what is RTV in automotive science

Room Temperature Vulcanization
Rubber such as tires needs to be vulcanized with heat. RTV is catalized, but doesn't require heat. It doesn't stick to anything but other Silicone. It doesn't required a barrier coat or mold release. That's why it is so popular for mold making. Silicone caulk requires a release agent.
It allows the material to withstand heat and increases some of it's other properties. The only thing that I would add is that RTV is a process - not a product. Although most commonly associated with silicone molding materials, there are also RTV urethanes etc. Other types of vulcanization are the boiling process to vulcanize latex and using high pressure for certain silicones and urethanes. When molds are made of pewter miniatures for example - RTV silicone is not used, rather they put it all into a high pressure apparatus and vulcanize that way.