Polyurethane Composite with Enhanced Mechanical and Damping Properties Filled with Surface-Grafted Hollow Poly(styrene-alt-maleic anhydride) Microsphere

Nano/microsized organic fillers play an important role in developing new types of polyurethane (PU) composites. In this study, microsized hollow poly(styrene-alt-maleic anhydride) (PSMA) microsphere was grafted with polytetramethylene glycol (PTMG) or 4-butanediol (BDO) and subsequently incorporated into a PU matrix to fabricate composites. For comparison, composites containing pristine hollow PSMA microsphere and neat PU were also prepared. The mechanical properties, damping properties, thermal stability, crystalline structure and water uptake of the composites and neat PU were investigated. The results show that the incorporation of surface-grafted hollow PSMA microspheres could effectively improve the mechanical and damping properties of PU, increasing tensile strength to 18.7 MPa, raising the tanδ peak to 1.05 and broadening the effective damping range (tanδ > 0.3) to 39.1-40.4 °C. Both PU composites and neat PU exhibited three-step decomposition regions. In the first decomposition region, the thermal stability of PU composites was improved slightly except that it was filled with BDO-graft-PSMA microspheres. But in the second and third decomposition regions, all PU composites showed lower thermal stability than neat PU. The introduction of hollow PSMA microspheres also reduced the crystallinity of the PU matrix, which is attributed to the large diameter of the microspheres disrupting crystalline order.