MELTING POINT DEPRESSION OF NYLON-6 BY METHOXYMETHYLATION (III)

Abstract

A unique relationship was found between the melting peak temperature and the degree of methoxymethylation (substitution) for nylon-6 films, the substitution being made to different extents after annealing at 220°C (near the melting point of nylon-6). In the 1st-run of the DSC measurement, the melting peak temperature was almost constant against the degree of substitution. In the 2nd-run after cooling the same sample, however, the melting peak temperature was depressed with the increase of the degree of substitution, in accordance with the modified Flory's equation employing a=2 and the lower side peak temperature, as T°_m, of double melting peaks. This result means that the methoxy-methylation of the nylon-6 chain randomly took place and subsequently the recrystallization by cooling after melting gave rise to formation of an appreciable amount of fringed-type crystals.