高分子反应原理
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CH3 CH2 C COOCH3 CH2 CH3 C
n
COOCH3
St
MMA
2) Condensation polymerization
O HOCH2CH2OC O OCH2CH2OC O COCH2CH2OH O C n
O ClC O CCl
HOCH2CH2OH
HO
OH
HOCH2CH2OH
3) Complicated structure polymers can be designed and prepared. For example:
nwenku.baidu.com
Conversion
Well-defined block copolymers can not be
synthesized by condensation polymerization
H O OCH2CH2OC O C OCH2CH2OH n OCN CH2 n NCO
H
O OCH2CH2OC O O(CH2)4OC O C
Chapter 1 Basic Concept of Living Polymerization
§ 1-1. Significances of Living Polymerization
1. Control molecular weight
O
[CH2CH2CH2CH2O] n
Initiator: CF3SO3H, BF3 OEt2
Due to the rate of chain transfer to vinyl chloride is much bigger than termination rate, Rtr,M>Rt, thus
1/Xn =Rp/(Rt + Rtr,M) ～ Rp/ Rtr,M=kp/ktr,M=1/CM
Living polymerization of styrene
+ Na [
. .. -
] Na +
[
. .. ] + [
CH = CH2
.. CH CH
+
2
.. CH . CH
2
]
No termination;
No transfer reactions
+ Na [ -CH CH2 CH2 CH - ] Na+
1. First-order kinetics
Rp=kpapp[M-][M] d[M]/[M]=kpapp[M-]dt ln[M]0/[M]t = kpapp[M-] t
ln[M]0/[M]
Reaction time
2. Molecular weight can be controlled
Molecular weight
.
2. Control of molecular weight distribution
It is important to the polymer properties : Solution property; Mechanical properties. For examples, PTHF in the preparation of elastic polyurethane, polymer processing, viscosity Phase separation in the blends
Synthesis of amphiphilic copolymers
CH3 O CH3 CH2CH2O C CH CH2 C m CH2 n CH2CH3 C O O CH3 CBr C O O
NO2 RNH2 CH3
NO2 CH3 CBr C O NHR HO NO2
O CH3 CH2CH2O C CH CH2 C m CH2 n CH2CH3 C O NHR
PDI = Mw/Mn = 1 + 1/DP
PDI is mainly due to different initiation time.
Initiation step
t1 (10 M)
t2 (20 M)
4. The produced polymer is living
Chain extending polymerization Higher molecular weight polymer Block copolymerization Block copolymer Functionalization reaction Telechelic polymer, Macromonomer.
2. No chain transfer reactions.
3. Initiation rate is faster than
propagation rate
4. Homogeneous system
5. Stringent conditions
§1-3 Identification of Living Polymerization
Initiation rate is faster than propagation rate
C4H9Li + CH2=CH-Y C4H9CH2-CH: -Li+
Y= CH2=C(CH3)-, Ph, CH2=CH-, etc
Generally, alkyl lithium can initiate anionic polymerization of styrene, 1,3-butadiene etc in alkane immediately.
Characteristics of free radical polymerization.
Dead macromolecule is formed in short time.
Radical polymerization
Molecular weight
CH2 CH
Condensation polymerization
Conversion (%)
Number-average molecular weight is proportional to conversion, thus degree of polymerization can be calculated.
DP=([M]0 –[M]t)/[M-]
3. Narrow molecular weight distribution
葡萄糖
糖 糖 胰岛素
Why do we develop the living polymerization
Control of molecular weight Prepare polymers with narrow molecular weight distribution Preparation of complicated architecture polymers, such as block copolymers, nonlinear polymers, including star, star block, hyperbranched, dendrimerlike copolymers etc.
§1-2. Concept of Living Polymerization
What is living polymerization?
No termination
No chain transfer reaction
Initiation rate is faster than propagation rate
Conversion up to100%
No termination
The polymerization can continue when monomers are added.
+ Na [ -CH CH2CH2 CH - ] Na+
St
+ Na+ -CH CH2 CH CH2 nCH CH2CH2 CH CH2 CH nCH2CH - Na
MMA
PMMA b PSt b PMMA
No chain transfer reaction
The big effect of chain transfer on molecular weight and polydispersity, One example : Chain transfer reactions in polymerization of vinyl chloride
Need stringent conditions
High High Dry
purity monomer vacuum
reaction system
Summary for requirements of living polymerization 1. No termination
Cl Cl CH2 CH CH CH2 CH2=CHCl
.
Cl CH2 CH CH CH2 Cl
.
CH2 CH CH CH2Cl + ClCH2
. CHCl
Kinetics in the presence of chain transfer reaction
When only chain transfer to the monomer exists in the polymerization, such as, AIBN used as initiator in bulk polymerization, the DP can be calculated : 1/Xn= 2kt/kp2 · p/[M]2 + CM R
3. Control of polymer structure
1) General free radical polymerization:
Only synthesis of linear homopolymers or
copolymers, such as 普通自由基聚合只 能合成共聚物和均聚物！
Introduction of Polymer Structure
Linear polymers and linear block copolymers
Monomer 1, Monomer 2, Monomer 3
Nonlinear copolymers
Grafting polymer Comb polymer
Coupling reaction star polymer
5. Conductivity measurement
If free anionic or cationic ions exist in polymerization system, the solution is conductive. Conductivity is measured, confirming the existence of free ions. If no conductivity, we can not say “no anionic polymerization”
Molecular weight is determined by CM, polymerization at 50oC, CM =1.35 x 10-3, Xn=740, which is similar to the measured MW. MW is determined by concentration of transfer agent, Temp;
★ ★
两亲性； 高反应性
囊泡的形成过程
O C CH
CH3 CH2CH2O n
CH2
CH3 CH3 C m CH2 CBr C O O C O O
CH2CH3
NO2
NO2
伴刀豆蛋白与对硝基苯酚酯的反应
O NO2
CH3
CH2CH2O
n
CON-A
胰岛素
葡萄糖
伴刀豆蛋白 （CON A）
葡萄糖和胰岛素交换反应原理图
Grafting polymer
Comb polymer
Star block copolymer
Miktoarm star polymer
General radical polymerization can not prepare block copolymers and other nonlinear polymers, the reason is:
O C
OCH2CH2OH n
H
O(CH2)4OH m
OCN CH2
n
NCO
Any application of block copolymers and nonlinear polymers
1. SBS is a thermoplastic elastomer.
2. Control of drug release: For example: synthesis of amphiphilic copolymers.
n
COOCH3
St
MMA
2) Condensation polymerization
O HOCH2CH2OC O OCH2CH2OC O COCH2CH2OH O C n
O ClC O CCl
HOCH2CH2OH
HO
OH
HOCH2CH2OH
3) Complicated structure polymers can be designed and prepared. For example:
nwenku.baidu.com
Conversion
Well-defined block copolymers can not be
synthesized by condensation polymerization
H O OCH2CH2OC O C OCH2CH2OH n OCN CH2 n NCO
H
O OCH2CH2OC O O(CH2)4OC O C
Chapter 1 Basic Concept of Living Polymerization
§ 1-1. Significances of Living Polymerization
1. Control molecular weight
O
[CH2CH2CH2CH2O] n
Initiator: CF3SO3H, BF3 OEt2
Due to the rate of chain transfer to vinyl chloride is much bigger than termination rate, Rtr,M>Rt, thus
1/Xn =Rp/(Rt + Rtr,M) ～ Rp/ Rtr,M=kp/ktr,M=1/CM
Living polymerization of styrene
+ Na [
. .. -
] Na +
[
. .. ] + [
CH = CH2
.. CH CH
+
2
.. CH . CH
2
]
No termination;
No transfer reactions
+ Na [ -CH CH2 CH2 CH - ] Na+
1. First-order kinetics
Rp=kpapp[M-][M] d[M]/[M]=kpapp[M-]dt ln[M]0/[M]t = kpapp[M-] t
ln[M]0/[M]
Reaction time
2. Molecular weight can be controlled
Molecular weight
.
2. Control of molecular weight distribution
It is important to the polymer properties : Solution property; Mechanical properties. For examples, PTHF in the preparation of elastic polyurethane, polymer processing, viscosity Phase separation in the blends
Synthesis of amphiphilic copolymers
CH3 O CH3 CH2CH2O C CH CH2 C m CH2 n CH2CH3 C O O CH3 CBr C O O
NO2 RNH2 CH3
NO2 CH3 CBr C O NHR HO NO2
O CH3 CH2CH2O C CH CH2 C m CH2 n CH2CH3 C O NHR
PDI = Mw/Mn = 1 + 1/DP
PDI is mainly due to different initiation time.
Initiation step
t1 (10 M)
t2 (20 M)
4. The produced polymer is living
Chain extending polymerization Higher molecular weight polymer Block copolymerization Block copolymer Functionalization reaction Telechelic polymer, Macromonomer.
2. No chain transfer reactions.
3. Initiation rate is faster than
propagation rate
4. Homogeneous system
5. Stringent conditions
§1-3 Identification of Living Polymerization
Initiation rate is faster than propagation rate
C4H9Li + CH2=CH-Y C4H9CH2-CH: -Li+
Y= CH2=C(CH3)-, Ph, CH2=CH-, etc
Generally, alkyl lithium can initiate anionic polymerization of styrene, 1,3-butadiene etc in alkane immediately.
Characteristics of free radical polymerization.
Dead macromolecule is formed in short time.
Radical polymerization
Molecular weight
CH2 CH
Condensation polymerization
Conversion (%)
Number-average molecular weight is proportional to conversion, thus degree of polymerization can be calculated.
DP=([M]0 –[M]t)/[M-]
3. Narrow molecular weight distribution
葡萄糖
糖 糖 胰岛素
Why do we develop the living polymerization
Control of molecular weight Prepare polymers with narrow molecular weight distribution Preparation of complicated architecture polymers, such as block copolymers, nonlinear polymers, including star, star block, hyperbranched, dendrimerlike copolymers etc.
§1-2. Concept of Living Polymerization
What is living polymerization?
No termination
No chain transfer reaction
Initiation rate is faster than propagation rate
Conversion up to100%
No termination
The polymerization can continue when monomers are added.
+ Na [ -CH CH2CH2 CH - ] Na+
St
+ Na+ -CH CH2 CH CH2 nCH CH2CH2 CH CH2 CH nCH2CH - Na
MMA
PMMA b PSt b PMMA
No chain transfer reaction
The big effect of chain transfer on molecular weight and polydispersity, One example : Chain transfer reactions in polymerization of vinyl chloride
Need stringent conditions
High High Dry
purity monomer vacuum
reaction system
Summary for requirements of living polymerization 1. No termination
Cl Cl CH2 CH CH CH2 CH2=CHCl
.
Cl CH2 CH CH CH2 Cl
.
CH2 CH CH CH2Cl + ClCH2
. CHCl
Kinetics in the presence of chain transfer reaction
When only chain transfer to the monomer exists in the polymerization, such as, AIBN used as initiator in bulk polymerization, the DP can be calculated : 1/Xn= 2kt/kp2 · p/[M]2 + CM R
3. Control of polymer structure
1) General free radical polymerization:
Only synthesis of linear homopolymers or
copolymers, such as 普通自由基聚合只 能合成共聚物和均聚物！
Introduction of Polymer Structure
Linear polymers and linear block copolymers
Monomer 1, Monomer 2, Monomer 3
Nonlinear copolymers
Grafting polymer Comb polymer
Coupling reaction star polymer
5. Conductivity measurement
If free anionic or cationic ions exist in polymerization system, the solution is conductive. Conductivity is measured, confirming the existence of free ions. If no conductivity, we can not say “no anionic polymerization”
Molecular weight is determined by CM, polymerization at 50oC, CM =1.35 x 10-3, Xn=740, which is similar to the measured MW. MW is determined by concentration of transfer agent, Temp;
★ ★
两亲性； 高反应性
囊泡的形成过程
O C CH
CH3 CH2CH2O n
CH2
CH3 CH3 C m CH2 CBr C O O C O O
CH2CH3
NO2
NO2
伴刀豆蛋白与对硝基苯酚酯的反应
O NO2
CH3
CH2CH2O
n
CON-A
胰岛素
葡萄糖
伴刀豆蛋白 （CON A）
葡萄糖和胰岛素交换反应原理图
Grafting polymer
Comb polymer
Star block copolymer
Miktoarm star polymer
General radical polymerization can not prepare block copolymers and other nonlinear polymers, the reason is:
O C
OCH2CH2OH n
H
O(CH2)4OH m
OCN CH2
n
NCO
Any application of block copolymers and nonlinear polymers
1. SBS is a thermoplastic elastomer.
2. Control of drug release: For example: synthesis of amphiphilic copolymers.