Nanostructure, dynamics, and mechanical properties of nanocomposites based on polyurethane‐poly (2‐hydroxyethyl methacrylate) semi‐interpenetrating polymer network with ultra‐low MWCNT contents

Nanocomposites based on polyurethane‐poly(2‐hydroxyethyl methacrylate) semi‐interpenetrating polymer network (PU‐PHEMA semi‐IPN) doped with 0.01, 0.05, 0.1, or 0.25 wt% of non‐functionalized multi‐walled carbon nanotubes (MWCNTs) were synthesized. Their nanostructure was studied by small‐angle X‐ray scattering (SAXS) and transmission electron microscopy (TEM) techniques, and their dynamics and properties were characterized over the temperature range from −100°C to 180°C using dynamic mechanical analysis (DMA) and laser‐interferometric creep rate spectroscopy (CRS). It was shown that ultra‐low MWCNT contents (0.01%–0.1%) substantially modified matrix nanostructure due to the influence of nanofiller on the processes of micro‐phase separation and mixing of matrix components, the changes in the molecular packing density, and good dispersion of MWCNTs. The structural changes were somewhat smaller at 0.25% nanotubes where tendency to formation of their aggregates was observed. Accordingly, the strong changes in dynamic behavior, elastic properties and creep resistance in the studied materials were caused by ultra‐low MWCNT additives. The strong effect of extraordinary broadening of the PHEMA relaxation peak in the nanocomposites and, simultaneously, the strongly improved creep resistance over the 80°C–160°C temperature range (at 0.1% MWCNTs) were shown that is of importance for the application of these nanocomposites as perspective damping materials. POLYM. COMPOS., 39:263–273, 2018. © 2016 Society of Plastics Engineers