3.2 Addition Polymers
Module 2
Lesson 3.2 Addition Polymers
Key Concepts
Addition polymers are produced by the polymerization of monomers that contain a double bond. The mechanism by which the monomers combine involves an addition reaction in which the double bond is broken. The resulting free electrons bond the monomer units together. In addition polymerization, only one product is formed.
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You may recall from Module 1 that ethane is extracted from natural gas. Then, hydrogen is removed from the ethane to produce ethene, also known as ethylene. The ethene monomer is considered a primary petrochemical because it can be used to make many new compounds, including polymers. |
Consider polyethene as an example of an addition polymer. Polyethene (polyethylene) is used in the production of many plastics.
It is produced by an addition reaction that links ethene (ethylene) monomers together in a long chain.
Polypropene is also a commonly used polymer. For example, some ropes and certain carpets are made from polypropene. This polymer is produced by an addition reaction that links propene monomers.
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Propane is extracted from natural gas and converted into propene (propylene). The propene monomer is also considered a primary petrochemical. |
You probably have heard of the material known as "PVC". PVC is a polymer that is used to insulate electrical wires and coat upholstery fabrics. This polymer is produced by an addition reaction that links vinyl chloride monomers.
Read pages 445 to 458 in the textbook.
Watch
Although addition polymers are very useful, their widespread use had taken a heavy toll on our environment.
Watch the following videos to learn more about this problem and its possible solutions.
Check Your Understanding
Complete Practice Questions 1 (a, b) and 2-6 on page 448 of the textbook.
Check your work by clicking on the link below.
Page 448 Practice Question 2
Page 448 Practice Question 3
- but-2-ene
- 1-chloro-1,2-difluoropropene
If you are having difficulty determining the monomer from the polymer structure, write the formula for ethane. Then, replace the H atoms with the groups that are dangling off the polymer chain.
Page 448 Practice Question 4
The monomer should be an alkene or alkyne.
Page 448 Practice Question 5
monomers:
polymer:
Page 448 Practice Question 6
- Typical properties of a plastic are insolubility in water, good insulators of heat and electricity, flexibility, and high melting point for a molecular material.
- Within a polymer molecule, there are very strong covalent intramolecular bonds. Between the polymer molecules, there are always intermolecular London forces. Depending on the structure of the polymer, there may be dipole-dipole forces and hydrogen bonding.
- Plastics are flexible because the intermolecular bonds holding the polymer chains together are easily deformed. Plastics are good insulators because they are molecular, so they do not have freely moving ions or electrons. The intermolecular forces for such large molecules help explain the insolubility and high melting point of plastics.