1 INTRODUCTION We are concerned with understanding at a microscopic or molecular level the reorganization of the structure in polymers as part of phase transformations especially in the case of crystallization. We focus on new experimental facilities which are particularly suited to this purpose. 1.1 Small-angle and Wide-angle x-ray scattering The morphology of semi-crystalline polymers is dominated by the formation of chain folded lamellar crystals first discovered by Keller (1957) and shown schematically in Figure 1. These are typically ~10nm in thickness with a lateral dimension of 1μm. Alt- hough electron microscopy has proved to be a pow- erful route to study the morphology using a proce- dure of differential etching (Olley 1986) and then imaging the structured surface formed by the etching process which reveals the internal morphology, this is not directly adaptable to following the microscop- ic sequence by which the random coils in the poly- mer melt reorganize by adjustment of the chain con- formation in to regular sequences which are able to pack with translational symmetry in to a crystal lat- tice which forms the thin lamellar crystals. Monitor- ing this process is usually performed using time- resolved small-angle x-ray scattering often exploit- ing the intense radiation available at a Synchrotron radiation source such as ESRF in Grenoble or ALBA in Barcelona (Mitchell 2013).The SAXS approach provides a time resolution of 1s or better. Figure 1c shows an example of the scattering pattern obtained EXPERIMENTAL APPROACH TO THE STUDY OF MULTISCALE STRUCTURAL DEVELOPMENT IN POLYMERS Geoffrey Mitchell*, Artur Mateus, Ana Tojeria Centre of Rapid and Sustainable Product Development, Institute Polytechnic Leiria, Marinha Grande, Portugal Daniel Bowron ISIS, Science and Technology Facility Council, Didcot, UK Thomas Gkourmpis Innovation & Technology, Borealis AB, Stenungsund SE-444 86 Sweden Saeed Mohan and Fred Davis Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD ABSTRACT We use new neutron scattering instrumentation to follow, in a single quantitative time-resolving experiment, the three key scales of structural development which accompany the crystallisation of synthetic polymers. These length scales span 3 orders of magnitude. Time-resolving neutron scattering data for poly(ε caprolactone) during cooling from the melt reveals the variation in the structure related to the three key length scales for crystallisation. The study of polymer crystallisation dates back to the pioneering experiments of Keller and others who discovered the chain-folded nature of the thin lamellae crystals which are normally found in synthetic polymers. The inherent connectivity of polymers makes their crystallisation a multiscale transformation. Much understanding has developed over the intervening fifty years but the process has re- mained something of a mystery. There are three key length scales. The chain folded lamellar thickness is ~ 10nm, the crystal unit cell is ~ 1nm and the detail of the chain conformation is ~ 0.1nm. In previous work these length scales have been addressed using different instrumentation, or where coupled using compromised geometries. More recently researchers have attempted to exploit coupled time-resolved small-angle and wide- angle x-ray experiments. These turned out to be challenging experiments much related to the challenge of placing the scattering intensity on an absolute scale. However, they did stimulate the possibility of new phe- nomena in the very early stages of crystallisation. Although there is now considerable debate surroundingthese conclusions they drew attention to the basic question as to the process of crystallisation in long chain mole- cules. We have used NIMROD on the second target station at ISIS to follow all three length scales in a time- resolving manner for poly(e-caprolactone). The technique provides a single set of data on the same vertical scale. We present the results from using a multiple scale model of the crystallisation process in polymers to analyse the results. We find that the time-scales for the evolution of these length scales are different. We show how this varies with the molecular weight of the polymer.