C8 waterproofing agent has better waterproof performance than C6. Why is this?

It was born due to the needs of life and work, and it has brought people a lot of convenience and protection. In pursuit of perfect performance, it has undergone a transformation from fluorine-free to fluorine-based C8 with superior performance. After decades of development, the performance of C8 has become increasingly perfect. But just when the performance is perfect, it has to change to the fluorine-based short carbon chain C6 with slightly worse performance. Why is this?

Research has found that the production of C8 through electrolysis will be accompanied by a by-product called perfluorooctane sulfonic acid (PFOS), and the production of C8 through telomerization will be accompanied by a by-product called perfluorooctanoic acid (PFOA):

Through research, people have found that PFOS has:

Persistence – it will not decompose even if boiled in sulfuric acid; no degradation occurs when the pH of water at 50°C is from 1.5 to 11.0; the half-life of PFOS is determined to be more than 41 years.

Bioaccumulation—the accumulation level is higher than that of organochlorine pesticides and dioxins; fish bioconcentration coefficient: 2796-3100; half-elimination time: the human body takes 8.7 years.

Toxicity – genetic toxicity, male reproductive toxicity, neurotoxicity, etc.; animal experiments show that PFOS content of 2 mg per kilogram of animal weight can cause death.

The ability of long-distance environmental migration—In the Arctic region, wild animals are contaminated by PFOS; the PFOS in the Huangpu River is 26.46 mg/L.

PFOA is also a substance similar to PFOS. Compared with PFOS, PFOA has a shorter half-life and is less toxic, but it can also remain in the human body for as short as four years and as long as half a lifetime. Carcinogenic studies have found that it can induce Tumors in different parts of the testicle, pancreas, mammary gland, etc., and lead to weight loss in experimental animals.

It can be seen from the above that although the waterproof performance of C8 is perfect, it will cause great harm to people and pollute the environment. The new C6 will not produce PFOS and PFOA during production, and its performance is close to that of C8 after several years of careful research and development. Therefore, from an environmental point of view, the transformation from C8 to C6 is people’s emphasis on the environment, and it is also A manifestation of self-protection.