The effect of poly(dimethylsiloxane) segment content on the morphology of polyurethane composite materials

in this study, in situ polymerization procedure in solvent mixture was used for the preparation of thermosetting PU nanocomposites (PUNCs) with different content of soft segment (from 30 to 60 wt%), and with the addition of organomodified montmorillonite clay (Cloisite 30B®) as the nanofiller, in an amount of 0.5 wt.%. The PUNCs were based on poly(dimethylsiloxane) macrodiol (PDMS) that represents soft segment and 4,4′-diphenylmethane diisocyanate (MDI) and hyperbranched polyester (BH-30) which were selected as the hard segment. The PUNCs are marked. so that the last two numbers in title indicate wt.% of soft segment in materials. Namely, the main objective of this study is to analyze the effect of the soft segment content on the morphology of the prepared PU nanocomposite films using atomic force microscopy (AFM), scanning electron microscopy (SEM), and small- and near wide-angle X-Ray scattering (SWAXS) analyses. SEM images of the fractured surfaces were obtained on JEOL JSM-6610LV. AFM analysis was carried out by atomic force microscope (Dimension Icon, Bruker, USA). SWAXS measurements of the PUNCs were performed using SAXS instrument (originally Molecular Metrology, USA, recently considerably upgraded by SAXSLAB, now Xenocs)