POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction...
-
Upload
anissa-laureen-stevens -
Category
Documents
-
view
229 -
download
2
Transcript of POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction...
![Page 1: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/1.jpg)
POLYMERISATION OF ALKENES
Process • during polymerisation, an alkene undergoes an addition reaction with itself
• all the atoms in the original alkenes are used to form the polymer
• long hydrocarbon chains are formed
ADDITION POLYMERISATION
the equation shows the original monomer and the repeating unit in the polymer
ethene poly(ethene)
MONOMER POLYMER
n represents a large number
![Page 2: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/2.jpg)
Industrial Polymerisation
• Radical Polymerisation– 200°C and high pressure– Leads to branching of the polymer chain and
polymer mixtures– Poly(phenylethene), poly(styrene) and branched
Poly(ethene)
![Page 3: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/3.jpg)
Industrial Polymerisation
• Ziegler-Natta process– Specialist catalysts: TiCl3 and Al(C2H5)2Cl at 60°C– Alkene is passed over the catalyst– Conversion is low and any unreacted alkene is
recycled and passed over the catalyst repeatidly– Most common method for the manufacture of
non-branched poly(ethene)
![Page 4: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/4.jpg)
Questions
• State one key advantage of the Ziegler-Natta process over that of radical polymerisation– Greater control over the product formed leads to
more straight chain polymers• Draw a section of a polymer made from three
molecules of ethene
![Page 5: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/5.jpg)
Addition Polymerisation
• Drawing a polymer from a monomer– Draw the four groups at right angles– Replace the double bond with a single bond– Draw side links
![Page 6: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/6.jpg)
POLYMERISATION OF ALKENES
ETHENE
EXAMPLES OF ADDITION POLYMERISATION
PROPENE
TETRAFLUOROETHENE
CHLOROETHENE
POLY(ETHENE)
POLY(PROPENE)
POLY(CHLOROETHENE)
POLYVINYLCHLORIDE PVC
POLY(TETRAFLUOROETHENE)
PTFE “Teflon”
![Page 7: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/7.jpg)
Poly(propene)polypropylene
Poly(phenylethene) polystyrene
![Page 8: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/8.jpg)
POLYMERISATION OF ALKENES
SPOTTING THE MONOMER
![Page 9: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/9.jpg)
POLYMERISATION OF ALKENES
SPOTTING THE MONOMER
![Page 10: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/10.jpg)
POLYMERISATION OF ALKENES
SPOTTING THE MONOMER
![Page 11: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/11.jpg)
POLYMERISATION OF ALKENES
SPOTTING THE MONOMER
![Page 12: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/12.jpg)
POLYMERISATION OF ALKENES
SPOTTING THE MONOMER
![Page 13: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/13.jpg)
POLYMERISATION OF ALKENES
SPOTTING THE MONOMER
![Page 14: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/14.jpg)
Questions
• Draw a section of the polymer that can be made from 1-chloropropene, showing two repeat units.
• The polymer on the right is poly(vinyl alcohol), PVA.– Identify the repeat unit– Draw the structure of the
monomer that forms PVA
O
![Page 15: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/15.jpg)
“Plastic” wallets and carrier bags are often made from PVC PVC as a leather substitute
![Page 16: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/16.jpg)
Some uses of PTFE
Non-stick coating for pans
Low friction coating for surgical sutures
Insulating tapes
![Page 17: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/17.jpg)
Items made from polymers have recycling symbols moulded into them. High-density poly(ethene) HDPE and poly(propene) PP are particularly suitabel for recycling.
![Page 18: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/18.jpg)
Task• Working in pairs research how different types
of polymers are recycled.– Group 1 - PETE– Group 2 - HDPE– Group 3 - V– Group 4 – LDPE– Group 5 - PP– Group 6 - PS– Group 7 – Other
• Report back to the class
![Page 19: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/19.jpg)
POLYMERISATION OF ALKENES
PROBLEMS WITH POLYMERS
• Although polymers derived from alkenes are invaluable to modern society, their disposal creates widespread problems.
– they are unreactive to most chemicals and bacteria (non-biodegradable)
– if they are just discarded they add to the landfill problem
• recycling high cost of collection and re-processing
• burn waste saves on landfill sites and produces energy
• toxic fumes (HCl) can be removed from burning chlorinated polymers
• feedstock use the waste for the production of useful organic compounds• new technology can convert waste into hydrocarbons
• hydrocarbons can then be turned back into polymers.
![Page 20: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/20.jpg)
Questions
• Give two uses of polystyrene– Foam packaging, insulation, model making, food
retail trade• What do you understand by the term non-
biodegradable?– A non-biodegradable material does not break
down naturally or safely in the environment by biological means.
![Page 21: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/21.jpg)
Questions
• Why is it important to replace polystyrene as a packaging material?– The non-biodegradability of polystyrene means
that waste polystyrene ends up in landfill sites, which are rapidly running out of space.
• When PVC is burned poisonous gases may be released. Suggest two such gasses. – HCl and CO
![Page 22: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/22.jpg)
A summary of how poly(propene) can be recycled.
![Page 23: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/23.jpg)
Lactic acid is now used to make compostable polymers
© Pearson Education Ltd 2008This document may have been altered from the original
![Page 24: POLYMERISATION OF ALKENES Process during polymerisation, an alkene undergoes an addition reaction with itself all the atoms in the original alkenes are.](https://reader035.fdocuments.us/reader035/viewer/2022062217/56649e585503460f94b518a5/html5/thumbnails/24.jpg)
Summary
• Addition polymer – very long molecular chain, formed by repeated addition reactions of many unsaturated alkene monomers
• Repeat unit – specific arrangement of atoms that occurs in the structure over and over again
• Describe uses of certain polymers• Outline how waste polymers are recycled,
separated and processed• Revise section 2.1.20 other uses of polymer waste