聚合实施方法
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(1) Latex need to be coagulated, washed and drying, which is costly. (2) Some of the emulsifier may stay in the product, which may damage the electric properties of polymer.
单体在乳液中聚合，乳液由水和乳化剂配成。
The conditions under which radical polymerizations are carried out are of both the homogeneous and heterogeneous: Bulk Polymerization, Solution Polymerization －> homogeneous polymerization system； Suspension Polymerization, Emulsion Polymerization －>
12
4.5.2 Application of emulsion polymerization
（1）聚合后分离橡胶状或粉体的产品，如：丁苯橡胶（SBR）、丁腈橡 胶（NBR）、氯丁橡胶（CR）等合成橡胶，ABS、MBS等工程塑料，糊状 PVC、聚四氟乙烯（PTFE）等； （2）聚合后胶乳直接用作涂料和粘合剂的场合，如：丁苯胶乳、丙烯酸 胶乳、醋酸乙烯胶乳；
13
4.5.3 Components The main components are the monomer(s), dispersing medium, emulsifier, and water-soluble initiator.
monomer: water-insoluble or slightly water-soluble, dispersing medium: the liquid, usually water, emulsifier: usually anionic surfactants water-soluble initiator: such as potassium or ammonium persulfate
Vinyl chloride Styrene-methyl alcohol Acrylic acid-hexane Acrylonitrile-water Vinyl chloride Vinylidine chloride Vinyl chloride
heterogeneous
Suspension Emulsion
6
Utility:
工业上溶液聚合多用于聚合物溶液直接使用的场合，如：涂料、胶 粘剂、浸渍剂、合成纤维纺丝等。
7
4.4 Suspension Polymerization
Suspension polymerization is carried out by suspending the monomer (discontinuous phase) as droplets (50–500 mm in diameter) in water (continuous phase). The main components are the monomer(s), oil-soluble initiator. water and suspension stabilizers. The monomer suspending as droplets are prevented from coalescing by agitation and the presence of suspension stabilizers. Each monomer droplet in a suspension polymerization is considered to be a miniature bulk polymerization system. The kinetics of polymerization within each droplet are the same as those for the corresponding bulk polymerization. 悬浮聚合的反应机理与本体聚合相似，有均相聚合和沉淀聚合之分。
heterogeneous polymerization system
根据聚合物在其单体或聚合溶剂中的溶解性能，则本体聚合、溶液聚 合和悬浮聚合都有均相聚合和非均相聚合之分。 2
Table 4.1 Polymerization Process Conditions
Monomermedium homogeneous Polymerization method Bulk (Mass) Gas Liquid Solid Solution Polyபைடு நூலகம்er-monomer (solvent) homogeneous Ethylene Styrene, Acrylate Styrene-benzene Acrylic acid-water Acrylonitrile-DMF Styrene Methyl methacrylate Styrene, Butadiene heterogeneous
不加任何溶剂，加入或不加引发剂，用热、光辐射等方法进行聚合。
（2）Solution Polymerization 溶液聚合；
将单体和引发剂溶于适当的溶剂中进行聚合。
（3）Suspension Polymerization 悬浮聚合；
单体液滴悬浮于水中。
（4）Emulsion Polymerization 乳液聚合。
苯乙烯和甲基丙烯酸甲酯的悬浮聚合属均相聚合； 氯乙烯的悬浮聚合属沉淀聚合。
悬浮聚合产物的粒径在0.01-5mm之间，一般为0.05-2mm，随搅拌强度和分 散剂性质、用量而定。
8
悬浮聚合的液-液分散过程
停止搅拌 搅拌强度越大，液 滴越小，聚合生成的树 脂粒子越小
9
分散剂的作用机理：
（1）water-soluble polymers：吸附在液滴的表面，形成一层保护膜，起 到保护胶体的作用，同时使表面张力降低，有利于液滴分散； （2）water-insoluble inorganic compounds:（如：碳酸镁，碳酸钙、滑石粉 等）：细小粉末吸附在液滴表面，起机械隔离的作用。
5
4.3 Solution Polymerization
单体和引发剂溶于适当的溶剂中的聚合称为溶液聚合.
Advantages：
Polymerization of a monomer in a solvent overcomes many of the disadvantages of the bulk process. The solvent acts as diluent and aids in the transfer of the heat of polymerization. The solvent also allows easier stirring, since the viscosity of the reaction mixture is decreased. Thermal control is much easier in solution polymerization compared to bulk polymerization.
3
4.2 Bulk (Mass) Polymerization
不加任何溶剂（介质），只有单体本身在引发剂、热、光辐射等的作用 下进行的聚合，称为本体聚合(Bulk Mass Polymerization)。 实际生产中，往往还加入少量的色料、增塑剂、分子量调节剂等助剂。
Advantages：
Bulk or mass polymerization of a pure monomer offers the simplest process with a minimum of contamination of the product. So it is especially fit for the preparation of transparent product. Shortcoming： (1) heat dissipation is difficult, (2) local hot spots may occur, (3) molecular weight distribution is broadened. 自由基聚合、离子聚合、缩聚都可选用本体聚合，气态、液态、固态单 体均可进行本体聚合，其中以液态单体的本体聚合最重要。
10
Advantages
（1）体系粘度低，聚合热容易带走，散热和温度控制比本体聚合、溶液 聚合容易； （2）产物分子量及其分布稳定，分子量比溶液聚合的高； （3）产物分离的后处理工序比溶液聚合、乳液聚合容易。 Shortcoming 产物中多少带有少量分散剂残留物，要生产透明和绝缘性高的产品， 须将这些残留的分散剂除尽。 悬浮聚合在工业上应用广泛：
80-85％的PVC、苯乙烯离子交换树脂母体、很大一部分PS、PMMA采用 悬浮法生产。
11
4.5 Emulsion Polymerization
单体在水中由乳化剂分散成乳液状态进行的聚合，称为乳液聚合。
4.5.1 Characteristics of emulsion polymerization
Chapter 4. Polymerization Method
（聚合实施方法）
1
4.1 Introduction
Free radical polymerization has four main polymerization methods： （1）Bulk Polymerization 本体聚合 ；
4
Utility:
In industry, bulk polymerization can be carried out continuously or in stages. The key problem is the heat dissipation. Bulk polymerization is not used commercially for chain polymerizations nearly as much as for step polymerizations because of the difficulties indicated. It is, however, used in the polymerizations of ethylene, styrene, and methyl methacrylate.
Advantages： (1)The physical state of the emulsion system makes it easy to control the process.
(2)Being able to simultaneously attain both high molecular weights and high reaction rates. (3)The product can in many instances be used directly without further separations. Shortcoming：
Shortcomings：
(1) low concentration of monomer, slow rate of polymerization, low utilization ratio of production facility; (2) chain transfer to solvent, low molecular weigh, (3) the purity of the polymer may be affected if there are difficulties in removal of the solvent.
单体在乳液中聚合，乳液由水和乳化剂配成。
The conditions under which radical polymerizations are carried out are of both the homogeneous and heterogeneous: Bulk Polymerization, Solution Polymerization －> homogeneous polymerization system； Suspension Polymerization, Emulsion Polymerization －>
12
4.5.2 Application of emulsion polymerization
（1）聚合后分离橡胶状或粉体的产品，如：丁苯橡胶（SBR）、丁腈橡 胶（NBR）、氯丁橡胶（CR）等合成橡胶，ABS、MBS等工程塑料，糊状 PVC、聚四氟乙烯（PTFE）等； （2）聚合后胶乳直接用作涂料和粘合剂的场合，如：丁苯胶乳、丙烯酸 胶乳、醋酸乙烯胶乳；
13
4.5.3 Components The main components are the monomer(s), dispersing medium, emulsifier, and water-soluble initiator.
monomer: water-insoluble or slightly water-soluble, dispersing medium: the liquid, usually water, emulsifier: usually anionic surfactants water-soluble initiator: such as potassium or ammonium persulfate
Vinyl chloride Styrene-methyl alcohol Acrylic acid-hexane Acrylonitrile-water Vinyl chloride Vinylidine chloride Vinyl chloride
heterogeneous
Suspension Emulsion
6
Utility:
工业上溶液聚合多用于聚合物溶液直接使用的场合，如：涂料、胶 粘剂、浸渍剂、合成纤维纺丝等。
7
4.4 Suspension Polymerization
Suspension polymerization is carried out by suspending the monomer (discontinuous phase) as droplets (50–500 mm in diameter) in water (continuous phase). The main components are the monomer(s), oil-soluble initiator. water and suspension stabilizers. The monomer suspending as droplets are prevented from coalescing by agitation and the presence of suspension stabilizers. Each monomer droplet in a suspension polymerization is considered to be a miniature bulk polymerization system. The kinetics of polymerization within each droplet are the same as those for the corresponding bulk polymerization. 悬浮聚合的反应机理与本体聚合相似，有均相聚合和沉淀聚合之分。
heterogeneous polymerization system
根据聚合物在其单体或聚合溶剂中的溶解性能，则本体聚合、溶液聚 合和悬浮聚合都有均相聚合和非均相聚合之分。 2
Table 4.1 Polymerization Process Conditions
Monomermedium homogeneous Polymerization method Bulk (Mass) Gas Liquid Solid Solution Polyபைடு நூலகம்er-monomer (solvent) homogeneous Ethylene Styrene, Acrylate Styrene-benzene Acrylic acid-water Acrylonitrile-DMF Styrene Methyl methacrylate Styrene, Butadiene heterogeneous
不加任何溶剂，加入或不加引发剂，用热、光辐射等方法进行聚合。
（2）Solution Polymerization 溶液聚合；
将单体和引发剂溶于适当的溶剂中进行聚合。
（3）Suspension Polymerization 悬浮聚合；
单体液滴悬浮于水中。
（4）Emulsion Polymerization 乳液聚合。
苯乙烯和甲基丙烯酸甲酯的悬浮聚合属均相聚合； 氯乙烯的悬浮聚合属沉淀聚合。
悬浮聚合产物的粒径在0.01-5mm之间，一般为0.05-2mm，随搅拌强度和分 散剂性质、用量而定。
8
悬浮聚合的液-液分散过程
停止搅拌 搅拌强度越大，液 滴越小，聚合生成的树 脂粒子越小
9
分散剂的作用机理：
（1）water-soluble polymers：吸附在液滴的表面，形成一层保护膜，起 到保护胶体的作用，同时使表面张力降低，有利于液滴分散； （2）water-insoluble inorganic compounds:（如：碳酸镁，碳酸钙、滑石粉 等）：细小粉末吸附在液滴表面，起机械隔离的作用。
5
4.3 Solution Polymerization
单体和引发剂溶于适当的溶剂中的聚合称为溶液聚合.
Advantages：
Polymerization of a monomer in a solvent overcomes many of the disadvantages of the bulk process. The solvent acts as diluent and aids in the transfer of the heat of polymerization. The solvent also allows easier stirring, since the viscosity of the reaction mixture is decreased. Thermal control is much easier in solution polymerization compared to bulk polymerization.
3
4.2 Bulk (Mass) Polymerization
不加任何溶剂（介质），只有单体本身在引发剂、热、光辐射等的作用 下进行的聚合，称为本体聚合(Bulk Mass Polymerization)。 实际生产中，往往还加入少量的色料、增塑剂、分子量调节剂等助剂。
Advantages：
Bulk or mass polymerization of a pure monomer offers the simplest process with a minimum of contamination of the product. So it is especially fit for the preparation of transparent product. Shortcoming： (1) heat dissipation is difficult, (2) local hot spots may occur, (3) molecular weight distribution is broadened. 自由基聚合、离子聚合、缩聚都可选用本体聚合，气态、液态、固态单 体均可进行本体聚合，其中以液态单体的本体聚合最重要。
10
Advantages
（1）体系粘度低，聚合热容易带走，散热和温度控制比本体聚合、溶液 聚合容易； （2）产物分子量及其分布稳定，分子量比溶液聚合的高； （3）产物分离的后处理工序比溶液聚合、乳液聚合容易。 Shortcoming 产物中多少带有少量分散剂残留物，要生产透明和绝缘性高的产品， 须将这些残留的分散剂除尽。 悬浮聚合在工业上应用广泛：
80-85％的PVC、苯乙烯离子交换树脂母体、很大一部分PS、PMMA采用 悬浮法生产。
11
4.5 Emulsion Polymerization
单体在水中由乳化剂分散成乳液状态进行的聚合，称为乳液聚合。
4.5.1 Characteristics of emulsion polymerization
Chapter 4. Polymerization Method
（聚合实施方法）
1
4.1 Introduction
Free radical polymerization has four main polymerization methods： （1）Bulk Polymerization 本体聚合 ；
4
Utility:
In industry, bulk polymerization can be carried out continuously or in stages. The key problem is the heat dissipation. Bulk polymerization is not used commercially for chain polymerizations nearly as much as for step polymerizations because of the difficulties indicated. It is, however, used in the polymerizations of ethylene, styrene, and methyl methacrylate.
Advantages： (1)The physical state of the emulsion system makes it easy to control the process.
(2)Being able to simultaneously attain both high molecular weights and high reaction rates. (3)The product can in many instances be used directly without further separations. Shortcoming：
Shortcomings：
(1) low concentration of monomer, slow rate of polymerization, low utilization ratio of production facility; (2) chain transfer to solvent, low molecular weigh, (3) the purity of the polymer may be affected if there are difficulties in removal of the solvent.