C11 - Polymers Flashcards
What is a polymer?
A long chain of repeating units/molecules.
What is a monomer?
A molecule that can be bonded to other identical molecules to form a polymer.
What 2 methods are there for making polymers?
1) Addition Polymerisation - monomers of the same molecule.
2) Condensation Polymerisation - monomers of different molecules.
What type of molecule is most commonly used as monomers in addition polymerisation?
Alkenes (C=C functional group) undergo addition polymerisation.
E.g Ethene Monomers —> Poly(ethene)
Propene Monomers —> Poly(propene)
How do ethene monomers become a polymer by addition polymerisation? How do you write polymers?
The C=C bond will ‘open up’ (break), allowing the ethene molecules to join together.
This long repeating chain is called poly(ethene) OR polythene.
Writing polymers:
- If the monomer is (x).
- -The polymer will be poly(x)
E.g Ethene —> Poly(ethene).
What is the type of bond that makes up polymers called?
Covalent Bonds
What other products are formed when addition polymerisation takes place? Why?
None.
-Because no other monomers are joining on - nothing else is produced.
How do you write a simplified chemical structure for a really long polymer?
You just draw one monomer of the polymer (the unit that repeats) and draw brackets around the molecule, with an ‘n’ outside showing the number of repeating units.
E.g Ethene —> Poly(ethene):
H H
| |
[—(— C — C —)— ] *n
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H H
*n - the number of repeating units.
What type of materials are made up of polymers?
Plastics, packaging, super glue, perspex etc…
What is the everyday name of poly(ethene)? What are its uses?
Polythene
Uses: Bags, bottles
What is the everyday name of poly(propene)? What are its uses?
Polypropylene
Uses: Crates, Ropes
What is the everyday name for poly(phenylethene)? What is its main use?
Polystyrene (phenylethene is also called styrene)
Uses: Packaging Foam
What monomers does Condensation Polymerisation involve?
2 DIFFERENT monomers - each with its own functional group present at both ends of the molecule.
E.g Monomer 1 has OH at both ends. Monomer 2 has COOH at both ends.
What feature of a monomer undergoing condensation polymerisation must be present? How is a condenation polymer formed?
The functional group of each monomer, must be present at BOTH ENDS of each monomer (a ‘di’ molecule).
This is because:
-The different monomers can only combine by releasing a small molecule to form a stable polymer.
What extra product is released from Condensation Polymerisation?
A small molecule
What is usually the small molecule released?
Water
Why is a small molecule released?
A small molecule is released so that the monomers can join to form a stable chain.
What is a polyester?
A condensation polymer containing the Ester functional group (COO).
How is a polyester formed?
By reacting a dicarboxylic acid with a diol.
*Think: Ester = Alcohol + Carboxylic Acid
Polyester = Diol + Dicarboxylic Acid
What is a dicarboxylic acid?
A carboxylic acid with the presence of 2 functional groups (one at either end) - COOH.
What is a diol?
An alcohol with the presence of 2 functional groups (one at either end) - OH.
What product is released when a diol and a dicarbocxylic acid react together to form a polyester?
Water - as a small molecule
Show how to determine the structure of a polyester and the repeating unit. Show how water is released as a small molecule.
🟢 = Diol - E.g Ethanediol (C2H6O2) 🔵 = Dicarboxylic Acid - E.g Hexanedioc Acid (C6H10O4)
HO — 🟢 — OH - Diol
HOOC — 🔵 — COOH - Dicarboxylic Acid
'HO — 🟢 — *OH + *HOOC — 🔵 — COOH'
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V
*H + HO = H2O
'H + OH = H2O
Polyester formed is:
[O — 🟢 — CO — OOC — 🔵 — COO ] n - This is the Repeating Unit.
2nH2O is the water released.
What is a polyamide?
A condensation polymer with repeating units linked by amide bonds.
