Controlled Competitive Vulcanization of Rubber Blends

这项研究计划包括控制竞争性硫化的使用，以开发具有增强物理和机械性能的混合弹性体系统。目前唯一可行的技术提供了研究橡胶共混物组分之间交联的化学结构和分布的机会是固态13C核磁共振波谱。现在有可能获得这些不溶性网络的高分辨率核磁共振光谱，并使用这些光谱来确定加速硫化弹性体体系中的微结构和交联的化学性质和数量。硫化剂的不同溶解度和反应性，以及它们从一个聚合物相到另一个聚合物相的扩散，在确定共混物中各个相交联的性质和程度方面的作用尚未确定。我们目前对橡胶共混物硫化过程中特定化学反应的知识还不足以设计出最佳的促进剂体系。橡胶共混物的混合工艺和适当的固化周期将导致产品在物理或机械性能方面有特定的改善。聚合物共混物的竞争性硫化在橡胶生产中发挥着越来越重要的作用。为了优化硫化工艺，他们必须了解硫化过程中共混物组分中分别形成的微观结构和交联。研究共混物组成、共混物微观结构和共混物相间填料分布的技术已经开发出来，但尚未开发出评估共混物中不同橡胶相的化学性质和交联程度的技术。如果不知道如何控制竞争性交联过程，竞争性硫化在橡胶中的应用将继续是经验性的。

This research proposal involves the controlled use of competitive vulcanization to develop blended elastomeric systems with enhanced physical and mechanical properties. The only presently viable technique which offers the opportunity to study the chemical structure and distribution of crosslinks between the components of the rubber blend is solid state 13C NMR spectroscopy. It is now possible to obtain high resolution NMR spectra of these insoluble networks and to use these spectra to determine the microstructures and the chemical nature and number of the crosslinks in accelerated vulcanized elastomeric systems. The role of differential solubility and reactivity of vulcanizing agents, coupled with their diffusion from one polymer phase to another, in determining the nature and extent of crosslinking in the individual phases of the blend has not been determined. Our present knowledge of the specific chemical reactions during vulcanization of rubber blends is insufficient to permit the design of optimum accelerator systems, mixing processes and the appropriate cure cycles for rubber blends which will lead to products with specific improvements in the physical or mechanical properties. Competitive covulcanization of polymer blends is playing an increasing role in rubber production. To optimize the vulcanization process they must understand the microstructures and crosslinks developed separately in the components of the blends during the vulcanization process. Techniques have been developed for the study of the blend composition, blend microstructure and distribution of fillers between the phases of a blend, but no technique has been developed for estimating the chemical nature and extent of crosslinking in the different rubber phases of the blend. Without a knowledge of how to control the competitive crosslinking process, competitive vulcanization will continue to be empirical in its applications to rubber.