ABSTRACT We report preliminary results from a Small Angle Neutron Scattering (SANS) study of nylon rope fibres treated with environmentalcontaminants of the type that the fibres may experience in everyday use. Introduction Modern high performance ropes are no longer made from siselor hemp but from synthetic polymers such as nylon-6 (e.g. Perlon®, Ultramid B®, Zytel PA®, and Akulon®), nylon-6/6, polyesters, polypropylene, high-modulus polyethylene (e.g. Dyneema® or Spectra®), aramids (e.g. Twaron® orKevlar®), and more recently even liquid crystalline polymers(e.g. Vectran®).Another major difference is in the construction of the rope.Natural fibre ropes have traditionally been hawserlaid (orplaited), but modern synthetic fibre ropes have a kernmantelconstruction in which a core bundle (the kern) of coiled yarnsis encased in a woven outer sheath (the mantle), free to slipagainst the core (Figure 1).and sheath are different polymer fibres. This allows theperformance of the rope to be matched to particularapplications.Whilst the condition of the sheath is clearly easy to establish,the same is not true of the core fibres. Contemporary methodsof rope testing are reliant on destructive mechanical tests (andit has been said that the interpretation of some of the data oftenleave a great deal to be desired).