Nylon 6 can be modified using comonomers or stabilizers during polymerization to introduce new chain end or functional groups. It is a semicrystalline polyamide. Unlike most other nylons, nylon 6 is not a condensation polymer, but instead is formed by ring-opening polymerization; this makes it a special case in the comparison between condensation and addition polymers. Its competition with nylon 6,6 and the example it set have also shaped the economics of the synthetic fiber industry..
Nylon 6 fibres are tough, possessing high tensile strength, as well as elasticity and lustre. They are wrinkleproof and highly resistant to abrasion and chemicals such as acids and alkalis. The fibres can absorb up to 2.4% of water, although this lowers tensile strength. The glass transition temperature of Nylon 6 is 47 °C.
As a synthetic fiber, Nylon 6 is generally white but can be dyed to in a solution bath prior to production for different color results. Its tenacity is between 6 and 8.5 gm/den with a density of 1.14 gm/cc. Its melting point is at 215 °C and can protect heat up to 150 °C on average