1. Chapter 10. Step-Reaction and Ring-Opening Polymerization
10.1 Introduction
Chapter 10. Step-Reaction and Ring-Opening
               Polymerization
10.2 Step-reaction polymerization---Kinetics
10. 3 Stoichiometric Imbalance.
10. 4 Molecular weight Distribution
10. 5  Network Step Polymerization
10. 6 Step-Reaction Copolymerization.
10. 7 Step polymerization Techniques.
10. 8 Dendritic Polymers.
10. 9 Ring-opening polymerization.
POLYMER CHEMISTRY

2. 10.1 Introduction A. Characteristics of step-reaction polymers.
a. Polymers containing functional group in backbones
b. Synthesizing dendritic polymers
B. Examples of commercialized step-reaction polymers.
  Note) Table 10.1
POLYMER CHEMISTRY

3. POLYMER CHEMISTRY

4. POLYMER CHEMISTRY

5. 10.2 Step-reaction polymerization---Kinetics
A. Types of monomer
  a. AB type
 b. AA and BB type
 c. Three functional group for crosslinked polymers
POLYMER CHEMISTRY

6. 10.2 Step-reaction polymerization---Kinetics
B. Condensation of difunctional monomers. a.
 b.
POLYMER CHEMISTRY

7. C. Kinetics of step-polymerization.
a. Assumption : Independence on chain length.
b. Rate equation and 2
 Integration
 Combining Carothers equation.
POLYMER CHEMISTRY

8. C. Kinetics of step-polymerization.
 c. Polyesterification : self-acid catalyzed reaction.
Integration
 Combining Carothers equation.
POLYMER CHEMISTRY

9. 10. 3 Stoichiometric Imbalance.
A. Chain length control.
a. High molecular weight.
b. Oligomers for free polymer.   
1) Epoxy oligomer.
   2) Unsaturated polyester.
   3) Polyamide
B. Preparing methods for oligomers.
 a. Quenching : unsaturated polyester.
 b. Stoichiometric imbalance : epoxy resin.
 c. Addition of monofunctional reactant.
POLYMER CHEMISTRY

10. 10. 3 Stoichiometric Imbalance.
C. Modification of Carothers equation.
 a. parameter r : stoichiometric imbalance. ,
: initial unreacted groups. ,
: unreacted group.
 if        , then
: Carothers equation.
 if        , then

11. 10. 4 Molecular weight Distribution
A. Conversion and Nx

12. 10. 4 Molecular weight Distribution
B. Conversion and Wx
C. Polydispersity index
POLYMER CHEMISTRY

13. POLYMER CHEMISTRY

14. 10. 5 Network Step Polymerization
A. Greater than two functionality polymers.
a. Alkyd-type polyester :  
b. Phenol-formaldehyde resin : 
c. Melamine-formaldehyde resin : 

15. 10. 5 Network Step Polymerization
B. Gelatin : High conversion of greater than two functionality.
a. Gel point : onset of gelatin.
        sudden increase in viscosity.
        change from liquid to gel.
       bubbles no longer rising.
        impossible stirring.
POLYMER CHEMISTRY

16. 10. 5 Network Step Polymerization
C. Gel point conversion.
   : critical reaction conversion.   
 : average functionality.
POLYMER CHEMISTRY

17. 10. 5 Network Step Polymerization
D. Examples of gel point conversion.
3mol of 1
2mol of 4
Gel point conversion : 77% (Experiment)
                      83% (Calculate)
POLYMER CHEMISTRY

18. 10. 6 Step-Reaction Copolymerization.
A. Random copolymers.
  1:1:2 mixture of terephthalic acid, isophtahlic acid, ethylene glycol.
B. Alternating copolymers. a.
b. Randomization : Trans-esterification.
POLYMER CHEMISTRY

19. 10. 6 Step-Reaction Copolymerization.
C. Block copolymer.
    Telechelic polymers.
 a.
 b.
 c.

20. 10. 7 Step polymerization Techniques.
A. Significant difference between vinyl and nonvinyl polymerization.
a. Vinyl polymerization : Large enthalpy factor.
                          Exotherm reaction.
b. Nonvinyl polymerization : High activation energy.
                          Low exotherm.
POLYMER CHEMISTRY

21. 10. 7 Step polymerization Techniques.
B. Step polymerization techniques.
a. Bulk polymerization.   
1) Advantage : Free of contaminants.
2) Disadvantage : High viscosity.
b. Solvent polymerization.
1) Advantage : Lower viscosity.
        Removing by products by azeotropic distillation.
 2) Disadvantage : Solvent removing process.
POLYMER CHEMISTRY

22. 10. 7 Step polymerization Techniques.
 c. Interfacial polymerization.   
 Polymerization at the interface between immiscible two solvents.
    Water : Diamine.
    Organic solvent : Diacid chloride.
1) Low temperature polymerization.
   2) Rapid polymerization.
   3) Higher molecular weight.
   4) Not necessary stoichiometric balance.
    
 ․Schotten-Baumann reaction.
POLYMER CHEMISTRY

24. 10. 7 Step polymerization Techniques.
 d. Phase-transfer catalysis polymerization(PTC).   
1) Phase-transfer catalyst : Benzyltriethylammonium chloride.
        C6H5CH2N+(C2H5)3Cl-
2) Mechanism : Dissolve in water and make ion pair.
        Move to organic layer.

25. 10. 8 Dendritic Polymers. A. Terminology (Since 1980s)
   
Dendrimer : Dendron = like tree.
   Starburst polymer.
B. Commercial application.
 a. Drug delivery system : Controlled release of agricultural chemicals
 b. Molecular sensors.
 c. Rheology modifiers.
POLYMER CHEMISTRY

26. 10. 8 Dendritic Polymers. C. Characteristics feature.
 a. Structure : Three component parts.
  1) Core.
   2) Interior dendritic structure.
   3) Exterior surface.
b. Easy control macromolecular dimension by a repetitive sequence of step.
c. More soluble than linear polymer : high surface functionality.
d. Low viscosity : No entanglement.
e. Supramolecular assembly : Guest molecules among the interior branches
POLYMER CHEMISTRY

27. 10. 8 Dendritic Polymers. D. Synthsis of dendrimer. a. Divergent :
 1) Polyamidamine (PAMAM).

28.  2)

29. 10. 8 Dendritic Polymers.
b. Convergent.

30. 10. 8 Dendritic Polymers. E. Hyperbranched polymer.
a. Types of monomer : AxB ( x > 1).
F. Nanostructure of dendrimer.
a. Molecules dimension : 1-100nm.
b. Molecules devices : Mimicking nanoscopic biomolecules.
POLYMER CHEMISTRY

31. 10. 9 Ring-opening polymerization.
A. Commercially important ring-opening polymers.
Ring-opening polymers : Condensation polymers.
              
 Not polycondensation reaction.
 No byproduct.
POLYMER CHEMISTRY

32. POLYMER CHEMISTRY

33. B. Mechanism of ring-opening polymerization.
a. Initiator : Ionic or coordination species (X*).    1)
 2)
 b. Initiator : XY.    1)

34. 10. 9 Ring-opening polymerization.
 C. Ring strain : Possibility of ring-opening polymerization.
     
 3 > 4 > 8 > 7 > 5 > 6
 D. Ring-opening block copolymerization.
    
AB,  [AB]  , ABA Block copolymer.
POLYMER CHEMISTRY