Here's why:

* Structure: Plastics are made of long chains of molecules called polymers. These molecules are held together by weak bonds, making it difficult for electrons to flow freely.

* Electron Mobility: Electrons in plastics are tightly bound to their atoms and don't move easily. This lack of free electrons makes them poor conductors.

* Resistance: Plastics have very high electrical resistance, meaning they oppose the flow of electricity.

However, some plastics can be conductive under specific circumstances:

* Carbon-filled plastics: Adding carbon particles to plastics can increase their conductivity, making them suitable for applications like anti-static coatings.

* Conductive polymers: Some polymers, like polyacetylene, exhibit conductive properties due to their unique molecular structures.

* Electrostatic discharge: While generally insulators, plastics can accumulate static charges, leading to an electrostatic discharge, which can be considered a form of temporary conductivity.

In summary, while plastic bottles are generally considered insulators, there are exceptions depending on the specific type of plastic and its composition.