Controlled Competitive Vulcanization of Rubber Blends

这项研究方案涉及控制使用竞争性硫化来开发具有增强物理和机械性能的共混弹性体体系。目前唯一可行的技术是固体13C核磁共振波谱，它为研究橡胶共混物各组分之间的化学结构和交联剂的分布提供了机会。现在有可能获得这些不溶网络的高分辨率核磁共振谱，并使用这些谱来确定加速硫化弹性体体系中的微观结构以及交联剂的化学性质和数量。硫化剂的不同溶解性和反应性，以及它们从一种聚合物相扩散到另一种聚合物相，在确定共混物各相中的交联性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了解不足以设计出最佳的橡胶共混物加速器系统、混炼工艺和适当的硫化循环，从而使产品的物理或机械性能得到特定的改善。聚合物共混物的竞争性共硫化在橡胶生产中发挥着越来越大的作用。为了优化硫化过程，他们必须了解在硫化过程中共混物各组分中分别形成的微观结构和交联剂。已经开发了研究共混物组成、共混物微观结构和填充物在共混物相之间的分布的技术，但还没有开发出估计共混物不同橡胶相中的化学性质和交联度的技术。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.