Fluorocarbon rubber FKM:
Composing:
Fluorocarbon rubber is well known by its trade name of Viton. Based on vinylidene fluoride and hexafluoro-propylene the grades available differ in the chemical building blocks which were used to construct the polymer.

Properties and Applications:
Like silicone rubber, FKM has excellent high temperature resistance with an upper continuous heat aging temperature limit of 205℃. Although FKM has good resistance to many chemicals, excessive swelling occurs in some polar solvents such as low molecular weight ethers, esters and ketones. Applications for FKM include automotive fuel hose liners and seals and flue duct expansion joints, where high temperatures and acidic products from gas desulfurization are involved. The relative cost of FKM is high, more than any of the elastomers mentioned so far, also a high specific gravity (around 1.8) means less cured product (volume) per unit weight.