1. Odian Book
Chapter 7

2. Ring-opening Polymerization (I)

3. Ring-opening Polymerization
Anionic
Cationic
Ring Opening Metathesis Polymerization (ROMP)

4. Commercially Important ROP
Tg Tm
cationic
anionic
PTMO
(57)

5. Commercially Important ROP
cationic
anionic
Tg Tm
Poly(caprolactone)
Poly(caprolactam)
D4, D3, Di

6. Ring-opening PolymerizationkP
kdp
linear
cyclic
X = ; ; ; ;
Heteroatom provide site for coordination w/ appropriate anionic,
cationic or coordinating initiator (kinetic accessibility)
Keq= kP / kdp = 1 / [Monomer]e
G= - R T ln Keq= R T ln [M]e

7. Ring Strain of Cycloalkanes
CYCLOALKANE (kcal/mole) (kJ/mole)
Cyclopropane
Cyclobutane
Cyclopentane
Cyclohexane
Cycloheptane
Cyclooctane
Cyclononane
Cyclodecane
Cyclopentadecane

8. Ring Strain
Ring Size
3,4
5,6,7 8

9. Free Energy G= H -TS  H  S  G [M]e # atoms in Ring 3,4
ext. of Equil
3,4

10. Ring Opening Pzn Types of Ring Compound Mx detected up to x =
Propagating
Species
Cycloalkenes
Cyclic Ethers
Caprolactam
Cyclic Siloxanes 14 9 5
400
Metal Carbene
THF w/ CF3SO3H
Anionic
Anionic KOH
Series of Ring Sizes
Concentration Distribution
% Cyclics  w/ decreasing [M]

11. (substituents usually will prevent it)
Cyclic Ethers
polymerization
difficult
(substituents usually will prevent it)
unreactive
tertrahydropyran
dioxane

12. Cyclic Ethers
1) Ethylene Oxide
Living Polymerization
(DMSO)
PEO

13. Cyclic Ethers Monomer is usually a racemic mixture of enantiomers
2) Propylene Oxide
Monomer is usually a racemic
mixture of enantiomers

14. Poly(propylene oxide)
Initiation
Propagation
Soft segments in polyurethane
Avg Mn limited to ~5,000 g/mol
Limited by CT to monomer
acidify
Termination
1o & 2o

15. Chain Transfer to Monomer
200 oC
Proton abstraction
Leads to imperfect networks
with “dangling ends”
fast
allylic structure
f = 1
Allylic end group

16. Functionality Control
Polyhydroxy compounds  CTA
(CTA)
networks
fAVG ~ 2.5
f = 3