Polyamide is a synthetic fiber formed of linear macromolecules having in the chain the recurring amide functional group. There are polyamides of low affinity and high affinity. They have low flammability, it starts to weaken at 180-200 ° C and melts at about 215-260 ° C. Good elasticity (greater than typical polyester). The polyamide yarn can have the strength of steel and fine wire of the spider. Depending on the weaving, the fabric may exhibit a very close silk appearance. Polyamide fabrics are often in the name of nylon which designated the base polyamide 6-6 whose current usage returns to generically polyamides.
Ethlylene Propylene Diene Monomer is a copolymer of ethylene and propylene and a smaller amount of a diene monomer which forms chemically unsaturated ethylene groups pendant from the main saturated chain. These facilitate cross-linking reactions which do not affect the integrity of the polymer backbone. This feature gives EPDM excellent heat, ozone and chemical resistance. Physical properties are very good and resistance to polar fluids is generally good. Low temperature resistance is very good and EPDM can be compounded to give excellent electrical resistance.