Thanks Africa for the add'l information. Yeah there are more ingredients that provide protection from heat (most conditioners do) but I singled out the silicones due to their durability. Like I said in a previous post, the burning point of a silicone is MANY times higher a degree than [healthy] hair, and that's why many heat protectant products contain more than one type of silicone.
Now that said, this is all under the preface that the appliance is used correctly, meaning one pass of the flat iron, for instance.
Lets say for kicks, the flat iron is set at 375 degrees (medium textured 4a hair). The burning point for cyclomethicone is something like 1000 degrees (*I believe--don't quote me; I have to find the old thread). Anyhoo for example's sake, if you pass the iron on the hair once, the hair is protected, but of course if you go over the hair 2, 3, 20 times then the temp of the hair doubles, triples, etc, thusly you burn the silicones off and then end up burning into the threshold of the hair...
I hope I explained this clearly--this is just off the top of the dome...
Also, far infrared heat (like was discussed in that post link I shared) is not the same as that Gold n Hot y'all have in your closet. As stated, if far infrared heat is used for treating cancer patients (to destroy damaged cells without harming the healthy ones) the
n that's the only kind of heat I want on my hair. Far infrared heat also carries antimicrobial properties...but like Gymfreak said, another thread--another day.