Investigation of Nylon `texture' by X-ray diffraction

Abstract

The manner in which minor changes in the molecular and crystalline arrangement are mirrored by corresponding changes in the X-ray diffraction pattern has been used as a method of following the effects of a number of treatments and modifications in the structure and composition of the Nylons. The crystalline diffraction pattern was taken from the branches of spherulites. Ageing after spinning from the melt, caused by the dissipation of strains (a fairly rapid process for the first two days) and uptake of water from the atmosphere (a process completed in 50 min), shows as increased distortion and crystallinity. The effect of swelling agents is to relieve strain and convert to the more stable α form. Phenol acts as a swelling agent in concentrations greater than 2%. The effect of introducing side-chains is to decrease the probability of links between main molecular chains (e.g. hydrogen bonds) and at the same time decrease the probability of plastic flow, so that greater reversible extensibility (i.e. rubber-like elasticity) results. The diffraction pattern of 11 Nylon, [(CH2)10-NH.CO-]n, is consistent with the unit cell a = 9.6 ± 0.5 A α = 72 ± 2° b = 4.2 ± 0.2 A β = 90 c = 15.0 ± 0.2 A γ = 63½ ± 1°