mm
L/D ratio: 25:1
Application : Single screw compounding extruder is use for checking the decrease in properties
of material after no. of passes.
B) Twin screw compounding extruder:
Type: Co-rotating twin screw extruder
Make: Omega 30 STEER
Machine Specifications:
Screw diameter: 30mm
Application : Twin screw extruder is use mainly for PVC
C) Pulverizing Unit:
The pulveriser unit is capable of pulverizing polymer granules 500μm to 1.75mm.
Make: Fixopan Machines Pvt Ltd.
Model no: FP14-SGL
Capacity: 40-60 kg per hour
Grinding teeth: Multiple (Over 250)
55. References
Organic Chemistry (6E 2005) L. G. Wade
PSLC-The Polymer Science Learning Centre
ASTM Standards Handbook
Polymer Science and Technology- V. Gowarikar
J. Heo, K. J Lim, Member, IEEE, J. N. Lim and E. H. Jung, AC Insulation
Performance of HDPE Mixed with EVA Applied for Power
Cable Insulation, page no.1-5
BRYDSON, J. A. (1999) Plastics Materials (7th edition)
Handbook of Plastics Testing and Failure Analysis 3rd
edition (2007)
Stress crack resistance of structural members in Corrugated High Density
Polyethylene pipe, John M. Kurdziel, P.E. and Eugene F. Palermo, page
No 1-2
