You can find research plans for acid grenades G-1 and pack of acid grenades G-1 as you progress through the game plot. You can find research plans for incendiary grenades G-1 and pack of incendiary grenades G-1 for attacking and defeating one of the wandering merchants. 

You can receive more powerful versions of grenades of these types as a reward for playing nuclear version of the"Mole" mini-game.