Spray-polymerization

SPP工艺喷雾的目标是评价流体特性、喷涂参数和合成粉体特性之间的相互依赖性。喷雾聚合法合成了一种聚合物固体。单体形成聚合物的合成已经在喷管内开始，并在雾化后在液滴内继续进行。固体是由于反应过程以及由于载体溶剂的干燥而形成的。在一步工艺中，工艺策略将聚合物的合成与颗粒特性的设计结合起来，这通常需要至少两个独立的步骤。喷雾聚合应能合成5-100µm粒径范围内具有特定颗粒性能的聚合物颗粒。这里的一个特殊技术挑战是聚合物的整体交联。目前的技术水平只有有限的选择来生产尺寸范围为1-50微米的聚合物颗粒。乳液聚合和悬浮聚合产生致密的球形颗粒。由于聚合物材料的弹性特性，自上而下的干式细铣削方法在达到约50微米以下的粒径方面存在严重问题。专利审查显示喷淋聚合的原理证明，但没有与工艺设计相关的定量数据。聚合反应和干燥过程的动力学是实验室和中试规模实验工作的主要重点，它伴随着反应的理论描述。技术实现还需要开发专门的技术组件来控制反应的起始阶段。这些组分的布局是由实验室规模表征聚合在一个分析流变仪，提供反应过程和粘度的关系强有力的支持。后者是保证雾化工艺应用的关键性能。所使用的材料是（中和）丙烯酸为单体，这导致颗粒聚丙烯酸钠盐。这种盐可以合成成线性聚合物或交联凝胶。此外，还评估了喷雾聚合过程中现有聚合物链交联的可能性。

The vision of the SPP Process Spray is the evaluation of the interdependency of the fluid properties, spraying parameters and the properties of the synthesized powder. The process of spray-polymerization synthesizes a polymeric solid. The synthesis of the polymer form the monomer starts already within the spraying nozzle and is continued within the drop after atomization. The solid is formed due the reaction progress as well as due to the drying of the carrier solvent. In a one-step-process the process strategy combines the synthesis of the polymer with the design of the particle properties, which typically needs at least two independent steps. The spray polymerization is supposed to allow the synthesis of polymeric particles in the size range of 5-100 µm with specified particle properties. A special technical challenge here is the integrated crosslinking of the polymer. The state of technology has only limited options to produce defined polymeric particles in the size range from 1-50 µm. Emulsion- and suspension polymerization lead to compact dense spherical particles. The top-down approach by dry fine milling has severe problems in reaching a particle size below about 50 µm due to the elastic properties of the polymer material. A patent review shows a prove of principle for spray polymerization, but no quantitative data related to process design. The kinetic of the combined polymerization reaction and drying process is the main focus of experimental work in lab and pilot scale, it goes along with a theoretical description of the reaction. The technical realization also needs the development of a specialized technical components to control the start phase of the reaction. The layout of these components is strongly supported by lab scale characterization of the polymerization within an analytical rheometer, providing the relation of reaction progress and viscosity. The latter is the key property to ensure the application of the atomization process. The materials used are (neutralized) acrylic acid as monomer, which leads to particles of poly- -acrylic-acid sodium salt. This salt is synthezied either as linear polymer or as crosslinked gel. Furthermore it is also evaluated whether it is possible to crosslink existing polymer chains during spray polymerization.