Influence of microphase separation and crosslinking density on dynamic viscoelastic properties of nano‐Fe3O4 modified polyurethane

Abstract

AbstractAlthough there have been some studies on the preparation and characteristics of nano‐Fe3O4‐filled polyurethane (PU) composites, research focusing on the quantitative influence of the degree of microphase separation (DPS) and the crosslinking density (CLD) on dynamic viscoelastic properties is rare. In this paper, PU composites are synthesized by incorporating nano‐Fe3O4 as fillers. The dynamic mechanical properties under alternating loads are investigated using dynamic mechanical analysis. The influences of the DPS and the CLD on the dynamic hysteresis loss are analyzed. The experimental results show that the DPS and CLD of PU nanocomposites increase and then decrease with the increase of nano‐Fe3O4 addition and reached a maximum at the addition amount of 1.0 wt%. The quantitative relationships between DPS, CLD and the dynamic hysteresis loss of PU nanocomposites at different filler ratios are obtained. With a 1.0 wt% nano‐Fe3O4 content, the strain energy density (SED) and hysteresis energy density (HED) are increased by 416% and 354%, respectively. The hysteretic loss H indexes of all composites are kept lower than that of pure PU. These characteristics make nano‐Fe3O4‐filled PU a promising material for reducing the rolling resistance and increasing the service life of fuel‐saving tire materials.