加入收藏| 关于我们 您好,欢迎来到济南金日和化工用品生产厂家,免费售后,欢迎咨询!

全国咨询热线:13386411819
0531-81762771

当前位置:首页>>热门资讯>>新闻动态>>丙烯酸乳液的合成应该注意哪些变化?
联系我们
联系我们

咨询热线:13386411819

QQ:

联系地址:济南市新材料化工市场北区536

丙烯酸乳液的合成应该注意哪些变化?
来源:http://www.jnjrh.com 日期:2019-09-03 发布人:admin
在乳液聚合过程中,乳液的稳定性会发作变化。乳化剂的品种、用量与用法、pH值、引发剂的类型、搅拌外形与搅拌速度、加料方式、聚合工艺等都会影响到聚合物乳液的稳定性。
During the emulsion polymerization, the stability of the emulsion will change. The variety, dosage and usage of emulsifier, pH value, type of initiator, stirring shape and stirring speed, feeding mode and polymerization process will affect the stability of polymer emulsion.
功用性单体如硅烷偶联剂、丙烯酸、丙烯酰胺、丙烯酸羟乙酯等作为交联单体参与共聚,在一定水平上可进步乳液的稳定性,但因其具有极强的亲水性,聚合过程中若在水相发作均聚构成水溶性大分子,会产生絮凝作用,极易破乳。因而选择适宜的乳化体系和聚合工艺对乳液聚合过程的稳定性具有极重要的意义。
Functional monomers, such as silane coupling agents, acrylic acid, acrylamide, hydroxyethyl acrylate, etc., are used as crosslinking monomers to participate in copolymerization, which can improve the stability of emulsion at a certain level. However, because of its strong hydrophilicity, polymerization of water soluble macromolecules in the process of polymerization will produce flocculation. Demulsification. Therefore, choosing suitable emulsifying system and polymerization process is very important for the stability of emulsion polymerization process.
聚合物乳液接受外界要素对其毁坏的才能称为聚合物乳液的稳定性。在乳液聚合过程中部分胶体稳定性的丧失会惹起乳胶粒的聚结构成宏观或微观的凝聚物,即凝胶现象。凝胶多为大小不等、形态不一的块状聚合物,有的发软、发粘,有的发硬、发脆、多孔。在搅拌作用下凝胶分散在乳液中,可经过过滤法或沉降法除去,但有时也会构成大量肉眼看不到的、普通办法很难别离的微观凝胶,使乳液蓝光削弱颜色发白,外观粗糙。
氨基磺酸
Polymer emulsion can only be destroyed by external factors, so it can be called the stability of polymer emulsion. In the process of emulsion polymerization, the loss of colloidal stability causes the aggregation of latex particles to form macroscopic or microscopic aggregates, that is, gelation. Most of the gels are block polymers of different sizes and shapes. Some of them are soft and sticky, and some are hard, brittle and porous. Under the action of agitation, the gel is dispersed in the emulsion, which can be removed by filtration or sedimentation, but sometimes it can also form a large number of microgel which is invisible to the naked eye and difficult to separate by ordinary methods. The blue light of the emulsion weakens the color and gives a rough appearance.
严重时以至整个体系完整凝聚,形成抱轴、粘釜和挂胶现象。凝聚物的生成在乳液研讨和消费中具有极大的危害性,它不只降低单体的有效应用率,增加聚合安装的停机时间和处置的费用,而且还会加大各釜和各批次间产品性能的不分歧性,污染环境。
In serious cases, even the whole system is completely condensed, forming the phenomenon of holding axle, sticking kettle and hanging glue. The generation of condensed matter is of great hazard in the discussion and consumption of emulsion. It not only reduces the effective application rate of monomer, increases the downtime and disposal cost of polymerization installation, but also increases the disagreement of product performance between various kettle and batch, and pollutes the environment.
目前比拟权威的用于解释聚合物乳液稳定性的理论是双电层理论和空间位阻理论。乳胶粒子的外表性质与吸附或分离在其上的起稳定作用的物质有关,酸性、碱性离子末端以及吸附在乳胶粒外表上的乳化剂在一定的pH值下都是以离子方式存在的,使乳胶粒子外表带上一层电荷,从而在乳胶粒子之间就存在静电斥力,乳胶粒难于相互接近而不发作聚结。
At present, the theory which is more authoritative to explain the stability of polymer emulsion is double electric layer theory and steric hindrance theory. The exterior properties of latex particles are related to the stable substances adsorbed or separated on them. The acidic and alkaline ion ends and the emulsifiers adsorbed on the surface of latex particles exist in the form of ions at a certain pH value, which makes the surface of latex particles charged with a layer of electricity, thus there is static electricity between the latex particles. Repulsion, latex particles are difficult to approach each other without coalescence.
当乳胶粒外表吸附有非离子型乳化剂或高分子维护胶体时,其稳定性则与空间位阻有关。
When non-ionic emulsifiers or macromolecule maintenance colloids are adsorbed on the surface of latex particles, their stability is related to space steric resistance.
乳化剂的选择是决议乳液聚合体系稳定性的关键要素之一。乳化剂虽不直接参与反响,但乳化剂的品种及用量将直接影响到引发速率、链增长速率以及聚合物的分子量和分子量散布。
The choice of emulsifier is one of the key elements of the stability of the emulsion polymerization system. Although emulsifiers do not directly participate in the reaction, the variety and dosage of emulsifiers will directly affect the initiation rate, chain growth rate and molecular weight and molecular weight dispersion of polymers.
此外乳化剂的类型、用量和参加方式对乳胶粒的粒径和粒径散布、乳液粒度也有着决议性的影响。假如所选用的乳化剂不合适本乳液聚合体系,则不管怎样改动乳化剂的浓度和调理聚合工艺参数,乳液聚合仍不能平稳停止或是所得到的乳液产品缺乏适用价值。
In addition, the type, dosage and mode of emulsifier have a decisive influence on the size and size distribution of latex particles and the particle size of emulsion. If the emulsifier is not suitable for the emulsion polymerization system, no matter how to change the concentration of emulsifier and the process parameters of polymerization, emulsion polymerization can not stop smoothly or the emulsion product is lack of application value.