[推荐] 分散剂的分子结构和在配方中应用的重要性.散剂, 配方, 分子结构, 重要性, 应用分散剂的分子结构和在配方中应用的重要性.分散剂的分子结构和在配方中应用的重要性.王盛龙谈谈分散剂摘要:分散剂的分子结构和在配方中应用的重要性.关键词:分散剂在涂料配方设计中有些存在很多的误区.认为分散剂无关紧要.其是不然,分散剂在涂料配方中起着非常重要的作用,它迁涉到,光泽,流平,丰满度,以及施工的性能和生产效益以及存储等等方面.现将Ciba的EFKA分散剂的组成及分子结构和应用提给大家也许有一些帮助.Wetting and Dispersing Agents润湿分散剂Dispersing agentsSolvent-based溶剂型分散剂China Road Show March 2004Martin PhilipoomWetting and Dispersing Agents润湿分散剂They should not be considered as member of the substrate-wetting group of surfactants which are used to improve theleveling of a liquid resin formulation or to prevent theformation of craters但润湿分散剂不应作为表面活性剂中用来提高液体树脂流平性或者防止缩孔形成的基材润湿剂的一员来考虑。
Wetting and Dispersing Agents润湿分散剂The quality of a dry paint or ink film is strongly dependant on how finely and uniformly distributed are the solidparticles in the resin matrix涂料或者油墨干膜层的质量强烈地依赖于固体粒子在树脂体系中良好而均一地分散。
Defects like poor colour strength, insufficient hiding power low gloss and decreased weather resistance are typicalexamples known to the technician诸如着色力差，遮盖力不足，光泽低，耐候性降低等缺陷是涂料技术人员所知道的典型例子。
Furthermore, a poorly dispersed system results inferior mechanical properties of the dry film而且，差的分散体系导致干膜的机械性能变差。
To obtain a finely dispersed system, the solid-liquid interface has to be modified during the grinding step 为了获得良好的分散体系，固液界面必须在研磨阶段得到改进。
During grinding, the pigment agglomeratesand aggregates are crushed to primaryparticles and the newly formed surfacesare wetted by the liquid carrier在研磨过程中，大块颜料和颜料凝聚体被粉碎成接近初级粒子，同时新形成的表面被液体载体湿润。
The use of a wetting agent can increasethe speed at which the liquid phase wetsthe pigment surface润湿剂的使用能提高液相润湿颜料表面的速度。
This is important as the grinding step isthe most time- and energy-consumingphase during the paint and ink productionprocess研磨阶段是涂料和油墨生产过程中最耗时，耗能的重要阶段。
Another important consideration is the consecutivestabilization of the fresh dispersion of the particles另外值得重要考虑的是新的粒子分散体的连续稳定性Grinding flocculates研磨絮凝Agglomerates凝聚体 Primary particles初级粒子 Flocculates絮凝Flocculation can cause colour shift, sedimentation andchanges in viscosity of the dispersion絮凝能导致分散体发生颜色偏移，沉降和粘度变化The origin of flocculation is found in the Brownian motion of particles絮凝的起因是建立在粒子布朗运动的基础上。
Small particles (typically 0.01-1 micron) move randomly in the suspension, collide with each other and form flocculates, reducing their total energy. The smaller the particles, the stronger the flocculation 微小的粒子（粒径0.01-1微米）在悬浮液中自由移动，相互碰撞形成絮凝，降低总能量。
粒子越小，絮凝作用越强。
If, in addition to being smaller, their concentration is also high, the probability of encounter is increased and the tendency to flocculationis increased粒子越小，浓度越高，相遇的可能性越大，絮凝倾向越强。
Stabilization mechanism稳定机理Scientifically, two main stabilization mechanisms can be distinguished: electrostatic and steric stabilization.按科学的方法，主要分为两种稳定机理：静电排斥和空间位阻Electrostatic stabilization takes place when particles bear the same electrical surface charge and as a result, repulsion take place 当粒子表面带有相同的电荷而发生排斥时便形成静电稳定As this mechanism relies on the separation of ionic charges, it is mainly relevant in systems of high polarity like aqueous paints由于这种机理依赖于带电离子排斥，因此主要对于象水性涂料这种高极性体系有用Electrostatic repulsion静电排斥 The charge around the particle isorganized into a double layer inwhich each layer possesses equalCharge粒子周围的电荷形成一个双电层，每层带有等量的电荷。
When two particles approach one another, their charged double layersoverlap and repulsion take place当两个粒子相互接近时它们所带的双电层发生交迭并产生排斥Electrostatic repulsion静电排斥At the same time, London-van-der-Waals forces leads to attraction ofthe particles同时伦敦－范德瓦力使粒子相互吸引。
If the attractive forces are stronger than the repulse forces, the dispersion will be unstable. However, if repulse forces predominate, the system willbe non-flocculating如果吸引力大于排斥力，分散就不稳定。
而如果排斥力占优，体系就不会絮凝。
Steric stabilization is brought about by adsorbed polymersand applies to both water- and solvent-based sytems空间位阻稳定是由所吸附的高分子带来的作用，它对水性体系和溶剂型体系都适用。
This stabilization is dependant on the structure anddimensions of the adsorbed polymer layer这种稳定依赖于吸附的高分子层的结构和厚度In general, effective steric stabilization has to fulfill several conditions: 一般说来，有效的空间位阻稳定必须具有几个条件：the particle surface has to be totally covered with dispersant粒子表面必须被分散剂完全包覆the layer has to be of sufficient diameter高分子层的直径足够大the polymer has to be strongly adsorbed on the surface to avoid de-adsorption upon collision or dilution of the dispersion高分子必须被有力的吸附在表面避免在分散体碰撞或稀释时脱吸。
the steric chains should be linear and extend into the medium to buildup a protective layer空间位阻链应该是线性的并且可以伸展到介质中形成保护层Steric stabilization空间位阻稳定The polymer can adsorb onto a particlethrough the so-called “anchoring groups”or segments that have strong affinity forthe chemistry of the surface聚合物通过在粒子表面具有强烈化学吸附能力的“锚定基团”或者链段吸附在粒子上The remainder of the polymer can beseen as dissolved and can extend into theresin medium聚合物的其余链段能与树脂相混溶并能伸展到树脂介质中These extended parts of the stabilizing polymer become the first contactsbetween two approaching particles这些具有稳定作用的聚合物伸展开来的部分成为两个相互接近粒子最先接触的部分A certain degree of inter-penetrationbetween the polymer layers from theadjacent pigments particles is possible邻近的颜料粒子所带的聚合物层之间会有一定程度的互穿As the concentration of solvated chains increases with decreasing distance, the free energy of the system increases随着距离的减小溶解链段的浓度升高，体系的自由能也随之升高。