A fluorosilicone raw rubber with high isotacticity is provided. In the fluorosilicone raw rubber with high isotacticity, the content of a cis-methyl trifluoropropyl siloxane structure is not less than 20%, and the content of a vinyl siloxane chain link is 0-50%. Compared with traditional fluorosilicone raw rubber, the fluorosilicone raw rubber with high isotacticity prepared by the present disclosure has a higher degree of isotacticity in a molecular chain structure thereof; accordingly, a self-enhancing effect can be obtained by producing microcrystalline particles by means of strain-induced crystallization during stretching of cis fluorosilicone rubber, thereby greatly improving the mechanical properties of fluorosilicone rubber.

A process for preparing a rubber article involves modifying the crosslinking density in one region of the article relative to another region of the article. The modification can be carried out by increasing or decreasing the energy transferred to the first region relative to the energy transferred to the second region during vulcanization. In one implementation, the process is conducted in a mold. Rubber parts described have two or more regions that differ from one another with respect to their crosslinking density.