高分子化学浙江大学
合集下载
相关主题
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
1 Introduction
1
1.1 Concept
• Homopolymerization —— polymerization of one kind of monomer;
• Copolymerization (addition polymerization) —— polymerization of more than one kind of monomer;
Sequence distribution
the way in which these monomer units are arranged within a polymer chain; AA or AB
2. Copolymer composition
7
Essential Point
The composition of a copolymer does not necessarily match the composition of the comonomers used in the reaction ( feed ratio 投料比).
dM1
dt
R11
R21
k11 M1
•M1
k21 M 2
•M1
ignore the initiation
dM2
dt
R12
R22
k12 M1
•M 2
k22 M2
•M 2
The expression for instantaneous copolymer composition (F1/F2)
reactivity • no side reactions, such as depropagation, monomer
partitioning, and various forms of complex formation
10
Reactions in copolymerization
ki,1 R + M1
dt
k11
M1 + M1
M1
k12
M1 + M2
M2
k21
M2 + M1
M1
k22Leabharlann Baidu
M2 + M2
M2
d
M1
dt
•
k12
M1
•M
2
k21M
2
•M1
d
M 2
dt
•
k21M
2
•M1
k12
M1
•M
Key topics in copolymerization
-ABABBAABABBAAABABA-
Composition distribution
the relative amounts of each monomer unit incorporated into the copolymer, A% or B%
poly(ethylene-co-propylene) poly(ethylene-r-propylene) poly(ethylene-b-propylene) poly(ethylene-g-propylene) poly(ethylene-a-styrene)
乙烯-丙烯共聚物 乙烯-丙烯无规共聚物 乙烯-丙烯嵌段共聚物 乙烯-丙烯接枝共聚物 乙烯-苯乙烯交替共聚物
molar fraction of M1
molar fraction of M2
F1 F2
dM1 dM 2
k11 M1 •M1 k21M 2 •M1 k12M1 •M 2 k22M 2 •M 2
12
Steady-state assumption
dR • 0
dt
dM1 • 0
dt
dM 2 • 0
M1
ki,2 R + M2
M2
M1 + M1 M1 + M2 M2 + M2
kt,11 kt,12 kt,22
k11
M1 + M1
M1
k12
M1 + M2
M2
k21
M2 + M1
M1
k22
M2 + M2
M2
11
2.1 Copolymer composition equation
The overall rates of consumption of monomers [M1],[M2] then follow these expressions:
Examples
Styrene Styrene + Acrylonitrile Styrene + Butadiene Styrene + Acrylonitrile+ Butadiene
PS SAN SBR ABS
Brittle, transparent, poor solvent toleration High impact, good solvent toleration High elasticity Engineering plastics
Maleic anhydride Styrene + maleic anhydride
O
No polymer SMA
O
O
3
1.2 Type of copolymer
Normally prepared by other methods
also obtained by other methods
1.2 Nomenclature of copolymer
New kinds of copolymer can be synthesized by copolymerization of different combination of various monomers. Copolymer generated from same monomers can have different compositions and topologies.
9
assumptions in copolymerization
• the rate of the propagation be chain-length-independent. • only the terminal unit of the polymer radical can affect its
Ethylene-vinyl acetate copolymer
vinyl acetate % 10 ~ 20 30 ~ 40 50
property plastic adhesive rubber
8
Possible propagation sequences in free-radical copolymerization
1
1.1 Concept
• Homopolymerization —— polymerization of one kind of monomer;
• Copolymerization (addition polymerization) —— polymerization of more than one kind of monomer;
Sequence distribution
the way in which these monomer units are arranged within a polymer chain; AA or AB
2. Copolymer composition
7
Essential Point
The composition of a copolymer does not necessarily match the composition of the comonomers used in the reaction ( feed ratio 投料比).
dM1
dt
R11
R21
k11 M1
•M1
k21 M 2
•M1
ignore the initiation
dM2
dt
R12
R22
k12 M1
•M 2
k22 M2
•M 2
The expression for instantaneous copolymer composition (F1/F2)
reactivity • no side reactions, such as depropagation, monomer
partitioning, and various forms of complex formation
10
Reactions in copolymerization
ki,1 R + M1
dt
k11
M1 + M1
M1
k12
M1 + M2
M2
k21
M2 + M1
M1
k22Leabharlann Baidu
M2 + M2
M2
d
M1
dt
•
k12
M1
•M
2
k21M
2
•M1
d
M 2
dt
•
k21M
2
•M1
k12
M1
•M
Key topics in copolymerization
-ABABBAABABBAAABABA-
Composition distribution
the relative amounts of each monomer unit incorporated into the copolymer, A% or B%
poly(ethylene-co-propylene) poly(ethylene-r-propylene) poly(ethylene-b-propylene) poly(ethylene-g-propylene) poly(ethylene-a-styrene)
乙烯-丙烯共聚物 乙烯-丙烯无规共聚物 乙烯-丙烯嵌段共聚物 乙烯-丙烯接枝共聚物 乙烯-苯乙烯交替共聚物
molar fraction of M1
molar fraction of M2
F1 F2
dM1 dM 2
k11 M1 •M1 k21M 2 •M1 k12M1 •M 2 k22M 2 •M 2
12
Steady-state assumption
dR • 0
dt
dM1 • 0
dt
dM 2 • 0
M1
ki,2 R + M2
M2
M1 + M1 M1 + M2 M2 + M2
kt,11 kt,12 kt,22
k11
M1 + M1
M1
k12
M1 + M2
M2
k21
M2 + M1
M1
k22
M2 + M2
M2
11
2.1 Copolymer composition equation
The overall rates of consumption of monomers [M1],[M2] then follow these expressions:
Examples
Styrene Styrene + Acrylonitrile Styrene + Butadiene Styrene + Acrylonitrile+ Butadiene
PS SAN SBR ABS
Brittle, transparent, poor solvent toleration High impact, good solvent toleration High elasticity Engineering plastics
Maleic anhydride Styrene + maleic anhydride
O
No polymer SMA
O
O
3
1.2 Type of copolymer
Normally prepared by other methods
also obtained by other methods
1.2 Nomenclature of copolymer
New kinds of copolymer can be synthesized by copolymerization of different combination of various monomers. Copolymer generated from same monomers can have different compositions and topologies.
9
assumptions in copolymerization
• the rate of the propagation be chain-length-independent. • only the terminal unit of the polymer radical can affect its
Ethylene-vinyl acetate copolymer
vinyl acetate % 10 ~ 20 30 ~ 40 50
property plastic adhesive rubber
8
Possible propagation sequences in free-radical copolymerization