PROPERTIES AND STRUCTURES OF NYLON 3 DERIVATIVES

Abstract

Choosing α methyl nylon 3, β methyl nylon 3, α, α, dimethyl nylon 3, and β, β, dimethyl nylon 3 as the nylon derivatives, the effects of substituents on the properties and structures were investigated by the methods of X-ray diffraction, infra-red spectra, and thermal analysis, and following results were obtained. Melting points of the polymer increase with in following order. α, α, dimethyl<β, β, dimethyl<α methyl≤β mthyl_??_no substituent. The NH streching absorptions were observed at 3380cm-1 in α, α, dimethyl nylon 3, at 3340cm-1 in β, β, dimethyl nylon 3, and at 3300cm-1 in other nylons. NH--O distances of the derivatives are estimated, and melting point of the polymers and location of the NH streching absorptions were found to be mainly determined by the NH-O distances. Though nylon 3 derivatives belong to short methylene polyamides, a distort of molecular chain occurs around amide groups. This may be due to the favorable NH-O hydrogen bond distances under the steric hinddrances of the substituents.