Compatibilization of Polymer Blends

Macosko-Abstract-9527940不相容聚合物-聚合物共混物在聚合物工业中的份额越来越大。它们可以提供协同特性，这是这两个组件的最佳特征。它们还提供了一种回收混合聚合物废物的方法。因为组分聚合物是不相容的，所以它们的混合物必须稳定，以防聚结。为了获得所需的性能，次要成分必须很好地分散，其大小和形状必须控制在通常亚微米级。为了达到这种分散水平，通常在双螺杆挤出机中制备共混物，并加入嵌段或接枝共聚物来增容共混物，即帮助分散和防止合并。这些共聚物预计将存在于两个组分之间的界面上，也有助于机械粘合。将共聚物添加到共混物中有两种方法：(1)在单独的步骤中合成嵌段共聚物，然后在共混过程中将其与其他组分一起添加；(2)原位生成嵌段或接枝共聚物，通过在组分之间的界面上偶联反应来控制共混过程。在这个项目中，探索了几种使预制共聚物更有效的策略。该研究计划的目标是：1.开发一个聚合物熔体共混过程中的形态生成模型，该模型通过反应耦合来实现界面的稳定。2.确立了反应性共混与预制嵌段共聚相比的竞争优势。3.将1和2的结果应用于等规聚丙烯。4.评价优化后的两相形态对力学性能的影响。5.建立生产可用数量的功能聚合物的可行方法。6.量化界面厚度和反应动力学对反应共混效率的影响。

Macosko - Abstract - 9527940 Immiscible polymer-polymer blends are a growing part of the polymer industry. They can offer synergistic properties, the best features of both components. They also provide a means for the recycling of mixed polymer waste. Because the component polymers are immiscible, their blends must by stabilized against coalescence. To obtain the desired properties, the minor component must by well dispersed and its size and shape controlled, typically at the submicron scale. To achieve this dispersion level, blends are usually prepared in a twin screw extruder and block or graft copolymers are added to compatibilize the blend, i.e. to aid in dispersion and prevent coalescence. These copolymers are expected to reside in the interface between the two components also aiding mechanical adhesion. There are two ways to add copolymers to a blend: (1) Synthesize the block copolymers in a separate step and then add it with the other components during blending; and (2) Create the block or graft copolymer in situ, ruing the blending process by coupling reactions across the interface between the components. In this project, several strategies for making pre-made copolymers more effective are explored. The objectives of the research program are: 1. Develop a model for morphology generation during polymer melt blending that accounts for interfacial stabilization via reactive coupling. 2. Establish the competitive advantage to reactive blending versus addition of pre-made block copolymer. 3. Apply results of 1 and 2 to isotactic polypropylene. 4. Evaluate the effects of optimized two-phase morphology on mechanical properties. 5. Establish viable means of producing functional polymers in usable quantities. 6. Quantify the role of interfacial thickness and reaction kinetics on the efficiency of reactive blending.