Final answer:
Nylon 6,6 is a polyamide, a class of polymer known for its durability and wide range of uses including in synthetic fabrics and high-strength materials like Kevlar.
Step-by-step explanation:
The repeating unit for nylon 6,6 belongs to a class of polymers known as polyamides. This synthetic fabric was first created in 1935 and has found wide-ranging applications due to its favorable properties, such as high tensile strength, resistance to wrinkles, abrasion, and various chemicals. Nylon 6,6 consists of monomeric units linked by amide bonds resembling the peptide bonds found in proteins, which accounts for some of its physical properties akin to natural proteins. Notably, the '6,6' in its name indicates that the polymer is made from hexanedioic acid and hexane-1,6-diamine, reflecting the number of carbon atoms present in each monomer.
Nylon synthetic fabric is notable for its use in clothing, but it also extends to other products such as fishing lines, guitar strings, and even high-tech applications like Kevlar, which is another form of polyamide used in bulletproof vests and other high-strength materials.