Transcript 슬라이드 1 - Hannam

Chapter 10. Step-Reaction and Ring-Opening
Polymerization
10.1 Introduction
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
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
POLYMER CHEMISTRY
POLYMER CHEMISTRY
10.2 Step-reaction polymerization---Kinetics
A. Types of monomer
a. AB type
HO
COOH
b. AA and BB type
HOOC
COOH
HOCH2CH2OH
c. Three functional group for crosslinked polymers
HOCH 2CHCH 2OH
OH
POLYMER CHEMISTRY
10.2 Step-reaction polymerization---Kinetics
B. Condensation of difunctional monomers.
a.
b.
POLYMER CHEMISTRY
C. Kinetics of step-polymerization.
a. Assumption : Independence on chain length.
b. Rate equation and
A
+ B
d [ A]

 k[ A][ B ]
dt
Integration
Polymers
condensation
[ A]  [ B]
d [ A]
2

 k[ A]
dt
1
1

 kt
[ A] [ Ao]
Combining Carothers equation.
DP  [ Ao]kt 1
POLYMER CHEMISTRY
C. Kinetics of step-polymerization.
c. Polyesterification : self-acid catalyzed reaction.

d [ A]
 d [ A]3
dt
Integration
1
1

 2kt
2
2
[ A] [ Ao ]
Combining Carothers equation.
DP 
2
 2kt [ Ao ]2  1
POLYMER CHEMISTRY
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. 3 Stoichiometric Imbalance.
C. Modification of Carothers equation.
a. parameter r : stoichiometric imbalance.
N Ao
r o
NB
N Ao , N Bo : initial unreacted groups.
N A  (1  p) N Ao
N Ao
N B  (1  p) N  (1  pr)
r
o
B
1 r
DP 
r  1  1rp
if
N A, N B
r  1 , then
if
: unreacted group.
1
: Carothers equation.
DP 
1 p
p  1 , then
1 r
DP 
1 r
10. 4 Molecular weight Distribution
A. Conversion and Nx
No  N
p
No
N x  Np x1 (1  p)
10. 4 Molecular weight Distribution
B. Conversion and Wx
xN x M o xN x
Wx 

No M o
No
Wx  x(1  p)2 p x1
C. Polydispersity index
Mo
Mn 
1 p
M o (1  p)
Mw 
1 p
Mw
PI 
 1 p
Mn
POLYMER CHEMISTRY
POLYMER CHEMISTRY
10. 5 Network Step Polymerization
A. Greater than two functionality polymers.
a. Alkyd-type polyester :
OH
HOCH 2CHCH 2OH
OH
b. Phenol-formaldehyde resin :
c. Melamine-formaldehyde resin :
NH 2
N
H2N
N
N
NH 2
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
10. 5 Network Step Polymerization
C. Gel point conversion.
No  N
p
No
pc 
2
f av
pc : critical reaction conversion.
f av : average functionality.
pc 
1

[r  r    
POLYMER CHEMISTRY
10. 5 Network Step Polymerization
D. Examples of gel point conversion.
O
O
OH
HOCH 2CHCH 2OH
O
3mol of 1
2mol of 4
(3  2)  (2  3)
f av 
 2.4
5
Gel point conversion : 77% (Experiment)
83% (Calculate)
POLYMER CHEMISTRY
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
10. 6 Step-Reaction Copolymerization.
C. Block copolymer.
Telechelic polymers.
a.
b.
c.
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
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
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
10. 7 Step polymerization Techniques.
d. Phase-transfer catalysis polymerization(PTC).
1) Phase-transfer catalyst : Benzyltriethylammonium chloride.
C6H5CH2N+(C2H5)3Cl2) Mechanism : Dissolve in water and make ion pair.
Move to organic layer.
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
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
10. 8 Dendritic Polymers.
D. Synthsis of dendrimer.
a. Divergent :
1) Polyamidamine (PAMAM).
2)
10. 8 Dendritic Polymers.
b. Convergent.
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
10. 9 Ring-opening polymerization.
A. Commercially important ring-opening polymers.
Ring-opening polymers : Condensation polymers.
Not polycondensation reaction.
No byproduct.
POLYMER CHEMISTRY
POLYMER CHEMISTRY
B. Mechanism of ring-opening polymerization.
a. Initiator : Ionic or coordination species (X*).
1)
2)
b. Initiator : XY.
1)
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