The hydroxides and hydrates used as flame-retardants only degrade once they reach their decomposition temperature. For magnesium hydroxide, the decomposition temperature ranges from 250 to 340 degrees Celsius. For aluminum hydroxide, the decomposition temperature is much lower at approximately 230 degrees Celsius. Hydrates usually have similar decomposition temperatures. These temperatures are relatively low when you think about the operating temperatures of plastic manufacturing lines. Molten plastic often reaches temperatures anywhere from 200 to 275 degrees Celsius in an extruder. Some of these chemicals would start to degrade in the extruder and that could be a big problem so you must be careful to consider your operating parameters when choosing a flame retardant.