All of the non-heat-friendly synthetic hair in my store is virtually the same, with only minor variation. It is ALL kanekalon modacrylic (petroleum-based) fiber that has been treated with silicates and other chemical agents for static- and flame-retardancy. The only real differences are in the denier (the diameter) of the fiber and the amount of stuff used on it to prevent tangles after processing.
There is slightly more variation in the heat-friendly synthetics. Each company has their own special cocktail of what they put into the hair and they keep it a trademarked, patented, tight-lipped secret. Hence why you have Futura, True2Life, Heat Defiant, EnvyHair, and all the other variations.
From a customer FB question:
Heather, do you know if HD fiber varies a bit from brand to brand? Others have mentioned that the HD fiber by some of the lower-priced brands actually seems better than the HD by JR and RW. All HD needs more work than regular synthetic, but apparently some may be less clumpy than others?
They do seem to vary a bit, with many manufacturers patenting their proprietary formulas, as mentioned above. They all have one thing in common though: they are more akin to a traditional polyester fiber than a modacrylic. (These are different things, though they both have a shared petrochemical source.)
Modacrylic is generally resistant to stretching, flame retardant, quick-drying, soft, and retains its shape. This is the fiber most regularly used in synthetic wigs.
The type of polyester used in heat friendly wigs – which is virtually the same among the brands with only slight variation – is considered quick-drying and flame retardant as well (yay!) but the added chemicals used to make the fiber hold up to higher heat sacrifices this material’s inherent resistance to stretching when pulled, resulting in a slightly less lustrous fiber that is highly elastic and prone to clumping due to static build-up.
A note about heat-friendly synthetic + human hair blends. I really like blends. EnvyHair, for example, with that human hair blended in, REALLY is quite nice. I like it better than Amore’s blended fiber. Either way, though, the human hair in the mix really helps the wigs hold up a little better, especially at the ends.