The two monomers for the synthesis of Nylone 6,6 are :

$\mathrm{HOOC}\left(\mathrm{CH}_{2}\right)_{6} \mathrm{COOH}, \mathrm{H}_{2} \mathrm{~N}\left(\mathrm{CH}_{2}\right)_{6} \mathrm{NH}_{2}$

$\mathrm{HOOC}\left(\mathrm{CH}_{2}\right)_{4} \mathrm{COOH}, \mathrm{H}_{2} \mathrm{~N}\left(\mathrm{CH}_{2}\right)_{4} \mathrm{NH}_{2}$

$\mathrm{HOOC}\left(\mathrm{CH}_{2}\right)_{6} \mathrm{COOH}, \mathrm{H}_{2} \mathrm{~N}\left(\mathrm{CH}_{2}\right)_{4} \mathrm{NH}_{2}$

$\mathrm{HOOC}\left(\mathrm{CH}_{2}\right)_{4} \mathrm{COOH}, \mathrm{H}_{2} \mathrm{~N}\left(\mathrm{CH}_{2}\right)_{6} \mathrm{NH}_{2}$