1. Case Western Reserve University
Chapter 28
Synthetic Polymers
Organic Chemistry
4th Edition
Paula Yurkanis Bruice
Irene Lee
Case Western Reserve University
Cleveland, OH
©2004, Prentice Hall

2. A polymer is a large molecule made by linking together
repeating units of small molecules called monomers

3. Chain-growth polymers, also known as addition polymers, are made by chain reactions

4. Step-growth polymers, also called condensation
polymers, are made by combining two molecules by
removing a small molecule

5. Chain-Growth Polymers
Chain-growth polymers proceed by one of three
mechanisms:
radical polymerization
cationic polymerization
anionic polymerization

7. Radical Polymerization

10. The molecular weight of the polymer can be controlled by
a process known as chain transfer

11. Chain-growth polymerization of monosubstituted
ethylenes exhibits a marked preference for head-to-tail
addition

12. Head-to-tail addition of a substituted ethylene results in a
polymer in which every other carbon bears a substituent

13. Head-to-tail addition is favored for steric reasons
Groups that stabilize radicals also favor head-to-tail
addition

16. Branching of the Polymer Chain

17. Branched polymers are more flexible

18. Cationic Polymerization
the alkene monomer
reacts with an electrophile

21. The carbocation intermediates formed during
polymerization can undergo rearrangement

22. Monomers that are best able to undergo cationic
polymerization are those with electron-donating
substituents

23. Anionic Polymerization
Nonterminated chains are called living polymers
The chains remain active until they are killed

26. Ring-Opening Polymerization

28. Stereochemistry of Polymerization
substituents on the same side
substituents regularly alternate on both sides

29. Long, unbranched polymers can be prepared using an
aluminum–titanium initiator (Ziegler–Natta catalyst)

31. Polymerization of Dienes

32. Synthesis of Synthetic Rubber

33. The product resulting from polymerization of different
monomers is called a copolymer

34. Four Types of Copolymers

35. Progress of a Step-Growth Polymerization

36. Nylon 6 is an example of a step-growth polymer formed
by a monomer with two different functional groups

37. The incorporation of aromatic rings into polymers
improves the physical strength of the polymers

39. Polyesters are step-growth polymers in which the
monomer units are joined together by ester groups

40. Polyesters with two ester groups bonded to the same
carbon are known as polycarbonates

41. Epoxy resins are the strongest adhesive known

42. A urethane (carbamate) is a compound that has an
OR group and an NHR group bonded to the same
carbonyl compound

43. Thermosetting Polymers
Very strong and rigid materials can be obtained by
cross-linking

44. Oriented Polymers These polymers are stronger than steel
They can conduct electricity

45. Biodegradable Polymers
These polymers can be broken into small segments by
enzyme-catalyzed reactions

46. Other Polymers Thermoplastic polymers have both ordered crystalline
regions and amorphous, noncrystalline regions
Elastomers are polymers that stretch and then revert to
the original shape
Plasticizer is an organic compound that is added to a
polymer to make it more flexible