Investigation of Multifilament Polyamide (PA6) Yarn Fastness to Light - the Impact of Specific Surface

Abstract

The impact of light (produced by xenon lamps) on mechanical properties and structure of multifilament PA6 yarn made from microfilaments and filaments of standard quality is systematically investigated. The yarns exposed to light exhibit considerably lower tensile strength, lower breaking elongation, strength and elongation at break, besides becoming rather brittle. Depending upon the duration of exposure to light, modulus of elasticity is initially reduced for all the samples tested, to rise later above the initial values. The above changes in mechanical properties are the results of depolymerisation and modifications in supermolecular structure occurring in the course of irradiation. All the changes of properties and structure are related with fineness (linear density), e.g. specific surface of multifilament yarns tested. Sensibility to light and degradation of multifilament yarns is at least twice as big as the degradation of single filament yarns of standard fineness.