The blending of different rubbers is one of the effective methods to achieve required performance properties in their final products. This article reviews the thermodynamic considerations of rubber–rubber blends and their filled systems. Factors affecting the rubber blend morphology (i.e. distribution mechanism of fillers, curatives and other compounding ingredients) and preparation techniques for rubber–rubber blends emphasizing their advantages and disadvantages are well discussed in this review. Microscopy is the field of interest to all material scientists. In the case of rubber blends, microscopy is an essential tool in order to understand the morphology, that is, size, shape and distribution of phases and filler particles in the rubber–rubber blend. In this review, selected scientific reports based on optical microscopy, electron microscopy and atomic force microscopy in rubber–rubber blends are discussed. Rubber material is a complex macromolecule; it has significant proportion of fillers, processing aids and curing agents; therefore, only a very few studies have been reported on the microscopic aspects of filled rubber–rubber blends. In particular, influence of rubber blend composition, fillers (micro and nano length scales) and processing additives on the morphology of rubber blends systems has not been systematically reviewed and discussed in the scientific literature. Therefore, in the present scenario, this review was thought of, which deals with the essential background to rubber–rubber blends, miscibility and morphological characterization of various rubber blend systems by microscopy. It is very important to add that although there is scattered information on these aspects in the scientific literature, to date a comprehensive review has not been published. The pros, cons, artefacts and the new challenges on the use of microscopy for the characterization of rubber–rubber blends are also discussed here.

不同橡胶的共混是在其最终产品中实现所需性能的有效方法之一。本文回顾了橡胶-橡胶混合物及其填充系统的热力学考虑。本篇综述充分讨论了影响橡胶共混物形态的因素（即填料，固化剂和其他配料的分布机理）以及强调其优缺点的橡胶－橡胶共混物的制备技术。显微镜是所有材料科学家感兴趣的领域。对于橡胶混合物，显微镜是了解形态的重要工具，即了解橡胶-橡胶混合物中相和填料颗粒的大小，形状和分布。在这篇评论中，我们选择了基于光学显微镜的科学报告，讨论了橡胶-橡胶混合物中的电子显微镜和原子力显微镜。橡胶材料是复杂的高分子；它含有大量的填料，加工助剂和固化剂；因此，关于填充橡胶-橡胶混合物的微观方面的报道很少。特别地，尚未在科学文献中系统地审查和讨论橡胶共混物组成，填料（微米和纳米级刻度）和加工助剂对橡胶共混物系统形态的影响。因此，在目前的情况下，考虑到了本综述，该综述涉及橡胶-橡胶混合物的基本背景，通过显微镜对各种橡胶混合物系统的混溶性和形态学表征。重要的是要补充一点，尽管科学文献中关于这些方面的信息分散，但迄今为止尚未发表全面的综述。本文还讨论了使用显微技术表征橡胶-橡胶共混物的利弊，人工制品和新挑战。