Nanostructure Transitions and Their Relation to Mechanical Properties in Polyethylene/ P olyamide 6 Microfibrillar Composites as Revealed by SAXS / S training Studies

Microfibrillar composites (MFC) with a matrix of high‐density polyethylene (HDPE) and reinforcements of polyamide 6 (PA6) are tensile tested while collecting 2D small‐angle X‐ray scattering patterns. The scattering of the isotropic matrix is separated from that of the oriented fibrils and the chord distribution functions (CDF) are computed. The changes in CDF peaks during the stretching process are registered and related to the nanostructure evolution in the samples. It is demonstrated how compatibilization of the HDPE and PA6 components and additional reinforcement of the PA6 fibrils with nanoclays influence the nanostructure of the fibrils and the mechanical behavior of the MFCs. The structural changes in the transcrystalline HDPE are consistent with a reversible strain‐induced crystallization.