When you rub a plastic comb against your hair what does it produce?

If the hair is dry, and the air is also very dry, plastic combs (especially nylon) may generate static electricity, and this can result in the hairs standing on end as the charged hair shafts repel each other.

In most circumstances, there is enough moisture in the air, in the hair, or on the hair to keep it combed in place. The low relative humidity in heated interior air during the winter is usually the culprit.