Gelation and Crystallisation of Nylon‐6 from Dilute Solution

Dilute solutions of nylon‐6 in benzyl alcohol transform to heavy transparant gels upon cooling, in contrast to the solutions in 1,4‐butanediol, which yield flaky precipitates in a similar concentration range. Differential scanning calorimetry and electron microscopy indicate that the gels are composed of an interlacement of thin fibrillar crystals with constant lateral dimensions partially aggregated in larger ribbons. On the other hand, a sheaflike morphology, characterised by strongly tapered and corrugated lath shaped crystals, developed in 1, 4‐butanediol. The crystals from both solvents have the monoclinic α‐structure with the hydrogen bonds parallel to the long axis and the chains perpendicular to the growth direction. The difference in morphology of the present crystals is explained by specific interaction of the benzyl alcohol and 1,4‐butanediol molecules on the growing crystal faces in the laterial as well as the H‐bond direction.