SEMESTER –VII THESIS TITLE “STUDY OF PET WASTE RECYCLING“ PROJECT ADVISOR ASSOCIATE PROFESSOR ARSHAD FARUQUI GROUP MEMBERS QASIR NAZIR 16-PE-12 YASIR ABBAS 16-PE-18 ADIL HANIF KALWAR 16-PE-20 ISRAR AHMAD 16-PE-22 IJAZ HUSSAIN 16-PE-07 FARAZ ALI KHAN 16-0-PE-05 MUHAMMAD FAIZAN KHALID 16-0-PE-12 SALEEM SIDDIQUI 16-0-PE-18
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SEMESTER –VII
THESIS TITLE
“STUDY OF PET WASTE RECYCLING“
PROJECT ADVISOR
ASSOCIATE PROFESSOR ARSHAD FARUQUI
GROUP MEMBERS
QASIR NAZIR 16-PE-12
YASIR ABBAS 16-PE-18
ADIL HANIF KALWAR 16-PE-20
ISRAR AHMAD 16-PE-22
IJAZ HUSSAIN 16-PE-07
FARAZ ALI KHAN 16-0-PE-05
MUHAMMAD FAIZAN KHALID 16-0-PE-12
SALEEM SIDDIQUI 16-0-PE-18
ACKNOWLEDGEMENT
In the name of Allah, the Most Gracious and the Most Merciful Alhamdulillah, all praises to Allah for the strength and blessing in completing this thesis. Special appreciation goes to Professor Dr. Naim Masood Hasan , Associate Professor Zaheer Ahmed Chaugtai , Associate Professor Tariq Jamal . Associate Professor Arshad Faruqui for his supervision and constant support. We also wish to acknowledge Laboratory & Technical staff for helping us. Sincere thanks to all our seniors for their support during the study.
Last but not least, deepest gratitude goes to our beloved parents for their endless love, prayers and encouragement. To those who indirectly contributed in this research, your kindness means a lot to us. Thank you very much.
FOLLOWING STEPS INVOLVE IN PHYSICAL RECYCLING OF PET BOTTLE TO FORM FIBR Step 1 Bale Breaking Stage
Used plastic bottles are collected from municipal curbside systems and deposit centers and are compressed into half-ton bales for delivery to the Carbon LITE process facility in Riverside CA. A bale-breaking machine de-compresses the
bales back into single bottles. Step 2 Bottle Cleaning Stage
The single bottles are separated from any trash and debris and washed in hot
caustic water.
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Step 3 Bottle Sorting Stage
Automatic sorting equipment segregates the bottles into three streams: clear
PET, green PET and non-PET. The non-PET stream is re-baled and sold to others for subsequent processing into various plastic products.
Step 4
Washing Stage
The clear and green streams of bottles are ground into cornflake-like flakes. These flakes are intensively washed, rinsed and dried.
Step 5
Solid State De-contamination Stage
The dried clean flakes are heated under vacuum to remove any contaminates that may exist. This system of de-contamination is recognized by the FDA as
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acceptable for subsequent use in direct food packaging. The purified flakes are melted and extruded into pellets. This is our finished product and it is similar in consistency to rice. Step 6 Final Packaging Stage
The food-grade pellets are transported to bottle manufacturers and other customers in bulk hopper road trucks or railcars. Some customers prefer the pellets to be packaged in one-ton plastic bags on pallets. And then these bags of flakes goes to different industries to achieve final production just like these flakes can be use in the production of Synthetic fiber, films, Gel Coats, Coating applications and different other applications. The example of Polyester Synthetic fiber with processing is given bellow:
Synthetic Fibers
Synthetic fibers are "man-made textile fibers produced entirely from chemical substances, unlike those man-made fibers derived from such natural substances as cellulose or protein." The polymers of synthetic fibers do not occur in nature, instead, they are produced from scratch in chemical plants or laboratories, "usually from by-products of petroleum and natural gas." Of these polymers is polyethylene terephthalate/polyester. Synthetic fibers are "spun and woven into huge consumer and industrial products", from garments such as shirts and scarves, home furnishings such as carpets ad drapes, to industrial parts such as flameproof linings and drive belts.
Stages in the Melt Spinning of polyester fibers
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3.5. PET BOTTLES RECYCLING IN PAKISTAN
Bales of used bottles (Post Consumer Bottles for Recycling)
Crusher used for cutting the used bottles into flakes
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Crusher front view
Washing line used for cleaning up the pet flakes
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PET flakes are drying in SUN
Final Recycled PET flakes (Final Product)
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CHAPTER 4
CHEMICAL RECYCLING OF PET TO FORM UNSATURATED POLYESTER
RESIN
Chemical recycling is also an established method for the recovery of process
waste. However, equipment costs are high and require large turnovers to be
economically viable.
4.1. GLYCOLYSIS
Glycolysis is a chemical process of PET waste recycling which required heat for
processing so it is an endothermic reaction. If recycled PET is treated with excess
glycol, a transesterification reaction takes place. The reduction of high molecular
weight PET to short-chain fragments is achieved by heating the PET with a glycol
such as propylene glycol (PG) in the presence of a catalyst. Typical catalysts are
zinc, manganese, or cobalt acetic acid. Typically this glycolysis reaction takes
place over an 8 hour period at 200 °C with a PG/PET and major products are bis-
hydroxyethyl terephthalate, bis-bydroxypropyl terephthalate, and mixed EG/PG
terephthalate diesters, plus some free EG and PG. The reaction is carried out
under continuous nitrogen purge to inhibit degradation of the resulting polyols.
Under these reaction conditions, the resulting polyol has a number average
molecular weight of 480 and a hydroxyl number of 480. If a higher molecular
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weight polyol were desired, the PG/PET ratio is lowered; i.e. less PG is used per
mole of PET. Glycolysis reaction can also be done using glycerol, which produces
a polyol with higher hydroxyl number, or with diethylene or dipropylene glycol
(DEG). [17]
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PIOLET PLANT
4.2. HYDROLYSIS
Treating PET with water in excess at an elevated temperature of 150-250 °C in
the presence of sodium acetate as catalyst produces terephthalic acid (TPA) and
ethylene glycol (EG) in four hours. Catalysts for hydrolysis are either acids (such
as sulfuric) or bases (such as ammonium hydroxide) [16]. An acid catalyst will
promote the hydrolysis in 10-30 minutes at 60-95 °C. Alternatively, PET can be
treated with an excess of methanol, to produce dimethyl terephthalate (DMT)
and EG. A typical PET/methanol ratio is 1:4. [17]
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4.3. METHANOLYSIS
Weighed amounts of PET (w1), methanol and ionic liquids were added in an
autoclave with a stirrer and a thermometer. The mixture was heated up to the
given temperature for certain time. The reaction mixture was filtered to remove
the unreacted PET (w2). The obtained filtrate was diluted with an equal volume
of water and a precipitate was obtained and filtered. The obtained filtrate was
distilled under vacuum to remove water and ethanediol, the residue that is
mainly composed of ionic liquid and catalyst was reused directly as solvent and
catalyst. The filter cake which is mainly composed of dimethyl
terephthalate(DMT) was dried to obtain DMT product . [17]
4.4. CHEMICAL RECYCLING OF PET ON LABORATORY SCALE
It is a process in which polymer chain breakdown into oligomer. Such as PET flakes are converted to BHET (Bis Hydroxyethyl Terephthalate). So this process consists of following Steps. i- First PET bottle Cut into Flakes of size 10mm ii- We take three neck Flask in which we put PET flakes and Diethylene Glycol
(DEG) as we know that glycolysis consist of transesterifaction of PET. As transesterifaction decrease the molecular weight of the polymeric chain.
iii- And then Zinc Acetate is added which is used as a catalyst and temperature is 210oC for 5 hour. And this reaction takes place in three neck round bottle flask.
iv- Nitrogen gas is supplied throughout the reaction. v- After this it is cooled down to 100oC at room temperature.
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vi- Now After this the solution is filtered and again pour it in to the flask vii- Then nitrogen supply is started to the flask to avoid oxygen to react with the
solution. viii- After this heating is started and phthalic anhydride, hydroquinone and maleic
anhydride is added to the flash. Due to which unsaturated polyester resin is formed
ix- After this styrene, monomer is added to the flask because it can start cross linking and stop the pre maturing.
x- And our unsaturated polyester resin is ready to use.
FORMULATION OF RECYCLED UNSATURATED POLYESTER
The Below formulation is approximate by weight.
S.No MATERIALS PERCENTAGE % 1 PET Flakes 24
2 DEG 27
3 MA 18
4 Styrene 28
5 THQ 0.01
6 HQ 0.001
7 WAX 0.05
8 Zn. Act 0.007
9 St. Acid 0.05
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CHAPTER 5
APPLICATION OF RECYCLED PET
Regrind PET can be used for reprocessing into cheap fiberfill for pillows and
sleeping bags or used directly in filled and reinforced PET molding compounds.
Another outlet for used PET is as a fuel source. According to Eastman, PET burns
cleanly to produce carbon, oxygen, and water, and one pound of PET has the
same heating value as one pound of soft coal. There are different uses of waste
PET it will be converted in to UP resin which is thermosetting material and it can
be uses for variety of purposes and PET waste can also be converted to polyols
for use in rigid or flexible urethane foams. Urethane foams made from recycled
PET are relatively cheaper than those made from normal virgin polyols. A variety
of clothing, including uniforms, working wear, T-shirts, polo shirts, sweatshirts
and using filament yarn, sweatshirts (jersey), windbreakers (woven), bags
(woven), tents (woven) and umbrellas (woven), are being manufactured from
recycled PET bottles. Recycled PET is also used as the plastics clamshells for
bakery and deli products.
This clamshell is produced by thermoforming a 3-layer sheet in which the middle
layer contains the recycled PET. Previously recycled PET cannot be used for food
packaging due to the restriction of Food and Drug Association (FDA). Now after
the development of new, advanced and sophisticated recycling processes, the
FDA has started giving approval to recycled PET up to a certain level. This has
opened new doors for the use of recycled PET. As one of the major users of
plastic containers for food use, and as a leader in the beverage industry, The
Coca-Cola Company has been involved in PET recycling from the start and was
one of the first companies to receive a "no-objection" letter from U.S. FDA,
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allowing the use of recycled PET for food-contact application. Since then many
different companies have taken an interest in developing some process for
recycling PET so that it can be used in direct food contact packaging and have
gained success [18]. The market of recycled PET for beer bottles is also igniting
interest of various manufacturers [19].Development in the field of reinforced
recycled PET is also catching up. Glass/mineral filled PET is now being used as
automotive grille opening retainers by Ford Motor Company, Mitsubishi Motors
and Toyoda Gosei Co. Ltd. jointly are now molding car engine covers entirely
from recycled PET soft drink bottles. [20]
RECYCLED PET T SHIRT & Lamp made with recycled PET straps
Extensive research investigated the use of resin based on recycled poly (ethylene
terephthalate) plastics waste for the production of a high performance
composite material, namely polyester concrete, for the construction industry.
Resins using recycled PET offered the lower source cost of materials for forming
good quality polyester concrete. Other applications include polyester resin for
Consist of two sections on which our work is based. The content to be covered in two
sections is summarized below according to the semester.
SEMESTER-7
In this semester our strategy consist of theoretical detail about,
Bottle Grade & Fiber Grade Recycling
Physical Recycling Process
Chemical Recycling Process
Market Survey
Testing Techniques
Application of Unsaturated Polyester Resin
SEMESTER-8
Semester 8th will include brief detail about,
the structural analysis of material on which the PET recycling is based.
Practical work will include physical and chemical recycling to form fiber and
unsaturated polyester (UP) resin respectively.
Testing results and data from recycling process will be obtained and discussed in
detail.
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REFERENCES
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*16+ Lamparter R. A., Barna B. A., and Jonsrud D. R., “Process for Recovering Terephthalic Acid from Waste Polyethylene Terephthalate”, U.S. Patent 4,542,239, (1985) *17+ Gruschke H., et al. “Process of Depolymerization of Polyethylene Terephthalate to Terephthalic Acid and Dimethyl Ester”, U.S. Patent 3,403,115, (1968) [18] Doba J., "FDA Gives Go-Ahead for Recycled PET Use", Plastics News,Vol. 11, p. 4 (2000) [19] Defosse M., "Promising Beer Bottle Market is Igniting Interest in Recycled PET", Modern Plastics International, Vol. 29, p. 38 (1999) [20] Moore S., "Auto Engine Cover is Made from PET Bottles", Modern Plastics International, Vol. 30, p. 32-36 (2000) *21+ Jang B. Z., “Advanced Polymer Composites: Principles and Applications”, ASM International, Materials Park (1994) [22] http:// www.accessscience.com McGraw-Hill Encyclopedia of Science & Technology Online *23+ Simon G. P., “Polymer Characterization Techniques and Their Applications to Blends”, Oxford University Press, (2003) *24+ Strong A. B., “Plastics, Materials & Processing”, Prentice Hall, New York, (2000) *25+ Yılmazer U., Cansever M., “Effects of Processing Conditions on the Fiber Length Distribution and Mechanical Properties of Glass Fiber Reinforced Nylon-6”, Polymer Composites, Vol. 23, p. 61-71 (2001)
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